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Products => Test Equipment => Topic started by: Martin72 on September 21, 2023, 10:20:43 pm

Title: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on September 21, 2023, 10:20:43 pm
Hi folks,

No no, I don't have the scope yet, I also have to wait about 2 weeks for it....
This is already a placeholder or should give the possibility to consider it in advance, what I should test everything.
And compare, because I still have other scopes here....
First my own, quasi as a reference, the SDS2504X HD.
Then from work the Rigol DS1054Z and the Siglent SDS1104X-E.
The predecessor and the current competitor, so to speak.
Other existing measuring equipment:
- SDG2122X 120Mhz function generator.
-R&S SML01 1.1Ghz signal generator
-Tektronix A6302/AM502 current clamp combination
- Demoboards with several signals (and decoder functions) from Batronix and Siglent
- Deskew fixture from Siglent
- Analog 10Mhz test oscillator for ENOB determination
- Ultra low distortion 1khz sine generator (still to be tested)
- Leo Bodnar pulser 40ps risetime

So think about something, I'll get back to you here when the Rigol has arrived.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: tautech on September 22, 2023, 12:20:47 am
USB keyboard and mouse performance in the UI compared to 2kX HD.
Also webserver UI performance with PC mouse, keyboard, scroll wheel etc.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Njk on September 22, 2023, 01:16:33 am
Fan noise measurement. That'll be real challenge
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: tautech on September 22, 2023, 01:32:05 am
Fan noise measurement. That'll be real challenge
Not.

Piss easy with a phone app like this:
Audio Spectrum Analyzer dB RTA
https://apps.apple.com/nz/app/id1281873790

Dozens of them on the www, some vastly better than others.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on September 22, 2023, 01:50:32 am
Piss easy with a phone app like this:

An app won't tell you how whiny or annoying a sound is, only how loud it is.

USB keyboard and mouse performance in the UI compared to 2kX HD.

Mouse: It works
Keyboard: It doesn't

Well, there goes Martin72's shiny new topic...  :popcorn:
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: tautech on September 22, 2023, 02:43:00 am
Piss easy with a phone app like this:

An app won't tell you how whiny or annoying a sound is, only how loud it is.

Really ::)

About time you did some research instead of spouting about shit you have no experience with.
Audio spectrum analyzers give frequency and level measurements just in case you didn't know.

Their measurement only need be qualified by the distance to microphone measurement and I'm very sure Martin already knows how these things work.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: hbozyq on September 22, 2023, 06:53:51 am
Piss easy with a phone app like this:

An app won't tell you how whiny or annoying a sound is, only how loud it is.

Really ::)

About time you did some research instead of spouting about shit you have no experience with.
Audio spectrum analyzers give frequency and level measurements just in case you didn't know.

Their measurement only need be qualified by the distance to microphone measurement and I'm very sure Martin already knows how these things work.

I guess the real problem is can you trust those result?
I bet that no one is calibrated.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: tautech on September 22, 2023, 07:02:04 am
Piss easy with a phone app like this:

An app won't tell you how whiny or annoying a sound is, only how loud it is.

Really ::)

About time you did some research instead of spouting about shit you have no experience with.
Audio spectrum analyzers give frequency and level measurements just in case you didn't know.

Their measurement only need be qualified by the distance to microphone measurement and I'm very sure Martin already knows how these things work.

I guess the real problem is can you trust those result?
I bet that no one is calibrated.
They don't need be for comparative measurements or would you rather trust Dave's ear to judge fan noise ?  :-DD
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on September 22, 2023, 07:22:22 am
About time you did some research instead of spouting about shit you have no experience with.
Audio spectrum analyzers give frequency and level measurements just in case you didn't know.

Please tell us what a whiny/annoying spectrum looks like compared to a nice relaxing one.
This needs to be precisely defined if the results are to be valid.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: tautech on September 22, 2023, 08:08:10 am
About time you did some research instead of spouting about shit you have no experience with.
Audio spectrum analyzers give frequency and level measurements just in case you didn't know.

Please tell us what a whiny/annoying spectrum looks like compared to a nice relaxing one.
This needs to be precisely defined if the results are to be valid.
Oh FFS Fungus, must you be spoon fed ?  :palm:
Did you not follow this link posted above:
https://apps.apple.com/nz/app/id1281873790
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on September 22, 2023, 08:20:00 am
Quote
Please tell us what a whiny/annoying spectrum looks like compared to a nice relaxing one.
This needs to be precisely defined if the results are to be valid.
Oh FFS Fungus, must you be spoon fed ?  :palm:
Did you not follow this link posted above:
https://apps.apple.com/nz/app/id1281873790

It's a spectrum analyzer (for a device not everybody has).

OK, please tell us what a whiny/annoying spectrum looks like compared to a nice relaxing one.

ie. How does that amazing app help us put a neat numerical score on each fan?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on September 22, 2023, 08:25:16 am
Their measurement only need be qualified by the distance to microphone measurement and I'm very sure Martin already knows how these things work.

Maybe it's no surprise but I have a calibrated microphone at home. ;)
And access to a ISO calibrated Class 1 SPL meter..
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: tautech on September 22, 2023, 08:26:08 am
It's a spectrum analyzer (for a device not everybody has).
No it's not.
Audio analyzer that does LF which you can find online for many smartphones not just fruity phones and tablets.

An annoying audio spectrum might be heard by the young and not the old therefore annoying is NOT universal.
Do some homework Fungus just like I had to a few months back to sort an issue I could not hear.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: tautech on September 22, 2023, 08:28:05 am
Their measurement only need be qualified by the distance to microphone measurement and I'm very sure Martin already knows how these things work.

Maybe it's no surprise but I have a calibrated microphone at home. ;)
And access to a ISO calibrated Class 1 SPL meter..
Not that its needed for a comparative test.  ;)
And a measuring tape I hope.

Anyways, sure lots better than Dave's ear.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Njk on September 22, 2023, 11:27:55 am
Piss easy with a phone app like this:
Audio Spectrum Analyzer dB RTA

App is not a problem. The problem is to collect a relevant and stable data. For that, an acoustically representative model of typical work place will be required. With the microphones located into artificial head, etc. Environment is a critical thing. With existing technologies such as Audyssey, the results are relevant as long as the environment remains the same. When something changed, all the measurement needs to be performed again. And I'm not sure a single model will be enough (e.g. a server room is very different from a bed room). It's a lot of work to design and build that models.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on September 22, 2023, 01:03:21 pm
Whiny fans are just that: instead of producing wideband noise, they make sound that has peaks in spectrum that allows our ear to recognize tones.
If you have any tone between 400-4000Hz where our ears are most sensitive, you will hear annoying whine (tone). Simple as that. It can also be at other frequencies, but between 400-4000Hz we are very sensitive.

As long as you do it the same for all of them you will have good relative measurements. Then compare spectrum to how it sounds to you and you will quickly find what the "whine" is all about.

I did just that to few devices. One good example of device that is not completely silent but has very "noise like" sound is Keysight MSOX3000T. Just a whooshing, not very silent but with no distinguishing tones so no whining.. Excellent acoustic design.

Best one is, of course, Siglent SDS2000X HD. Pretty much completely silent. Large, low speed fan, and cooling based on low pressure/low speed airflow volume.
Siglent SDSD6000H12 Pro OTOH is quite louder. But that one needs to expel much more thermal energy out of the case... It is still not annoying because there are no large peaks inside so you forget about it, but after few hours, when you switch it off you suddenly realize how quieter the room is. Of course, that is my very quiet lab, in open space office not so much.

DHO800 has miniscule fan that pretty much guarantees whine and noise by itself. Offending tones will be easily measured.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on September 22, 2023, 01:25:00 pm
Hi folks,

No no, I don't have the scope yet, I also have to wait about 2 weeks for it....
This is already a placeholder or should give the possibility to consider it in advance, what I should test everything.
And compare, because I still have other scopes here....
First my own, quasi as a reference, the SDS2504X HD.
Then from work the Rigol DS1054Z and the Siglent SDS1104X-E.
The predecessor and the current competitor, so to speak.
Other existing measuring equipment:
- SDG2122X 120Mhz function generator.
-R&S SML01 1.1Ghz signal generator
-Tektronix A6302/AM502 current clamp combination
- Demoboards with several signals (and decoder functions) from Batronix and Siglent
- Deskew fixture from Siglent
- Analog 10Mhz test oscillator for ENOB determination
- Ultra low distortion 1khz sine generator (still to be tested)
- Leo Bodnar pulser 40ps risetime

So think about something, I'll get back to you here when the Rigol has arrived.

Martin,

in my opinion, testing the new DHO800 should be more about usability and how it can be used to measure than the basics of analog performance. It is already proven that Rigol made decent 12 bit converter and that it has low noise front end.

What is not clear is:
- overload recovery.
- distortion (two tone test)
- BW in sampling restricted modes (that is for DHO900 or DHO900 hacked 800) - what happens with 250 MHz BW when you drop to 312.5 MSps/s
 - What is utility of UltraAcquire mode, i.e. what can you do with it except replay it on screen. Does it have any functionality to compare it to other scopes segmented mode where all measurements, math decoding etc. works.
 - In a similar manner, what is utility of Record/replay mode, i.e. what can you do with it except replay it on screen. Does it have any functionality to compare it to other scopes segmented mode where all measurements, math decoding etc. works.
- Is FFT still half implemented where you cannot control directly FFT parameters? What can be controlled and how it impacts capability to measure
-It has 4 ch of math. What are capabilites? For instance, on Siglent you have arbitrary formula math with multiple sources (including reference, channels or other math channels). Micsig has something similar, slightly less capable. The way I see it on DHO800 math channel is single operator per channel (FFT and filtering are some of the operators) but that is it. If you want more sophisticated expression, you need to nest more math cahnnels. So if you want AxB than lowpass filter anything more than 10kHz and then do FFT of that, you need to nest 3 math channels. On SDS2000X HD (and incoming SDS100X HD) you can combine that expression (and even more) in single of the 4 math channels. This is not a show stopper, just to make sure we know how it works. 4ch of nested math on very inexpensive scope is still better than MSOX3000T that has same thing but only 2.....Just to put it in perspective..

I'm sure as you start using it you will find more  both good and bad stuff...
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Performa01 on September 22, 2023, 01:50:27 pm
What is not clear is:
- overload recovery.
Since this depends on the input buffer design and the crossover frequency particularly, it is not that easy to make a fair comparison. Chances are you test this at certain conditions (vertical gain, offset, signal frequency, percentage of overload) that make one scope look much better than the other, but there might be other conditions, where it is exactly the other way round.

Especially for a cheap scope like the DHO804, which has to make do with a single attenuator stage (by contrast, even bottom end SDS1000X-E has two attenuator stages!), things will only be comparable at a setting where no attenuator kicks in on either of the contenders. But even that could be unfair, because that point might be very different for a single or double attenuator design. And of course, the higher the sensitivity (lower V/div), the better the overload recovery will be. So it might be safest to do it at maybe 50 mV/div uniformely...

- distortion (two tone test)
People are often tempted to use the "Wave Combine" function of the SDG for this. Unfortuanetely, this generates some 3rd oder intermodulation products itself - at least at higher frequencies. So for this test, we need to use the two outputs of the SDG individually and have a resistive wideband power-combiner to create the test signal. This gives only 6 dB isolation between channels, but in my experience this is sufficient and no additional attenuators for the individual channels are required.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: mawyatt on September 22, 2023, 03:01:50 pm

People are often tempted to use the "Wave Combine" function of the SDG for this. Unfortuanetely, this generates some 3rd oder intermodulation products itself - at least at higher frequencies. So for this test, we need to use the two outputs of the SDG individually and have a resistive wideband power-combiner to create the test signal. This gives only 6 dB isolation between channels, but in my experience this is sufficient and no additional attenuators for the individual channels are required.

Recall the Wave Combine on the SDG2XXX is pretty good, vaguely remember we measured such on the SSA3021X+, but may not be good enough for a 12 bit DSO. WRT to using separate AWG outputs, adding a 6~10dB pad in each AWG output before the resistive combiner should eliminate any potential IMD between the AWG channels, and still have enough signal level at the test DSO input.

Anyway, this new low end 12 bit DSO series from Rigol is creating lots of interest, and many like ourselves are anxious is see how well it behaves and performs. Rigol took a huge risk in attempting a 12 bit chip-set, especially after the disappointing 8 bit chip-set & front end performance (noisy), evidently learned from such and have produced apparently a good low noise front end to supplement the 12 custom ADC chip-set. The various tests mentioned by 2N3055, especially if performed by knowledgable unbiased folks will be highly beneficial in getting grips on just how good a bargain these new DSO will be :-+

Best,
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: TimFox on September 22, 2023, 06:44:54 pm
I recently ordered a DHO914S, expected sometime in November.
I will see how well it works for harmonic distortion measurements, analyzing the "Monitor" output of my -hp- 339A analyzer (distortion products after removing the fundamental).
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on September 22, 2023, 10:10:30 pm
Not that its needed for a comparative test.  ;)
And a measuring tape I hope.
Anyways, sure lots better than Dave's ear.

I could take this to the extreme.... ;)
With a structure born noise test. 8)
No, I will do the classical test.
Once SPL, which first reveals only the level.
Then with an RTA to capture the spectrum - and actually only that is interesting.
Because whether something is perceived as annoying depends on the frequency and that can only be captured with an RTA.
Then you have to accept that the actual test procedure does not say much.
Usually you don't have such conditions, but the scope is on the table and immediately there are boundary surfaces that reflect/amplify the sound of the fan.
I will play through the normalized case, i.e. as free standing as possible with few early reflections, then the practical case.
For the tests, I benefit from the fact that we regularly perform airborn noise tests at work and I measure loudspeakers in the room at home.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Performa01 on October 04, 2023, 12:53:18 pm
Recall the Wave Combine on the SDG2XXX is pretty good, vaguely remember we measured such on the SSA3021X+, but may not be good enough for a 12 bit DSO. WRT to using separate AWG outputs, adding a 6~10dB pad in each AWG output before the resistive combiner should eliminate any potential IMD between the AWG channels, and still have enough signal level at the test DSO input.
Just to know the truth once and for all - and to have it documented, I've done a couple of tests to finally conclude that the internal "Wave Combine" feature unsurprisingly would be barely adequate even at low frequencies. Not to mention the catastrophy at high frequencies (Reply #460):

https://www.eevblog.com/forum/testgear/siglent-sdg6000-series-awg_s/msg5093877/#msg5093877 (https://www.eevblog.com/forum/testgear/siglent-sdg6000-series-awg_s/msg5093877/#msg5093877)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Njk on October 04, 2023, 01:43:28 pm
I'm not sure about the generalization. The fact that it does not work well with one particular instrument does not mean the whole idea of the internal combining is compromised. Perhaps generally it'll be wise to try the internal combining first and to take a more complex approaches only if necessary.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 10, 2023, 06:21:33 pm
Hi,

The scope arrived today, I had picked it up right after work - And of course had to switch on once.... ;)
Optical impression, it is "terribly" small, really tiny, as if half was forgotten. :D
And it smells like melting plastic, but you get used to it. ;)
Turn on...
The fan is now not super loud, but has an annoying frequency, I had the scope now but not in the quiet study.
Boot time: 1min20sec. Edit: Time for the first boot, after this it´s about 50sec. ...
First technical impressions:

-Only one "normal" USB port, which I consider a big minus.
I could always swap between Bodnar and USB stick for the pictures earlier.
- Display is very sharp, you notice the higher resolution immediately, very pleasant, BUT:
The display itself is very reflective and not super bright, rather somewhat "dimmed". Edit: Now it seems brighter.
-Bodnar pulser connected via 50Ohm resistor, risetime is 3.6ns which makes something around 100Mhz, not bad.
Or if you put in the formula 0.45, you get exactly 125Mhz...Aha.
But I will check this correctly.
-Bodnar, the second:
Memory on automode, when the sample rate drops, the signal is already visibly changed.
As soon as a third channel is active, the sample rate has already reached the minimum of 312.5.
When you enable Ultraacquire, things get weird, but more on that later.
Oh, and it takes a long time until the scope reports the USB stick as "connected". OK, not sooo long..
That's it for now, more soon.

Martin
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 10, 2023, 06:45:40 pm
Boot time: 1min20sec.
:o  That's even longer than the 47 seconds or so which Dave had reported! Maybe this was just the first initialization for the brand-new unit? Does it get any faster on subsequent boot cycles?

Quote
The display itself is very reflective and not super bright, rather somewhat "dimmed".
The photos show that you clearly need new (different) ceiling lights to work with that scope. ;)

Quote
-Bodnar, the second:
Memory on automode, when the sample rate drops, the signal is already visibly changed.
Makes sense that one sees the effect of capturing fewer harmonics with the reduced sampling rate. But why does the curve appear noisier too? Is that an effect of phase fluctuations between the incoming pulses and the sampling clock?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: TurboTom on October 10, 2023, 06:58:26 pm
Did some tests on a newly arrived DHO914S. Here are a few of my findings:

The traces look nice and crisp at the first glance, but it gets quickly glear that the intensity grading is way worse than on Rigol's legacy scopes. Even the DS1000Z is performing far better than this new 12-bit series. See RigolDS18 -- this is as good as it gets! It seems like they have got only four gradations and need to dither in between...

Rise time is pretty decent for a 125MHz scope @ 1.87ns (rise time of the source < 500ps, everything's properly terminated), see RigolDS11

Colour grading doesn't seem to work properly with infinite persistance, but that may have to be expected. I tried to use it while evaluating time base jitter which apparently is quite decent with one or two channels active but gets much worse when three or all channels are enabled (RigolDS17:16:15). I used a highly stable 10MHz signal with the timebase delayed by 100ms and looked at the neares positive slope. The screenshots show approx. one minute of recording. The few traces that deviate from the "bulk" are the result of me pressing the "quick" (screenshot) button and thus applying a little pressure on the scope. This seems to slightly shift the scope's internal reference oscillator (probably a digital TCXO since during warmup, the "bulk" of the delayed traces doesn't seem to slowly walk but rather "jumps" in increments of ~1.2ns. But nothing really to complain about here.

The internal AWG won't "pull the butter off the bread" (direct translation of a local idiom... ;)) -- especially the reconstruction filter doesn't seem to do a good job. I'm very surprised that despite the differential design of the DAC output, we see substantially asymmetric ringing of the analog output signal (RigolDS19). The cause for this may be too high tolerances in the components of the reconstruction filter or not quite the best choice of the amplifier(s) that follow the filter. Rise- and fall times of the AWG (square wave) are in the ballpark of 10ns.

I've got the impression that there's still a considerable way to go for Rigol with this platform (both hard- and software-wise) and very likely I'll return the instrument since I'm far from satisfied, even with my initial findings. The step back in some areas vs. Rigol's legacy products really comes unexpected.



Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 10, 2023, 07:01:53 pm
@ ebastler:

I find it a little bit too dim, like the MSO5000 once.

Boot-Time : You´re right! Second Boot is 50sec, don´t know why it took so long by the first time...
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 10, 2023, 07:17:32 pm
Quote
I find it a little bit too dim, like the MSO5000 once.

Interesting...
Ambient lights are the same, but now I didn´t find it too dim anymore.. ??? 8)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 10, 2023, 07:34:20 pm
it gets quickly glear that the intensity grading is way worse than on Rigol's legacy scopes. Even the DS1000Z is performing far better than this new 12-bit series. See RigolDS18 -- this is as good as it gets! It seems like they have got only four gradations and need to dither in between...

That screenshot looks nasty indeed. I find it hard to believe that this is the best the scope can do, given that the datasheet specifically advertises "real-time 256-level intensity grading".

My DS1054Z display looks a bit like that if I switch it to "Dot" mode. But I understand that option is not even avaialble with the DHO 800, so it can't be behind that ugly dithering. Have you checked the other display and aquisition settings to see whether anything might be sub-par? I don't want to give up hope just yet that Rigol did a decent job with the intensity grading...

Quote
Colour grading doesn't seem to work properly with infinite persistance, but that may have to be expected.

Agree. I don't see how grading (whether intensity or color based) would go together with infinite persistence, which saturates all pixels which see a signal at all. Hence no concern over that one.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 10, 2023, 07:46:18 pm
What are the settings to get this signal ? AM modulation carrier/signal frequencies?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 10, 2023, 08:17:33 pm
Quick and dirty, intensity grading....looks very good.
But switching to color grade mode will deactivate the intensity adjustment.
(DS5: 25Mpts, DS7:1Mpts)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 10, 2023, 09:08:40 pm
So, but now is really enough for today... ;)

Quote from: Me
-Bodnar pulser connected via 50Ohm resistor, risetime is 3.6ns which makes something around 100Mhz, not bad.
Or if you put in the formula 0.45, you get exactly 125Mhz...Aha.

When I connected my SDG2122X earlier, I thought to myself, oh run through the frequencies up to 120Mhz.
1Vrms.
At 120Mhz it was just under 700mVrms, from about 100Mhz the level became smaller.
Before that, starting at about 70Mhz the level swung up to 1.5Vrms.
A resonance point ?
What I also find interesting:
In the options menu there are three options, twice decoding, once bandwidth(100Mhz).
The first two are marked as "forever" (makes sense), the bandwidth as "limit".
So it may well be that the 70Mhz models first have 100Mhz, so I understand that anyway.
It is also interesting under the point that you can not officially buy a bandwidth upgrade for the 70Mhz model.

Title: Re: Rigol DHO804 Test and Compare Thread
Post by: iMo on October 10, 2023, 09:27:02 pm
The 1.5V peak at 70MHz comes from the higher order low-pass.
It could be the 100MHz "Limit" means "limited time", like a demo version for the first 10days.. But they forgot to install the RTC, thus it means forever.. :)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 10, 2023, 09:33:25 pm
It could be the 100MHz "Limit" means "limited time", like a demo version for the first 10days.. But they forgot to install the RTC, thus it means forever.. :)

They could always enable it for a limited number of power cycles or power-on time. But it would be kind of mean to tease users with the 100 MHz performance when one can't even buy an upgrade for permanent 100 MHz bandwidth later...

Maybe the scope will replace the "limit" message with "hack me now" when time is up?  ::)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 10, 2023, 10:27:12 pm
The 1.5V peak at 70MHz comes from the higher order low-pass.

Like I said, a resonance point.
If you hack the 804 to 100Mhz now, this should disappear.
If not, this is a hardware filter, but then the specification in the options menu makes no sense... :P
On the other hand, there is no official bandwidth option...
Oh Rigol, you're killing me.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: TurboTom on October 10, 2023, 10:32:10 pm
Actually, I still like the intensity grading of the DS1000Z series better, not to speak of the higher models of this heritage...

Settings for the AM signal were 1MHz 7Vpp, AM 1kHz 100%. Timeout / duration trigger works best with the time set to 1/5 to 1/10 of the modulation frequency period.

On the DS1000Z, enabling the anti-aliasing function helps cleaning up the display. Playing with the intensity permits intensity grading configurations that are way more pronounced than on a real analog scope. The attached photo IMO shows a very nice configuration, not exaggerated but nicely visible. I won't get it better than that on the DHO914S, though. The screenshot of the scope may actually look better than the image on the scope screen itself, That's why I took a photo of a direct comparison.

Btw, the horizontal pattern visible on the DS1000Z in the photo doesn't appear on the screen to the bare eye. It may be a dynamic thing that the still camera catches but the (my... ;)) eye is to slow to notice...
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: TurboTom on October 10, 2023, 11:05:28 pm
Okay, so here's some more testing, especially regarding timebase accuracy, frequency response and aliasing...

For my first test, I connected the (warmed-up) scope to my rubidium source (square wave output) and increased the time base delay until it was possible to comfortably measure a certain deviation of the rising slope to the screen's vertical center line. This was the case at 10ms delay, and the offset measured -62.39ns (RigolDS20). So the time base of this particular scope is running approx. 6ppm too slow. This also explains why the frequency counter shows the frequency of the rubidium source 100Hz too high (one least digit). These are very acceptable figures for a scope.

The next tests were intended to evaluate the 3dB drop-off frequency for the scope at a range of signal levels. For this, I pulled an R&S SM300 RF signal generator from the basement and wired everything up, using a BNC through-terminator at the scope. I tested at levels of +10dBm, 0dBm, -10dBm, -20dBm, -30dBm and -40dBm. Initially, I checked every level at 10MHz and stored a reference to be sure the displayed AC RMS amplitude matches the expected value (shown for +10dBm in RigolDS22).

The following screenshots (RigolDS23:28) show that the -3dB frequency threshold of this DHO914S is around 180MHz with the "sweet spot" at 100mV/div with 205MHz. So it's far beyond the manufacturer's spec of 125MHz, yet one has to consider that these measurements had been performed without the supplied probes. Moreover, there's no frequency dropoff or limiter present at the lower voltage ranges (tested down to 1mV/div).

TBC...
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: TurboTom on October 10, 2023, 11:06:33 pm
Let's continue with the tests...

In order to check the aliasing properties, I generated five frequencies in sequence at +7dBm (since this nicely filled the screen at a 200mV/div sensitivity setting) which were 100MHz, 125MHz, 150MHz, 175MHz and 200MHz. I meassured each of the frequencies initally with only one active channel and afterwards with all four channels enabled (btw, the reason for using channel 4 for the measurement was due to the length -- or rather the lack thereof -- of the semi-rigid connection cable from the signal generator to the scope  ;))
The screenshots (RigolDS29:38) are attached in sequence.

As you can see, at 100MHz everything's still "nice and dandy", so the scope is definitely usable with all four channels active up to this frequency. Also the statistics of the frequency counter doesn't show any deviation. The latter is still the case at 125MHz, but the signal trace starts to show some smearing / modulation, an indication that the sin(x)/x reconstruction isn't working quite as good anymore. At 150MHz, the counter deviates heavily from the correct value and there's a lot of modulation on the signal. Here we're far beyond the useful rage of the scope with four channels active. With up to two active channels, though, the scope is performing flawlessly. Beyond 150MHz, the modulation reduces and the scope appears to show a proper waveform, except now it's aliasing completely, visible in the displayed frequency dropping with increasing input signal frequency. Since the scope's front ends work beyond the aliasing limit, there's no direct hint to this problem visible on the screen  -- the user has got to check frequencies with two or less channels active.

Another detail to observe is that an active counter or trigger source assigned to an otherwise inactive channel enables this channel internally. Even the frequency counter operates on the digitized data stream after the ADC(s)!

So to cut a long story short, consider the DHO800/900 with more than two channels active to be a 100MHz scope, and you are on the safe side. If it makes much sense to spend the premium on the DHO924(S) can definitely be questioned. I probably wouldn't even apply a hack regarding the frequency upgrade if one should become available.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: TurboTom on October 10, 2023, 11:45:54 pm
Unfortunately, here's one more, rather disappointing finding: The true vertical resolution of the DHO900 (at least of the specimen that I've got that is) is rather poor:

Just let the scope auto-trigger in the 1V/div range (in my particular case, I capped the input with a 50R BNC terminator) and stopped the digitizing engine then.
After that, zoom the vertical scale to 20mV/div (that's the last step provides proper magnification). You will find a peak-to-peak noise in the ballpark of 80mV! If the range at 1V/div is 10Vpp (considering one division of margin beyond the screen limits), this means there's a resolvable range of 1:125 which equals just 7 bits of true resolution (I know, this calculation isn't completely correct, but for "home use", it should fairly accurately fit the bill). This figure is more or less independent of time base setting and initial sensitivity.

It may be interesting to check if other HDO800/900 specimen perform better, especially since the test is rather easy to perform.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: rpro on October 11, 2023, 01:18:05 am
It may be interesting to check if other HDO800/900 specimen perform better, especially since the test is rather easy to perform.

On my DHO804, using your parameters (20us/ timebase, 1.25GSa/s) the noise of the 1V/div stopped 50ohm capped signal I can measure (as std-deviation or AC-RMS) is 9.5mV at 20mv/div, 1.1mV at 2mV/div and 260uV at 500uV/div.  (I prefer to use std-dev to measure noise, rather than Vpp, since Vpp could be reflecting real tail excursions in the sampled distribution, which can make the signal Vpp noise look "better" in less capable scopes.)   
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: DaneLaw on October 11, 2023, 02:17:23 am
Quick and dirty, intensity grading....looks very good.
But switching to color grade mode will deactivate the intensity adjustment.
(DS5: 25Mpts, DS7:1Mpts)
Seems weird if you lose the intensity grading in color-corrected temperature mode.
How many levels of intensity grading do the DHO800 & DHO900 series operate with? just 64 levels, like DS1054Z or even less.?
Wonder about the step-up model DHO1000 series (which I have had my eye on, because of the big screen) would be a shame if waveform-eyepron, like intensity grading, were somewhat limited on that big gorgeous screen.
The DHO800/900 series does have an inbuilt drive, If I recall alongside ext thumb drive ability.... Can you record videos, if you wanna show others how a waveform fx behaves in certain scenarios..?

Nothing pops up checking Google for gradings levels on DHO800 & 900 series:?

//
Example of another older Android-based entry scope, I believe it's 256 levels, even though I saw a seller list it as 512 levels, but with full intensity control also in color-corrected CCT mapping.

https://www.youtube.com/watch?v=Iy2NvuZUYXk (https://www.youtube.com/watch?v=Iy2NvuZUYXk)https://www.youtube.com/watch?v=xV40hZCkfek (https://www.youtube.com/watch?v=xV40hZCkfek)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 11, 2023, 02:23:42 am
-Only one "normal" USB port, which I consider a big minus.

I bought one of these a few weeks ago:
(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1896609;image)

Hope it works with the Rigol...

(It seems to have a "hub" chip hidden inside it somewhere)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 11, 2023, 02:53:53 am
So to cut a long story short, consider the DHO800/900 with more than two channels active to be a 100MHz scope, and you are on the safe side.

That's obvious from the sample rate.

If it makes much sense to spend the premium on the DHO924(S) can definitely be questioned. I probably wouldn't even apply a hack regarding the frequency upgrade if one should become available.

It's a 250MHz 'scope when there's only one/two channels enabled.

If you:
a) Work with 50 Ohm stuff and know to stick to two channels when doing that.
b) Need four channels for working with probes at other times.

Then ... it might be worth it.

For everybody else? Probably not.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 11, 2023, 07:33:00 am
Quick and dirty, intensity grading....looks very good.
But switching to color grade mode will deactivate the intensity adjustment.
(DS5: 25Mpts, DS7:1Mpts)
Seems weird if you lose the intensity grading in color-corrected temperature mode.

Looking at screenshots from various scope brands on the web, they all seem to show color grading without putting intensity grading on top, and I think that is what you want for clarity. For me, the whole point of using color grading (rather than intensity grading) is that you want to also see the infrequent signals clearly, in "cooler" colors but not dimmed. The frequent traces will still be clearly highlighted by their "hot" colors.

Which does not rule out the possibility that some scopes may let you combine both grading modes, and their combined use is just never shwon in screenshots. Anyone with hands-on experience who can comment?

Quote
How many levels of intensity grading do the DHO800 & DHO900 series operate with? just 64 levels, like DS1054Z or even less.?
Nothing pops up checking Google for gradings levels on DHO800 & 900 series:?

The datasheet states "Digital phosphor display with real-time 256-level intensity grading". Let's hope the developers have read that too... (Google finds that nicely for me, btw.)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Serg65536 on October 11, 2023, 07:46:07 am
Rigol DHO800 Aliasing effect
Press "Default", use 12.5 MHz (or 25, 20, 10, 5 MHz), 1k memory depth, increase the timebase until aliasing appears. Firmware version 1.00.
https://youtu.be/D_kHEUk-zKo (https://youtu.be/D_kHEUk-zKo)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 11, 2023, 07:46:22 am
Quote
with hands-on experience who can comment?

Rigol MSO 5000 and Siglent models could do this.
The first I've shown here long ago, the second I could post it here in the later evening.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 11, 2023, 07:50:55 am
Just let the scope auto-trigger in the 1V/div range (in my particular case, I capped the input with a 50R BNC terminator) and stopped the digitizing engine then.
After that, zoom the vertical scale to 20mV/div (that's the last step provides proper magnification). You will find a peak-to-peak noise in the ballpark of 80mV!

Hmm... Dave did the same measurement in his review video, starting at 1V/div and zooming in to 50 mV/div, then 20 mV/div. I would eyeball the noise at 20 mV peak-peak in his quick test, so 2 bits more than what you found. Might there be something wrong with your scope -- a power supply issue maybe?

Code: [Select]
[url]https://www.youtube.com/watch?v=S8jrpCoZyx8&t=2130s[/url]

Edit: Trying to fix that Youtube link to point to the relevant time in the video...
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: TurboTom on October 11, 2023, 08:02:24 am
...
Hmm... Dave did the same measurement in his review video, starting at 1V/div and zooming in to 50 mV/div, then 20 mV/div. I would eyeball the noise at 20 mV peak-peak in his quick test, so 2 bits more than what you found. Might there be something wrong with your scope -- a power supply issue maybe?
...

The noise readings actually depend a lot on the particular configuration of the acquisition engine (sample rate, memory depth). Indeed my own findings pretty accurately match @rpro's so I don't think there's anything wrong with the scope that I'll probably return to the vendor...  :-//
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 11, 2023, 09:40:17 am
It may be interesting to check if other HDO800/900 specimen perform better, especially since the test is rather easy to perform.

On my DHO804, using your parameters (20us/ timebase, 1.25GSa/s) the noise of the 1V/div stopped 50ohm capped signal I can measure (as std-deviation or AC-RMS) is 9.5mV at 20mv/div, 1.1mV at 2mV/div and 260uV at 500uV/div.  (I prefer to use std-dev to measure noise, rather than Vpp, since Vpp could be reflecting real tail excursions in the sampled distribution, which can make the signal Vpp noise look "better" in less capable scopes.)


This might point to a bad design. This scope seems to (again like DS1000Z did) derive measurements from screen decimated data. MSO5000 had capability to work from full data, much better design, despite being a bit noisy..

To explain: If you capture data at 1 V/div and do AC RMS or P-P measurement then stop the scope, changing V/div on stopped data must not change any measurement. Only thing that could change will be number representation (on different ranges it will have different display).

For instance, on different scope that I have,  If I capture at 1V/div I get 5,0484 mV AC RMS. If I view that at 10 mv/div I get 5,048367 mV, and at 10V/div I get 5,083 mV RMS. That is with 200 MHz BW. If I go to 500 µV/DIV it show over-range as it should.

If DHOX00 changes value it means that is another thing done really wrong....

@ebastler, it is not visual trace thickness that is wrong but automated measurements.
@TurboTom, time base settings are only one that in theory should change AC RMS of noise (BW changes). Rest of changes are because front end creatively combines ADC, VGA and attenuators for whole range of input sensitivities and not all combinations are best case. But S/N ratio should stay same order of magnitude except for most sensitive ranges....

P.S. did anybody notice in that video how Dave compares how blocky Siglent trace looks despite using 3 Bit ERES? Problem is that Siglent is set to 0.5 Bit ERES not 3 Bit.... If it where 3 Bits it would look much better, if not the same in reduced BW that gives...
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 11, 2023, 09:48:28 am
On my DHO804, using your parameters (20us/ timebase, 1.25GSa/s) the noise of the 1V/div stopped 50ohm capped signal I can measure (as std-deviation or AC-RMS) is 9.5mV at 20mv/div, 1.1mV at 2mV/div and 260uV at 500uV/div.

I understood from Dave's review video that the scope will not actually "zoom in" any further below 20 mV/div, although it claims to change the vertical scale. Are the 2mV and 500µV values really meaningful, or did I misunderstand?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 11, 2023, 09:53:05 am
So to cut a long story short, consider the DHO800/900 with more than two channels active to be a 100MHz scope, and you are on the safe side.

That's obvious from the sample rate.

If it makes much sense to spend the premium on the DHO924(S) can definitely be questioned. I probably wouldn't even apply a hack regarding the frequency upgrade if one should become available.

It's a 250MHz 'scope when there's only one/two channels enabled.

If you:
a) Work with 50 Ohm stuff and know to stick to two channels when doing that.
b) Need four channels for working with probes at other times.

Then ... it might be worth it.

For everybody else? Probably not.

You seem to forget what I warned you about.

If scope keeps full 250MHz BW while decreasing it's sample rate to 312.5 MSp/s that is bad design.

If scope knows sample rate is insufficient, it should enable antialiasing filters to prevent aliasing.
Scope should drop to 100Mhz (or 70MHz) BW if needed to prevent aliasing and show that on screen.

Saying it is 250 MHz 4 ch scope is firstly lying trough your teeth, second is going to get users in trouble.
Especially because target market are hobby/beginner users...

Signals that have BW in excess of 100 MHz are very common today. Arduino has less than 1ns edges on outputs and RaspberryPI has them several times faster...
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: DaneLaw on October 11, 2023, 10:14:36 am
Looking at screenshots from various scope brands on the web, they all seem to show color grading without putting intensity grading on top, and I think that is what you want for clarity.


For clarity?.. it's a scope, you want "information", and whatever that can visualize that information, the better.
and what do you mean by "puttng on intensity"? it's a grading that scales the signal intensity'  so you in fact get better clarity.
It's exactly what you want, for "clarity.
I do recall that mid to higher-end models, will often let you work with the intensity grading, also in color-corrected mode, which I find very handy, but you mention you have been looking at screenshots online, likely not the best approach to sense levels...maybe take a look on YT.

A good intensity grading is a must for a modern digital bench scope, it would be a shame if it's not up to par with the latest Rigol entry DS1000Z series with 64 levels., but it's a new model, so it will evolve, be optimized.
Would puzzle me, if DSO800 & 900 don't build on, pretty much all factors vs their older entry model.
Actually, I still like the intensity grading of the DS1000Z series better, not to speak of the higher models of this heritage...

What 7" LCD panel are Rigol using in DHO800 & DHO900 series? TFT or IPS?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: csuhi17 on October 11, 2023, 10:18:28 am

Which does not rule out the possibility that some scopes may let you combine both grading modes, and their combined use is just never shwon in screenshots. Anyone with hands-on experience who can comment?



Did you mean this effect??
Micsig STO2202C
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: TurboTom on October 11, 2023, 11:02:01 am
I find a lot of spurious signal at 1/8 of the sampling frequency superimposed to low-level signals -- Here's 1MHz 8mVpp sine fed to channel 1. and the FFT of the waveform. I know this is scraping at the edge of the intended envelope of this instrument, but interesting to know anyway. It may point in the direction of asymmetries between the individual sctions of the pipelined ADC...

Okay, seems like the forum's file upload is working again  :)

In between I made a new observation that alleviates the previous apparent problem: I've been using a 90cm BNC cable to connect the DHO914S's AWG output to channel 1 input without termination. It may have well been possible that this contraption has a resonance frequency close to the 156.25MHz which is 1/8 Fs, that may have been excited by some leakage of this signal from the scope. Using a short cable (30cm) and proper termination reduces this spurious signal considerably, see RigolDS43. So probably nothing to worry about here...  :D
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 11, 2023, 11:56:30 am
For clarity?.. it's a scope, you want "information", and whatever that can visualize that information, the better.
and what do you mean by "puttng on intensity"? it's a grading that scales the signal intensity'  so you in fact get better clarity.
It's exactly what you want, for "clarity.
If I want to see frequent and rare signals, intensity grading will limit the dynamic range of "rareness": Very infrequent signals will become invisibly dim, or frequent signals will saturate. That's where I think color grading is most useful -- it lets the scope visualize that larger dynamic range on a color scale. But making the infrequent traces not only blue, but also very dim, seems to negate that benefit?

Quote
I do recall that mid to higher-end models, will often let you work with the intensity grading, also in color-corrected mode
What do you mean by "color-corrected" mode? Are we really talking about the same thing, i.e. false color or heatmap encoding?

Quote
A good intensity grading is a must for a modern digital bench scope, it would be a shame if it's not up to par with the latest Rigol entry DS1000Z series with 64 levels.
I certainly agree, as far as (pure) intensity grading is concerned. As mentioned earlier, the datasheet does specify "real-time 256-level intensity grading" for the DHO 800/900 scopes. So let's hope that is what we actually get -- eventually maybe, if and when properly implemented in software...
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 11, 2023, 12:23:44 pm
In color grading mode, Intensity button usually controls color saturation.  Since not all colors are perceived by eye as same brightness  there could be illusion of varied brightness.

The problem here is that it seems that 16 or less levels are used to render waveforms.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 11, 2023, 12:43:55 pm
The problem here is that it seems that 16 or less levels are used to render waveforms.

Agreed, if that should indeed be the case (for intensity grading), it would be very disappointing. But it is not the problem I -- and I believe DaneLaw too -- were discussing. Rather, I was referring to:

Quick and dirty, intensity grading....looks very good.
But switching to color grade mode will deactivate the intensity adjustment.

Which, I thought, is the normal way of doing color grading. If it not only deactivates intensity adjustment, but also does not allow any adjustment of the color scale as you described, that would indeed be annoying.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: DaneLaw on October 11, 2023, 12:45:08 pm
For clarity?.. it's a scope, you want "information", and whatever that can visualize that information, the better.
and what do you mean by "puttng on intensity"? it's a grading that scales the signal intensity'  so you in fact get better clarity.
It's exactly what you want, for "clarity.
If I want to see frequent and rare signals, intensity grading will limit the dynamic range of "rareness": Very infrequent signals will become invisibly dim, or frequent signals will saturate. That's where I think color grading is most useful -- it lets the scope visualize that larger dynamic range on a color scale. But making the infrequent traces not only blue, but also very dim, seems to negate that benefit?

Quote



I do recall that mid to higher-end models, will often let you work with the intensity grading, also in color-corrected mode
What do you mean by "color-corrected" mode? Are we really talking about the same thing, i.e. false color or heatmap encoding?


The specific comment you replied & commented on #40 - had two long videos of this exact feature, so not sure why you're unsure what we are talking about.
It goes under tons of different names & labels from vendor to vendor, some call it "heatmap" some calls its "color grading", some call it "Color Corrected Temperature" and some just label it as CCT, it goes under a lot of different names.

The videos on the comment you replied to, are done with a Micsig scope, and Micsig labels it as Color Corrrected Temperature, (CCT) and gives full intensity grading in CCT mode, as you can see in the context, so it shouldn't be up for debate what we are talking about.
https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/msg5106732/#msg5106732 (https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/msg5106732/#msg5106732)

There is also a screen dump above your comment #52 highlighting it.

Quote
If I want to see frequent and rare signals, intensity grading will limit the dynamic range of "rareness": Very infrequent signals will become invisibly dim, or frequent signals will saturate. That's where I think color grading is most useful -- it lets the scope visualize that larger dynamic range on a color scale. But making the infrequent traces not only blue, but also very dim, seems to negate that benefit?

The aspect of rareness, and being able to decipher that, is the exact thing you get with intensity grading, and the more levels the better, as it will segment the waveform into "rareness" as you adjust the intensity accordingly.
Its an extremely useful feature to decipher the information in a given waveform and how present they are.

It's not plug-and-play..like with all meters you will get familiar with your scope, and adjust it accordingly, so don't worry about "rareness" disappearing.. it aint, quite the contrary, it will show you which part of the signal is "rare" - if you adjust & monitor it accordingly...having features that can segment the information in the waveform is quite handy, both in single color and in a color palette, that again will grade each color into many tone-levels, as you can see in the video, how "blue" starts out, very dark royal blue, and toning into a lighter blue shade, flipping over to light green, and vice versa down the wavelength scale.

One thing that would be nice add on to CCT - is like I have on my thermal cameras, where I can make up my own color palette from scratch,  like I also got on certain spectrum waterfalls.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: nctnico on October 11, 2023, 12:47:06 pm
For clarity?.. it's a scope, you want "information", and whatever that can visualize that information, the better.
and what do you mean by "puttng on intensity"? it's a grading that scales the signal intensity'  so you in fact get better clarity.
It's exactly what you want, for "clarity.
If I want to see frequent and rare signals, intensity grading will limit the dynamic range of "rareness": Very infrequent signals will become invisibly dim, or frequent signals will saturate. That's where I think color grading is most useful -- it lets the scope visualize that larger dynamic range on a color scale. But making the infrequent traces not only blue, but also very dim, seems to negate that benefit?
I agree. Making infrequent signals dim is pretty useless. It only serves mimicking analog scope like behaviour while forgetting the main problem of analog scopes is that they hardly show infrequent signals.  :palm: At my first employer I had an analog Hameg scope with overrange indicators (LEDs). I used those regulary to catch pulses which where invisible on the screen.

When I want to see infrequent signals I use infinite persistence, color grading or reverse intensity (the latter is a feature I've only seen & used on R&S scopes).
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 11, 2023, 02:38:11 pm
You seem to forget what I warned you about.

Huh?

Scope should drop to 100Mhz (or 70MHz) BW if needed to prevent aliasing and show that on screen.

I've been saying that for months (and you know it (https://www.eevblog.com/forum/testgear/rigols-new-dho800-oscilloscope-unbox-teardown/msg5063266/#msg5063266)).
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 11, 2023, 02:40:06 pm
The specific comment you replied & commented on #40 - had two long videos of this exact feature, so not sure why you're unsure what we are talking about.

I must admit that I did not make it far into the videos, sorry! Long silent films where I am expected to stare at the screen and figure out what is happening and what the message is don't work well for me. But yes -- we are talking about he same thing, color grading or whatever. Thanks for confirming.

Quote
It goes under tons of different names & labels from vendor to vendor, some call it "heatmap" some calls its "color grading", some call it "Color Corrected Temperature" and some just label it as CCT, it goes under a lot of different names.

Actually no-one (including MicSig) calls it "color corrected mode" or "color corrected temperature". CCT apparently stands for color-correlated temperature (*), which makes more sense to me.  "Color temperature correction" is an entirely different thing in photography; hope you can understand where my confusion came from.

Regarding the benefit (or lack thereof) of showing intensity grading at the same time as color grading, you and I still seem to talk at cross-purposes. I am reassured to see nctnico's comment, and also 2N3055's pointing out that "In color grading mode, Intensity button usually controls color saturation". I certainly see the benefit of that.

(*) Edit: Actually I can't find any documents where MicSig themselves use the "CCT" acronym or spell it out. The "correlated color temperature" meaning seems to come from a different discipline too, unrelated to false color scales. I stand correlated.  ::)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 11, 2023, 04:23:55 pm
In color grading mode, some scopes have option to change between different color palettes (color ranges and color mapping).
As Nico said, interesting mode is inverse palette (both color and intensity grading) where signal is rendered brighter/hotter color when it is RARE (repeating rarely) to make it easier to see...

There are also different color grading plot types: density plot, pixel frequency plot, phosphorus emulation....

Title: Re: Rigol DHO804 Test and Compare Thread
Post by: DaneLaw on October 11, 2023, 04:47:50 pm
sorry! Long silent films where I am expected to stare at the screen and figure out what is happening and what the message is don't work well for m
Actually no-one (including MicSig) calls it "color corrected mode" or "color corrected temperature".  "Color temperature

As explained, a few times now.. a lot of different labels are used amongst scope vendors for the "color temperature" function.
Micsig uses
"color temperature mode" STOxxxC/E
"correlated color temperature" STOxxxC/E (CCT)
"color temperature open mode" STOxxxC/E
"color temperature display" (ETO/MDO)


So the simple wording "color temperature" should cut it.. (color corrected or not)
and dear, what you wanna see or don't in a given comment, got little bearing, when it's the first few seconds, so one would take for granted that you at least related the content on the exact comment you replying to - when there is even an example there for the claim your making'..  one even got a tune for your pleasure for short focus-span.. next time I will give you a timestamp +0.00sec.
but let's move, been explained back and forward in both words, visual and screen dumps from other users.
you stated that color intensity temperature grading, aint a feature that you have seen on scopes, and you came to that conclusion after you have been looking at many screenshots on Google/web.

Quote
Looking at screenshots from various scope brands on the web, they all seem to show color grading ]without putting intensity grading on top, and I think that is what you want for clarity.

Tried to explain that wasn't the case and so did others, alongside WHY I find it very useful as it gives me more information on the signal I am looking at..
but as mentioned, let's move on...

Personally, I would love to see a shootout from Dave on the intensity grading on modern scopes, and how they stack up, current Rigol DHO800/1000/4000, R&S2 & 4series, Tek2 series, and what abilities they each have, also in color temperature mode.

//
Quote
(*) Edit: Actually I can't find any documents where MicSig themselves use the "CCT" acronym or spell it out. The "correlated color temperature" meaning seems to come from a different discipline too, unrelated to false color scales.
Its Micsig'slabel in the OS-menu/display/waveform "CCT"..you can see it in the first post... and "correlated color temperature" [CCT] does confuse, as it very common label  in lighting for light temperature, but in newer models like ETO/MDO.. it seems be exchanged for "Color temperature display" but this aint a Micsig thread.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: TurboTom on October 11, 2023, 04:57:45 pm
The "noise signal" output of the "S"-Model's  ;) AWG appears to be very decent. The valley at 78.125MHz indicates the Nyquist frequency (due to a DAC sample rate of 156.25MHz = 1/8 Fs of the scope's ADC). Unfortunately, there's quite some amount of the sampling frequency leaking through to the AWG output (and it's not related to the scope section's ADC as I assumed in this contribution (https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/msg5107203/#msg5107203)).

Considering these figures, I'm a little bit surprised that Rigol limited this AWG to 25MHz, the reconstruction filter and the other components appear to be laid out for a 50MHz AWG. Also the noise signal output appears to indicate this. So we may actually be up to a surprise eventually. For a "real" 25MHz AWG, I would have expected the reconstruction filter to be configured for a lower cut-off frequency with a steeper slope...

Btw, I like the handling and the speed of the scope's FFT along with the overall responsiveness of the U/I. That's quite an improvement vs. the "legacy" models. Once the problems are ironed out, this is going to be a nice instrument.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: DaneLaw on October 11, 2023, 05:06:44 pm
The "noise signal" output of the "S"-Model's  ;) AWG appears to be very decent. The valley at 78.125MHz indicates the Nyquist frequency (due to a DAC sample rate of 156.25MHz = 1/8 Fs of the scope's ADC). Unfortunately, there's quite some amount of the sampling frequency leaking through to the AWG output (and it's not related to the scope section's ADC as I assumed in this contribution (https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/msg5107203/#msg5107203)).

Considering these figures, I'm a little bit surprised that Rigol limited this AWG to 25MHz, the reconstruction filter and the other components appear to be laid out for a 50MHz AWG. Also the noise signal output appears to indicate this. So we may actually be up to a surprise eventually. For a "real" 25MHz AWG, I would have expected the reconstruction filter to be configured for a lower cut-off frequency with a steeper slope...

Btw, I like the handling and the speed of the scope's FFT along with the overall responsiveness of the U/I. That's quite an improvement vs. the "legacy" models. Once the problems are ironed out, this is going to be a nice instrument.
Its a bargain for the price, does the display have any off-center axis to conclude if its TFT or IPS LCD?
not that is meens much, as a good TFT is prefered over a bad IPS and vice versa but the TFT could be a problem from certain angles if people got it up on a VESA mount/arm
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 11, 2023, 05:15:48 pm
Which does not rule out the possibility that some scopes may let you combine both grading modes, and their combined use is just never shwon in screenshots. Anyone with hands-on experience who can comment?

Did you mean this effect??
Micsig STO2202C

Thanks! The attachments finally showed up now, after what appeared to be some forum glitch.

The first picture seems to use intensity grading to extend the color grading scale towards the low end: There's blue for less frequent signals, and dark blue for even rarer signals. That's a nice way of doing it, which I had not (consciously) come across before.

The other two pictures, at least to my eyes, show pure color grading: The information is in the color, I don't perceive additional information in intensity variations. That's what I had typically seen before.

All three pictures nicely illustrate what 2N3055 pointed out, namely that the "intensity" slider actually shifts the color scale in this mode. Which apparently it cannot do in the Rigol DHO models, since it gets disabled entirely -- that's a pity.

My preliminary takeaways regarding "grading" on the DHO 800/900 are:
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 11, 2023, 05:30:54 pm
Btw, I like the handling and the speed of the scope's FFT along with the overall responsiveness of the U/I. That's quite an improvement vs. the "legacy" models. Once the problems are ironed out, this is going to be a nice instrument.
(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1896849;image)

Also the windowing feature which nobody seems to mention. Having two full height signal displays without overlay (as shown above) seems like a huge benefit.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 11, 2023, 05:46:13 pm
Rigol MSO 5000 and Siglent models could do this.
The first I've shown here long ago, the second I could post it here in the later evening.

Pics from the SDS2104X+ at work and the SDS1104X-E at home.

Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 11, 2023, 05:48:14 pm
Quote
Having two full height signal displays without overlay (as shown above) seems like a huge benefit.

This only makes the small screen smaller, which you soon need a magnifying glass. ;)
But I'm still testing how practical this function is.
Edit:
Forgot the pics with 5ms timebase from the 1104X-E...
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 11, 2023, 06:05:04 pm
Btw, I like the handling and the speed of the scope's FFT along with the overall responsiveness of the U/I. That's quite an improvement vs. the "legacy" models. Once the problems are ironed out, this is going to be a nice instrument.
(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1896849;image)

Also the windowing feature which nobody seems to mention. Having two full height signal displays without overlay (as shown above) seems like a huge benefit.

You have that function on many other scopes. You just didn't have opportunity to try out more than few scopes that you had.
And as Martin says, other manufacturers usually split screen horizontally, because X axis carries more details.
Also decoding in vertical window on 7" screen sounds quite claustrophobic.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 11, 2023, 06:08:50 pm
Quote
other manufacturers usually split screen horizontally, because X axis carries more details.

You can move the windows..
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 11, 2023, 06:24:03 pm
Quote
You can move the windows..

Like this...
Vertical view is on this tiny screen not recommendable(my opinion)..
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 11, 2023, 06:28:37 pm
Which does not rule out the possibility that some scopes may let you combine both grading modes, and their combined use is just never shwon in screenshots. Anyone with hands-on experience who can comment?

Did you mean this effect??
Micsig STO2202C

Thanks! The attachments finally showed up now, after what appeared to be some forum glitch.

The first picture seems to use intensity grading to extend the color grading scale towards the low end: There's blue for less frequent signals, and dark blue for even rarer signals. That's a nice way of doing it, which I had not (consciously) come across before.

The other two pictures, at least to my eyes, show pure color grading: The information is in the color, I don't perceive additional information in intensity variations. That's what I had typically seen before.

All three pictures nicely illustrate what 2N3055 pointed out, namely that the "intensity" slider actually shifts the color scale in this mode. Which apparently it cannot do in the Rigol DHO models, since it gets disabled entirely -- that's a pity.

My preliminary takeaways regarding "grading" on the DHO 800/900 are:
  • It does do intensity grading. Specified as 256 levels in the datasheet, looking good in screen captures on the PC (Martin72), looking less convincing on actual photos of the built-in screen (TurboTom).
  • It does color grading. Looking alright if the fixed color scale is a good match (Martin72), but offering little or no flexibility to tweak it. Various other scopes offer more flexibility, notably among entry-level scopes the MicSigs.
Well said.
In addition, and as a reply to @DaneLaw, color grading has been called all kinds of things, for all kinds of marketing reasons.

History of intensity grading starts with phosphorus emulation. If electron beam stayed in one place longer, that part of screen shone brighter. Brightest part of trace was achieved on any time base if there was no signal and we had only horizontal sweep by timebase. As soon as there was signal, electron gun has to swep in both X and Y. Parts where we had fast edge, trace was barely visible. There was also phosphorus persistence, so if signal repeated  faster than decay it was brighter....
Since people demanded from manufacturers that digital scopes display signals more like they were used to, varios phosphorus emulations were created.

Most of the intensity grading was just that, with caveat that you can create nonlinear response, so eye still feels like it is "analog" but you don't let parts of trace go invisible..
But still we have paradox that rare events (that might be the ones we are looking for) are least visible.
Also intensity is very much based on individual perception.  There is limited amount of statistical info that can be extracted from looking at it.

Here we enter color grading.  All statistical info about how much time signal spent in certain place and/or traversed through same place is converted to color palette..
Some of the names mentioned have no root in manufacturer calling this feature "color temperature" or something.
Those names come from color encoded graphs in other parts of human activity, where colored graphs are abundant.
Those are actually names of palettes. There are color palettes that are coded by color temperature (black body temp-color mapping), some have other color mappings.

Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 11, 2023, 06:29:58 pm
Quote
You can move the windows..

Like this...
Vertical view is on this tiny screen not recommendable(my opinion)..

That is good news!!
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Performa01 on October 11, 2023, 06:37:23 pm
Quote
other manufacturers usually split screen horizontally, because X axis carries more details.

You can move the windows..
Welll, member 2N3055 and me are used to that, since we have PicoScopes.

Movable windows are great - if they are flexible, i.e. you can have as many windows you need (and like), can resize them to any form factor you prefer and have a large screen to arange them. That describes a PicoScope on a decent PC workstation.

Things are very different for a tiny little instrument with tiny screen: there I cannot benefit from multiple freely resizable windows, as there is simply no space for them. Quite the contrary, I want a clever layout of the UI, as little waste of precious screen space as possible, hence no window frames, no wide symbol bars and no playful menus.

You have the SDS2000X HD. Turn it on, let the side menu disappear and then compare the relation of the screen area available for signal display and measurement results to the space taken up by the top menu bar and the channel cards at the bottom. Am I the only one who spots the difference? And the SDS2000X HD has a big screen by comparison.

Title: Re: Rigol DHO804 Test and Compare Thread
Post by: nctnico on October 11, 2023, 06:46:18 pm
That is not the point. The moveable/sizeable windows allow the user to make the most of what already is a tiny screen. Bonus points if you have the money to buy a scope with a bigger screen where moveable/sizeable windows are even better. On the RTM3004 I use the sizeable windows to allow me to keep an eye on the signal in a small window and have the FFT display at almost the full visible area of the screen. Cramming everything into the same viewport doesn't help in some cases.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: TurboTom on October 11, 2023, 06:50:32 pm
...
Its a bargain for the price, does the display have any off-center axis to conclude if its TFT or IPS LCD?
not that is meens much, as a good TFT is prefered over a bad IPS and vice versa but the TFT could be a problem from certain angles if people got it up on a VESA mount/arm

The display is fairly well readable when tilted up to approx. 45° in any direction without any changes in hue/colour. Yet, it seems that the backlight is quite directional and the display gets considerably darker the shallower the viewing angle gets. I'm not certain if it's IPS but IMO, except for the glare of the touch panel surface, the display is better than those on Rigol's legacy gear. Especially, there's no prefered viewing position (on-shelf / above the (seated) user vs. desktop positioning). Of course, things can always be improved...  ;)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 11, 2023, 06:50:43 pm
Quote
You can move the windows..

Like this...
Vertical view is on this tiny screen not recommendable(my opinion)..

Martin,

I have a small ask?
Could you please check can you reposition/resize measurements window?

Thanks!
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 11, 2023, 07:02:40 pm
To take it to the extreme, I activated all the math channels....
Rigol has learned, with the MSO5000 each math channel was the same from the color... ;)
Remarkably, the scope does not go down on its knees with all the renderings.
(Note: I only play around with the scope after work, "real" measuring/testing will follow later)


Quote
Could you please check can you reposition/resize measurements window?

Do you mean the windows with the measured values ?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 11, 2023, 07:03:50 pm
That is not the point. The moveable/sizeable windows allow the user to make the most of what already is a tiny screen. Bonus points if you have the money to buy a scope with a bigger screen where moveable/sizeable windows are even better. On the RTM3004 I use the sizeable windows to allow me to keep an eye on the signal in a small window and have the FFT display at almost the full visible area of the screen. Cramming everything into the same viewport doesn't help in some cases.

I agree with you (and not the first time on this topic) but with a caveat. Screen has to be at least some minimum size otherwise, like Performa01 well said, borders and decorations use up most of the screen...

On 23" screen I absolutely use many resizable windows.. On my smartphone, I have split screen function.. Used it once to try it... Not usable...
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 11, 2023, 07:32:24 pm

Martin,
I have a small ask?
Could you please check can you reposition/resize measurements window?

Thanks!

Now I get what you mean... ;)
You can swap the windows left/right, upper/lower, "delete" them and/or add.
Thats all, you can´t define a size or drag it on the screen where you want and if you close a window, for example ch1 and leave the "measure" window on, measure is now fullscreened.
But to get ch1 displaying back, you must go in the windows menu and add this again, annoying..
Edit: Or close the "last" window.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 11, 2023, 08:12:36 pm
You have that function on many other scopes.

I've seen it on R&S, etc, but not on anything for $400 (or anywhere close).

Maybe you guys are surrounded by that stuff all day long and lost sight of what you're dealing with here.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 11, 2023, 08:26:14 pm

Martin,
I have a small ask?
Could you please check can you reposition/resize measurements window?

Thanks!

Now I get what you mean... ;)
You can swap the windows left/right, upper/lower, "delete" them and/or add.
Thats all, you can´t define a size or drag it on the screen where you want and if you close a window, for example ch1 and leave the "measure" window on, measure is now fullscreened.
But to get ch1 displaying back, you must go in the windows menu and add this again, annoying..
Edit: Or close the "last" window.

Thank you Martin!
That is good news that you can detach it like that.. I don't like bad use of space though. How does it look when statistics is enabled ?

EDIT: I see that is ALL measurements.. How about that measurement window on the right , with stats too..
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 11, 2023, 08:28:06 pm
Quote
I've seen it on R&S, etc, but not on anything for $400 (or anywhere close).

Maybe you guys are surrounded by that stuff all day long and lost sight of what you're dealing with here.

If you could freely move and zoom in/out the windows, this kind of display would be a very useful feature.
As it is, it is currently more of a gimmick.(Maybe it will be enhanced someday...)
I wouldn't want to have more than two windows open on the small screen.
However:
Yes, it's unique in the class and yes, you could connect a larger screen, no question. ;)
And I also like, as with the DHO4000 before, the tabular display of the measured values, which is very easy on the eyes.
We don't always want to just complain. ;)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 11, 2023, 08:32:47 pm
You have that function on many other scopes.

I've seen it on R&S, etc, but not on anything for $400 (or anywhere close).

Maybe you guys are surrounded by that stuff all day long and lost sight of what you're dealing with here.
On a screen this small it has limited use but yes they provided it.. I see that external screen would be pretty much necessary if you want to make it bussy.
If you have external screen already, of course. Buying a scope and touch screen might shift you towards just buying something with bigger screen....
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 11, 2023, 08:40:39 pm
@2N3055:

Here an example when you want to have the measures in a window (they´re also on the right side of the screen, but hiding).

Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 11, 2023, 08:48:52 pm
@2N3055:

Here an example when you want to have the measures in a window (they´re also on the right side of the screen, but hiding).

I like the one on the bottom. That one is quite OK..

Thanks!
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: tautech on October 11, 2023, 08:50:58 pm
@2N3055:

Here an example when you want to have the measures in a window (they´re also on the right side of the screen, but hiding).

I like the one on the bottom. That one is quite OK..
Even though just 5 lines of statistics eat half of the display ?  :-//
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 11, 2023, 08:59:20 pm
I wouldn't want to have more than two windows open on the small screen.

But you would want to have two, right?

We don't always want to just complain. ;)

I don't remember seeing positive things in these threads apart from size and cuteness. Everything else has been a mad rush to see who can find the most things to complain about.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 11, 2023, 09:12:53 pm
@2N3055:

Here an example when you want to have the measures in a window (they´re also on the right side of the screen, but hiding).

I like the one on the bottom. That one is quite OK..
Even though just 5 lines of statistics eat half of the display ?  :-//

I'm not comparing with my scopes that have several display modes and many other details not present here.
I still prefer Siglent measurements that are much more powerful implementation (I refuse to buy any scope without histicons ever again).

It is not perfect.. For instance in this table there is no P-P stat..
But it is actually usable (compared to the vertical table on the right it is much better)..
It is better than DS1000Z that cost the same.

But that is graphical representation. My bigger concern is discussion from today with @TurboTom about how measurements are being calculated  and if they are on decimated data and how accurate they are...
That needs to be tested in depth.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 11, 2023, 09:22:18 pm
@Fungus:
Quote
I don't remember seeing positive things in these threads apart from size and cuteness

For me, that is rather not a positive thing. ;)

Quote
Everything else has been a mad rush to see who can find the most things to complain about.

If everything was great, they would report on it accordingly.
You can be sure that I will do it.
Or you, you'll get yours soon and I'm looking forward to your tests. :-+
Getting hold of a 12 bit scope for 475€ is very tempting for people who don't have or want to spend enough money, but even Rigol can't do magic plus their "specialty" is to unleash a rather immature software product on the clientele.
I have it only since yesterday and play around only sporadically, because no time for it - But I have already experienced two system crashes.
That doesn't exactly make for enthusiasm. ;)

Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 11, 2023, 09:22:55 pm
I don't remember seeing positive things in these threads apart from size and cuteness. Everything else has been a mad rush to see who can find the most things to complain about.

People here don't need more Rigol marketing and hype. Leave that to Rigol salesmen.
People want to know does it work, how it works etc.

If there are bugs or deficiencies they need to be discovered, documented and Rigol needs to be pressured to fix them.
So those that want to buy scope to actually use it get scope that actually works.

I know of one person here that said they will return DHO900 because it is so full of bugs and problems that he has no patience for it and at this point does not consider it a finished product. And he has many Rigol products. He said that at this point if he had to do some work he would use DS1000Z. He said he might reconsider it in a year or so if they fix at least majority of problems....

That is your situation today.. Or shall we lie to people ?
No. I prefer constructive way where we unearth all the problems and force Rigol to fix them if they want to sell their stuff.
A win for my fellow prospective Rigol owners...
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 11, 2023, 09:35:21 pm
I know of one person here that said they will return DHO900 because it is so full of bugs and problems that he has no patience for it and at this point does not consider it a finished product. And he has many Rigol products. He said that at this point if he had to do some work he would use DS1000Z. He said he might reconsider it in a year or so if they fix at least majority of problems....

That was TurboTom in post #25, right? While I found his observations most helpful, the only major criticism he had was that intensity grading looked very disappointing in the measurements he took. (While quite decent results were shown shortly after by Martin72.) So I found his conclusion "I'll probably return that scope" rather unexpected.

Otherwise, I fully agree with you. Let's put all the critical findings on the table and "encourage" Rigol to fix them -- which they should be able to do since all of them so far seem software-related.

This is not meant to be a "Rigol sales pitch" thread, after all. Although it would help if the Siglent salesman could tone it down too.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 11, 2023, 09:45:16 pm
Quote
This is not meant to be a "Rigol sales pitch" thread

This is not what I had in mind with this thread either.... ;)
Apropos, perhaps I should change the title / expand to the 900 model, even if I do not have it.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: TimFox on October 11, 2023, 09:57:10 pm
Is there a contact at Rigol that reads unsolicited bug reports?
I sent an e-mail a few days ago, with no reply.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: TurboTom on October 11, 2023, 10:02:55 pm
Most likely @2N3055 was referring to me. I've posted several findings in the "bugs" and "Bode Plot" threads that weigh in much heavier for me. Basically, the Bode Plot function isn't usable as-is and my take is that Rigol will still need a year to get it right if they prioritize it. I've got an audio project that I want to get done and I basically considered the DHO914S for its stand-alone Bode plot function which basically isn't there. So for that reason, I'll very likely return it -- not for its mediocre intensity grading. While I've got the scope here, I do all the tests that come to my mind and throw all sorts of signals at it and report my findings, my own errors, what's nice and also what's not so much...

And I hope others may find this information helpful for deciding if this scope may be worth getting.

For my own part, as I reported, most of my negative findings would be tolerable since I know I'm just evaluating an entry level scope -- except for the Bode plot failure, which is a show stopper for me. There are many nice and interesting details and features, and I made my own share of errors (suspecting the Scope's ADC for causing a spur in the signal while it was sampling clock feed-trough of the AWG along with a too long, improperly terminated BNC cable that basically caused the spur) that I also report -- somebody may learn from them.

Following all this information is somewhat troublesome since there are at least four threads that directly deal with findings on this new insturment. I guess this may have added its share to the confusion  ;).
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 11, 2023, 10:04:40 pm
Hi Tim,

Maybe you can try this here:

info-europe@rigol.com

During the time I had the MSO5074, I was in contact with them almost every week and I was also almost always answered quite quickly.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: tautech on October 11, 2023, 11:03:05 pm
@2N3055:

Here an example when you want to have the measures in a window (they´re also on the right side of the screen, but hiding).

I like the one on the bottom. That one is quite OK..
Even though just 5 lines of statistics eat half of the display ?  :-//

I'm not comparing with my scopes that have several display modes and many other details not present here.
I still prefer Siglent measurements that are much more powerful implementation (I refuse to buy any scope without histicons ever again).

It is not perfect.. For instance in this table there is no P-P stat..
But it is actually usable (compared to the vertical table on the right it is much better)..
Lets say we wanted stats on just 1 measurement as we sometimes do.
Will half the display still be wasted ?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: rpro on October 12, 2023, 12:09:36 am
On my DHO804, using your parameters (20us/ timebase, 1.25GSa/s) the noise of the 1V/div stopped 50ohm capped signal I can measure (as std-deviation or AC-RMS) is 9.5mV at 20mv/div, 1.1mV at 2mV/div and 260uV at 500uV/div.

I understood from Dave's review video that the scope will not actually "zoom in" any further below 20 mV/div, although it claims to change the vertical scale. Are the 2mV and 500µV values really meaningful, or did I misunderstand?

Not meaningful and most probably wrong. The given numbers must be computed using some decimation scheme, as pointed out by @2N3055, but they do not seem to come from the screen data either. The shown waveform does change as expected from 50mV/div to 20mV/div, but then too little from 20mV/div to 10mV/div, and not any further with lower mV/div. The measurements, given by the scope, are as reported.

Title: Re: Rigol DHO804 Test and Compare Thread
Post by: UK on October 12, 2023, 05:50:16 am
During the time I had the MSO5074
Can you give us some of your personal pros/cons for comparison of MSO5000 and DHO800/900?
I'm also wondering why u decided to get this new DHO, because of the smaller size or fancy 12-bit resolution?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 12, 2023, 10:13:37 am
Lets say we wanted stats on just 1 measurement as we sometimes do.
Will half the display still be wasted ?

No, of course not.

There's a pop-out side panel with measurements on it. Any measurement can be expanded to see stats by clicking the arrow at the bottom of the measurement.

You can see Dave opening/closing the pop-out here:
https://youtu.be/S8jrpCoZyx8?t=1718 (https://youtu.be/S8jrpCoZyx8?t=1718)

He has the stats unfolded on Vpp here:
(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1897539;image)

Notice how much faster/easier it is to do than menu diving and using a twisty knob to turn things on/off.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: csuhi17 on October 12, 2023, 10:34:30 am
On my DHO804, using your parameters (20us/ timebase, 1.25GSa/s) the noise of the 1V/div stopped 50ohm capped signal I can measure (as std-deviation or AC-RMS) is 9.5mV at 20mv/div, 1.1mV at 2mV/div and 260uV at 500uV/div.

I understood from Dave's review video that the scope will not actually "zoom in" any further below 20 mV/div, although it claims to change the vertical scale. Are the 2mV and 500µV values really meaningful, or did I misunderstand?

From the datasheet.
[4]: 500 μV/div is a magnification of 1 mV/div setting. For vertical accuracy calculations, use full scale of 8 mV.

Maybe so that you can enlarge the small display better.

I don't know exactly how it works, but doesn't 12bit mean that at 1mV/div, that is, 8mV/4098 = 1.95uV, the smallest voltage difference that the scope still detects?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 12, 2023, 10:36:33 am
I just noticed that the DHO1000/4000 do the sidebar much better:
(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1897551;image)

I wonder why that is? It surely can't be just because of the screen size. The DHO800 sidebar looks like it has enough room.

(and I'd trade another dozen pixels of horizontal space for more measurements...)

I wonder if that can be hacked... maybe there's a boolean that controls it in the firmware ???
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 12, 2023, 10:49:06 am
People want to know does it work, how it works etc.

But nobody has commented on that yet.

eg. How's the UI compared to old twisty-knob UIs?

I'm guessing it must be really good if it manages to go unnoticed and uncommented - just like the windowing that everybody ignored.

Would you go back to twisty knobs after using one of these for a week?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 12, 2023, 10:52:46 am
I understood from Dave's review video that the scope will not actually "zoom in" any further below 20 mV/div, although it claims to change the vertical scale. Are the 2mV and 500µV values really meaningful, or did I misunderstand?

From the datasheet.
[4]: 500 μV/div is a magnification of 1 mV/div setting. For vertical accuracy calculations, use full scale of 8 mV.

Thanks. But what I was referring to is the limited ability to zoom in after taking a measurement at a larger vertical scale, then stopping it. There seems to be a bug where the DHO lets you select sensitivities beyond 20 mV/div, but does not actually magnify the trace accordingly.

Quote
I don't know exactly how it works, but doesn't 12bit mean that at 1mV/div, that is, 8mV/4098 = 1.95uV, the smallest voltage difference that the scope still detects?

In theory, yes. But in reality there will be analog noise which limits what you can actually distinguish. The "effective number of bits" (ENOB) will be less than 12. -- Also, with a smaller effect: The scope will have some "headroom" when sampling the data, so mapping the 4096 counts to 10 divisions (of 1 mV each) is probably the right starting point in your example.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: TurboTom on October 12, 2023, 12:10:47 pm
The properly working vertical zoom range of the DHO800/900 series covers five vertical increments (regardless at what sensitivity you start at), i.e. depending on the start position, a vertical magnification factor of 40 or 50 results. Indicative for this is that amplitude measurements (as long as the signal doesn't get clipped by the visible screen area) stay accurate almost to the last decimal digit. A sixth zoom increment may provide some further enlargement of the signal, but it's not as per the specified scale factor.

My take of the sampling/display engine's working model is like this: The signal is digitized into the sampling memory at 12bits words. The signal "window" to be displayed on the screen is then transfered/decimated to a shadow memory with 6 bits of headroom, LSB aligned (maybe only 10bits of the ADC data get transfered into a 16bit wide shadow memory, flushing the two least significant ADC bits). This leaves the upper six bits free for scaling. Measurements are taken from this shadow memory and not from the screen directly (hence the pretty accurate results as long as the scaling factor doesn't exceed 5 increments). If the acquisition engine is stopped and the user zooms into the signal, the contents of the shadow memory is scaled by utilizing the "upper" six bits which results in a maximum scaling factor of 64, of which up to 50x is useful.

Rigol now implemented the "nonsense" to scale during the sixth increment to the maximum possible 64x (which must not be exceeded otherwise data would get lost and loss-less zooming back out wouldn't be possible anymore). Further increments obviously won't permit to zoom in anymore.

Rigol may have to face the question why they permitted to zoom in beyond the "scaleable range" in stop mode, but the answer isn't that simple: The user may want to continue acquisition at a higher sensitivity, and since "display factor" and input attenuator / amplifier setting are adjusted with the same knob (even though they have a completely different effect on signal processing), the discrepancy between the two figures comes into existance.

My approach (and suggestion to Rigol) would be the following:

Either: Do away with the "in-between" zoom factor of 64x completely (sixth increment). This only causes confusion. When exceeding the five zoom increments in stop mode, show a small information banner in the corner of the screen that tells that display and input factor are no longer synchronous (Gain Factor Mismatch) -- maybe show it only temporarily in the middle of the waveform screen after changing the vertical sensitivity. If this mismatch situation is present, disable all amplitude measurements.

Or: Use a wider shadow memory to be able to scale the contents over the full vertical zoom range. Yet, this may affect responsiveness of the U/I or may even be completely impossible due to hardware resource limitations.

Either approach should pretty much solve the problem that apparently confused so many users.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 12, 2023, 12:18:40 pm
People want to know does it work, how it works etc.

But nobody has commented on that yet.

eg. How's the UI compared to old twisty-knob UIs?

I'm guessing it must be really good if it manages to go unnoticed and uncommented - just like the windowing that everybody ignored.

Would you go back to twisty knobs after using one of these for a week?

Since you are asking for it: I personally would rather use DS1000Z U/I than Touchscreen on 7" screen.
Why? Because it is too small. I can't see a thing and my fingers are too big.

I hate touchphones for same reasons..

I personally think that 10" is smallest usable screen size on touchscreen scope..
And additional data point, I have 8,5" touchscreen Keysight. It is barely usable, you need to press for the menu in very corner, with a nail. Only thing that is usable is virtual keyboard and zone trigger (and that one is fiddly).
And all the screen elements are larger than on Rigol with smaller screen.

There you are, your answer.

Of course, that is me. Someone with Superman's vision and small fingers might think 7" is just fine.
You will see when you get it. You will be able to use it. It just won't be comfortable and will be fiddly.
Don't expect it to be as good as Micsig. Probably even HDO1000/4000 with bigger screen,at this stage of development does not have touch as well made as for instance Micsig that is something you are familiar with. Micsig has been doing it for a long time now. Rigol still has to learn all the details of how it's done. And no, you can't just hire phone app GUI developers. First, phone GUIs are not that good benchmark anyways and pattern usage on a scope is vastly different.
Devil is in details...

Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 12, 2023, 12:23:25 pm
I understood from Dave's review video that the scope will not actually "zoom in" any further below 20 mV/div, although it claims to change the vertical scale. Are the 2mV and 500µV values really meaningful, or did I misunderstand?

From the datasheet.
[4]: 500 μV/div is a magnification of 1 mV/div setting. For vertical accuracy calculations, use full scale of 8 mV.

Thanks. But what I was referring to is the limited ability to zoom in after taking a measurement at a larger vertical scale, then stopping it. There seems to be a bug where the DHO lets you select sensitivities beyond 20 mV/div, but does not actually magnify the trace accordingly.

Quote
I don't know exactly how it works, but doesn't 12bit mean that at 1mV/div, that is, 8mV/4098 = 1.95uV, the smallest voltage difference that the scope still detects?

In theory, yes. But in reality there will be analog noise which limits what you can actually distinguish. The "effective number of bits" (ENOB) will be less than 12. -- Also, with a smaller effect: The scope will have some "headroom" when sampling the data, so mapping the 4096 counts to 10 divisions (of 1 mV each) is probably the right starting point in your example.

ENOB is declared as >8bits  in datasheet, whatever that means.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 12, 2023, 12:25:38 pm
ENOB is declared as >8bits  in datasheet, whatever that means.

"We promise this is better than our 8-bit scopes."  :P
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 12, 2023, 01:15:33 pm
Why? Because it is too small. I can't see a thing and my fingers are too big.

Of course, that is me. Someone with Superman's vision and small fingers might think 7" is just fine.

I guess I'm superman. My Windows laptop is 10" touch screen and I'm very happy with it.

Have you tried a stylus or a mouse? I use a stylus with my laptop (or tip of my fingernail if I have to hit something small and don't have the stylus in my hand).

nb. The laptop has the usual trackpad below the keyboard but I never touch it. Ever.


I personally think that 10" is smallest usable screen size on touchscreen scope..

You have the option of an external screen of any size you want. Screens are cheap these days. You can get an 11" touch screen for $100 or 15" for $150.

Or use a non-touch screen with a mouse.

I hate touchphones for same reasons..

Yet most of the world loves them.

You will see when you get it. You will be able to use it. It just won't be comfortable and will be fiddly.

We'll see when it arrives tomorrow.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 12, 2023, 01:19:38 pm
ENOB is declared as >8bits  in datasheet, whatever that means.

8-bit 'scopes will have <8 ENOB so >8 is a big improvement.  :-+

FWIW: Noise and ENOB is one thing I haven't seen people complaining about so far.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 12, 2023, 01:39:03 pm
Why? Because it is too small. I can't see a thing and my fingers are too big.

Of course, that is me. Someone with Superman's vision and small fingers might think 7" is just fine.

I guess I'm superman. My Windows laptop is 10" touch screen and I'm very happy with it.

Have you tried a stylus or a mouse? I use a stylus with my laptop (or tip of my fingernail if I have to hit something small and don't have the stylus in my hand).

nb. The laptop has the usual trackpad below the keyboard but I never touch it. Ever.


I personally think that 10" is smallest usable screen size on touchscreen scope..

You have the option of an external screen of any size you want. Screens are cheap these days. You can get an 11" touch screen for $100 or 15" for $150.

Or use a non-touch screen with a mouse.

I hate touchphones for same reasons..

Yet most of the world loves them.

To first 2 comments: I NEVER learn to live with stupid things and never find ways to justify why I'm suffering.
If something is frustrating me I try to solve it instead of coping..
If possible I  simply save for few more months and just buy a thing that will be joy to use instead of never ending source of frustration..
That is my hard learned life lesson.

And to 3rd, no, world does not love them. Many people hate them, use them in very limited ways, and are endlessly frustrated with how stupidly they are made.. It is just that we have no choice anymore...

Title: Re: Rigol DHO804 Test and Compare Thread
Post by: csuhi17 on October 12, 2023, 02:05:30 pm
thank you for your answers, I have learned a few things.

The small display is not a problem for me, I will use it with a higher resolution external monitor on the table.  on the other hand, the fact that the windows cannot be resized affects me unpleasantly, I hope the updates will solve it. 

The question is, if you open several windows on the external high-resolution monitor, will the scope's image freeze, crack or affect its operation.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 12, 2023, 02:19:48 pm
To first 2 comments: I NEVER learn to live with stupid things and never find ways to justify why I'm suffering.
If something is frustrating me I try to solve it instead of coping..
If possible I  simply save for few more months and just buy a thing that will be joy to use instead of never ending source of frustration..
That is my hard learned life lesson.

And to 3rd, no, world does not love them. Many people hate them, use them in very limited ways, and are endlessly frustrated with how stupidly they are made.. It is just that we have no choice anymore...

No need to go all fundamentalist here... For phones, where "small" is one of the key requirements, I think touch screens are a great interface choice to make all the functionality accessible. And I am prepared to live with a certain degree of fumbling, even though I struggle with the little on-screen keyboard, because "small" is important for me in this context.

For oscilloscopes, the jury is still out (for me personally) whether 7" is still OK for a touch screen or too small. I want an easily transportable, compact scope, hence am prepared to accept some compromises. But maybe the DHO800/900 series are pushing things too far: When I use the scope, I tend to spend significant time interacting with it and looking at details on the screen... And there are other prices to pay for the small form factor too: small knobs and a small fan which is apparently a bit whiny.

I was (and still am) hoping that this could be my next hobbyist scope and cover the use cases of both, bench and travel use -- maybe with an external touch monitor on the bench. I guess I'll have to find an opportunity to try one of these hands-on to make up my mind.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: nctnico on October 12, 2023, 02:21:41 pm
thank you for your answers, I have learned a few things.

The small display is not a problem for me, I will use it with a higher resolution external monitor on the table.  on the other hand, the fact that the windows cannot be resized affects me unpleasantly, I hope the updates will solve it. 

The question is, if you open several windows on the external high-resolution monitor, will the scope's image freeze, crack or affect its operation.
I doubt you will be getting more work space. From what I have gathered so far it looks like the screen is rendered using the 3D GPU so it is easy to just scale it up/down to any resolution but the relative size of the elements will stay the same. IOW: on a bigger screen you'll get fatter lines and bigger text.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 12, 2023, 02:24:21 pm
ENOB is declared as >8bits  in datasheet, whatever that means.

8-bit 'scopes will have <8 ENOB so >8 is a big improvement.  :-+

FWIW: Noise and ENOB is one thing I haven't seen people complaining about so far.

Nobody actually tested any of the claims... Wait for it... I don't actually expect any large surprises but until it is properly tested....
If you look at all the problems it is obvious not even Rigol did full characterization. Other manufacturers will actually state ENOB to 0.1 dB accuracy, and it will be different for same scope with different BW...

To explain: We weren't making fun of ENOB magnitude, but fact that they didn't even specify it to any sensible degree.  And that specification is SAME for all DHO scopes (7 and 10" ones). I'm pretty much sure that DHO800 with 70MHz BW should have better ENOB than 800MHZ DHO4000.. Because physics...
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 12, 2023, 02:41:27 pm
To first 2 comments: I NEVER learn to live with stupid things and never find ways to justify why I'm suffering.
If something is frustrating me I try to solve it instead of coping..
If possible I  simply save for few more months and just buy a thing that will be joy to use instead of never ending source of frustration..
That is my hard learned life lesson.

And to 3rd, no, world does not love them. Many people hate them, use them in very limited ways, and are endlessly frustrated with how stupidly they are made.. It is just that we have no choice anymore...

No need to go all fundamentalist here... For phones, where "small" is one of the key requirements, I think touch screens are a great interface choice to make all the functionality accessible. And I am prepared to live with a certain degree of fumbling, even though I struggle with the little on-screen keyboard, because "small" is important for me in this context.

I'm not, just responding to mass generalization by our friend here.

I also (like I said) use smartphone a one of the important tools. And like you understand necessity.  But that doesn't detract from fact that phones nowadays (mainly because of featurism and some kind of fashion of a sorts) have no place to hold them (screen is actually going over the edge), they are too thin sometimes and most of them are as slippery as a fish. Screens have higher and higher resolution so screen elements get smaller so the can cram more "cool look" stuff.
Etc etc.. They are increasingly morphing into something that is not optimized for any kind of use...

And while I can understand it is a chicken/egg problem (users demand more of stuff they were conditioned to want instead of utility) and can understand that for a consumer device it might be acceptable.

But measurement devices are different. They need to be utilitarian.

Yes, I would strongly advise trying one first.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: UK on October 12, 2023, 02:43:52 pm
I just noticed that the DHO1000/4000 do the sidebar much better:
(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1897551;image)

I wonder why that is? It surely can't be just because of the screen size. The DHO800 sidebar looks like it has enough room.

(and I'd trade another dozen pixels of horizontal space for more measurements...)

I wonder if that can be hacked... maybe there's a boolean that controls it in the firmware ???

I'm also curious about changing HDMI resolution after activation test mode. On its higher settings of 1080p will the scope UI resize properly to get closer to DHO1000/4000 or stay the same and just scale up proportionally?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 12, 2023, 03:04:47 pm
I'm also curious about changing HDMI resolution after activation test mode. On its higher settings of 1080p will the scope UI resize properly to get closer to DHO1000/4000 or stay the same and just scale up proportionally?

Not sure what you mean by "activation test mode". But when an external monitor is connected, the screen content does not appear to be any different from the internal screen -- although it is rendered with more pixels, and apparently rendered "properly", not by upscaling the pixelated 7" picture.

You can see a bit of that in Dave's review video. Even the relative portion of the vertical screen real estate which is taken by the settings displays (and touch buttons) at the top and bottom remains the same. Which is a pity -- these take a somewhat large portion of the 7" screen, and have to in order to be properly "touchable". But they could be relatively smaller on a larger external screen, leaving more room for the curve display.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: dmulligan on October 12, 2023, 03:05:37 pm
I'm wondering if the HDMI display can be used for different windows and information than is being shown on the main display.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 12, 2023, 03:07:10 pm
The question is, if you open several windows on the external high-resolution monitor, will the scope's image freeze, crack or affect its operation.

The external monitor will make no difference to that. It's the exact same UI and content but bigger.

I'm wondering if the HDMI display can be used for different windows and information than is being shown on the main display.

No.

I'm also curious about changing HDMI resolution after activation test mode. On its higher settings of 1080p will the scope UI resize properly to get closer to DHO1000/4000 or stay the same and just scale up proportionally?

From what's been reported so far it seems to show the same content as the main screen but it uses properly scaled fonts and graphics in the UI so it doesn't pixellate.

The part the shows the oscilloscope traces, OTOH, is just an upscale.

ie. There's nothing extra. It's useful for people with less-than-perfect eyesight and for boardroom presentations, that's it.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: UK on October 12, 2023, 03:22:03 pm
From what's been reported so far it seems to show the same content as the main screen but it uses properly scaled fonts and graphics in the UI so it doesn't pixellate.

The part the shows the oscilloscope traces, OTOH, is just an upscale.

ie. There's nothing extra. .

My dream just got broke...

But since it has an android I'm 100% ensure that DHO800/900 utilizes the same UI framework as DHO1000/4000 with just another scale ratio. So I hope in the near future someone brings us this option to change the UI scale ratio.

Maybe I should request this in the hack thread.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 12, 2023, 03:30:08 pm
My dream just got broke...

Well, if the fonts and the touch buttons on the 7" screen are a bit small for your taste, you could still add an external touch screen to make them more accesible. (And when you travel with the scope, be happy about the scope's small form factor and live with the screen size compromise.)

I am considering a 14" touch screen on the bench, or VESA-mounted above the bench, for that reason.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 12, 2023, 03:31:27 pm
Don't expect it to be as good as Micsig. Probably even HDO1000/4000 with bigger screen,at this stage of development does not have touch as well made as for instance Micsig that is something you are familiar with. Micsig has been doing it for a long time now. Rigol still has to learn all the details of how it's done.

We'll see.

It's true that Micsig does some things in a particular way that would horrify an engineer but in practice work well enough once you realize that you don't NEED perfect accuracy for most things.

Micsig also has the "fine" buttons at the bottom that let you make single pixel adjustments to the last thing you touched (switching between up/down and left/right depending on what it was). Maybe I'll miss those.

Examples of "weirdness":

a) Input of cutoff frequency for the low pass filter. You have a slider and two buttons to select either "MHz" (digits before the decimal point) and "kHz" (digits after the decimal point) and "+/-" for single digit tweaks. There's no option to type in a number.

Entering a very precise number like (1.75Mhz) can be done but it's a pain in the ass and do you really need that precision? Answer: No. The difference on screen between 1.6Mhz and 1.9Mhz will be half a bee's dick.

(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1897713;image)


b) How about this one for entering the pulse width for triggering? You have a logarithmic scale at the bottom that you can drag with your finger and a fine tuning slider above it which you can drag left/right. Again: NO option to type in a number.

Engineers will be horrified that you can't type in a number and that everything has to be done with fingers but in practice it's easy, it's fast and it gets the job done. The logarithmic scale maps very well to what you actually need from this trigger mode.

(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1897719;image)

Would either of those have made it past an initial design meeting at a big corporation? Probably not ... they'd want an input box and an on-screen numeric keypad for entering precise numbers.

Micsig? They did it their way.  :)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Njk on October 12, 2023, 03:48:33 pm
From the images here I've a feeling that the effective screen size is actually smaller. If anyone measured the size of the waveform drawing area to compare it with that in DS1000Z?
Edit: in metric units, not in pixels
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 12, 2023, 05:43:52 pm
Hi,
Measured the DS1054Z today at work..
"Usable" values:

Rigol DS1054Z: Width: 115mm / Height : 70mm /Diagonal: 135mm
Rigol DHO804:  Width: 150mm / Height: 60mm / Diagonal : 160mm

This is probably called an optical illusion. ;)

Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 12, 2023, 06:05:23 pm
Hi,
Measured the DS1054Z today at work..
"Usable" values:

Rigol DS1054Z: Width: 115mm / Height : 70mm /Diagonal: 135mm
Rigol DHO804:  Width: 150mm / Height: 60mm / Diagonal : 160mm

This is probably called an optical illusion. ;)

That's about what I expected - DHO is wider because there's no side menus but vertical is less because the bars at top/bottom are bigger.

The DHOs have 12% more overall area... but really it's a toss-up because vertical is arguably more important than horizontal.

OTOH the DHOs have nearly twice as many vertical pixels so they easily win in terms of information displayed.

Edit: Not true, they only have 25% more vertical pixels (600, not 800 as I thought)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: TurboTom on October 12, 2023, 07:00:10 pm
Interesting find -- the DHO900 (and probably the 800 as well) invokes automatic boxcar averaging if the sampling rate/sample memory combination is lower than the speed the physical sampling engine is running at. I recorded a "null" signal (input terminated 50 Ohms) into a 1kSa buffer at 1V/Div and maximum sample rate. Then I exported the buffer via CSV and visualized it via a spreadsheet program since this way, I've been able to retrieve sample data and won't get confused by the sinx/x interpolation.

The bin spacing clearly shows that we've got 4096 bins (12 bit) of sample depth and an input range at the 1V/Div sensitivity setting of ~9.5Vpp, so in total approx. 0.75 vertical divisions beyond the visible screen range.

After that, I changed the time base to result in a sampling rate of 100kSa/s and did the same test -- this time observing a much closer bin spacing which is somewhat more difficult to analyze, but it appears now we've got close to 20500 bins (~14.3 bit) of resolution.

So the arrangement of the shadow memory has got to be much more complex than I initially assumed here https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/msg5108949/#msg5108949 (https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/msg5108949/#msg5108949). Probably the shadow memory is much wider and the 12-bit wide sampling memory area to be displayed gets copied/added at a certain position to result in the actual / decimated sample rate that's selected. This way, the boxcar averaging happens more or less automatically and virtually doesn't take any additional time, at least if it's done in multiples of 2.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Njk on October 12, 2023, 07:00:57 pm
Hi,
Measured the DS1054Z today at work..
"Usable" values:

Rigol DS1054Z: Width: 115mm / Height : 70mm /Diagonal: 135mm
Rigol DHO804:  Width: 150mm / Height: 60mm / Diagonal : 160mm

This is probably called an optical illusion. ;)

Hi Martin,
Thanks for the data. So my illusion is proven correct. It is vertically smaller. Although TV-like "aspect ratio". OHOH I have old analog scope where the screen is of 42x60mm. No problem. But it's true CRT
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: TurboTom on October 12, 2023, 07:19:33 pm

...
That's about what I expected - DHO is wider because there's no side menus but vertical is less because the bars at top/bottom are bigger.

The DHOs have 12% more overall area... but really it's a toss-up because vertical is arguably more important than horizontal.

OTOH the DHOs have nearly twice as many vertical pixels so they easily win in terms of information displayed.

DS1000Z: 800 x 480
DHO800 / 900: 1024 x 600

This is 25% more vertical resolution than the DS1000Z, which easily explains the somewhat crowded appearance of the DHO800 / 900's screen vs. the DHO1000 / 4000 series...
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 12, 2023, 07:55:19 pm
There's a pop-out side panel with measurements on it. Any measurement can be expanded to see stats by clicking the arrow at the bottom of the measurement.
Notice how much faster/easier it is to do than menu diving and using a twisty knob to turn things on/off.

Seconds counts.. ;)
Yes, that's not bad - But it would only be consistent if you could add several parameters once you have already activated the measuring panel.
This is not possible, you always have to call the measuring menu for each new parameter.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: nctnico on October 12, 2023, 08:22:17 pm

...
That's about what I expected - DHO is wider because there's no side menus but vertical is less because the bars at top/bottom are bigger.

The DHOs have 12% more overall area... but really it's a toss-up because vertical is arguably more important than horizontal.

OTOH the DHOs have nearly twice as many vertical pixels so they easily win in terms of information displayed.

DS1000Z: 800 x 480
DHO800 / 900: 1024 x 600

This is 25% more vertical resolution than the DS1000Z, which easily explains the somewhat crowded appearance of the DHO800 / 900's screen vs. the DHO1000 / 4000 series...
Resolution doesn't matter. Screen size does. A higher resolution (as in smaller dot size) gives a nicer image though. In some of my own projects that need a nice graphic interface I choose a display with a higher resolution so the UI is prettier to look at.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 12, 2023, 08:32:20 pm
Last play before it´s getting serious... ;)

Testing the decodings...
With the batronix board, RS232, SPI and I²C.
First the positive:
The table, I love how clearly you can see the values through the white/gray, that's a real benefit, I'd love to see it on my Siglent too.
Definitely a plus point.
And:
You can move the decoded values up/down (see RS232 and 232_1), very nice to make it better visible.
Then less great:
The menu...You go in via the selection button at the bottom left of the screen, so far so good.
But as soon as the decoder menu is hidden, you have to go the same way again, there is no dedicated button for it.
Also, the equipment for the respective decoders is rather sparse, as with the FFT.
And there is no copy to trigger function, only the other way around.
And I kept falling for the "Roll Mode" earlier:
Default is from 50ms/div the roll mode active, I find not bad.
However, one is then immediately thrown out of the decoding and rigorously:
No warning, it is simply deactivated and you have to reactivate it.
SPI and RS232 were easy to set, with I²C it is a bit more difficult, you can't get a halfway stable trigger.
But I'll deal with it more deeply when I test the demo board completely on the Rigol.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 12, 2023, 08:34:58 pm
Resolution doesn't matter. Screen size does. A higher resolution (as in smaller dot size) gives a nicer image though. In some of my own projects that need a nice graphic interface I choose a display with a higher resolution so the UI is prettier to look at.

And it really is, it just looks better and sharper than the other 7" scopes I know.
The same effect can be seen on the 10" models, it just looks better, so the UI.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: tv84 on October 12, 2023, 08:59:10 pm
Resolution doesn't matter. Screen size does. A higher resolution (as in smaller dot size) gives a nicer image though. In some of my own projects that need a nice graphic interface I choose a display with a higher resolution so the UI is prettier to look at.

And it really is, it just looks better and sharper than the other 7" scopes I know.
The same effect can be seen on the 10" models, it just looks better, so the UI.

Sincerely I have an hard time swallowing these DHO pictures. The menus seem rendered in 4K but the signal looks like Minecraft.  ???

Well, maybe it's just me..  :-//
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 12, 2023, 09:01:55 pm
DS1000Z: 800 x 480
DHO800 / 900: 1024 x 600

My bad, I thought it was 800 pixels vertical.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 12, 2023, 09:21:43 pm
Sincerely I have an hard time swallowing these DHO pictures. The menus seem rendered in 4K but the signal looks like Minecraft.  ???
Well, maybe it's just me..  :-//

No. ;)
I see it exactly the same way.
The presentation of the graphical elements benefits a lot from it, everything just looks sharper/better.
But the actual signal does not benefit from it.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 12, 2023, 09:26:02 pm
No. ;)
I see it exactly the same way.
The presentation of the graphical elements benefits a lot from it, everything just looks sharper/better.
But the actual signal does not benefit from it.

The UI graphics and text are scaled vectors, they can be antialiased.

The traces aren't, they can't.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 12, 2023, 09:35:20 pm
This does not change the fact that it is visually striking.
But that's not a big minus point now.
I have now ordered USB adapter, A/B.
This gets on my nerves, this eternal swap because only one port A is available.

Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 12, 2023, 09:40:55 pm
Can you give us some of your personal pros/cons for comparison of MSO5000 and DHO800/900?
I'm also wondering why u decided to get this new DHO, because of the smaller size or fancy 12-bit resolution?

Just out of curiosity, that alone is worth it to me. 8)
I don't like to talk about things I don't know.
I think a comparison to the MSO5074 is still premature, I'll comment on that when I've tested more.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 12, 2023, 09:50:07 pm
Sincerely I have an hard time swallowing these DHO pictures. The menus seem rendered in 4K but the signal looks like Minecraft.  ???

Maybe Android will let you install crude bitmap fonts to make the display look more familiar. ;)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 12, 2023, 10:33:16 pm
Sincerely I have an hard time swallowing these DHO pictures. The menus seem rendered in 4K but the signal looks like Minecraft.  ???

Maybe Android will let you install crude bitmap fonts to make the display look more familiar. ;)

First of all, I know you're joking, but made me want to comment.. I know, shocker, right...  :-DD

"Crude" fonts relay same information as super high resolution anti-aliased fonts.

Fonts on very low resolution screen on MSOX3000T are very easy to read and clear. It is waveform that is thick and even that is looking quite good when you enable HiRes. And that is 800x480 pixel 8.5"screen.

All of that is nice but is irrelevant, same as watching some really stupid movie on super hi res 8K screen. Still stupid movie not worth watching. There are many movies I would rather watch on VHS than really bad movie on super resolution.
Race car won't go faster if you paint racing stripes on it... Or coolest painting imaginable...

Super high resolution and/or large screen does not provide more information... It simply presents opportunity to  provide more.
If more information is provided depends on how it is used. Large thick window edges take space, taskbars, icons etc..
And then it is matter of organizing info and how it is presented. etc etc..

Fonts cannot be too small, either.. Scope is not a phone so you stick it in your face. Scope is used at arm's length on a desk, or on a shelf... Physical font size of cca 3mm on the screen is smallest you can comfortably read..
And that is for a person with OK eyesight.  We need to include people that does not have perfect eyesight.
As a side note, on latest FW, SDS2000X HD can change font size for that reason. Some other scopes do that too.

I prefer that scope should minimize usage of screen for anything that is not related to waveforms, or other useful data..
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 12, 2023, 10:42:30 pm
Quote
I prefer that scope should minimize usage of screen for anything that is not related to waveforms, or other useful data..

I would also like to have this with my Siglent. ;)
As with Windows, for example.
Fades out after a few seconds, is back again at the touch of a finger/mouse.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: tautech on October 12, 2023, 11:42:49 pm
Quote
I prefer that scope should minimize usage of screen for anything that is not related to waveforms, or other useful data..

I would also like to have this with my Siglent. ;)
As with Windows, for example.
Fades out after a few seconds, is back again at the touch of a finger/mouse.
Menu fade/hide is a 2 edged sword especially when set to a fast hide as it's often gone before you can take a screenshot.  :horse:
We disable menu hide before dispatch so new users don't have it disappear while finding their way around a new DSO.
Later when they are conversant with the UI and featureset they can easily re-enable menu hide or just continue to touch or click a vacant area on the display to hide it.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 13, 2023, 01:41:38 am
We disable menu hide before dispatch so new users don't have it disappear while finding their way around a new DSO.

They enable it by default?  :palm:
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 13, 2023, 06:18:50 am
I prefer that scope should minimize usage of screen for anything that is not related to waveforms, or other useful data..

I certainly agree that any additional screen detail should (a) not waste space, and (b) not distract from the data and curves. But I don't think Rigol have done too much of that with the DHO800. My first reaction to seeing screenshots from the DHO800 was indeed "They have gone a bit overboard with the decorations". But having looked closer, I don't think so:

The height of the settings displays at the top and bottom of the screen is determined by the need to provide large-enough touch areas there. (And yes, they take up a relatively large part of the small screen.) Given that height requirement, I think Rigol have done a nice job packing useful information into these areas and structuring it well -- and in a way that does not disctract from the net content.

Regarding the anti-aliased, nice-looking fonts: Why not? The screen resolution and grading capability is there anyway (driven by the need to display information-rich curves), so anti-aliased fonts come for free. They do not take up more space than crude bitmap fonts in lower resolution, and they do make the information easier to read.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: tautech on October 13, 2023, 06:44:33 am
We disable menu hide before dispatch so new users don't have it disappear while finding their way around a new DSO.

They enable it by default?  :palm:
Enabling menu hide is what experienced users need as it saves considerable time however it's a suboptimal choice for the new user of a scope.
However when I brought it to Siglents attention they rightly changed the default setting in later firmware.

Still we have 5 auto hide settings from 3-60s before the menu auto hides or we can leave OFF to be hidden manually with a touch or click of a mouse.
Much depends on how you want to use the scope and the range of options for how the menu interacts with the display where it can float over the display or be embedded and compress the active display.

Choices are good and the more the better.
Edit to add better images.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 13, 2023, 10:24:51 am
Regarding the anti-aliased, nice-looking fonts: Why not? The screen resolution and grading capability is there anyway (driven by the need to display information-rich curves), so anti-aliased fonts come for free. They do not take up more space than crude bitmap fonts in lower resolution, and they do make the information easier to read.

To make it clear I don't mind if things are "prettier"... I'm a geek too and like "cool looking" design.
But I'll take "blocky fonts" and 4 math channels any day over scope that is "cool looking" but has 1 math channel with only +/- operations...
But I don't mind blocky (retro looking) fonts either if they do the job..

I see people getting downright giddy how cool it looks and not even noticing when it is missing basic features...
Form over substance and utility.

And that is fine if I need a movie prop... 

But all I see that super high resolution, anti aliased, fully graphically designed display of screen elements was given priority over waveform update rate.. Phosphorus emulation is worse than DS1000Z and WFMs/s also...
Useless segmented mode is only made for screen display... Etc... Whole purpose of segmented mode is to capture bunch of data blocks with minimum blind time and analyze it (measurements, decode) later. Without that, it has same analytic capabilities as DS1000Z that also had same useless "Recording mode".

To explain it further, while working with a scope I was in a situation where I did say: "darn, if this screen was taller (physically, as in 20cm instead of 14cm) so I can fit 20 decode lines instead of 10 I have now, I would do this job better, faster or whatnot".
Never, ever, I was in a situation that I said : "man, if only these menus were prettier and fonts were nicer looking, I would be able to measure more data at the same time"...

To summarize, I'm not against "cool" and sophisticatedly looking GUI. I'm against that being replacement for actual capabilities.

If you ask me, Rigol should have pushed for 10" screens even with lower resolution than they have now (to make it cheap enough to make to keep the product price range), not use use panoramic display ratio and therefore provide larger screen real estate to show information, even if fonts were a bit blocky...

But... Rigol knows all this. They know that DHO800/900 with lover resolution 10" screen would be perceived as same as DHO1000  (hint: they are pretty much same except screen and slightly higher sampling rate which makes no difference for a 100MHz scope). 800 and 900 are artificially created to make product for that range and make scope lineup differentiation.
Actually DHO900 with lover res 10" screen would make DHO1000 pretty much dead in a water, sales vise ...
Same as there is no DHO1000MSO (HDO2000 ??) at the time. Why? We know motherboard has it all already.

At this moment, they want to sell you DHO4000 if you want a 12 bit MSO in that range...
As competition responds with their models and pricing reshuffling, expect changes... And the game goes on...
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 13, 2023, 11:22:21 am
I see people getting downright giddy how cool it looks and not even noticing when it is missing basic features...
Form over substance and utility.
[...]
To summarize, I'm not against "cool" and sophisticatedly looking GUI. I'm against that being replacement for actual capabilities.

Fully agree; choosing a scope based on its looks while ignoring the capabilities is not wise. Although, on second thought, that approach is probably not harmful for the (large?) share of hobbyists who only use very basic DSO functionality anyway -- essentially using it like a CRO which takes up less space, plus maybe the ability to stop and capture a trace. I am pretty sure that Rigol gets an above-average share of those users, and there's no harm in that. (Except for the missed opportunity to discover more advanced scope capabilities...)

Quote
If you ask me, Rigol should have pushed for 10" screens even with lower resolution than they have now (to make it cheap enough to make to keep the product price range), not use use panoramic display ratio and therefore provide larger screen real estate to show information, even if fonts were a bit blocky...

Yes indeed. Their screen design works fine on the 10" screen, I think, so there is nothing wrong with the choice of fonts, frames, colors per se. It's just that the settings displays and controls take up a rather large part of the 7" screen, which causes usability compromises some will be happy to accept while others will not.

Quote
But... Rigol knows all this. They know that DHO800/900 with lover resolution 10" screen would be perceived as same as DHO1000  (hint: they are pretty much same except screen and slightly higher sampling rate which makes no difference for a 100MHz scope). 800 and 900 are artificially created to make product for that range and make scope lineup differentiation.
Actually DHO900 with lover res 10" screen would make DHO1000 pretty much dead in a water, sales vise ...

No doubt, a lot of these design choices are marketing-driven. And I don't blame Rigol (or the other scope manufacturers) for that. Hobbyists benefit from this "market segmentation" approach, since they get a lot of functionality at an attractive price point, while the manufacturers still find differentiators to motivate commercial customers to pay much more. Screen size and bandwidth are nicely obvious differentiators which pretty much all manufacturers have relied on.

I am curious to see how Siglent will play this with the SDS1000X HD vs the 2000X HD. With the most recent spec changes they have positioned them even closer to each other, so it seems that they will either need to make the 1000X HD relatively expensive, or will lose a significant share of potential 2000X HD customers to it.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 13, 2023, 11:47:12 am
I see people getting downright giddy how cool it looks and not even noticing when it is missing basic features...
Form over substance and utility.
[...]
To summarize, I'm not against "cool" and sophisticatedly looking GUI. I'm against that being replacement for actual capabilities.

Fully agree; choosing a scope based on its looks while ignoring the capabilities is not wise. Although, on second thought, that approach is probably not harmful for the (large?) share of hobbyists who only use very basic DSO functionality anyway -- essentially using it like a CRO which takes up less space, plus maybe the ability to stop and capture a trace. I am pretty sure that Rigol gets an above-average share of those users, and there's no harm in that. (Except for the missed opportunity to discover more advanced scope capabilities...)

Quote
If you ask me, Rigol should have pushed for 10" screens even with lower resolution than they have now (to make it cheap enough to make to keep the product price range), not use use panoramic display ratio and therefore provide larger screen real estate to show information, even if fonts were a bit blocky...

Yes indeed. Their screen design works fine on the 10" screen, I think, so there is nothing wrong with the choice of fonts, frames, colors per se. It's just that the settings displays and controls take up a rather large part of the 7" screen, which causes usability compromises some will be happy to accept while others will not.

Quote
But... Rigol knows all this. They know that DHO800/900 with lover resolution 10" screen would be perceived as same as DHO1000  (hint: they are pretty much same except screen and slightly higher sampling rate which makes no difference for a 100MHz scope). 800 and 900 are artificially created to make product for that range and make scope lineup differentiation.
Actually DHO900 with lover res 10" screen would make DHO1000 pretty much dead in a water, sales vise ...

No doubt, a lot of these design choices are marketing-driven. And I don't blame Rigol (or the other scope manufacturers) for that. Hobbyists benefit from this "market segmentation" approach, since they get a lot of functionality at an attractive price point, while the manufacturers still find differentiators to motivate commercial customers to pay much more. Screen size and bandwidth are nicely obvious differentiators which pretty much all manufacturers have relied on.

I am curious to see how Siglent will play this with the SDS1000X HD vs the 2000X HD. With the most recent spec changes they have positioned them even closer to each other, so it seems that they will either need to make the 1000X HD relatively expensive, or will lose a significant share of potential 2000X HD customers to it.

There is nothing wrong with instrument being simple. I dislike hype and false expectations.
Frankly, very many people still uses analog CRT scopes and get by with that. In comparison, DHO800 is space ship...

As for SDS1000X HD vs 2000 that one I'm also curious how it's going to play out.
Analytically they are going to be quite close.
But 2000 has twice the sampling troughput (2x2GS/s), 500 Mhz max BW, Zone triggering and MSO and AWG built in...
It is quite a lot more, really...
But hey, they are looking identically, save for the label...  :-DD

Jokes on the side, I look at it differently: this is going to be most powerful 1000 series scope ever built....  :clap:  ;D
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: TurboTom on October 13, 2023, 12:07:48 pm
Here are some DHO914S U/I findings that I really don't like and that don't make sense IMO: When changing parameters with encoders 1 and 2, and crossing decade boundaries (i.e. the unit multiplier changes), the digit that's going to be adjusted changes as well.

Example: In FFT, I manually set center frequency to 1kHz. This parameter gets automatically linked to encoder 1 (it's a pretty clever approach to link the lastly adjusted parameter to one of the "universal" encoders -- I like that). Now I use encoder 1 to increase the center frequency, it affects the 10Hz digit, so far so good. If I reverse the rotation, as expected the 10Hz digit gets decremented until I reach 1.00kHz again. If I continue to decrement, the next center frequency is 990Hz, only to decrement the 1Hz digit afterwards.

To me, this unaccounted digit jumping is utter nonsense. Moreover, if I press the encoder, the center frequency gets (re-) set to 1MHz, far off the range that had been selected before. I think for adjusting numeric parameters, the twist/push function of the universal encoders could have been utilized much more conveniently: Twisting changes a selected digit and stays on the (decimal) digit regardless of multiplier changes. Pushing the encoder toggles through the decimals/digits to be changed. The "reset" function is in most cases useless or rather counterproductive, especially if a wide range is covered by the parameter. There's the touchscreen pop-up keypad available to enter a numeric value if a wide-range adjustement to a certain value is desired.

I feel like complaining to Siglent who kept this same behavior on their legacy AWGs since a long time, though there it's a little bit worse still.

Stay on the digit without exceptions!  ;)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: iMo on October 13, 2023, 12:22:12 pm
So, it seems Rigol's strategy with the 800/900 series is perhaps following - the buyer makes the purchase because the box is cute, has got VESA mount, there is a 12bit logo and it could be battery powered.. And with the other parameters the buyer will perhaps slowly and laboriously find a mental justification why the purchase has been actually made, and even though the justification will not be found the Rigol is hoping the buyer is lazy enough to return the box after he/she/it realizes the box is not performing well, perhaps overpriced and may be the worst buy..
 :D
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: tv84 on October 13, 2023, 02:27:56 pm
So, it seems Rigol's strategy with the 800/900 series is perhaps following

Exactly. And it has been working for some time. So, why change?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 13, 2023, 02:46:46 pm
So, it seems Rigol's strategy with the 800/900 series is perhaps following

Exactly. And it has been working for some time. So, why change?

It's no different than any other product ever made since the dawn of time.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 13, 2023, 02:54:02 pm
Ok, let's do some test and compare, starting with the UI:

It's definitely a lot slower and more clunky than a Micsig. Far too many unnecessary dropdowns and typing-in of numbers.

eg. Channel selection on the trigger menu. There's only four options, why can't it be radio buttons? A dropdown is an extra click plus you have to pause and look at the screen every time a dropdown appears.
(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1898514;image)

This is so much faster:
(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1898520;image)

If you want to change the trigger holdoff you have to pop up a keyboard and type in a number. With the Micsig you just swipe your finger on the box, it's a logarithmic scale so it takes about a second to get it in the ballpark, and that's all the accuracy you normally need. If you need more there's a fine adjust above it (see pic).

Compare with Rigol:
(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1898526;image)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: TurboTom on October 13, 2023, 03:06:27 pm
... Of course, this could have been arranged differently (like five direct selections CH1~CH4 plus "Digital", where tapping the latter would have opened a new window to select the digital channel), but this way it makes some sense as well...
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 13, 2023, 03:08:51 pm
So, it seems Rigol's strategy with the 800/900 series is perhaps following - the buyer makes the purchase because the box is cute, has got VESA mount, there is a 12bit logo and it could be battery powered.. And with the other parameters the buyer will perhaps slowly and laboriously find a mental justification why the purchase has been actually made, and even though the justification will not be found the Rigol is hoping the buyer is lazy enough to return the box after he/she/it realizes the box is not performing well, perhaps overpriced and may be the worst buy..
 :D

Biased a bit?  ???

For many hobbyist users, this will be all the scope they were looking for and ever need. For others, it might be a compromise consciously made, in view of portability, space or budget constraints. For some it might be a second scope for portable use only. And for some, it will be just a vehicle to feel superior because they bought something else.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 13, 2023, 03:12:32 pm
Next up: What's with all the stupid on/off things? Haven't they heard of checkboxes? They take up far less space, they're much easier to use, and it's easier to see if something is enabled or not...

(Plus people are used to using them...they don't have to adapt to something new)

Why is it OFF/ON? Surely it should be ON/OFF? Does pale green mean it's on or off?  :-//
(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1898544;image)

Checkboxes are much clearer and the word "Label" is much better positioned:
(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1898550;image)

Also: The channel name input box should be grayed out when the selection is "off" - a visual clue that it needs to be enabled.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 13, 2023, 03:22:50 pm
... Of course, this could have been arranged differently (like five selections CH1~CH4 plus "Digital", where tapping the latter would have opened a new window to select the digital channel), but this way it makes some sense as well...

On the DHO900 I'd put CH1~CH4 plus "Digital" as radio buttons and have a separate dropdown to select the digital channel.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: tv84 on October 13, 2023, 03:27:52 pm
For many hobbyist users, ...

Agree and let me add 2 more categories:

- those for whom this is better than what they'll ever need
- those that only buy it to be able to participate in the EEVBlog "pissing contests"
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 13, 2023, 03:48:24 pm
For many hobbyist users, ...

Agree and let me add 2 more categories:

- those for whom this is better than what they'll ever need
- those that only buy it to be able to participate in the EEVBlog "pissing contests"

 :-DD
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 13, 2023, 03:54:34 pm
Edit: I moved this to the bugs thread...

https://www.eevblog.com/forum/testgear/rigol-dho800900-oscilloscope-bug-reports-firmware/msg5111436/#msg5111436 (https://www.eevblog.com/forum/testgear/rigol-dho800900-oscilloscope-bug-reports-firmware/msg5111436/#msg5111436)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 13, 2023, 04:03:40 pm
Should there be a separate thread for real bugs just in case Rigol is watching this?

Won't this one do?
https://www.eevblog.com/forum/testgear/rigol-dho800900-oscilloscope-bug-reports-firmware/ (https://www.eevblog.com/forum/testgear/rigol-dho800900-oscilloscope-bug-reports-firmware/)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 13, 2023, 04:05:12 pm
Should there be a separate thread for real bugs just in case Rigol is watching this?

Won't this one do?
https://www.eevblog.com/forum/testgear/rigol-dho800900-oscilloscope-bug-reports-firmware/ (https://www.eevblog.com/forum/testgear/rigol-dho800900-oscilloscope-bug-reports-firmware/)

Yep!
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Neutrion on October 13, 2023, 04:24:20 pm
Is anybody going to do a test about general scoping abilities?
Like waveform update rate with full mem depth, channel noise, offset, accuracy, etc. ?
Just to know what to expect about when the bugs are eventually getting corrected.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: mwb1100 on October 13, 2023, 05:32:02 pm
For many hobbyist users, this will be all the scope they were looking for and ever need. For others, it might be a compromise consciously made, in view of portability, space or budget constraints. For some it might be a second scope for portable use only. And for some, it will be just a vehicle to feel superior because they bought something else.

Definitely.

A couple years ago when I was looking for an entry level scope, the DS1054Z and SDS1104X-E are the two that most reviews pointed to as very good bang for buck (with the GDS-1054B being thrown into the mix sometimes) - especially if hacking for extra bandwidth/features is acceptable.  I'd think that the DHO804 deserves to be in that list.  After a couple rounds of firmware fixes, it might even be considered the "go to" entry level scope.  At the very least it should drive down the prices of the other entry level scopes (the DS1054Z has already been dropped to $315).

If I were scopeless, I'd almost certainly choose the DH0804 over the DS1054Z or the SDS1104X-E - even with all the unknowns about it that are still floating around out there.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Serg65536 on October 13, 2023, 06:02:24 pm
Rigol DHO800 waveform update freezing bug
This bug occurs at a horizontal scale of 200 ms per division and above, when you set the trigger position to the time before the capture starts.
Setting the trigger some time before the capture is used widely to debug large signal sequences. By moving the trigger position, you can study the whole signal in small portions.
Firmware version 1.00
https://youtu.be/FyM5jibkgfE (https://youtu.be/FyM5jibkgfE)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 13, 2023, 07:50:16 pm
I had to play around again this evening, but now it's the weekend....
My ordered stuff arrived, the USB adapter and a powermeter for USB-C.
The latter seems to work fine, the adapter did me no good, the stick is not recognized by the Rigol in the back(but not by the 1104X-E either).
The current shown in the picture is from the on state of the scope and that changes only marginally even if you enable everything possible.
But it decreases when the time base becomes longer..
I had taken the demo board for this and kept all 4 channels busy, 2 channels were allowed to decode, the other two to display a sine.

Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 13, 2023, 07:54:14 pm
Agree and let me add 2 more categories:

- those for whom this is better than what they'll ever need
- those that only buy it to be able to participate in the EEVBlog "pissing contests"

I also have another category:
- Those who bought it out of curiosity and are playing guinea pig by proxy with their tests.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: tautech on October 13, 2023, 08:02:08 pm
The latter seems to work fine, the adapter did me no good, the stick is not recognized by the Rigol in the back(but not by the 1104X-E either).
Yes well, it is the 'USB Device' port same as X-E.

These will fix the miserly USB A port allocation:
https://www.ebay.com/itm/255819611500 (https://www.ebay.com/itm/255819611500)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 13, 2023, 08:37:08 pm
The latter seems to work fine, the adapter did me no good, the stick is not recognized by the Rigol in the back(but not by the 1104X-E either).
Yes well, it is the 'USB Device' port same as X-E.

These will fix the miserly USB A port allocation:
https://www.ebay.com/itm/255819611500 (https://www.ebay.com/itm/255819611500)

I've got a 3 Euro USB hub connected to mine and it works perfectly. I've got mouse and USB stick working together.

(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1899483;image)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: tautech on October 13, 2023, 08:42:54 pm
The latter seems to work fine, the adapter did me no good, the stick is not recognized by the Rigol in the back(but not by the 1104X-E either).
Yes well, it is the 'USB Device' port same as X-E.

These will fix the miserly USB A port allocation:
https://www.ebay.com/itm/255819611500 (https://www.ebay.com/itm/255819611500)

I've got a 3 Euro USB hub connected to mine and it works perfectly. I've got mouse and USB stick working together.
Yeah of course but in a new design in this day and age a single USB A port is just plain being mean. It's not like there isn't any realestate to have added more.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 13, 2023, 08:44:54 pm
I still haven't managed to update my firmware.  >:(

I know the USB stick works because I can see in the file manager.

(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1899663;image)

I even copied the .gel file from USB to internal storage but it still didn't seem to recognize it.

The readme with that .gel file says "Version 1.01" and my 'scope has version "1.00" so I have no idea what's wrong.
(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1899759;image)

Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 13, 2023, 08:45:35 pm
A new update is avaible ?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: dmulligan on October 13, 2023, 08:47:35 pm
So the front USB A port is a host port, the rear USB B port is a device port.  I wonder if the USB C port is power only or if it is capable of being a device or host port as well, this would have to be through a powered hub of course.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: TurboTom on October 13, 2023, 08:48:17 pm
...
Yeah of course but in a new design in this day and age a single USB A port is just plain being mean. It's not like there isn't any realestate to have added more.

Not true in case of the DHO900 where the digital probe connector takes up all the space between the USB host port and CH1 BNC. And the '800 and '900 share the same PCB. But it should have been possible to place another USB host connector at the rear.

Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 13, 2023, 08:49:04 pm
I still haven't managed to update my firmware.  >:(
I know the USB stick works because I can see in the file manager.

Have you tried a different USB stick anyway, not too large, freshly formatted with FAT32, nothing else in the root directory?

I recall that this has historically been an issue with other scopes. And there were a couple of posts here relating to the DSO800 DHO800, with one user experiencing software freezes when saving files to USB, while it worked fine for someone else.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 13, 2023, 08:53:02 pm
A new update is avaible ?

Yep, see here: https://www.eevblog.com/forum/testgear/rigols-new-dho800-oscilloscope-unbox-teardown/msg5109042/#msg5109042 (https://www.eevblog.com/forum/testgear/rigols-new-dho800-oscilloscope-unbox-teardown/msg5109042/#msg5109042)

Some users have reported that a couple of fixes not mentioned in the release notes were also made, e.g. the "crash when turning the encoder past a certain value" thing.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 13, 2023, 08:55:26 pm
A new update is avaible ?

Yes!

https://www.eevblog.com/forum/testgear/rigol-dho914s-bode-plot/msg5109180/#msg5109180 (https://www.eevblog.com/forum/testgear/rigol-dho914s-bode-plot/msg5109180/#msg5109180)

(unless it's just a cruel joke...)

nb. The Bode Plot isn't fixed.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 13, 2023, 08:56:21 pm
...
Yeah of course but in a new design in this day and age a single USB A port is just plain being mean. It's not like there isn't any realestate to have added more.

Not true in case of the DHO900 where the digital probe connector takes up all the space between the USB host port and CH1 BNC. And the '800 and '900 share the same PCB. But it should have been possible to place another USB host connector at the rear.

I guess it's a market segmentation thing. A second USB host port is clearly a feature found only in midrange scopes, never mind the fact that it only costs 30 cents to add.  ::)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 13, 2023, 09:02:26 pm
Quote
v00.01.01.00.01  2023/08/10

1. Remove all time-related displays on the instrument
2. To modify the vertical interface, click the wiring diagram to modify the AC coupling function
3. Modify the delayed scan Chinese display as Zoom
4. Modify the order of the menu in the upper right corner, put the measurement in the front and Default in the back
5. The probe ratio interface is removed, and the probe ratio option is added to the vertical first-level menu

Hm, ok I´ll try it now.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 13, 2023, 09:12:45 pm
I guess it's a market segmentation thing. A second USB host port is clearly a feature found only in midrange scopes, never mind the fact that it only costs 30 cents to add.  ::)

The HDO1000 has three and it's the exact same chipset.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: tautech on October 13, 2023, 09:13:44 pm
...
Yeah of course but in a new design in this day and age a single USB A port is just plain being mean. It's not like there isn't any realestate to have added more.

Not true in case of the DHO900 where the digital probe connector takes up all the space between the USB host port and CH1 BNC. And the '800 and '900 share the same PCB. But it should have been possible to place another USB host connector at the rear.

I guess it's a market segmentation thing. A second USB host port is clearly a feature found only in midrange scopes, never mind the fact that it only costs 30 cents to add.  ::)
Define a midrange scope.  :P
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 13, 2023, 09:14:09 pm
Upgrade done.. ;)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 13, 2023, 09:18:10 pm
Upgrade done.. ;)

 >:( >:( >:(

Let me download that file again...
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: LonnieU on October 13, 2023, 09:21:22 pm
I spent several minutes there....

You have to select (check) the circle to the right of the filename. Then it will show up in the "Upgrade" window.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 13, 2023, 09:22:32 pm
Define a midrange scope.  :P

10" screen, price close to or above 1000€, multiple USB ports.  ;)

Naming of the ranges is debatable, of course. But the manufacturers seem to agree that their entry-level scopes are characterized by a 7" screen, a price tag in the mid-3-digits, and apparently a single USB port. 
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: LonnieU on October 13, 2023, 09:23:38 pm
Upgrade done.. ;)

 >:( >:( >:(

Let me download that file again...

I spent several minutes there....

You have to select (check) the circle to the right of the filename. Then it will show up in the "Upgrade" window.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: tautech on October 13, 2023, 09:27:20 pm
Define a midrange scope.  :P

10" screen, price close to or above 1000€, multiple USB ports.  ;)

Naming of the ranges is debatable, of course. But the manufacturers seem to agree that their entry-level scopes are characterized by a 7" screen, a price tag in the mid-3-digits, and apparently a single USB port.
Nearly, $499 7" display 4ch X-E has 2x USB A, one front, one rear.

Also $639 7" display 200 MHz 2 GSa/s SDS2202X-E same ^
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 13, 2023, 09:28:49 pm
You have to select (check) the circle to the right of the filename. Then it will show up in the "Upgrade" window.

Yepp....
After checking the circle press OK.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 13, 2023, 09:43:19 pm
Upgrade done.. ;)

 >:( >:( >:(

Let me download that file again...

I spent several minutes there....

You have to select (check) the circle to the right of the filename. Then it will show up in the "Upgrade" window.

Oh...

You have get the .gel file name in the input box.
(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1899912;image)

In the instructions it says "copy the file into the root folder..." and I thought that was enough (it always was in the past on other 'scopes).

I got it to work now.  :-BROKE
(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1899918;image)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 13, 2023, 09:46:41 pm
Update: I just noticed one of my USB sticks is NTFS and it was working just fine in the 'scope.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 13, 2023, 09:49:06 pm
I must confess before finding it out what the circle means, I´ve copied the file to the local disk and then did the upgrade.. ;)

Quote
4. Modify the order of the menu in the upper right corner, put the measurement in the front and Default in the back
5. The probe ratio interface is removed, and the probe ratio option is added to the vertical first-level menu

Confirmed, last is really useful.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: tautech on October 13, 2023, 09:54:07 pm
Do show the range of probe attenuation available and any custom attenuation, if available.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 13, 2023, 10:10:05 pm
Sir, yes Sir !  ;)

More than enough to select.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: tautech on October 13, 2023, 10:11:39 pm
Sir, yes Sir !  ;)

More than enough to select.
Custom ?
How many ?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 13, 2023, 10:12:53 pm
Custom ?
How many ?

None. Put it on the Siglent sales pitch list.  :=\
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 13, 2023, 10:16:42 pm
Quote
Custom ?
How many ?

There is no such thing, and with 28 options, you don't need it.
For example, we have many differential probes with 200x, 500x, 1000x and even 1500x.
And we have mostly scopes that "offer" only 3 fixed ratios, I find manual input annoying, such a selection as the DHO offers it more practical.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: tautech on October 13, 2023, 10:26:32 pm
Quote
Custom ?
How many ?

There is no such thing, and with 28 options, you I don't need it.
Correction made.  :P

Quote
For example, we have many differential probes with 200x, 500x, 1000x and even 1500x.
And we have mostly scopes that "offer" only 3 fixed ratios, I find manual input annoying, such a selection as the DHO offers it more practical.
:-//
Hmmm, use 100x and 1000x passive probes here which of course there should be selections for and as you say differential probes offer many different attenuations as do current probes.

However when working with shunts one does need custom attenuation which it seems Rigol has not allowed for.  :-BROKE
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 13, 2023, 10:44:41 pm
Uh, oh!

Is somebody compiling a new Rigol vs. Siglent comparison chart?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: TurboTom on October 13, 2023, 10:45:33 pm
Here's a very peculiar finding: https://youtu.be/3TAeSheBUl4 (https://youtu.be/3TAeSheBUl4)
I guess this is due to the AWG using the highest output level configuration via the THS3095 which is most probably supplied via rails that aren't regulated on the AWG piggyback board and that may slightly get affected by the power consumption (balance) of the Rigol's frontend chip which apparently draws some substantial current that may be affected by the input signal / trace position input. What a sentence... :phew: When trying to talk in a foreign language while recording a video clip, I'm less eloquent  ::)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 13, 2023, 10:54:50 pm
Quote from: tautech
However when working with shunts one does need custom attenuation which it seems Rigol has not allowed for.

When is the magic word..
I don't think that's a flaw that would be game-changing.
For one or the other it might be, then he has to buy another scope, but seen on the majority this is rather void.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: tautech on October 13, 2023, 10:59:54 pm
Quote from: tautech
However when working with shunts one does need custom attenuation which it seems Rigol has not allowed for.

When is the magic word..
I don't think that's a flaw that would be game-changing.
For one or the other it might be, then he has to buy another scope, but seen on the majority this is rather void.
Yet when you consider this DSO is targeted at the price conscious buyer that's very unlikely to have the additional budget for a $ current probe the lack of custom attenuation might be just that.
These are features the discerning buyer needs to be aware of.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: tautech on October 13, 2023, 11:01:14 pm
Uh, oh!

Is somebody compiling a new Rigol vs. Siglent comparison chart?
Best you stay away then as it's more complex than getting a USB stick to work.  :P
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 13, 2023, 11:10:10 pm
Quote
Custom ?
How many ?

There is no such thing, and with 28 options, you don't need it.
For example, we have many differential probes with 200x, 500x, 1000x and even 1500x.
And we have mostly scopes that "offer" only 3 fixed ratios, I find manual input annoying, such a selection as the DHO offers it more practical.

For the record, I have been using custom probe ratios for shunts, homemade probes and for adjusting for probe gain to make them more accurate. Or you can map some signal range to some more round value for the sake of easier reading: you map 0-33mV to 0-100mV as a proxy for 0-100 %...
None of it is "must have" but very useful. It is one of those things that you start inventing new ways of doing things when you know you have that freedom. For instance, a common mode choke becomes impromptu AC current probe in few minutes...

I got used to it with Picoscope....

For standard use with standard probes not needed... This simply shows it is simple, not analytical scope.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 13, 2023, 11:25:41 pm
Here's a very peculiar finding: https://youtu.be/3TAeSheBUl4 (https://youtu.be/3TAeSheBUl4)
I guess this is due to the AWG using the highest output level configuration via the THS3095 which is most probably supplied via rails that aren't regulated on the AWG piggyback board and that may slightly get affected by the power consumption (balance) of the Rigol's frontend chip which apparently draws some substantial current that may be affected by the input signal / trace position input. What a sentence... :phew: When trying to talk in a foreign language while recording a video clip, I'm less eloquent  ::)

It almost looks like channel offset DAC loses resolution when AWG is enabled. So you get same offset steps as if you are on 2V/div. This might even be code bug, where programer did some mess with numerous variables named offset_xxxx

Does it happen with all channels?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: TurboTom on October 14, 2023, 12:11:00 am

It almost looks like channel offset DAC loses resolution when AWG is enabled. So you get same offset steps as if you are on 2V/div. This might even be code bug, where programer did some mess with numerous variables named offset_xxxx

Does it happen with all channels?

Yes it "works" on all channels identically.

I'm certain it's a hardware thing since it requires some particular configuration settings in order to behave like this: The signal must originate from the internal AWG and the AWG has to be configured to high output amplitude so the signal gets routed through the THS3095 output amplifier. I tried feeding in an identical signal from an external AWG which made the effect disappear. Same situation if the input to the low pass network is just terminated with 50 Ohms.

I'm sure shifting the trace vertically is accomplished by feeding an analog current/voltage into Rigol's analog front end chip to modify its internal DC balance. Obviously, this may have an effect on its presumably considerable current consumption (just look at the power consumption/dissipation in general) and change its balance. If this just slightly changes the pre-regulator rail voltages that (once again presumably) also supply the AWG's high-level output amplifier chip, this observation is easily understandable. One would have to measure the internal rail voltages when moving around the traces.

I'm almost certain that the low-level output amplifier of the AWG (AD8009) is supplied by a pre-regulator so the front-end-fed supply imbalance wouldn't affect its performance.

Edit: Just verified - changing any trace position affects the DC output component of the AWG in its higher output amplitude ranges by some ten millivolts -- well done, Rigol  :palm:
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: iMo on October 14, 2023, 12:20:58 am
Quote
Custom ?
How many ?

There is no such thing, and with 28 options, you don't need it.
For example, we have many differential probes with 200x, 500x, 1000x and even 1500x.
And we have mostly scopes that "offer" only 3 fixed ratios, I find manual input annoying, such a selection as the DHO offers it more practical.

The famous 1:21 is missing..  ;)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 14, 2023, 06:00:59 am
However when working with shunts one does need custom attenuation which it seems Rigol has not allowed for.  :-BROKE

You can always use a math channel to convert to your custom scale.
Strike it off the sales pitch list, it's a bit lame.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: tautech on October 14, 2023, 06:05:26 am
However when working with shunts one does need custom attenuation which it seems Rigol has not allowed for.  :-BROKE
You can always use a math channel to convert to your custom scale.
:-+
Good idea and overlooked.

So now we need investigate Math capabilities.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 14, 2023, 09:04:35 am
However when working with shunts one does need custom attenuation which it seems Rigol has not allowed for.  :-BROKE

You can always use a math channel to convert to your custom scale.
Strike it off the sales pitch list, it's a bit lame.

Yes you can use math channel for that.. I checked datasheet and it has Ax+B function. But you use up math channels fast that way. And they are very limited in a frist place so you will sometimes need several just to achieve some math..
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 14, 2023, 09:15:17 am
But you use up math channels fast that way. And they are very limited in a frist place so you will sometimes need several just to achieve some math..

You are obvioously a more advanced user than me -- I don't see myself using up 4 math channels anytime soon. No doubt that one can construe use cases where one could use more, but certainly not a deal breaker for me...
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 14, 2023, 09:32:25 am
But you use up math channels fast that way. And they are very limited in a frist place so you will sometimes need several just to achieve some math..

You are obvioously a more advanced user than me -- I don't see myself using up 4 math channels anytime soon. No doubt that one can construe use cases where one could use more, but certainly not a deal breaker for me...

Well filters is in math channel, FFT is in math channel, you have 4 arithmetic operations and few functions. But you can use only 1 at the same time. So if you want to filter out PWM on 2 channels that's 2 math gone and then you multiply them there goes 3rd...
That is my point. Whether people use math channels (how or at all) is up to them..

I'm not even criticizing here, just point out realities.. 
I already pointed out this is very basic scope.
But people say "it also has 4 math channels"  without realizing not all math is created equal. For instance Micsig has filter on every channel. It has only 1 math channel but has advanced math where you can use complex formula. With that you can create many things you cannot with DHO800/900/1000/4000. And that is inexpensive scope. Touchscreen Siglents have 4 math channels that are even more advanced than Micsigs one. But those are advanced analytical scopes and price is quite different....

That being said, DHO has basic math that will do basic stuff we expect.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 14, 2023, 04:21:45 pm
So now I have actually "moved" with the Rigol.... ;)
And the USB port extender also arrived today, very nice.
Then I can continue with the testing...
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 14, 2023, 08:52:32 pm
I had tried a little bit with the demo board earlier.
That has two outputs for the test signals, one directly after the DAC, unfiltered, the other with a filter.
The Rigol seems to run a filter, the staircase signal does not look so pronounced, compared to another 12-bit scope.
The last two pictures show both signals from the demo board.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: tautech on October 14, 2023, 09:13:24 pm


Also, does the "DC1M" on the Siglent meant that it has a 1 MHz lowpass activated?
No.
It's the channel tab showing DC coupled with 1M Ohm input vs 50 Ohm.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 14, 2023, 09:15:18 pm


Also, does the "DC1M" on the Siglent meant that it has a 1 MHz lowpass activated?
No.
It's the channel tab showing DC coupled with 1M Ohm input vs 50 Ohm.

Ah, right, that scope can switch in internal 50 Ohm termination. Luxury!  :)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 14, 2023, 09:21:28 pm
Quote
And finally, in the second pair of screenshots (including CH2) it looks like multiple overlaid captures are shown in the Rigol screenshot, vs. a single capture on the Siglent, which makes them hard to compare.

in both cases I had simply pressed the stop button and made a screenshot.
Evtl I have a "wrong moment" caught at the rigol, I make another picture.
Oh well, earlier I had again had a crash at the rigol.
For the second time a phenomenon where the scope after plugging in the usb connector from the demoboard just "turns off the light" and nothing happens until you turn it off and on again.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 14, 2023, 09:47:02 pm
Picture made, compare it to the siglent pic 19.
And I´ve found out what made the scope crashing, it´s the USB splitter.
When you connect it while the scope is running/booting, the scope will crash.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 14, 2023, 09:58:34 pm
The signal is a 50Hz sine with 3.3V amplitude, filtered to one output, to the other directly from the DAC.
If one then resolves accordingly, one can well recognize the stair steps of the non-filtered sine.
And that surprises me, that it looks with the Rigol rather like the filtered signal.
Edit: Ignore the arrow in the picture...
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 14, 2023, 10:11:50 pm
I´ve tried it a dozen of times* but yes, for you I´ll try it one more time... ;)

*)I had tried to set the same values at the rigol, but that would not work in the sense of no signal on the screen then.

Here is a picture of the siglent sds1104x-e, but with 50µs, I will add 100µs later...

Title: Re: Rigol DHO804 Test and Compare Thread
Post by: tautech on October 14, 2023, 10:16:00 pm
Here is a picture of the siglent sds1104x-e, but with 50µs, I will add 100µs later...
Better comparison would be to be using channels 1&3 to maintain sampling rates, but you already know such as that's how you use your HD.  ;)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 14, 2023, 10:25:53 pm
Therefore new screenshots, Rob.. ;)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 15, 2023, 01:07:20 am
Picture made

Did you know you can turn off the "DHO804" overlay in your screenshots?
(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1901511;image)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 15, 2023, 01:08:31 am
Now yes, thank you !
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 15, 2023, 07:10:15 am
I´ve tried it a dozen of times* but yes, for you I´ll try it one more time... ;)

Thanks so much -- I did not mean to annoy you! But I am afraid I might still not have gotten my point across.

If you look at e.g. RigolDS15.png in reply #219, you have apparently captured the signal shorty after the minimum of the sine wave -- the curves are almost horizontal on the left of the screen and then begin to climb gradually. Overall, their slope is significantly lower than on the Siglent screenshots, where the signal goes up by a total of > 200 mV over the capture time of 1 ms, or even 350 mV over 0.65 ms in the SDS1104X-E screenshot.

Larger slope -> larger DAC step size -> more pronounced steps in the unfiltered signal. Hence my suggestion to try and make sure that you capture the signal at the same phase of the sine oscillation on both scopes. (Or use a sawtooth instead if that's available on the demo board.)

Instead of thinking on terms of time, it is better to make sure that trigger level is same. Maybe trigger level of 1.5V and 0 delay ? That will insure look at the same position in a slope.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Performa01 on October 15, 2023, 08:43:25 am
Ah, right, that scope can switch in internal 50 Ohm termination. Luxury!  :)
It's not just an "internal termination", but a proper 50 ohms channel that maintains a VSWR of <1.5 over the full bandwidth of 500 MHz (and beyond).

Any 50 ohm termination of a 1meg scope input, be it internal or external via through terminator, yields acceptable results up to 100 MHz at best.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 15, 2023, 09:01:09 am
It's not just an "internal termination", but a proper 50 ohms channel that maintains a VSWR of <1.5 over the full bandwidth of 500 MHz (and beyond).

Any 50 ohm termination of a 1meg scope input, be it internal or external via through terminator, yields acceptable results up to 100 MHz at best.

So how do passive probes with bandwidths up to 500 MHz manage to push the signal over a much longer 1 MOhm connection?

I don't mean to quarrel, but am genuinely curious -- if the short internal high-impedance connection from BNC jack to front end is already considered problematic at > 100 MHz, what is the impact of a passive probe's cable?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 15, 2023, 09:15:45 am
We had this topic before, regarding the probes, I just don't know in which thread it was.

Quote
Yes, that's what I tried to say in #222 -- different trigger levels were apparently used on the Siglent vs. Rigol captures.

Then look again at the pictures to see if the difference can really be decisive.
But I will do it again and "normalize" and keep me at the rigol from the values and then set the siglent so.
Is easier, because the rigol is a bit bitchy with the trigger.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: TurboTom on October 15, 2023, 09:27:18 am
The problem isn't so much the distance from through-terminator / BNC to the scope's internal circuitry but rather the few tens of picofarads of input capacitance. Rigol's specified 15pf input capacitance result in a reactance of 106Ohms at 100MHz. An there goes the 1Mohm input impedance by a large margin...

Passive high bandwidth probes are always 10:1 (or another scaling factor that is) and use a capacitive/resistive divider approach along with a dissipative cable. The approximately divide the input capacitance by their scaling factor, as their ohmic resistance increases likewise. Designing good high bandwidth probes is difficult, that's why they aren't cheap.

The channel input capacitance is required to achieve the required linearity of the high-impedance attenuator. A low-impedance attenuator may be designed differently and with lower capacitance.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Performa01 on October 15, 2023, 09:49:24 am
So how do passive probes with bandwidths up to 500 MHz manage to push the signal over a much longer 1 MOhm connection?

I don't mean to quarrel, but am genuinely curious -- if the short internal high-impedance connection from BNC jack to front end is already considered problematic at > 100 MHz, what is the impact of a passive probe's cable?
A passive high impedance probe is a rather complex construction. The key is in the attenuation (20 dB for x10), which leaves enough headroom to compensate for the mismatch on both ends of the probe cable. Here I've "designed" some simple passive x10 high impedance probe, that performed well up to at least 300 MHz in the simulation (reply #521):

https://www.eevblog.com/forum/testgear/siglent-sds1204x-e-released-for-domestic-markets-in-china/msg1434317/#msg1434317 (https://www.eevblog.com/forum/testgear/siglent-sds1204x-e-released-for-domestic-markets-in-china/msg1434317/#msg1434317)


It is no secret that passive high impedance probes with their high input capacitances have limited use, as the above posting illustrates. Even the not too high source impedance of 1 kohm limits the bandwidth to about 10 MHz. Consider how many wannabe experts might have gotten just house numbers as results because of ignoring this.

It all gets worse if you use your probes with the supplied ground lead, as the following posting demonstrates (reply #62):

https://www.eevblog.com/forum/testgear/siglent-sds1104x-e-in-depth-review/msg1435196/#msg1435196 (https://www.eevblog.com/forum/testgear/siglent-sds1104x-e-in-depth-review/msg1435196/#msg1435196)


Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 15, 2023, 09:59:45 am
Then look again at the pictures to see if the difference can really be decisive.

Yes, I think so. Half the DAC step size in mV, a vertically compressed display due to the "letterbox" format, and fatter traces due to more noise -- all three taken together seem to explain why the steps are less obvious on the DHO800. I don't think one has to assume the presence of any filtering.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 15, 2023, 10:36:57 am
Something about the topic..
I have now measured again, both scopes have been set exactly the same, at each step.
And this is the result, I can not change... ;)


Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 15, 2023, 10:49:55 am
Something about the topic..
I have now measured again, both scopes have been set exactly the same, at each step.
And this is the result, I can not change... ;)

I don't get it. If you compare e.g. the "Rigol_50mV" vs. "Siglent_50mV" screenshots: Why does the signal rise by 2*50mV on the Rigol, but by 5*50mV on the Siglent, during the same capture period of 10*50µS?  ???

Am I reading the displays wrong or have some other kind of mental block? Or are the two scopes still showing different segments of the sine function, with different slopes and hence different DAC step sizes?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 15, 2023, 10:52:21 am
OK,
I'm ashamed it took me so long....
Not enough coffee I guess..

It is obvious why steps on Siglent are higher.
Because screen display is taller. 
Rigol has weird panoramic ratio, waveform plot area is some 20% "squished" vertically compared to Siglent.

EDIT.

Yeah something not right anyways..


Look at the graticule.

Aside from that, I see slight noise in DHO800 trace and less details on top.. That is partially because 1/3 of sampling rate too.. (625MS/s compared to 2GS/s)
So it is not really as good as better 12 bit scopes.

But for the price it looks good... Now they should finish the product  >:D




Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 15, 2023, 10:56:56 am
It is obvious why steps on Siglent are higher.
Because screen display is taller. 
Rigol has weird panoramic ratio, waveform plot area is some 20% "squished" vertically compared to Siglent.

That's what I meant in #236 when talking about the vertically compressed display due to the "letterbox" format.

But as mentioned I don't think that is the only effect. The displayed step size in mV also seems to differ, unless I am looking at things totally wrong. Please see my post #238 and Martin's most recent screenshots.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 15, 2023, 11:03:53 am
Now something completely different, before I leave for the next hours...Just for fun. ;)

https://youtu.be/UOFe9wmdIKk
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Performa01 on October 15, 2023, 11:13:22 am
Just a little demonstration of internal/external termination vs. a proper 50 ohms signal path. This seems to be required, as I’ve often seen claims like “who needs a scope with 50 ohms inputs, we can always use a BNC-T with a terminator”.

Initially I should define the goal: a return loss of 14 dB (VSWR 1.5:1) is generally considered acceptable in the industry. This means, a proper scope shouldn’t drop below 14 dB RL (or above 1.5 VSWR) within its bandwidth, in order to be usable, i.e. show reasonable pulse fidelity and measurement accuracy for all the ones who use their oscilloscopes for serious tasks.

First a proper through terminator, a venerable HP10100C. This performs beautifully when just connected at the end of a 50 ohms coax cable, but gets pretty ugly as soon as it’s connected to the scope input:

SDS2354X+_RL_200mV_HP10100C

The limit of 14 dB RL is reached at 64 MHz already. Now the alternative, even cheaper solution, a BNC-T with a terminator connected to one leg and the input signal to the other:

SDS2354X+_RL_200mV_BNC-T

As can be seen, the result is pretty much the same. Of course – at frequencies that low a few centimeters aren’t a big deal. This time I’ve measured the minimum RL within the 500 (actually 600) MHz bandwidth, and it’s only 6.94 dB. Utterly useless.

Finally the real thing – the scope switched to 50 ohms, which alters the internal signal path and eliminates the input capacitance that’s always present in high impedance mode:

SDS2354X+_RL_200mV

We get a return loss of more than 17 dB throughout the entire measured range (up to 1 GHz). At 200 MHz, we still have 30 dB RL, which is equivalent to 1.07:1 VSWR.

And now, what’s the consequence?

Look at the next screenshot:

SDS2504X HD_PR_50

This is with the scope switched to its 50 ohms input path. It shows a nice 10 ns wide pulse with 1 ns rise and fall times – exactly as I’ve programmed it on my pulse generator. Yes, there is a little overshoot – and we certainly want to know about that.

Now let’s try the HP10100C through terminator and use the 1 megohm input channel instead:

SDS2504X HD_PR_BNC-T

Some “experts” will say: “oh, this is much nicer now, without the ugly overshoot and ringing!”

The reality is, that we’ve lost all the fine detail due to linear distortion (frequency dependent amplitude error), so we don’t see the overshoot anymore and we also cannot measure the rise and fall times accurately.

But yes, you can say it’s not really a problem for low bandwidth oscilloscopes, because the 200 MHz bandwidth limit appears to have a far worse effect on that particular pulse measurement:

SDS2504X HD_PR_50_BWL200MHz
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 15, 2023, 12:08:10 pm
The Rigol seems to run a filter, the staircase signal does not look so pronounced, compared to another 12-bit scope.

That seem unlikely.

What's the bandwidth and/or input capacitance of the two? I bet that's the difference.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: csuhi17 on October 15, 2023, 12:25:34 pm
If I have seen and understood correctly, the steps at Rigol have two heights.
A large step and a small step add up to a whole step compared to Siglent.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: TurboTom on October 15, 2023, 12:36:32 pm
@Martin72: How many times/steps did you zoom in on the Rigol scope to get the "Stepped" sine screenshot from the original still? The one with the 1v/div setting cannot be the original since the trigger setting is different. If the original has also been recorded at 1V/div, zooming in to 50mV/div (4 steps) should be okay. But if it's been more than five increments, the shown effect is exactly what I'ld expect due to the "funny" behavior of Rigol's digital vertical zoom engine that I tried to analyze here: https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/msg5108949/#msg5108949 (https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/msg5108949/#msg5108949)

Edit: Apparently I got your approach wrong: The screenshot with the "stepped sine" isn't a magnification of the other one with the full sine. I tried to replicate your findings (though I haven't got a Siglent scope for comparison) and also no stepped sine waveform, but I "assembled" a stepped ramp of 3Vpp with 1000 3mV steps. Obviously, zooming into the still of the "whole" ramp doesn't show any steps at all, but the DHO914S resolves the magnified signal exactly as one would expect. The screenshots are in sequence: original ramp, magnified still of original ramp (vertical position slightly adjusted), triggered magnified signal.

I cannot find anything unexpected here.  :-//
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 15, 2023, 01:21:31 pm
It is obvious why steps on Siglent are higher.
Because screen display is taller. 
Rigol has weird panoramic ratio, waveform plot area is some 20% "squished" vertically compared to Siglent.

That's what I meant in #236 when talking about the vertically compressed display due to the "letterbox" format.

But as mentioned I don't think that is the only effect. The displayed step size in mV also seems to differ, unless I am looking at things totally wrong. Please see my post #238 and Martin's most recent screenshots.

So I made a coffee and went again, this time at least semi conscious ..
When in doubt measure and verify. Rinse and repeat until data starts to make sense..

First, we should measure in AC input mode. This way you keep offset 0, trigger level 0 etc.... This way we exclude DC offset accuracy and trigger level accuracy. Those can (and should) be measured separately.
Scope will center signal around DC mean, waveform being symmetric and all..

That been done, let's look at the signal.
Steps are not all exactly the same. There are some up to 13mV in vicinity.
Waviness on top of steps is there.

Rigol is the one not showing correctly.

Verified with SDS6000H12 Pro, Keysight MSOX3104T and king of the hill 16bit Pico 4262

Questions?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 15, 2023, 01:32:13 pm
And this is signal, up close and personal with full 1GHz BW.

Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 15, 2023, 01:38:54 pm
@Martin72: How many times/steps did you zoom in on the Rigol scope to get the "Stepped" sine screenshot from the original still? The one with the 1v/div setting cannot be the original since the trigger setting is different. If the original has also been recorded at 1V/div, zooming in to 50mV/div (4 steps) should be okay. But if it's been more than five increments, the shown effect is exactly what I'ld expect due to the "funny" behavior of Rigol's digital vertical zoom engine that I tried to analyze here:  (https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/msg5108949/#msg5108949)

Edit: Apparently I got your approach wrong: The screenshot with the "stepped sine" isn't a magnification of the other one with the full sine. I tried to replicate your findings (though I haven't got a Siglent scope for comparison) and also no stepped sine waveform, but I "assembled" a stepped ramp of 3Vpp with 1000 3mV steps. Obviously, zooming into the still of the "whole" ramp doesn't show any steps at all, but the DHO914S resolves the magnified signal exactly as one would expect. The screenshots are in sequence: original ramp, magnified still of original ramp (vertical position slightly adjusted) and magnified, triggered signal.

I cannot find anything unexpected here.  :-//

Batronix demo board makes simple sine with rather low res so steps are visible. Also steps are not clean, there are undulations on top of steps.
That makes it interesting signal with actual three levels of waveforms: full sine, steps and detail on top of steps.. 3V-10mV- sub mV level...

As for capture, what I understood, is that it was not "magnified after the fact" but simply captured at V/div as shown...

We need to check more but I see nonlinearities in ADC....  More specifically differential nonlinearities.. In some places it even seems non monotonic..
But we need to check more in detail before passing judgment.

P.S  this is one situation where we can "overdrive" input channels slightly. Since signal is slow moving, most of the overdrive recovery happens in few first pixels of screen on the left...
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 15, 2023, 01:55:11 pm
Heck, guys -- I don't know why I am having such a hard time to get my point across. I am not concerned about varying step sizes within one of the captures or such. I am pointing out that the images which have been compared were showing two different signals. Specifically, two different segments of the test board-generated sine waveform, with different slopes and hence step sizes (differing between the scopes). WHich made the steps look less pronounced on the Rigol.

Please have a look at the attached, which is an annotated combination of the screenshots "Rigol_50mv" and "Siglent_50mV" from Martin's post #237. Maybe that explains it better than another 1000 words?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: TurboTom on October 15, 2023, 01:56:55 pm
Tested some more since one detail slipped though my alertness (or rather lack thereof considering the time I went to sleep last night...  ;)):
@Martin72 applied a lot of vertical shift to the signal. And apparently, that's what explains the problem. Rigol's input stays linear up to a vertical shift of +-50 vertical divisions (10mV/div). Beyond this, ugly things appear to happen, a little bit more severe at positive shifts than negative ones, see screenshots...

Strange enough, the amplification factor appears to increase, but then there's also some kind of "integration" of the signal taking place. I didn't test further, it's important to keep in mind that (at least in the 10mV/div range), you're safe within a vertical shifting range of +-50 divisions. As yet I didn't test if the "Vertical Bias" setting may help...
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: TurboTom on October 15, 2023, 02:16:51 pm
It's worse, fellows, it's worse...

I just used 15mV steps with the otherwise identical signal as in my last post in order to "see" the steps better in lower sensitivity ranges. Finding: you can actually see the non-linearity at a vertical shift of 500mv (ten divisions of the 50mV/div range). That's practically a no-go. I'm very curious if this is a problem inherent to Rigol's new front-end ASIC and if this effect can be observed on their DHO1000 and 4000 instruments as well. IMO, this renders a 12 bit scope useless for anything else than most basic jobs. Btw, the "Bias" setting just works the same way as the "Offset".
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 15, 2023, 02:43:57 pm
Questions?

Where's the screenshot of the Rigol?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 15, 2023, 02:45:18 pm
It is obvious why steps on Siglent are higher.
Because screen display is taller. 

No, it's not that.

Look at the maximum/minimum voltages in each one. They're completely different ranges.

Turn on some cursors if it will help you see it.

Thank you, but you're late... I already corrected it.
We went on measuring and Thomas already found some very bad stuff.. That means that both 800 and 900 are suspect. We need someone to check with 1000 and 4000, they might not have the problem, different board..
Still in progress...

Best,
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 15, 2023, 02:47:03 pm
Questions?

Where's the screenshot of the Rigol?

Martin gave it.
I performed the important task of verifying test signal shape. 4 different scopes from 3 different manufacturers show exactly the same.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Performa01 on October 15, 2023, 02:51:25 pm
Finding: you can actually see the non-linearity at a vertical shift of 500mv (ten divisions of the 50mV/div range). That's practically a no-go.
Who needs a linear ADC, when we can have a prestigious 12 bit badge on the front cover and as long as it's cheap!
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 15, 2023, 02:52:30 pm
Strange enough, the amplification factor appears to increase, but then there's also some kind of "integration" of the signal taking place.

That's what I meant, a kind of "filtering", plus that with the same settings the signal curve tends to be flatter with the rigol, at least that should remain the same if you don't change anything except the vertical sensitivity.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 15, 2023, 02:59:25 pm
Strange enough, the amplification factor appears to increase, but then there's also some kind of "integration" of the signal taking place.

That's what I meant, a kind of "filtering", plus that with the same settings the signal curve tends to be flatter with the rigol, at least that should remain the same if you don't change anything except the vertical sensitivity.

Martin,

could you please repeat measurement: 20µs/div, 10mV/div no offset (offset 0), AC coupling, NO 20MHz BW limit. Triger 0V .
Signal should got straight through center of screen with no adjustments.
Post that image. We can directly compare that with my posted images.

To make it clear, this is not prove what Thomas found. This is to see firstly how step looks like, especially top of it. To prove if there is some filtering or diff nonlinearities and nonmonotonic behavior that would show as noise band or flat line instead of clear wave on top...

Thanks.
 Siniša
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 15, 2023, 03:01:25 pm
Heck, guys -- I don't know why I am having such a hard time to get my point across. I am not concerned about varying step sizes within one of the captures or such. I am pointing out that the images which have been compared were showing two different signals. Specifically, two different segments of the test board-generated sine waveform, with different slopes and hence step sizes (differing between the scopes). WHich made the steps look less pronounced on the Rigol.

Please have a look at the attached, which is an annotated combination of the screenshots "Rigol_50mv" and "Siglent_50mV" from Martin's post #237. Maybe that explains it better than another 1000 words?

Yes we understand. That is why we moved to AC coupling and offset and trigger level of 0.
But Thomas found that signal gets distorted at some points when offset is applied.....
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 15, 2023, 03:12:44 pm
Yes we understand. That is why we moved to AC coupling and offset and trigger level of 0.
But Thomas found that signal gets distorted at some points when offset is applied.....

It might be to do with the AC coupling. What size capacitor is in each device?

Who needs a linear ADC, when we can have a prestigious 12 bit badge on the front cover and as long as it's cheap!

It's not the ADC.

If it was the ADC it would be on every screenshot ever. No line would ever be straight.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Performa01 on October 15, 2023, 03:25:57 pm
Yes we understand. That is why we moved to AC coupling and offset and trigger level of 0.
But Thomas found that signal gets distorted at some points when offset is applied.....
There's a Déjà-vu: the ones brave enough to read my review of the SDS1104X-E back in late 2017, might have noticed the following statement in the "DC Accuracy" section:

Quote
The table below shows the results of all measurements. For each vertical gain setting, measurements have been performed for both polarities and three offsets (zero and ±3 divisions) with and without input signal respectively, resulting in a total of seven measurements per range. The reason why measurements with offset have been included is the probably widely unknown fact that not all DSOs will pass this test, so I wanted to be thorough.

Well, to be honest, I've not come across a single DSO so far, that would not pass this test - with one exception: it was ... a Rigol DS4000 (which wasn't exactly cheap back in 2015). And support never solved this problem. So Rigol and offset ... appears to be no good relationship.

I've never tested my old Rigol DS1052E though, just because i didn't think it was worth it, back when this scope still was a thing.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ptluis on October 15, 2023, 03:41:51 pm
Now something completely different, before I leave for the next hours...Just for fun. ;)

https://youtu.be/UOFe9wmdIKk

The RIGOL seems to have a really small display area to show waveforms, signals. It is possible to hide the top and lower bars?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Gortosch on October 15, 2023, 03:52:44 pm
Hello all,

I actually ordered a DHO924S from Batronix. But now I'm thinking about whether an MSO5000 would be better for me. Since I'm currently doing more digital technology than analogue technology, the 12 bits don't appeal to me at the moment. As I said, at the moment.
The form factor is great, especially because I don't have much space, but it's not really the deciding factor. Otherwise, I don't see any more advantages with the DHO924s. Rather only disadvantages. Am I missing something important? What do you think?

Best regards
Sven
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 15, 2023, 03:56:00 pm
I actually ordered a DHO924S from Batronix. But now I'm thinking about whether an MSO5000 would be better for me. Since I'm currently doing more digital technology than analogue technology, the 12 bits don't appeal to me at the moment. As I said, at the moment.
The form factor is great, especially because I don't have much space, but it's not really the deciding factor. Otherwise, I don't see any more advantages with the DHO924s. Rather only disadvantages. Am I missing something important? What do you think?

I would agree that, if you don't explicitly need the small form factor, potential for battery operation, and the somewhat better ADC resolution, the MSO5000 is the better choice.

The MSO5000 is relatively noisy for an 8-bit front end, but certainly good for digital electronics. It is also very hackable, all nicely documented, so you can start with an MSO5072. (which even comes with 4 probes, it seems? Nope, four inputs and front ends, but only two probes. The two included ones are 350 MHz however, according to Batronix.)

The DHO9xx is cute, but the small form factor also comes with a price to pay. The little fan is more noticeable than larger ones, and the small touch screen limits the space available for curve display. Also, it does not have individual controls for the four channels which the MSO5000 provides, of course.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 15, 2023, 03:58:14 pm
The RIGOL seems to have a really small display area to show waveforms, signals. It is possible to hide the top and lower bars?

No. While various overlays, results displays etc. are of course dynamic, the settings bars at the top and bottom are always there.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: TurboTom on October 15, 2023, 04:01:32 pm
I just found out another detail that may save Rigol's honor (...at least a little bit)  ;)

The observed effect of the nonlinearity at high vertical offsets appears to be only present if the total amplitude of the input signal far exceeds the screen range. Actually, we've been looking at a 3Vpp signal in the 50mv/div range, offset another 500~700mv in one vertical direction. So the maximum level of that signal outside of the "visible range" was 44 divisions -- about five vertical screen ranges.

An AC signal, riding on top of a DC signal is no problem for the scope if it is offset by 20 divisions (1V Offset in the 50mV/div range). The attached screenshot documents this, a 350mV ramp signal with -1V offset fed to channels 1 and 2, comparing the traces of channel 1 with DC coupling and vertial offset vs. channel 2, AC coupled and virtually no offset (only a little bit for trace separation).

So as long as the AC component of the input signal isn't exceeding the measurement range by far, things are okay.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 15, 2023, 04:03:55 pm
Quote
The table below shows the results of all measurements. For each vertical gain setting, measurements have been performed for both polarities and three offsets (zero and ±3 divisions)

Well, to be honest, I've not come across a single DSO so far, that would not pass this test - with one exception:

Finding: you can actually see the non-linearity at a vertical shift of 500mv (ten divisions of the 50mV/div range).

3 divisions != 10 divisions.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 15, 2023, 04:09:25 pm
Martin,
could you please repeat measurement: 20µs/div, 10mV/div no offset (offset 0), AC coupling, NO 20MHz BW limit. Triger 0V .
Signal should got straight through center of screen with no adjustments.
Post that image. We can directly compare that with my posted images.

Hi,

Of course I can...
Settings like you suggested: 20µs/div., 10mV/div, AC coupling (channel and trigger) and here we go...
Except the zero-crossing, all are looking the same, rigol dho, siglent sds1104x-e, siglent sds2504x hd..
Looks like the rigol have a DC "problem".
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Gortosch on October 15, 2023, 04:10:31 pm
Hello ebastler,

thank you for your quick reply. What exactly do you mean by "relatively noisy"? Are there any tests, maybe even a video?
But basically I have already decided on the MSO5000.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 15, 2023, 04:12:11 pm
I actually ordered a DHO924S from Batronix. But now I'm thinking about whether an MSO5000 would be better for me. Since I'm currently doing more digital technology than analogue technology, the 12 bits don't appeal to me at the moment. As I said, at the moment.

If you're doing mostly digital stuff then you should probably get the MSO5000. It has far higher sample rate, bandwidth and memory depth.

You can easily hack it to unlock all options.

You won't get the touch screen or the cuteness, but...  :-//
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 15, 2023, 04:16:22 pm
I just found out another detail that may save Rigol's honor (...at least a little bit)  ;)

The observed effect of the nonlinearity at high vertical offsets appears to be only present if the total amplitude of the input signal far exceeds the screen range.

So there could be some op-amp overload in there...
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 15, 2023, 04:26:36 pm
What exactly do you mean by "relatively noisy"? Are there any tests, maybe even a video?

There have been long (and sometimes heated) debates on this forum. Here's an entire thread about scope noise which talks about the MSO5000 a lot. The link goes to a page mid-thread which has some comparison screenshots, but other pages might be interesting as well: https://www.eevblog.com/forum/testgear/how-much-noise-floor-and-other-things-matter-in-oscilloscope-usability/150/ (https://www.eevblog.com/forum/testgear/how-much-noise-floor-and-other-things-matter-in-oscilloscope-usability/150/)

Nevertheless, if your main interest is digital electronics, I'd say this should not stop you from getting an MSO5000!

By the way: The 16 digital inputs are the same on the MSO5000 and the DSO924, it seems. Rigol's probe kit is expensive (but nice -- fast comparators which work up to +- 40V, good if you should also be interested in very vintage digital electronics). But there are cheap DIY solutions if you only need typical logic levels up to 5V.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 15, 2023, 04:33:06 pm
Martin,
could you please repeat measurement: 20µs/div, 10mV/div no offset (offset 0), AC coupling, NO 20MHz BW limit. Triger 0V .
Signal should got straight through center of screen with no adjustments.
Post that image. We can directly compare that with my posted images.

Hi,

Of course I can...
Settings like you suggested: 20µs/div., 10mV/div, AC coupling (channel and trigger) and here we go...
Except the zero-crossing, all are looking the same, rigol dho, siglent sds1104x-e, siglent sds2504x hd..
Looks like the rigol have a DC "problem".

Thanks Martin.

That actually looks OK.

Now back to what Tom experienced.
I agree that is some type of input overload/recovery.

What I tested is following (and I suggest you test the same on Rigol):
- same demoboard sine 50 Hz non filtered.
- Input in DC mode.
- position signal that you look at top of sine. (5 ms/div).
- try at 200, 100, 50 mV/div ( I don't know the offset range of top of my head.).
Look for distortion...
Hint: once you roughly get where it starts distorting, set vertical to fine for more precise point..
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: TurboTom on October 15, 2023, 04:37:52 pm
Hi,

Of course I can...
Settings like you suggested: 20µs/div., 10mV/div, AC coupling (channel and trigger) and here we go...
Except the zero-crossing, all are looking the same, rigol dho, siglent sds1104x-e, siglent sds2504x hd..
Looks like the rigol have a DC "problem".

I wouldn't say that they have a DC problem, it's rather an input overdrive problem that more or less is present on all oscilloscopes. It just seems that Siglent did a better job in this area than Rigol. As long as the input amplitude stays within safe limits, there's no problem. See the attached screenshots: Once a square signal of 2Vpp total amplitude with 20% of of ramp riding on top, the other one with 1.4Vpp and otherwise the same configuration, coupled to both channels 1 and 2, yet at different sensitivities and channel 1 (50mV/div) offset by 1V /500mV to visualize the "low part" of the signal. I guess this explains the situation quite clearly. It seems, other vertical ranges are more tolerant to high AC signals. Unfortunately, the 50mV range is very commonly used with a 10:1 probe...

...
So there could be some op-amp overload in there...

Exactly!  :D
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 15, 2023, 04:41:02 pm
The MSO5000 [...] is also very hackable, all nicely documented, so you can start with an MSO5072. (which even comes with 4 probes, it seems? Nope, four inputs and front ends, but only two probes. The two included ones are 350 MHz however, according to Batronix.)

Correcting my prior advice:

Having looked at the Batronix website, the MSO5074 is probably the better buy at the moment. The slightly higher price not only buys you two extra probes (which cost more than the price difference if bought separately). It also gets you a nice option bundle, including various decoders and the AWG license, so you can leave the scope unhacked at least early on during the warranty period.

And now back to our scheduled program...
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: mwb1100 on October 15, 2023, 04:41:34 pm
I actually ordered a DHO924S from Batronix. But now I'm thinking about whether an MSO5000 would be better for me.

The MSO5000 is relatively noisy for an 8-bit front end, but certainly good for digital electronics. It is also very hackable, all nicely documented, so you can start with an MSO5072. (which even comes with 4 probes, it seems? Nope, four inputs and front ends, but only two probes. The two included ones are 350 MHz however, according to Batronix.)

The MSO5074 is being sold in the US  on the rigolna.com site for $100 less than the MSO5072 right now ($800 vs $900).  I don't think that deal has made it to the EU or if it will.  But it would be worth asking Batronix (or whoever) if the deal is coming or if they can match.  The worst that can happen is they say no.

You won't get the touch screen or the cuteness, but...  :-//

The MSO5000 isn't as cute as the DHO900, but it does have a (larger) touchscreen.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 15, 2023, 04:43:46 pm
What exactly do you mean by "relatively noisy"? Are there any tests, maybe even a video?

There have been long (and sometimes heated) debates on this forum. Here's an entire thread about scope noise which talks about the MSO5000 a lot. The link goes to a page mid-thread which has some comparison screenshots, but other pages might be interesting as well: https://www.eevblog.com/forum/testgear/how-much-noise-floor-and-other-things-matter-in-oscilloscope-usability/150/ (https://www.eevblog.com/forum/testgear/how-much-noise-floor-and-other-things-matter-in-oscilloscope-usability/150/)

Nevertheless, if your main interest is digital electronics, I'd say this should not stop you from getting an MSO5000!

By the way: The 16 digital inputs are the same on the MSO5000 and the DSO924, it seems. Rigol's probe kit is expensive (but nice -- fast comparators which work up to +- 40V, good if you should also be interested in very vintage digital electronics). But there are cheap DIY solutions if you only need typical logic levels up to 5V.

At this point MSO5000 is actual functional product in comparison to DHOxxx series that is highly unfinshed in many regards.
If you need something that actually works and has to be Rigol, MSO5000 is actual working product. And yes it is noisy, but as other said, for digital work is much more powerful than any DHO scopes. And it has bigger screen.
Other (more expensive) option is SDS2000X +..

But I would not recommend anybody to buy DHO series today if it is going to be their only scope and they would depend on it to work flawlessly. It is in the early adopter phase...
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Gortosch on October 15, 2023, 05:05:56 pm
That's exactly what I was thinking. I have just ordered the MSO5074 and cancelled the DSO924S. Thank you.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Performa01 on October 15, 2023, 05:07:52 pm
Quote
The table below shows the results of all measurements. For each vertical gain setting, measurements have been performed for both polarities and three offsets (zero and ±3 divisions)

Well, to be honest, I've not come across a single DSO so far, that would not pass this test - with one exception:

Finding: you can actually see the non-linearity at a vertical shift of 500mv (ten divisions of the 50mV/div range).

3 divisions != 10 divisions.

Oh! So you really believe the DS4000 would have performed better if we'd measured it at 10 divisions offset instead of just three?

I just found out another detail that may save Rigol's honor (...at least a little bit)  ;)

The observed effect of the nonlinearity at high vertical offsets appears to be only present if the total amplitude of the input signal far exceeds the screen range.

So there could be some op-amp overload in there...

So you still believe in "OpAmp overload", even though David Hess and me have explained numerous times what causes overload distortion in a serious scope frontend?

Yes we understand. That is why we moved to AC coupling and offset and trigger level of 0.
But Thomas found that signal gets distorted at some points when offset is applied.....

It might be to do with the AC coupling. What size capacitor is in each device?

Do you even know where that capacitor sits? And how do you suppose anyone knows its value? Do you have a DMM? have you ever measured the input resistance (DC!) of any serious scope when it is AC coupled?

Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 15, 2023, 05:36:49 pm

What I tested is following (and I suggest you test the same on Rigol):
- same demoboard sine 50 Hz non filtered.
- Input in DC mode.
- position signal that you look at top of sine. (5 ms/div).
- try at 200, 100, 50 mV/div ( I don't know the offset range of top of my head.).
Look for distortion...
Hint: once you roughly get where it starts distorting, set vertical to fine for more precise point..

I had done this with the "lower peak" of the sinus, because from 100(or was it 50)mV the rigol allows an offset of +/-1V (above this it is 8V).
When I found nothing, I shortened the time base to 500µs, see picture.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 15, 2023, 05:38:03 pm
Oh! So you really believe the DS4000 would have performed better if we'd measured it at 10 divisions offset instead of just three?

No, I want to know how all the others perform at 10 divisions, just like we're applying to this $399 'scope to achieve a couple of pixels of distortion.

I demand a graph of number of pixels vs. price in dollars from 3 to 10 divisions of offset. It's the only way to form an unbiased opinion.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 15, 2023, 05:45:08 pm

What I tested is following (and I suggest you test the same on Rigol):
- same demoboard sine 50 Hz non filtered.
- Input in DC mode.
- position signal that you look at top of sine. (5 ms/div).
- try at 200, 100, 50 mV/div ( I don't know the offset range of top of my head.).
Look for distortion...
Hint: once you roughly get where it starts distorting, set vertical to fine for more precise point..

I had done this with the "lower peak" of the sinus, because from 100(or was it 50)mV the rigol allows an offset of +/-1V (above this it is 8V).
When I found nothing, I shortened the time base to 500µs, see picture.

Yes that is distortion....
Complete sinewave is "assembled" from straight vertical and horizontal segments...
You need to go to 50, 100 or more mV/div until there are no angled segment at all... Only clean steps...
That is point where no distortion occurs..
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 15, 2023, 05:49:25 pm
For the siglent, the upper area would not be a problem in terms of offset, but I also triggered on the lower tip for better comparison.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Performa01 on October 15, 2023, 05:51:11 pm
Of course word should have gotten around by now that we must not overload the inputs of modern DSOs – or any scope with split path input buffer, which are almost all scope designs today (Picoscope 4262 is one of the feew exceptions).

Just as a reference, here are tests with the Siglent SDS2504X HD, similar to what TurboTom did:

First the Overload test. 10 kHz triangle, 6 Vpp amplitude, viewed at 50 mV/div with an additional offset of 1.5V:

SDS2504X HD_Ramp_OVL

Now the offset challenge. A 350 mVpp triangle is fed into channel 2 as reference. Channel 4 gets a copy of that signal with 6 V DC offset. No worries, of course.

SDS2504X HD_Ramp_Offset

Fnally the question, why the heck does everyone always want to overload the oscilloscope input? Why not just use zoom if we want to inspect a signal in more detail?

The last screenshot shows a ten times zoom into the signal (5 mV/div in the zoom window) which has essentially the same effect as the overload method, just with the difference that we can feel better because we stayed away from unspecified territory.

SDS2504X HD_Ramp_Zoom

People will now bitch: “oh, we cannot compare the cheap rigol to an immensely expensive Siglent!”

First, there’s no point in having a scope advertised as 12 bits when its performance is just not there, no matter how cheap it is.

Second, The Siglent SDS1000X HD will perform just as well as the 2000 (except for the bandwidth and MSO option) and it will most likely be very affordable.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 15, 2023, 05:59:20 pm
The Siglent SDS1000X HD will perform just as well as the 2000 (except for the bandwidth and MSO option) and it will most likely be very affordable.

Here's hoping... I have actually decided to wait for the SDS1000X HD to become available. It will obviously outperform the DHO 800/900 in many respects, but whether I can justify the extra cost to myself will depend on the price tag. Looking at Siglent's recent tweaks to the positioning, I'm afraid it will be closer to 3x the DHO914 than 2x...
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 15, 2023, 07:17:32 pm
But then the dho800 surprises you with some gadgets:
It has not only a frequency counter, but also a dvm function at the start.
And zoom is also included, albeit somewhat hidden.
I think that's great for a 500€ scope.
And take a closer look at the dvm infobox, what else can be read there.
I find it.....interesting. ;)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 15, 2023, 07:18:31 pm
Fnally the question, why the heck does everyone always want to overload the oscilloscope input? Why not just use zoom if we want to inspect a signal in more detail?

Beats me...

The DS1054Z distorts a lot if you switch to fine vertical range adjust (push the vertical scale knob) and crank it up to maximum.

The fact that you could just use the next higher range instead didn't stop several threads about the "problem".

there’s no point in having a scope advertised as 12 bits when its performance is just not there, no matter how cheap it is.

You're saying there's no point at all in owning one of these 'scopes?

This 'scope is trying to replace the DS1054Z, not the SDS2000HD. Will it help you to see the value if I grab a sharpie and cross the "12bits" off the front?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 15, 2023, 07:22:40 pm
And zoom is also included, albeit somewhat hidden.

You only just found it? You can zoom with a setting in the "H" menu.

There's also an option in "setup" to make the timebase knob do "zoom" when you push it.

(but it doesn't seem to remember that setting when you power off  >:( )
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 15, 2023, 07:37:08 pm
There´s no dedicated zoom button on the front (like the dho4000 have), so I thought the 800 did not have it.
Then I´ve stumbled over it in the manual, the setup menu... :D
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 15, 2023, 07:44:37 pm
It took me a while to find it, too, but it has the zoom function you'd expect:
(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1902126;image)

It's good for serial decoding on long bursts of data. Drag the zoom window left/right to decode different packets.

It can also zoom out properly after you STOP it.  :)


There's an option for zoom in the 'H' menu at the top. I assume they put it there for when you're using a 50" touch screen in board meetings.
(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1902144;image)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 15, 2023, 07:48:46 pm
(but it doesn't seem to remember that setting when you power off  >:( )

I just turned the scope back on, zoom is still there because last state - but button is back to "fine"....
If you go to the horizontal menu, you will see that both modes are active (zoom and fine)...
Small bug, because last state should be completely last state.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: nctnico on October 15, 2023, 07:50:37 pm
It looks like somebody at Rigol was sleeping during the lecture about significant digits.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: iMo on October 15, 2023, 08:13:17 pm
It looks like somebody at Rigol was sleeping during the lecture about significant digits.

They create a platform for future enhancements, like a 24bit ADC..  :D
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 15, 2023, 09:00:26 pm
This is a three digit DVM with the same bandwith(aha...) like the one in the dho 900 series..
I had connected my DMMplus reference earlier and measured 5DC, 5Vac 100Hz and 10 Khz with accurate duty cycle.
The nice measure window unfortunately does not apply to the counter and DVM function.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Serg65536 on October 15, 2023, 09:53:11 pm
Rigol DHO800 and DHO900 don't have a PROPER ZOOM function.

That's because you can't move the waveform more than vertical offset allow. So you can't use 12 bit resolution outside ±1 V range because of this issue.
2^12 = 4096, so to fully zoom in on 5 V/div with offset range of ±100V you have to switch to the 1 mV range that has ±1V offset only. So more than 99% of the capture range is outside the zoomable area.
Here are offset ranges:
0.5, 1, 2, 5, 10, 20, 50 mV/div - ±1 V offset
100, 200  mV/div - ±8 V offset
500 mV, 1, 2  V/div - ±20 V offset
5, 10  V/div - ±100 V offset
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Circlotron on October 15, 2023, 10:05:24 pm
Whiny fans are just that: instead of producing wideband noise, they make sound that has peaks in spectrum that allows our ear to recognize tones.
If you have any tone between 400-4000Hz where our ears are most sensitive, you will hear annoying whine (tone). Simple as that. It can also be at other frequencies, but between 400-4000Hz we are very sensitive.

As long as you do it the same for all of them you will have good relative measurements. Then compare spectrum to how it sounds to you and you will quickly find what the "whine" is all about.

I did just that to few devices. One good example of device that is not completely silent but has very "noise like" sound is Keysight MSOX3000T. Just a whooshing, not very silent but with no distinguishing tones so no whining.. Excellent acoustic design.

Best one is, of course, Siglent SDS2000X HD. Pretty much completely silent. Large, low speed fan, and cooling based on low pressure/low speed airflow volume.
Siglent SDSD6000H12 Pro OTOH is quite louder. But that one needs to expel much more thermal energy out of the case... It is still not annoying because there are no large peaks inside so you forget about it, but after few hours, when you switch it off you suddenly realize how quieter the room is. Of course, that is my very quiet lab, in open space office not so much.

DHO800 has miniscule fan that pretty much guarantees whine and noise by itself. Offending tones will be easily measured.
Fans with evenly spaced blades are more likely to whine. The fan blades on a car alternator are unevenly spaced for this reason. Gives a spread spectrum effect so there won’t be sound concentrated at one frequency.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Serg65536 on October 15, 2023, 10:10:08 pm
In the "Vertical" window you can change the "bias" value.
But it's intended use, according to the manual, is for zero out the offset of the channel only.
BTW using bias at 100 and 200 mV/div gives OUTPUT VOLTAGE from -40 mV (for -8 V bias) to 60 mV (for 8 V bias). Yes, the scope can generate output voltage at its input!!
For the 500 mV, 1, 2 V/div ranges output voltage range is -1,7...3.5 mV.
So don't try to move you waveform with the "bias" field!!
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 15, 2023, 10:29:45 pm
the scope can generate output voltage at its input!!

Ummm... yes. It wouldn't be able to calibrate itself without that feature.

Rigol DHO800 and DHO900 don't have a PROPER ZOOM function.

Do you have an oscilloscope that can do better?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: csuhi17 on October 16, 2023, 05:08:43 am
the scope can generate output voltage at its input!!

Ummm... yes. It wouldn't be able to calibrate itself without that feature.

Rigol DHO800 and DHO900 don't have a PROPER ZOOM function.

Do you have an oscilloscope that can do better?
SDS2354X HD, if I saw it correctly, it's quite impressive.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 16, 2023, 05:32:22 am
Rigol DHO800 and DHO900 don't have a PROPER ZOOM function.
Do you have an oscilloscope that can do better?
SDS2354X HD, if I saw it correctly, it's quite impressive.

OK, so go get one of those instead of one of these Rigols...
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: csuhi17 on October 16, 2023, 05:47:45 am
I'm sorry, I didn't mean to be rude, I just saw that you compared the +4000 USD scope to this 300 USD cash.
I also ordered one of these...
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 16, 2023, 05:49:03 am
the scope can generate output voltage at its input!!

Ummm... yes. It wouldn't be able to calibrate itself without that feature.


What are you talking about? In what opposite universe channel offset settings is supposed to generate OUTPUT voltage on INPUT BNC of the scope...?
You better take a meter and measure if your scope has that problem or it is an error in measurement or some kind of misunderstanding....

This can be connected to offset/AWG problem Tom had..

P.S. Even those 70µV you see are generated by that being non-shielded measurement, all kinds of unwanted thermocouples and multimeter zero offset
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 16, 2023, 05:54:19 am
Rigol DHO800 and DHO900 don't have a PROPER ZOOM function.
Do you have an oscilloscope that can do better?
SDS2354X HD, if I saw it correctly, it's quite impressive.

OK, so go get one of those instead of one of these Rigols...

Rigol could have implemented that. It is a software thing. No BOM price attached.
And even the DHO4000 that is also expensive in comparison to dho800/900 does not have that.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 16, 2023, 06:20:43 am
the scope can generate output voltage at its input!!
Ummm... yes. It wouldn't be able to calibrate itself without that feature.
What are you talking about?

Calm down and count to 10 before posting.

 I'm referring to the "offset" part of the "offset+gain amplifiers" that ALL oscilloscopes have.

(Hopefully Mr. Red Ink is referring to the same thing)

It is a software thing. No BOM price attached.

I'm fairly sure offset amplifiers are hardware.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: tautech on October 16, 2023, 06:23:47 am
the scope can generate output voltage at its input!!
Ummm... yes. It wouldn't be able to calibrate itself without that feature.
What are you talking about?

Calm down and count to 10 before posting.

 I'm referring to the "offset" part of the "offset+gain amplifiers" that ALL oscilloscopes have.

(Hopefully Mr. Red Ink is referring to the same thing)

It is a software thing. No BOM price attached.

I'm fairly sure offset amplifiers are hardware.
You don't seem to get it.
Vertical zoom is a SW special feature and little to do with vertical offset limits.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Serg65536 on October 16, 2023, 06:27:42 am
P.S. Even those 70µV you see are generated by that being non-shielded measurement, all kinds of unwanted thermocouples and multimeter zero offset
If on DHO800 you set bias to 8 V on 100 or 200 mV/div vertical, you get 60 mV output voltage, not uV!
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 16, 2023, 06:33:53 am
If on DHO800 you set bias to 8 V on 100 or 200 mV/div vertical, you get 60 mV output voltage, not uV!

I have repeatedly been impressed by your findings on the DHO 800 -- great work! But may I suggest that you tone down the choice of fonts in your posts. The bold+red create a dramatic "red alert!" vibe which seems unhelpful for a productive discussion.

Using bold typeface without the red color should be enough to direct attention to very important messages, and italics or underlining work well for less pronounced emphasis.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 16, 2023, 06:37:52 am
You don't seem to get it.
Vertical zoom is a SW special feature and little to do with vertical offset limits.

You're saying a software feature can cancel out 10 screen divisions of offset?

(or whatever it is they were doing earlier in the thread)

Edit: Well, yes, it can, but then you'd complain about it not being 12 bits and more and besides, Mr Red Ink was specifically talking about the thing below:
(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1902468;image)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 16, 2023, 06:50:43 am
the scope can generate output voltage at its input!!
Ummm... yes. It wouldn't be able to calibrate itself without that feature.
What are you talking about?

Calm down and count to 10 before posting.

 I'm referring to the "offset" part of the "offset+gain amplifiers" that ALL oscilloscopes have.

(Hopefully Mr. Red Ink is referring to the same thing)

It is a software thing. No BOM price attached.

I'm fairly sure offset amplifiers are hardware.

Calm down and count to 10 check your information before posting.

Serg65536 reported that when he adjusts vertical offset (yes, that hardware one you are talking about) that results in output voltage appearing on input BNC.  There is absolutely nothing right about that, that is defect if true. That is either that he measured wrong (in which case it is false alarm) or his scope is damaged or all of the scopes have that defect. Thing to do here is for other users try to replicate same thing.

Zoom he is talking about is real proper vertical/horizontal zoom mode. I keep repeating that all the idiotic insistence of use of  word "zoom"  for changing the timebase or vertical attenuation/offset in channels is confusing as hell but nooo... I'm an word nazi...

To explain (I will use Siglent as example because that is what I have but other scopes have that too):  When I enter zoom mode, i can choose both vertical and horizontal magnification from captured data.
See image zoom1 where you can see a small box in upper overview. That part is magnified in bottom zoom window.
In image zoom2 you can see additional horizontal zoom (small box is smaller this time).
These two views are from the same physical capture, and works with stopped and live data...
There is no change in acquired time-base or physical vertical attenuation or voltage offset on channel.
It is post processing.
That is zoom.

So we don't have any more misunderstanding.



Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 16, 2023, 06:59:32 am
[...] So we don't have any more misunderstanding.

Thanks for the clarifying post. I was about to write something along those lines, but could not have provided the helpful illustrations.

I think the wording "Rigol DHO800 and DHO900 don't have a PROPER ZOOM function" from Serg65536's post above may have pushed this discussion in the wrong direction. The software functionality (user interface) is there, looking very similar to the Siglent screenshot you shared. The actual limitation is that Rigol do not allow large offsets in Y, right? Which Serg found and reported as a bug a while ago, https://www.eevblog.com/forum/testgear/rigol-dho800900-oscilloscope-bug-reports-firmware/msg5093817/#msg5093817. (https://www.eevblog.com/forum/testgear/rigol-dho800900-oscilloscope-bug-reports-firmware/msg5093817/#msg5093817.)

EDIT: Not sure why I can't get that link to point to the relevant post. It's reply #31 in that thread.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 16, 2023, 07:08:56 am
Serg65536 reported that when he adjusts vertical offset (yes, that hardware one you are talking about) that results in output voltage appearing on input BNC.  There is absolutely nothing right about that, that is defect if true. That is either that he measured wrong (in which case it is false alarm) or his scope is damaged or all of the scopes have that defect. Thing to do here is for other users try to replicate same thing.

Have you tried it yourself?

I just set mine to output 1kV and tried the tongue test. I didn't feel any tingle, so....  :-//
(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1902489;image)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: csuhi17 on October 16, 2023, 07:21:36 am
Can you set it so that you measure 0mV on the channel?
Did you try based on the description in the user manual? 
Has there been a change?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 16, 2023, 07:28:03 am
Serg65536 reported that when he adjusts vertical offset (yes, that hardware one you are talking about) that results in output voltage appearing on input BNC

Actually, Serg65536 reported a problem when he sets a large bias, not offset. Those seem to be different settings, and I just realize that I am not clear what the "bias" is and does. Maybe someone can confirm or correct my understanding:

The offset (position) knob on the front panel serves two different purposes, depending on the operating mode of the scope. During live acquisition is controls the physical offset input to the front end amplifier; during Stop mode it lets the user zoom in or out of the captured data via pure software functionality. So far, so good.

I always thought that "bias adjustment" uses a combination of hardware and software to compensate for small offset errors in the amplifier: Physically apply a small offset voltage, but call that "zero" in software, such that 0V signal input are actually reported as zero.

If my concept of "bias" is correct, that raises two questions for me: (a) I thought that this is adjusted automatically by the scope during self-calibration. Is it typical to have that as a user control? (b) Why would the "bias" mechanism cause an output voltage on the inputs, while adjusting the offset does not? (Or does it?)

Thanks for your thoughts or corrections of the above!
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 16, 2023, 07:42:39 am
Actually, Serg65536 reported a problem when he sets a large bias, not offset. Those seem to be different settings, and I just realize that I am not clear what the "bias" is and does. Maybe someone can confirm or correct my understanding:

I think it's this:
(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1902519;image)

If my concept of "bias" is correct, that raises two questions for me: (a) I thought that this is adjusted automatically by the scope during self-calibration.

Yes.

These Rigols also seem to have an extra manual adjustment for some reason.

(b) Why would the "bias" mechanism cause an output voltage on the inputs

It wouldn't.

(If it did then calibrating the 'scope would also produce a voltage there)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 16, 2023, 07:57:37 am
(b) Why would the "bias" mechanism cause an output voltage on the inputs

It wouldn't.
(If it did then calibrating the 'scope would also produce a voltage there)

Well, Serg65536 has apparently measured an output voltage -- for bias voltages which far exceed what would be required to compensate amplifier offset errors. Could you try and repeat that experiment on your scope?

BTW using bias at 100 and 200 mV/div gives OUTPUT VOLTAGE from -40 mV (for -8 V bias) to 60 mV (for 8 V bias). Yes, the scope can generate output voltage at its input!!
For the 500 mV, 1, 2 V/div ranges output voltage range is -1,7...3.5 mV.
So don't try to move you waveform with the "bias" field!!

I would not be too concerned, since I don't see any reason to input large "bias" settings. And Serg' has come to the same conclusion; just don't "abuse" the bias setting to enter large offsets. Still I am wondering why Rigol is exposing the "bias" control at all?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 16, 2023, 08:23:27 am
(b) Why would the "bias" mechanism cause an output voltage on the inputs
It wouldn't.
Well, Serg65536 has apparently measured an output voltage

His 'scope must be broken. I can't see anything on mine.

I would not be too concerned, since I don't see any reason to input large "bias" settings.

I just set mine to 1.8 Megavolts and there was no arc flash. I think we're safe.
(https://www.eevblog.com/forum/testgear/rigols-new-dho800-oscilloscope-unbox-teardown/?action=dlattach;attach=1902576;image)

(Sorry to disappoint those who wanted to use their 'scope as a bench power supply)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 16, 2023, 08:48:21 am
Serg65536 reported that when he adjusts vertical offset (yes, that hardware one you are talking about) that results in output voltage appearing on input BNC.  There is absolutely nothing right about that, that is defect if true. That is either that he measured wrong (in which case it is false alarm) or his scope is damaged or all of the scopes have that defect. Thing to do here is for other users try to replicate same thing.

Have you tried it yourself?

I just set mine to output 1kV and tried the tongue test. I didn't feel any tingle, so....  :-//
(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1902489;image)


Are you deliberately trying to provoke me, are you rushing to answer before thinking, or have trouble comprehending..??

He set "Scale" to 100 or 200mv/div and Bias to 8V.

Reproducing problem by definition means reproducing it.
You cannot just choose random settings and say "Ahaa!! See, no problem!"
You need to use exactly same settings to see if you can reproduce result.
Changing any variable is not valid.

If preamp injects voltage/current into input, if input range is set to such setting that preamp is not used will remove it by definition.
Also if input attenuator is used it will load/divide that said voltage too.

Any voltage seen on input will be maximized when front end is in a config where influence from input attenuation is minimal and preamp is used.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 16, 2023, 08:51:37 am
I just set mine to 1.8 Megavolts and there was no arc flash. I think we're safe.

Please note that Serg65536 found the largest voltages on the input (10s of mV) in the lower amplifier ranges (200 mV/div). A multimeter would be really helpful to repeat his test, rather than checking for tongue tingles or arc flashes.  ::)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: trp806mo on October 16, 2023, 08:54:38 am
May someone check the speed of the (statistical) measurement by fitting the scope with a 1Mhz waveforme and measuring the time to get 10K samples of width at 5us and 5ms of timescale ?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 16, 2023, 08:59:47 am
PS: Yes, I twisted the knobs all over the place. Didn't see a single microvolt.

Could you please confirm that your twisting of knobs also included a setting of 200 mV/div and +8V bias voltage? What voltage did your multimeter show on the scope input jack in that state?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: TurboTom on October 16, 2023, 09:08:33 am
Yes it's there. I measure approx. +60mV at 100 or 200mV/div (either of these two ranges "works"), 8V bias and approx. -45mV at -8V bias. The effect is highly non-linear, a bias of +4V results in ca. +12mV and -4V in just between one and two millivolts negative. But the ugly thing is: The effect is just the same if you use offset instead of bias! So they are basically just the same function and add up internally, bias probably meant to compensate for a few millivolts of thermal drift so offset could be kept at zero for a centered trace.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 16, 2023, 09:15:56 am
Could you please confirm that your twisting of knobs also included a setting of 200 mV/div and +8V bias voltage? What voltage did your multimeter show on the scope input jack in that state?

I'll do it after 2N3055 explains to us how measuring a voltage across something with a 1MOhm impedance has any significance.

FWIW I measured the current across the connector with those settings and saw 80nA.

Does that answer the question?
(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1902621;image)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 16, 2023, 09:37:11 am
I just measured the output of my Micsig and it can supply up to 6.5 millivolts with the right settings.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ptluis on October 16, 2023, 09:46:30 am

See image zoom1 where you can see a small box in upper overview. That part is magnified in bottom zoom window.
In image zoom2 you can see additional horizontal zoom (small box is smaller this time).
These two views are from the same physical capture, and works with stopped and live data...
There is no change in acquired time-base or physical vertical attenuation or voltage offset on channel.
It is post processing.
That is zoom.

So we don't have any more misunderstanding.

What's your Siglent scope model? That zoom feature looks really nice 👍
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 16, 2023, 10:01:52 am
What's your Siglent scope model? That zoom feature looks really nice 👍

The DHO800 zoom function looks quite similar to me? See the attached screenshot by Martin72, https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/msg5115042/#msg5115042. (https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/msg5115042/#msg5115042.)

Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 16, 2023, 10:03:34 am
Could you please confirm that your twisting of knobs also included a setting of 200 mV/div and +8V bias voltage? What voltage did your multimeter show on the scope input jack in that state?

I'll do it after 2N3055 explains to us how measuring a voltage across something with a 1MOhm impedance has any significance.

FWIW I measured the current across the connector with those settings and saw 80nA.

Does that answer the question?
(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1902621;image)

No it does not.

And 80nA will fully open MOSFET or FET if enough voltage is available and create all kinds of problems.  Fact that you don't work on high impedance circuits does not make it non problem for everybody...

Tom already confirmed that DHO900 behave the same ...

And to answer your other post, yes I am eager to find the truth..
As a service to my fellow Rigol users.. I don't care if DHO800 has defects because of me.
I'm not in a market for one, I would be more interested in DHO4000 series as a type of product.

Inexpensive does not mean cheap nonfunctional shit. DHO800 is limited enough in capabilities that it's price is very good only if it works flawlessly.
Who's side are you on? On your side and all other users and demand best product for your money, or you work for Rigol hiding stuff?
I actually think Rigol is decent company and all problems are there because of rushing to the market. Given the chance they will do you right and fix the stuff. But nobody ever fixes problems they are not aware of...

But hey, it might just one more of those imperfections that are simply showing it is entry level instrument and what is its price range.
Maybe I expect too much.

But this shows that sometimes you need to pay more to get more...
On SDS2000X HD I can have 80V offset on 200mV/div range. And it shows full 140µV on input in that case... yes 140 microvolts. That is worst case scenario. On average it is 20-30µV.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 16, 2023, 10:05:05 am

See image zoom1 where you can see a small box in upper overview. That part is magnified in bottom zoom window.
In image zoom2 you can see additional horizontal zoom (small box is smaller this time).
These two views are from the same physical capture, and works with stopped and live data...
There is no change in acquired time-base or physical vertical attenuation or voltage offset on channel.
It is post processing.
That is zoom.

So we don't have any more misunderstanding.

What's your Siglent scope model? That zoom feature looks really nice 👍
That is SDS2000X HD. But it is same on 6000A too. And incoming SDS1000X HD will be exactly the same.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 16, 2023, 10:07:44 am
What's your Siglent scope model? That zoom feature looks really nice 👍

The DHO800 zoom function looks quite similar to me? See the attached screenshot by Martin72, https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/msg5115042/#msg5115042. (https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/msg5115042/#msg5115042.)

If you look more closely, that is only horizontal zoom.
On my images you can see I selected a small square, both horizontally and vertically..
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 16, 2023, 10:28:52 am
If you look more closely, that is only horizontal zoom.
On my images you can see I selected a small square, both horizontally and vertically..

Ah -- I thought that you can also zoom in vertically in the lower part of the DHO screen, e.g. by a pinch/zoom finger gesture. Not sure whether that is actually supported, though; I don't see it mentioned in the manual.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 16, 2023, 10:48:48 am
And 80nA will fully open MOSFET or FET if enough voltage is available

Would 60mV be enough?

The Fluke 87V outputs over 7V in continuity mode. You'd imagine it would destroy half the circuits in its path...right?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 16, 2023, 10:50:08 am
Inexpensive does not mean cheap nonfunctional shit. DHO800 is limited enough in capabilities that it's price is very good only if it works flawlessly.

Please don't blow this out of proportion. Yes, I want to learn about bugs and limitations of the DHO series, so I can make an informed purchasing decision -- which might be a decision for a more expensive scope, if the limitations are too severe. But so far I have not seen anything that would make the scope "nonfunctional" for me. (And yes, that's subjective and depends on one's use cases and expectrations.) Swear words don't help either if we want a productive discussion here.

Quote
On SDS2000X HD I can have 80V offset on 200mV/div range. And it shows full 140µV on input in that case... yes 140 microvolts. That is worst case scenario. On average it is 20-30µV.

Has anyone tried whether setting an offset (rather than a bias) causes the same voltage output on the DHO? I am still unsure whether they are different hardware settings, or just two different ways to set and display the same physical adjustment in the front end.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 16, 2023, 10:53:06 am
e.g. by a pinch/zoom finger gesture. Not sure whether that is actually supported, though; I don't see it mentioned in the manual.

Yes, it is.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 16, 2023, 10:53:50 am
Has anyone tried whether setting an offset (rather than a bias) causes the same voltage output on the DHO? I am still unsure whether they are different hardware settings, or just two different ways to set and display the same physical adjustment in the front end.

Thomas did and it is the same. Those are just two names for null offset and trace offset. So you can compensate to DC offset in run time and leave it there and separately adjust vertical offset with a knob. It is actually nice idea.. Picoscope has something like this (they have it automated though but same concept of being able to null out any offsets in runtime)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 16, 2023, 10:55:10 am
e.g. by a pinch/zoom finger gesture. Not sure whether that is actually supported, though; I don't see it mentioned in the manual.

Yes, it is.

That is good news.  :-+ Can you please show how it looks ? Does it show smaller selection square in upper window similar to what I have shown?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 16, 2023, 10:59:04 am
Has anyone tried whether setting an offset (rather than a bias) causes the same voltage output on the DHO? I am still unsure whether they are different hardware settings, or just two different ways to set and display the same physical adjustment in the front end.

The voltage changes if you use the vertical position knob to move the trace up and down.

That's how I got a voltage on my Micsig, it doesn't have a box to type in a number.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: iMo on October 16, 2023, 10:59:50 am
..Inexpensive does not mean cheap nonfunctional shit. DHO800 is limited enough in capabilities that it's price is very good only if it works flawlessly..
Yep, as of today the box is overpriced actually.
Making it really useful 2ch o'scope (for example like 802/812/822 such it fits the LCD size, sampling rate/BW with 2channels) with a well polished fw/UI should have placed it somewhere around $199/$249/$299 excl. VAT and postage, IMHO.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 16, 2023, 11:01:46 am
e.g. by a pinch/zoom finger gesture. Not sure whether that is actually supported, though; I don't see it mentioned in the manual.
Yes, it is.

That is good news.  :-+ Can you please show how it looks ? Does it show smaller selection square in upper window similar to what I have shown?

Pinch-zoom works. Not selection window.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 16, 2023, 11:10:22 am
e.g. by a pinch/zoom finger gesture. Not sure whether that is actually supported, though; I don't see it mentioned in the manual.
Yes, it is.

That is good news.  :-+ Can you please show how it looks ? Does it show smaller selection square in upper window similar to what I have shown?

Pinch-zoom works. Not selection window.

So it does not have full vertical and horizontal zoom in zoom window ? I'm confused now...
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 16, 2023, 08:22:18 pm
Quote
I'm confused now...

I dissolve...

There is no vertical zoom option.
You can move the signal up and down, that's it.
If you change the vertical sensitivity, either by turning the corresponding button or by fingertouch, you change both, channel and zoom.
With my siglent, the basic vertical setting of the channel is retained when you increase the vertical resolution of the zoom signal.
You can also easily recognize it by the vertical labeling axes on the left, for both scopes.
On the rigol, both axes are labeled the same.
However, rigol has not claimed to be able to do both, so it is rather semi-tragic.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Circlotron on October 16, 2023, 09:20:53 pm
If you have a trace with some high level pulses and some low level detail between the pulses, can you wind up the vertical sensitivity very much to see the low level stuff without the X amplifier overloading and rendering the trace unusable?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 16, 2023, 09:21:39 pm
What if you connect a 32" 4K touch panel to this scope?

You will get a 1920*1080 picture with properly upscaled fonts, but no additional detail in the trace data. The graphical elements (settings bars at top & bottom, window frames etc.) will take up the same percentage of the screen real estate as on a small screen.

Hence, this is good for easier viewing and touch operation, but will not really fit more detail onto the screen.

EDIT: Heck, second time today that I respond to a post, and by the time I hit "send" the original post is gone. What gives?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 16, 2023, 09:39:48 pm
If you have a trace with some high level pulses and some low level detail between the pulses, can you wind up the vertical sensitivity very much to see the low level stuff without the X amplifier overloading and rendering the trace unusable?

Not as much as with a $2000 'scope.

OTOH you have 12 bits so you can get the whole wave on screen. press STOP, then magnify it and shift it around in software.

(and obviously a $3000, 12bit 'scope will do it even better)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 16, 2023, 09:47:26 pm
By the way, in my room where the three scopes are, the rigol is not the loudest one... ;)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 16, 2023, 10:17:51 pm
If you have a trace with some high level pulses and some low level detail between the pulses, can you wind up the vertical sensitivity very much to see the low level stuff without the X amplifier overloading and rendering the trace unusable?

Not as much as with a $2000 'scope.

OTOH you have 12 bits so you can get the whole wave on screen. press STOP, then magnify it and shift it around in software.

(and obviously a $3000, 12bit 'scope will do it even better)

Good advice. There are some limitations doing that as reported but that will avoid overdrive.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: EEVblog on October 17, 2023, 10:33:36 pm
A couple years ago when I was looking for an entry level scope, the DS1054Z and SDS1104X-E are the two that most reviews pointed to as very good bang for buck (with the GDS-1054B being thrown into the mix sometimes) - especially if hacking for extra bandwidth/features is acceptable.  I'd think that the DHO804 deserves to be in that list.  After a couple rounds of firmware fixes, it might even be considered the "go to" entry level scope.  At the very least it should drive down the prices of the other entry level scopes (the DS1054Z has already been dropped to $315).
If I were scopeless, I'd almost certainly choose the DH0804 over the DS1054Z or the SDS1104X-E - even with all the unknowns about it that are still floating around out there.

Is anyone actually having any showstopper problems in everyday use using the 1.00 firmware?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: mawyatt on October 17, 2023, 11:02:37 pm
No showstoppers yet.

We've been using the DH0814 (V 1.00) for some typical simple measurements for a few days, and outside display dimness/reflectivity no serious complaints. The display issue is resolved by dimming lab lights, positioning one's self up close in front of the screen, thus reducing reflections from behind, and up close we can see the small screen and details fine (our eyes aren't good).

However, our client requested this evaluation, and has a different use environment, with bright shop, bright objects, and viewed/operated from a long-arms distance will decide if the DGHO814 DHO814 is acceptable. Electrically we've found it acceptable  with our limited evaluation.

Best, 
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 17, 2023, 11:33:25 pm
Is anyone actually having any showstopper problems in everyday use using the 1.00 firmware?

Basic tasks are no problem.
And reduced to that, I would also currently recommend the DHO over other competitors in the absolute cheap segment.
I would not even cite the 12 bit resolution as a purchase argument.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 18, 2023, 01:58:14 am
Is anyone actually having any showstopper problems in everyday use using the 1.00 firmware?

Not me.

The only thing that really affects me is the serial decoding threshold voltage not taking into account the probe setting but it has a very easy workaround (set probes to 1x)

I haven't had any crashes or restarts yet.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 18, 2023, 02:06:18 am
I would not even cite the 12 bit resolution as a purchase argument.

Nor me. I only care that it has enough.

I'm much more into the form factor and the user interface.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: TurboTom on October 18, 2023, 08:57:06 am
I will return it. I ordered it expecting a functional Bode Plot implementation , and the recent findings by @Howardlong (https://www.eevblog.com/forum/testgear/rigols-new-dho800-oscilloscope-unbox-teardown/msg5119131/#msg5119131) regarding sample rate vs. digital channels and the limits using the digital channels as protocol decoder inputs make me believe that it's more like an unfinished toy. The DHO804 is probably an okay product at the price point, but the DHO914S is not!

Hence my disappointment with the scope and the decision to wait for a better choice (regardless of the brand). I've definitely got enough other scopes to keep me "in business" so no problem with waiting. The DHO800/900 series is definitely good to stir up the market. Maybe in two or three years, there will be an instrument available that checks all boxes at a reasonable price.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: mawyatt on October 18, 2023, 03:37:54 pm
Apparently the 900 series Bode function is a bad joke!! Rigol has had plenty of time to get this right as Siglent set the bar long ago for lower mid-level DSOs. Siglent learned from tier 1 folks like R&S, KS, LeCroy & Tek, and implemented a nice Bode function, albeit slow, but quite functional.....and they are "listening" to users an apparently will introduce a new version addressing some of the limitations (hints by some folks with early versions)!!

The 814 we have has an FFT implementation that's not applicable for professional use, nothing close to Siglent's. Suspect the 900 series has the same FFT as the 814 we have, if so then wouldn't bank on Rigol getting this right anytime soon, same as Bode Function.

The 814 is a really good basic DSO implementation, superb hardware & build, attractive form factor, good UI, nice HW features, and very good value IMO as a basic DSO. Most folks reporting haven't discovered any serious issues with the 800 series.

However, the 900 series seems riddled with issues, mostly related to the "expansion" from the 800 series, and not hardware related. This is likely the target for the upcoming Siglent SDS1000X HD, as Rigol hit a home run with the 800 series, but fouled out with the 900 series.

Without a custom ADC chip set, Siglent can't compete with the 800 series, so wisely focused on the higher price 900 series & market segment, and with the apparent issues with the 900, seems Rigol has left the door open.

Not surprised that some of the 900s are being returned, with what's been shown, we would have also done so. With the upcoming SDS1000X HD, expected polished performance like intro of the SDS2000X+, suspect the market for the 900 series will quickly shift away, especially if Siglent prices the HD within reasonable range of the 900 series.

We would have our own DHO814 if not for the upcoming SDS1000X HD, but may still get one since it's just a darn good little DSO in a small, stylish well build package, that's very reasonable and performs quite well as a basic DSO.

As mentioned we consider the DHO800 as the equivalent of a handheld DMM, and the larger more capable MSOs as Benchtop DMMs, gotta find an excuse, need, plan, requirement to have both  :-DMM

Best,
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 18, 2023, 06:53:57 pm
Apparently the 900 series Bode function is a bad joke!! [...]
The 814 we have has an FFT implementation that's not applicable for professional use, nothing close to Siglent's. [...]

Compared to your earlier, objective comments, I am surprised by your change to a "no facts, all opinion" approach. Could you explain a bit more? The Bode plot functionality obviously has a severe bug (causing the "wiggly" charts) which needs to be fixed. Where else does it fall short, to the extent of being a joke?

Likewise, what is missing in the FFT functionality besides the somewhat awkward, indirect control of span and resolution? It certainly outperforms Siglent's offering in this price range regarding speed (massively) and dynamic range (mildly), from what I have seen in Dave's review video. I don't think I have seen an in-depth review of the FFT on the forum, and would appreciate if someone could share their observations.

Quote
the 900 series [...] is likely the target for the upcoming Siglent SDS1000X HD, as Rigol hit a home run with the 800 series, but fouled out with the 900 series. Without a custom ADC chip set, Siglent can't compete with the 800 series, so wisely focused on the higher price 900 series & market segment, and with the apparent issues with the 900, seems Rigol has left the door open.

You wish -- and I wish, actually. As mentioned before, I have decided to wait for the SDS1000X HD before making the decision to potentially buy a DHO. But I don't have my hopes up. My guess is that the SDS1000X HD will be closer to 3x than 2x the price of the DHO 914, in which case it would be difficult for me to justify the extra cost for a hobby tool.

Rigol has left the door open, but I don't think Siglent plans to walk through it any time soon; they are taking a different route. There's just not enough margin for them in the entry-level scope class. And they can't price the 1000X HD too low, since that would cannibalize their 2000X HD sales too much.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: TimFox on October 18, 2023, 06:58:51 pm
I started a different thread about the "wiggly" Bode Plots on the 914S  https://www.eevblog.com/forum/testgear/rigol-dho914s-bode-plot/ (https://www.eevblog.com/forum/testgear/rigol-dho914s-bode-plot/)  but I haven't had any problems with the FFT function.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: mawyatt on October 19, 2023, 02:34:45 pm
Apparently the 900 series Bode function is a bad joke!! [...]
The 814 we have has an FFT implementation that's not applicable for professional use, nothing close to Siglent's. [...]

Compared to your earlier, objective comments, I am surprised by your change to a "no facts, all opinion" approach. Could you explain a bit more? The Bode plot functionality obviously has a severe bug (causing the "wiggly" charts) which needs to be fixed. Where else does it fall short, to the extent of being a joke?

Likewise, what is missing in the FFT functionality besides the somewhat awkward, indirect control of span and resolution? It certainly outperforms Siglent's offering in this price range regarding speed (massively) and dynamic range (mildly), from what I have seen in Dave's review video. I don't think I have seen an in-depth review of the FFT on the forum, and would appreciate if someone could share their observations.
Quote

As noted Apparently, which is why we used this as we don't have the 900 series, and generally don't provide direct statements wrt things we don't have "hands on" experience with. However, from what's been shown by folks that are knowledgable the Bode Function apparently is a bad joke!! Apparantly, one knowledgable individual has decided to return the DHO914 based on "hands on" experience related somewhat to the Bode Function experience. Just spend some time reviewing with an unbiased educated assessment of what's been reported wrt the Bode Function as implemented on the 900 series, you'll soon find all your answers!!!

We do have the DHO814 and can say the FFT implementation is not quite there for our professional use, the SDS2000X+ implementation is useful and we have both DSOs with "hands on". The 814 FFT implementation is Ok to play with, but lacks many of the necessary control & display features for our pro use. Couple examples, FFT averaging doesn't seem to work correctly, no FFT cursors which can be directly configured with peaks amplitude thresholds and directly displayed as table of amplitude and frequency, both of these are show stoppers for our pro use which directly relates to SA use (the SDS2000X+ has both features that work well). The 814 FFT speed is impressive tho, and with some work could be honed into a useful feature for our use.

Maybe we missed something, please enlighten if so!!

So as we've stated the 814 is quite an impressive little DSO for GP use, apparently the 900 series has missed the mark.

Anyway, YMMV as always ;)

Best,
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 19, 2023, 03:09:28 pm

Likewise, what is missing in the FFT functionality besides the somewhat awkward, indirect control of span and resolution? It certainly outperforms Siglent's offering in this price range regarding speed (massively) and dynamic range (mildly), from what I have seen in Dave's review video. I don't think I have seen an in-depth review of the FFT on the forum, and would appreciate if someone could share their observations.



Serious FFT review presumes knowledge, equipment and time. All at the same time.

One thing standing in a way is exactly FFT implementation. In order to make controlled experiment, you need control.
And control is what is missing. FFT automagically sets critical parameters as you change timebase and poke on the screen..

For instance, to compare noise levels, you need to compare two scopes at same bin width (number of bins) and sample rate...
Since you cannot force FFT to use exact numbers, you cannot compare...

It is good enough to see something is there and you can certainly twidle knobs until you generally see range you want and see vertical peaks where you visually adjust how thick you want them. And FFT has very decent refresh rate...
You can then use it to detect some peaks an you can also have relative comparisons.

But exact measurements and absolute comparison to other scopes.? Not so easy...

Problem with implementation is that is made like some kind of spectrum analyser app for a phone..
It wiggles, you get some idea, you can even relatively measure which car is louder, and general feeling of acoustic spectra...
But B&K audio analyser it ain't.

Funny thing is that if they implemented all the manual control, this auto mode would still be useful for quick and dirty "sniff around".

Title: Re: Rigol DHO804 Test and Compare Thread
Post by: switchabl on October 19, 2023, 03:25:40 pm
I'd be curious if all those (non-harmonic) spurs in the screenshot by mawyatt are actually still there if you download the data to a PC and do the FFT offline. I seem to recall that the FFT mode on the DHO4000 that Martin tested did some very weird resampling, potentially resulting in similar artefacts? I think it also showed the wrong units for the RBW. No units at all on the new one?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 19, 2023, 04:05:58 pm
I'd be curious if all those (non-harmonic) spurs in the screenshot by mawyatt are actually still there if you download the data to a PC and do the FFT offline. I seem to recall that the FFT mode on the DHO4000 that Martin tested did some very weird resampling, potentially resulting in similar artefacts? I think it also showed the wrong units for the RBW. No units at all on the new one?

That would be interesting to see. People reported that transfer to PC is much faster than on DS1000Z.
And I 'm afraid FFT offline on a PC is at the moment only way to actually take a look at how well ADC performs..
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: mawyatt on October 19, 2023, 05:04:58 pm
I'd be curious if all those (non-harmonic) spurs in the screenshot by mawyatt are actually still there if you download the data to a PC and do the FFT offline. I seem to recall that the FFT mode on the DHO4000 that Martin tested did some very weird resampling, potentially resulting in similar artefacts? I think it also showed the wrong units for the RBW. No units at all on the new one?

Those artifacts came directly from DHO814, as same source (AWG) was used for both scopes. I would expect they should show in data download as well, since they are displayed on screen, unless something really strange is going on with the FFT signal processing and/or display processing. Like 2N3055 mentioned we don't have a lot of direct control of the FFT engine it's very hard to compare and understand what's going on.

We posted both FFT results just to show the effects of spectrum averaging and amplitude and frequency table. The FFT averaging doesn't work properly on the DHO814 and messes up the signal amplitudes, whereas this works similar to doing spectral averaging on a SA with the Siglent SDS2000X+, giving the proper and executed results.

Here's the Siglent without spectral averaging to see if any artifacts show.

Best,
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: switchabl on October 19, 2023, 05:15:59 pm
Those artifacts came directly from DHO814, as same source (AWG) was used for both scopes. I would expect they should show in data download as well, since they are displayed on screen, unless something really strange is going on with the FFT signal processing and/or display processing. Like 2N3055 mentioned we don't have a lot of direct control of the FFT engine it's very hard to compare and understand what's going on.

I was asking specifically because something really strange seemed to be going on with the FFT on the DHO4000 on some settings. And I don't know if that was ever explained/fixed.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 19, 2023, 05:33:59 pm
Those artifacts came directly from DHO814, as same source (AWG) was used for both scopes. I would expect they should show in data download as well, since they are displayed on screen, unless something really strange is going on with the FFT signal processing and/or display processing. Like 2N3055 mentioned we don't have a lot of direct control of the FFT engine it's very hard to compare and understand what's going on.

I was asking specifically because something really strange seemed to be going on with the FFT on the DHO4000 on some settings. And I don't know if that was ever explained/fixed.

AFAIK it is still in the same condition.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 19, 2023, 06:06:33 pm
From memory, I can confirm that the FFT function of the 804 is no different from the 4204.
I just ran an FFT of a 10khz sine wave from the demo board, pictures to follow.
I can't find an Average function in the menu, so I guess it won't exist.
I just activated peaksearch, max 15 points, it doesn't matter where I put the threshold, all peaks "gather" around the 10khz fundamental.
It may be that the signal from the board is simply bad.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: mawyatt on October 19, 2023, 06:34:47 pm
From memory, I can confirm that the FFT function of the 804 is no different from the 4204.
I just ran an FFT of a 10khz sine wave from the demo board, pictures to follow.
I can't find an Average function in the menu, so I guess it won't exist.
I just activated peaksearch, max 15 points, it doesn't matter where I put the threshold, all peaks "gather" around the 10khz fundamental.
It may be that the signal from the board is simply bad.

There's a average option under Menu button as Horizontal, Acquisition, Average. This seems to do an average with the waveform before FFT. We got this to work and this is the FFT result. No luck with Cursor Peaksearch in FFT tho. The Siglent does the FFT average after the FFT we believe, more like a SA.

Best,
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 19, 2023, 06:59:48 pm
I had also discovered the averaging in the horizontal menu, but it didn't have a great effect now.
I must say, however, that I just went into the room and simply measured quick&dirty on it.
On the other hand, the scope also invites you to do this, because there is not much choice... ;)
What I like again is the table display.
What I don't like is that "RBW" has no unit of measurement.
The signal is as mentioned 10khz, I had set to 100ms/div, the display is already quite slow, about like my HD in the same time base.
Attached pictures of the FFT menu.
On the one hand, I find this kind of presentation, everything at a glance, good.
On the other hand, you can no longer see too much of the signal "behind", or it irritates (yes, I know the transparency function).
Also not so great:
You can only change the vertical offset position of the FFT with a button, if the menu is active and you have selected the offset there.
Outside of the menu, you can neither move the FFT up or down with the vertical knob, nor are the 2 action buttons responsible for this, they change span and center.
Only with the fingertouch you can change the position.
The vertical actuator should be active, as with the Siglent.
My HD scope shows impressively how useful an average function is for the FFT, see the two pictures.
And before they say yes again, it is also much more expensive:
The DHO4204 also has no average mode for FFT. ;)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: switchabl on October 19, 2023, 08:18:11 pm
There's a average option under Menu button as Horizontal, Acquisition, Average. This seems to do an average with the waveform before FFT. We got this to work and this is the FFT result. No luck with Cursor Peaksearch in FFT tho. The Siglent does the FFT average after the FFT we believe, more like a SA.

Acqusition averaging can be a bit misleading because it doesn't just suppress noise but also tones that don't have a stable phase relationship with the trigger signal. In any case, the lack of trace averaging/"VBW" is somewhat annoying in practice.

For reference, the HDO4000 FFT bug: https://www.eevblog.com/forum/testgear/rigol-hdo1000-and-hdo4000-12bit-oscilloscopes-launched-in-china/800/ (https://www.eevblog.com/forum/testgear/rigol-hdo1000-and-hdo4000-12bit-oscilloscopes-launched-in-china/800/)
That seems to have been related more to windowing/leakage after all. I guess the spurs might just be sampling clock spurs (~200kHz from some switching converter maybe?). At <65dBc it's not really a concern but they would be expected to increase with frequency.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 19, 2023, 09:01:05 pm
The DHO4204 also has no average mode for FFT. ;)

My memory ( when I had the scope in February) did not deceive me:
Functions and equipment of the FFT on the DHO4000 are absolutely identical to that of the DHO800 and now you can think for whom this is more embarrassing....
Not for the cheap DHO800, that's for sure.
Also the venerable MSO5000 has the same equipment.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Performa01 on October 20, 2023, 06:32:17 am
We do have the DHO814 and can say the FFT implementation is not quite there for our professional use, the SDS2000X+ implementation is useful and we have both DSOs with "hands on".
Thank you for demonstrating the difference between a measurement vs. a mess of noise and interference.

If we try to compare the two screenshots, we have all the information on the Siglent: FFT-sample rate, FFT-length and the Averaging mode. For convenience, we also get the frequency step - and in future versions of the FW we'll also get the RBW, which depends on the window function. About the only useful window for SA applications is Flattop, so we have to multiply the frequency step by ~3.8 and get a RBW of ~362 Hz in this case.

By contrast, the Rigol shows a much lower sample rate and claims a RBW of "20" - whatever that means. If we assume that the scope actually uses its maximum of 1 Mpts FFT, then the frequency step is about 30 Hz. How can we get a RBW of 20(Hz?) under these conditions? Only explanation could be the rather useless rectangle window, which can't be used for accurate measurements at all and doesn't have a constant RBW either - at the border between frequency bins it can be even much worse than a proper window function.

We can see the excessive noise and high internal spur levels. It does not look like it would measure the individual harmonics correctly. Considering the enormous difference in RBW (362/20), the dynamic appears to be inferior too. And don't forget, the Siglent is just an 8 bit DSO!

But then again, all this does not matter - it's incredibly fast after all!
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Antonio90 on October 20, 2023, 11:11:19 am
Thank you for demonstrating the difference between a measurement vs. a mess of noise and interference.

If we try to compare the two screenshots, we have all the information on the Siglent: FFT-sample rate, FFT-length and the Averaging mode. For convenience, we also get the frequency step - and in future versions of the FW we'll also get the RBW, which depends on the window function. About the only useful window for SA applications is Flattop, so we have to multiply the frequency step by ~3.8 and get a RBW of ~362 Hz in this case.

By contrast, the Rigol shows a much lower sample rate and claims a RBW of "20" - whatever that means. If we assume that the scope actually uses its maximum of 1 Mpts FFT, then the frequency step is about 30 Hz. How can we get a RBW of 20(Hz?) under these conditions? Only explanation could be the rather useless rectangle window, which can't be used for accurate measurements at all and doesn't have a constant RBW either - at the border between frequency bins it can be even much worse than a proper window function.

We can see the excessive noise and high internal spur levels. It does not look like it would measure the individual harmonics correctly. Considering the enormous difference in RBW (362/20), the dynamic appears to be inferior too. And don't forget, the Siglent is just an 8 bit DSO!

But then again, all this does not matter - it's incredibly fast after all!

FFT has always been an Achilles heel of cheap Rigol scopes if I'm not mistaken. Also, the screenshots are comparing a 500€ scope with a 1500€ one (assuming 4 channels in both cases). For many, that's peanuts. I don't work in an engineering environment, but, for my job, 1000€ is peanuts if it gets more work done, faster and more reliably.

For a hobbyist that can be the difference between 1 year of savings and 3. That's 3 years without a scope. If you extend that to the multimeters, power supply, AWG, logic analyzer, soldering iron, lab computer etc. it gets out of hand pretty fast. Ask me why I know.

There are a lot of problems, IMHO, with the DHO900, which roughly amounts to paying more for the same, as neither the bode plot nor LA work properly.

But the 800 is really good. It's cheaper than all the alternatives, Siglent, GWInstek or Micsig, its basic functionality is good, high resolution, reasonably low noise, fast interface, touchscreen, mouse support, HDMI out, fast data out to PC, good web interface, and a lot of other stuff.

I really don't get the hate. I mean, user 2N3055's criticism to the DHO900 is well deserved, I think. I would be really pissed with the FRA myself.
But why bash a bottom-of-the-barrel scope (in terms of it's price) comparing it with scopes 3 times (or even 7 with the 2000HD) the price?

The software is not finished, indeed, but everyone expected that, because that's how Rigol operates, at least with their entry-level scopes.

So, yeah, it's the best standalone scope you can buy for <500€. And yes, I don't think anybody would chose this over an SDS2000X+ or HD.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 20, 2023, 12:40:32 pm
Thank you for demonstrating the difference between a measurement vs. a mess of noise and interference.

If we try to compare the two screenshots, we have all the information on the Siglent: FFT-sample rate, FFT-length and the Averaging mode. For convenience, we also get the frequency step - and in future versions of the FW we'll also get the RBW, which depends on the window function. About the only useful window for SA applications is Flattop, so we have to multiply the frequency step by ~3.8 and get a RBW of ~362 Hz in this case.

By contrast, the Rigol shows a much lower sample rate and claims a RBW of "20" - whatever that means. If we assume that the scope actually uses its maximum of 1 Mpts FFT, then the frequency step is about 30 Hz. How can we get a RBW of 20(Hz?) under these conditions? Only explanation could be the rather useless rectangle window, which can't be used for accurate measurements at all and doesn't have a constant RBW either - at the border between frequency bins it can be even much worse than a proper window function.

We can see the excessive noise and high internal spur levels. It does not look like it would measure the individual harmonics correctly. Considering the enormous difference in RBW (362/20), the dynamic appears to be inferior too. And don't forget, the Siglent is just an 8 bit DSO!

But then again, all this does not matter - it's incredibly fast after all!

FFT has always been an Achilles heel of cheap Rigol scopes if I'm not mistaken. Also, the screenshots are comparing a 500€ scope with a 1500€ one (assuming 4 channels in both cases). For many, that's peanuts. I don't work in an engineering environment, but, for my job, 1000€ is peanuts if it gets more work done, faster and more reliably.

For a hobbyist that can be the difference between 1 year of savings and 3. That's 3 years without a scope. If you extend that to the multimeters, power supply, AWG, logic analyzer, soldering iron, lab computer etc. it gets out of hand pretty fast. Ask me why I know.

There are a lot of problems, IMHO, with the DHO900, which roughly amounts to paying more for the same, as neither the bode plot nor LA work properly.

But the 800 is really good. It's cheaper than all the alternatives, Siglent, GWInstek or Micsig, its basic functionality is good, high resolution, reasonably low noise, fast interface, touchscreen, mouse support, HDMI out, fast data out to PC, good web interface, and a lot of other stuff.

I really don't get the hate. I mean, user 2N3055's criticism to the DHO900 is well deserved, I think. I would be really pissed with the FRA myself.
But why bash a bottom-of-the-barrel scope (in terms of it's price) comparing it with scopes 3 times (or even 7 with the 2000HD) the price?

The software is not finished, indeed, but everyone expected that, because that's how Rigol operates, at least with their entry-level scopes.

So, yeah, it's the best standalone scope you can buy for <500€. And yes, I don't think anybody would chose this over an SDS2000X+ or HD.

I agree with you that cheap scopes don't have unlimited development budget..
And I can see that it can seen as bashing when someone has large list of problems to complaint about.
In addition to that, I'm old enough that I remember well how it is if you simply cannot afford 50€ more..

Problem is:
DHO4000 that is NOT cheap scope has equally bad BODE plot and FFT implementation as cheap DHO900/800.
Actually Rigol here developed a common platform. If they make excellent FFT for DHO4000, users of DHO800 could get same excellent FFT.
This is happening with Siglent: many features from Siglent's 10000 € scopes are available on much cheaper touchscopes...

Also cheap GW-Instek has very good FFT implementation, and slightly more expensive model has full realtime spectrum mode, well implemented.
Trust me, low price is not reason for shoddy FFT implementation.

So if all the problems, and unknowns are put together, DHO800 is not best scope you can buy today for 500ish €.
12 bit makes not such a big advantage to trade off that for many other (maybe necessary stuff, people need to decide for themselves what they need) that is missing or does not work well yet.

It does have capability to become good buy, when Rigol actually makes it work properly.
I can see future in which that statement might be true. But right now, today, no.

Of course, people, fully aware of current unfinished status, might chose to consciously buy it in this state of development and simply wait for as long as needed for Rigol to debug and finish it. We all have our own will, priorities, etc. But make sure you understand you are buying unfinished product and sort of promise that Rigol will eventually finish it in due time. If that is OK with you, it's perfect.

I must admit I tend to project a different perspective: I cannot afford to have a measurement instrument that I cannot trust. Even with very expensive instruments I sometimes measure with two different ones to verify.. Keysight has bugs too... R&S and Tek too...
My experience have proven that it is best to avoid ANY product for at least 1 year after initial release, if you actually need to depend on it...
With that in mind, my opinions are obviously influenced by that.

Best,
Siniša
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 20, 2023, 01:07:15 pm
FFT has always been an Achilles heel of cheap Rigol scopes if I'm not mistaken.

The DS1054Z initially did the FFT with just the data visible on screen, 1200 points. It wasn't great...

Later on they fiddled the firmware to use 64k points of data. It was a bit better but much slower...

These are 12-bit and up to 1Mpts. The "12 bits" seems to make about 10dB difference.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: mawyatt on October 20, 2023, 01:59:22 pm

FFT has always been an Achilles heel of cheap Rigol scopes if I'm not mistaken. Also, the screenshots are comparing a 500€ scope with a 1500€ one (assuming 4 channels in both cases). For many, that's peanuts. I don't work in an engineering environment, but, for my job, 1000€ is peanuts if it gets more work done, faster and more reliably.

For a hobbyist that can be the difference between 1 year of savings and 3. That's 3 years without a scope. If you extend that to the multimeters, power supply, AWG, logic analyzer, soldering iron, lab computer etc. it gets out of hand pretty fast. Ask me why I know.

There are a lot of problems, IMHO, with the DHO900, which roughly amounts to paying more for the same, as neither the bode plot nor LA work properly.

But the 800 is really good. It's cheaper than all the alternatives, Siglent, GWInstek or Micsig, its basic functionality is good, high resolution, reasonably low noise, fast interface, touchscreen, mouse support, HDMI out, fast data out to PC, good web interface, and a lot of other stuff.

I really don't get the hate. I mean, user 2N3055's criticism to the DHO900 is well deserved, I think. I would be really pissed with the FRA myself.
But why bash a bottom-of-the-barrel scope (in terms of it's price) comparing it with scopes 3 times (or even 7 with the 2000HD) the price?

The software is not finished, indeed, but everyone expected that, because that's how Rigol operates, at least with their entry-level scopes.

So, yeah, it's the best standalone scope you can buy for <500€. And yes, I don't think anybody would chose this over an SDS2000X+ or HD.

BTW the SDS2000X+ was available on sale for ~$1000 awhile back, good deal if acquired. Maybe this sale will reappear!!

Since "Best" and "Worst" are highly subjective, we tend to refrain from such, and our "Limited" opinion, limited in the sense we've only had a week to play around with such, the DHO814 has shown to be a good performer for General Purpose tasks, and has some unique/interesting properties that one might find useful.

Best,
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 20, 2023, 02:54:00 pm
BTW the SDS2000X+ was available on sale for ~$1000 awhile back, good deal if acquired. Maybe this sale will reappear!!

The SDS2104X+ is 1200€ before tax here at the moment. But we get a special deal on an "option bundle" -- 235€ for the LA and AWG license, and the logic probe kit which normally sells for more than that alone. That's 1435€ total, compared to 1000€ for the DHO914S with logic probes.

Proper 8-bit scope with large screen vs. corner-cutting 12 bit scope with better portability -- ah, decisions, decisions... I'll still wait to see the price for the SDS1000X HD (but am prepared to be put off by it).  ::)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Antonio90 on October 20, 2023, 03:32:43 pm

I agree with you that cheap scopes don't have unlimited development budget..
And I can see that it can see as bashing when someone has large list of problems to complaint about.
In addition to that, I'm old enough that I remember well how it is if you simply cannot afford 50€ more..

Problem is:
DHO4000 that is NOT cheap scope has equally bad BODE plot and FFT implementation as cheap DHO900/800.
Actually Rigol here developed a common platform. If they make excellent FFT for DHO4000, users of DHO800 could get same excellent FFT.
This is happening with Siglent: many features from Siglent's 10000 € scopes are available on much cheaper touchscopes...

Also cheap GW-Instek has very good FFT implementation, and slightly more expensive model has full realtime spectrum mode, well implemented.
Trust me, low price is not reason for shoddy FFT implementation.

So if all the problems, and unknowns are put together, DHO800 is not best scope you can buy today for 500ish €.
12 bit makes not such a big advantage to trade off that for many other (maybe necessary stuff, people need to decide for themselves what they need) that is missing or does not work well yet.

It does have capability to become good buy, when Rigol actually makes it work properly.
I can see future in which that statement might be true. But right now, today, no.

Of course, people, fully aware of current unfinished status, might chose to consciously buy it in this state of development and simply wait for as long as needed for Rigol to debug and finish it. We all have our own will, priorities, etc. But make sure you understand you are buying unfinished product and sort of promise that Rigol will eventually finish it in due time. If that is OK with you, it's perfect.

I must admit I tend to project a different perspective: I cannot afford to have a measurement instrument that I cannot trust. Even with very expensive instruments I sometimes measure with two different ones to verify.. Keysight has bugs too... R&S and Tek too...
My experience have proven that it is best to avoid ANY product for at least 1 year after initial release, if you actually need to depend on it...
With that in mind, my opinions are obviously influenced by that.

Best,
Siniša

BTW the SDS2000X+ was available on sale for ~$1000 awhile back, good deal if acquired. Maybe this sale will reappear!!

Since "Best" and "Worst" are highly subjective, we tend to refrain from such, and our "Limited" opinion, limited in the sense we've only had a week to play around with such, the DHO814 has shown to be a good performer for General Purpose tasks, and has some unique/interesting properties that one might find useful.

Best,
You are right. "The best scope" does not exist, and my assertion was baseless without taking individual needs into account.

However, in this thread and the other long thread about this same series, there are quite a few examples about how things should be done, and almost all of them, if not all, come from instruments of a different class, in capabilities and price, and with older and more mature firmware. And I'm not quite sure what should someone with 500 bucks to spend learn from it.

I do still think that it is a really good scope for the price, and will probably set a new standard for budget scopes. Just think about having a 12bit scope for less than 500 bucks five years ago. But yes, it is also buying into an implicit promise of future improvement and development.

$1000 for the SDS2000X-Plus is a really good price, and I might think about selling my scope if that offer was available in EU.

Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 20, 2023, 04:51:04 pm
Quote
And I'm not quite sure what should someone with 500 bucks to spend learn from it.

At least my examples with my SDS2504X HD are not intended for direct comparison in the sense of "competition"
Because that really doesn't make sense, given the price difference.
But that should be clear to everyone... ;)
No, at least my intention is to show how it could work.
The actual comparison is still to come.... 8)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 20, 2023, 05:12:12 pm
The actual comparison is still to come.... 8)

... provided that Siglent wants to play this game at all.  ::)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: rpro on October 20, 2023, 05:31:27 pm
What I don't like is that "RBW" has no unit of measurement.
Comparing spectra with my MSO5000, the RBW seems to be in Hz. 
Quote
You can only change the vertical offset position of the FFT with a button, if the menu is active and you have selected the offset there.
Outside of the menu, you can neither move the FFT up or down with the vertical knob, nor are the 2 action buttons responsible for this, they change span and center.
Only with the fingertouch you can change the position.
Maybe this is what you meant, but upon clicking on the Offset or Scale input fields in the FFT menu window, the two small yellow 1 & 2 hexagons appear at their corners, indicating you can change their values with the respective two "action encoders".
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: rpro on October 20, 2023, 05:47:48 pm
No luck with Cursor Peaksearch in FFT tho.
By clicking on the cursor panel and going into "Setting" you can change the source for the cursors to the FFT math channel, and then manually move the cursors with the respective 2 "action encoders", e.g. to match displayed frequencies on the peaksearch table. Far from ideal, but usable...
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: KedasProbe on October 20, 2023, 06:01:55 pm
I received my DHO914S this week, will do some tests this weekend.
I see there is an bandwidth option that is now showing "Limit" all other options show "Forever"

Does someone know how long the limited NW upgrade option will stay present?

I assume all current tests are done with DHO800 at 100MHz and DHO900 at 250MHz.

edit: see attachment
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 20, 2023, 06:53:17 pm
I wondered about that. Mine has a storage depth option with "Limit" but storage isn't an option on a DHO804.
(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1906404;image)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Mechatrommer on October 20, 2023, 07:37:45 pm
how do you know its boxcar averaging?
This is quite easy: When doing a single shot trace of preset sample count and analyze the individual samples, you can easily see the quntization of the values (like the "bins" in a histogram). At 1.25MSa/s, 1V/div you will find a quantization of approx. 2.31mv, which, assuming a quantization of 12bits (as per Rigol's specs), results in a total peak-to-peak range of approx. 9.5V which easily matches the 8 vertical divisions (8V) of visible vertical range.

The same test with a sampling rate of 100kSa/s has a quantization of approx. 0.2875mV which leads to a resolution in the ballpark of 15 bits. Since in a single shot, the calculation of a classic "isotemporal" average isn't possible, and the sampling engine itself can still be kept running at its "native" speed, it's a reasonable approach to average the "raw" samples that fall between two "shadow memory" (software) samples, into each adjacent s/w sample, resulting in the observed increase in resolution. And that's just boxcar averaging.

So to cut a long story short, just the fact to find a higher than hardware resolution in down-sampled single shot traces indicates that some kind of boxcar averaging has been applied to decimate the ADC raw data.

this post is continuation from...

...
I think people are confusing the several "sample rates" within a scope. The ADC sampling rate and acquisition sampling rate (which is the data stored to memory) are not always equal. And what happens between those steps is not consistent between difference scopes/brands.

The megazoom "issue" that you've pointed to (out of context) is those scopes reducing the acquisition sample rate when in non-8bit modes, (peak detect, averaging, high resolution) as the acquisition rate changes to fill the available aquitision memory (keeping the horizontal timebase the same). The ADCs keep running at their full rate for all acquisition modes, just as the Rigol do, tuning on more channels increases the multiplex to the ADCs and drops the per channel ADC sample rate (XXGS/s to 0.5*XXGS/s).

switchabl is correct that the ADC sample rate is determining the peak detect capture window (unless some scopes have analog domain peak detect?).

With "normal" sampling configuration, the DHO900 is actually boxcar averaging when the "Shadow Memory Sampling Rate" is lower than the ADC rate which apparently stays the same all the time (only activating additional channels multiplexes this sample rate over the enabled channels). See here: https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/msg5109618/#msg5109618 (https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/msg5109618/#msg5109618)
how do you know its boxcar averaging?

i tried the test you described. i got same bin size of around 2.2-2.4mV (very close to 12bits using your metric of 9.5Vpp) for both sample rate, so my setup is nowhere near your 20500 bins. maybe you've set other parameters/setting in your scope? Average acquisition maybe? or different FW? attached are my data and running FW version...
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 20, 2023, 07:41:45 pm
... provided that Siglent wants to play this game at all.  ::)

No I meant the scopes I have here or can loan "immediately" (SDS1104X-E, DS1054Z).

Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 20, 2023, 07:45:55 pm
I assume all current tests are done with DHO800 at 100MHz and DHO900 at 250MHz.

I assume so, because mathematically (0.35 /risetime) mine is currently at 100Mhz...125Mhz and in the "options" menu I also see a (nowhere to buy) limited bandwidth upgrade.
@Fungus:
I find that interesting that you don't have that....
Had you already determined the bandwidth of your scope ?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Mechatrommer on October 20, 2023, 08:45:06 pm
on to FFT plot (external PC SW and DSO's built in) DS1054Z vs DHO800...
signal source, EraSynth Micro 50/100/200MHz 0 and -50dBm output (output level not accurate due to uncertified front end amplifier part replacement sometime ago)

nomen:
left column (DS1054Z data)
right column (DHO800 data)

top row (noise floor) at 20mV/div, 1mV/div (DS1054Z), 500uV/div (DHO800)
2nd top row (50MHz 0dBm, -50dBm)
next row (100MHz 0dBm, -50dBm)
next row (200MHz 0dBm, -50dBm)

scope's built in FFT conclusion:
DS1054Z: less usefull
DHO800: usefull

fwiw, imho.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: iMo on October 20, 2023, 08:56:31 pm
..
It does have capability to become good buy, when Rigol actually makes it work properly.
I can see future in which that statement might be true. But right now, today, no.
..

That is the key question here - the "capability to become good buy"..
What the prospective buyers (like me) want to know is whether there is the "capability" actually existent. They want to know whether the current issues are because of the state of the current software implementation and could be fixed, or, that the current issues are there because of the hardware limitation which is the final state and cannot be improved..
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 20, 2023, 09:10:02 pm
Had you already determined the bandwidth of your scope ?

I don't have a fancy pulse generator like you guys but I've seen rise times around 4.8ns which would be ~70Mhz.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 20, 2023, 09:34:10 pm
..
It does have capability to become good buy, when Rigol actually makes it work properly.
I can see future in which that statement might be true. But right now, today, no.
..

That is the key question here - the "capability to become good buy"..
What the prospective buyers (like me) want to know is whether there is the "capability" actually existent. They want to know whether the current issues are because of the state of the current software implementation and could be fixed, or, that the current issues are there because of the hardware limitation which is the final state and cannot be improved..

If you want a prediction (educated guess or whatever) i haven't got a crystal ball.
I have no clue when or even if Rigol will fix problems, which ones they will ignore or even if they can fix all the stuf.
I know even less if they will enhance it with new features (like R&S, Keysight and Siglent do) and if they do to what extent.

But yeah, avoid DHO900, for that one I have enough data points to be able to make that recommendation.
For DHO800/1000/4000 I cannot see showstoppers to discount them up front. Them I would give a chance to prove themselves.

But in that particular lengthy post of mine is only answer to that pivotal question: don't buy experimental preproduction  batches of products. Wait at least few months to see how it progresses..
That is only way to know for sure.
I'm not a gambling man. That is all the advice I have...

Title: Re: Rigol DHO804 Test and Compare Thread
Post by: TurboTom on October 20, 2023, 09:44:04 pm

...
i tried the test you described. i got same bin size of around 2.2-2.4mV (very close to 12bits using your metric of 9.5Vpp) for both sample rate, so my setup is nowhere near your 20500 bins. maybe you've set other parameters/setting in your scope? Average acquisition maybe? or different FW? attached are my data and running FW version...

Thanks for repeating my tests. That's an interesting finding! I remember I did one more step after taking the "single shot" and saving the CSV of the sample memory: I zoomed into the trace data vertically to the maximum "linear" scale, this is five increments of the vertical encoder. So it must have been zoomed to the 20mV/div range. I assumed (which obviously was the wrong thing to do) that during this process, the sample data in the "shadow memory" won't be altered since this zooming process is completely reversible.

As it appears now, the sampling / decimation engine is way more complex than initially anticipated and moreover, it's questionable what data really gets stored when the user selects memory or screen as the source for the CSV to be generated. I'm sorry I cannot contribute to the testing anymore since my DHO914S is on its return trip to the distributor. Or maybe I should say I'm happy for this since this way, it saves me a lot of time  ;).
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 20, 2023, 09:51:34 pm
What pleased me is that both the large DHO4000 and the small DHO 800 have the same software platform.
As you may remember, I had the 4000 here for testing in February of this year.
And after 8 months, I receive the DHO804 and have to soberly note that nothing has changed since then.
I find that very sad - For the 4000 owners.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Mechatrommer on October 20, 2023, 10:01:15 pm
Had you already determined the bandwidth of your scope ?
I don't have a fancy pulse generator like you guys but I've seen rise times around 4.8ns which would be ~70Mhz.
if you have Uni-T UTG962 AWG, its Sync output terminated can give 1ns risetime, you can use that to check DHO800 https://www.eevblog.com/forum/projects/yet-another-fast-edge-pulse-generator/msg3615705/#msg3615705 (https://www.eevblog.com/forum/projects/yet-another-fast-edge-pulse-generator/msg3615705/#msg3615705). here (attached) i just tested it on DHO800...
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 20, 2023, 10:14:30 pm
This roughly coincides with my risetime:

https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/msg5106120/#msg5106120 (https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/msg5106120/#msg5106120)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 21, 2023, 04:51:57 am
if you have Uni-T UTG962 AWG, its Sync output terminated can give 1ns risetime, you can use that to check DHO800

Oh, that's handy...

If I do that I get 3.5ns rise time - it's 100MHz bandwidth right now!  :)
(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1906749;image)

(But no mention of it in the options...)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 21, 2023, 07:28:38 am
If I do that I get 3.5ns rise time - it's 100MHz bandwidth right now!  :)

I wonder if that's a bug in the options page - it says "Storage depth option" when it should really say "Bandwidth option".

FWIW I just turned mine into a 924 and I got a 1.5ns rise time using the siggen:  :)
(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1906779;image)

So it looks like I did have a pulse generator, I just didn't know it.  8)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 21, 2023, 07:50:18 am
Does anybody here own a DHO814?

If so, could you post the 814's vendor.bin... it's really easy to extract over Ethernet.

Title: Re: Rigol DHO804 Test and Compare Thread
Post by: tautech on October 21, 2023, 08:18:25 am
FWIW I just turned mine into a 924 ...............
Did that fix any bugs ?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 21, 2023, 08:30:11 am
FWIW I just turned mine into a 924

Interesting, how did you do it ?
Do you have more memory now (50Mpts instead of 25Mpts) ?
Can you set the horizontal smaller than 5ns/div ?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 21, 2023, 08:31:55 am
could you post the 814's vendor.bin...

https://www.eevblog.com/forum/testgear/rigols-new-dho800-oscilloscope-unbox-teardown/msg5062843/#msg5062843 (https://www.eevblog.com/forum/testgear/rigols-new-dho800-oscilloscope-unbox-teardown/msg5062843/#msg5062843)

Thanks! Now I have a HDO800 with 2.3ns rise time.  :-+
(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1906797;image)

Self-cal worked OK. All we need now is a 50MSample memory hack.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 21, 2023, 08:49:54 am
FWIW I just turned mine into a 924
Interesting, how did you do it ?

Download adb command line tools here: https://developer.android.com/tools/releases/platform-tools (https://developer.android.com/tools/releases/platform-tools)

(nb. You only need three files from that: adb.exe and AdbWin*.dll)

Now do this:

adb connect 192.168.1.205:55555            (or whatever your IP address is)
adb pull /rigol/data/vendor.bin            (keep this file safe - it's your vendor.bin)

Download the HDO924 vendor.bin from here (https://www.eevblog.com/forum/testgear/hacking-the-rigol-dho800900-scope/msg5074867/#msg5074867)

adb push vendor.bin /rigol/data
adb reboot                                                (do NOT power cycle it, there seems to be a delay before the file is written)

To switch it back just push your original vendor.bin

Do you have more memory now (50Mpts instead of 25Mpts) ?

I only had 25Mpts. I'm guessing that 924 didn't have the 50Mpts memory option.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 21, 2023, 08:52:12 am
Ah,
Now I understand - you had first gone to the 924 and then "back" to the 814 ?

Quote
I'm guessing that 924 didn't have the 50Mpts memory option.

The 50Mpts are standard for the 900 series.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 21, 2023, 09:12:42 am
The 50Mpts are standard for the 900 series.

I tried it again and yes, there's 50Mpts in 924 mode:
(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1906821;image)

It seems like there's a delay between pushing the file and it being written to flash. If you power off and on the change might not work (and bricking is possible? I don't know if the Android file system is atomic or not)

If you do "adb reboot" it syncs the file system and works every time.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Mechatrommer on October 21, 2023, 09:44:18 am
could you post the 814's vendor.bin...

https://www.eevblog.com/forum/testgear/rigols-new-dho800-oscilloscope-unbox-teardown/msg5062843/#msg5062843 (https://www.eevblog.com/forum/testgear/rigols-new-dho800-oscilloscope-unbox-teardown/msg5062843/#msg5062843)
Thanks! Now I have a HDO800 with 2.3ns rise time.  :-+
..snip..

Self-cal worked OK. All we need now is a 50MSample memory hack.
Now I understand - you had first gone to the 924 and then "back" to the 814 ?
why need to change back to 814 when 924 is much better spec? is there anything i'm not aware of? i will upgrade my scope to 924 when i settled tinkering with standard 804, backup the sd card and do the upgrade later.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 21, 2023, 09:50:09 am
why need to change back to 814 when 924 is much better spec? is there anything i'm not aware of? i will upgrade my scope to 924 when i settled tinkering with standard 804, backup the sd card and do the upgrade later.

I don't want this on the screen (or any LA-specific features in the menus if there are any):
(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1906833;image)

I'm sure there must be a way to enable bandwidth/memory without that.

I'm trying to find out how to decrypt vendor.bin so I can do a diff on them.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Mechatrommer on October 21, 2023, 09:57:32 am
why need to change back to 814 when 924 is much better spec? is there anything i'm not aware of? i will upgrade my scope to 924 when i settled tinkering with standard 804, backup the sd card and do the upgrade later.
I don't want this on the screen:
(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1906833;image)
so thats image for 924S? but you will lose 230MHz BW, i will just ignore that if i cant find 924 image or workaround imho.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 21, 2023, 10:17:11 am
so thats image for 924S? but you will lose 230MHz BW, i will just ignore that if i cant find 924 image or workaround imho.

The current plan is to get as many vendor.bin files as I can and diff them all.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: iMo on October 21, 2023, 11:38:10 am
..
I don't want this on the screen (or any LA-specific features in the menus if there are any)
..

A small squared black sticker glued on the LCD would fix it..  :P
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: rpro on October 21, 2023, 01:17:14 pm
I don't want this on the screen (or any LA-specific features in the menus if there are any):
On the DHO804, with vendor.bin 924, when you click/tap on the LA icon you get a small window saying "Please Insert LA Probe", that disappears on its own. Other than that, I can not find any traces of the LA in the menus (e.g. as sources for (logic) triggers, decoder, measurements, cursors, or math channels.) The code must be checking for the presence of the LA probe (and/or some other hardware clue) before it populates the menus.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 21, 2023, 07:28:43 pm
I have now started to go through the Batronix demo board, i.e. the examples given in the manual.
I also do this only with the two "small", dho804 and sds1104X-E.
Note that both scopes are set the same, nevertheless, on the siglent screen is "more going on" in the sense of more signals on the screen.
This is not a rating, just an observation.
The first trigger example "Pulsewidth" mastered both to the satisfaction, but already with the second I have a problem:
Interval trigger, is there an equivalent with the rigol ?
Siglent has this trigger, accordingly I could perform the example.
Not well visible on the photo:
To get about the same brightness as with the siglent, I had to set the corresponding "sliders" on the rigol to almost full stop.
This is also just an observation, not a judgement.
@Fungus:
I noticed earlier, I now also have the "Storage Depth" as a limit in the options menu, instead of the bandwidth.
I think this was "replaced" when we updated our firmware.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: tautech on October 21, 2023, 07:36:19 pm
Hide Menu, why ?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 21, 2023, 07:43:05 pm
Why not ? I like it better when you have as little superfluous content on the screen as possible.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: voltsandjolts on October 21, 2023, 07:44:40 pm
Interval trigger, is there an equivalent with the rigol ?

Pulse trigger with negative pulse?
Or maybe I don't understand what interval trigger is.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: tautech on October 21, 2023, 07:48:22 pm
Why not ? I like it better when you have as little superfluous content on the screen as possible.
Hides Interval trigger menu.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 21, 2023, 07:49:41 pm
Hi voltsandjolts,

https://www.tiepie.com/en/fut/interval-trigger (https://www.tiepie.com/en/fut/interval-trigger)
Or pic from the siglent manual below.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 21, 2023, 08:22:27 pm
https://www.tiepie.com/en/fut/interval-trigger (https://www.tiepie.com/en/fut/interval-trigger)
Or pic from the siglent manual below.

Isn't that a special case of the "Delay Trigger" on Rigol scopes, where you select the same channel for sources A and B? At least that should do the <= and >= timing conditions. I don't understand the [--,--] and --][-- notation in the Siglent manual though, what conditions do these denote?

Edit: Ah, saw it explained on the TiePie page. Looks like Rigol's <> and >< conditions are equivalent to Siglent's [--,--] and --][--.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 21, 2023, 09:21:00 pm
Hi,
Delaytrigger don´t work.
The best you can get with this is the same as when you use the edge trigger (stable signal with some "irritations" in it).
Another thing:
I couldn´t find in the manual how to set date and time...?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 21, 2023, 09:31:35 pm
Delaytrigger don´t work.
The best you can get with this is the same as when you use the edge trigger (stable signal with some "irritations" in it).

Strange. But do we agree that it should work, i.e. is equivalent to Siglent's interval trigger according to the manuals?
Edit: I'm referring to section 8.7.10 in the DHO800 manual.

Quote
Another thing:
I couldn´t find in the manual how to set date and time...?

I think this has been discussed somewhere in the various DHO 800 threads. Wasn't the conclusion that the only way is to get the time & date via NTP?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 21, 2023, 10:04:29 pm
Hi,

Quote
But do we agree that it should work, i.e. is equivalent to Siglent's interval trigger according to the manuals?

Hm..
I think it does not work because the delay trigger assumes two different sources with a phase shift.
Now we have only one.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 21, 2023, 10:09:22 pm
Another thing:
I couldn´t find in the manual how to set date and time...?

From the latest release notes:
Code: [Select]
...
1. Remove all time-related displays on the instrument
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 21, 2023, 10:13:32 pm
Hi,

Quote
But do we agree that it should work, i.e. is equivalent to Siglent's interval trigger according to the manuals?

Hm..
I think it does not work because the delay trigger assumes two different sources with a phase shift.
Now we have only one.

I'll give that a try with my venerable DS1054Z tomorrow -- no, actually today, but after getting some sleep... Thought I had used that trigger mode in the past with both sources set to the same channel.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 21, 2023, 10:14:28 pm
@Fungus:
Fu**... ;)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 21, 2023, 10:17:18 pm
I think it does not work because the delay trigger assumes two different sources with a phase shift.

You can set the sources to the same channel:

(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1907337;image)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: rpro on October 21, 2023, 10:19:03 pm
Hi,

Quote
But do we agree that it should work, i.e. is equivalent to Siglent's interval trigger according to the manuals?

Hm..
I think it does not work because the delay trigger assumes two different sources with a phase shift.
Now we have only one.

It does work. You can indeed set the sources to be the same channel, making "interval trigger" a special case of this trigger, as @ebastler pointed out. See attached...
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 21, 2023, 10:20:57 pm
Aha... :D

Then I still have something wrong set, I will try again tomorrow - thanks!
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 21, 2023, 10:27:37 pm
Hm ?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 21, 2023, 10:33:25 pm
So in fact the Rigol can do more than the Siglent - it allows the two trigger points to be on separate channels.  :popcorn:

(The list of available trigger types is also longer on the Rigol... I count 17 types on the Rigol and only 14 on the Siglent)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 21, 2023, 10:38:18 pm
Didn't we just prove with the missing interval trigger that you can replace it with another trigger type?
It will be the same the other way around. ;)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 21, 2023, 11:06:01 pm
Didn't we just prove with the missing interval trigger that you can replace it with another trigger type?
It will be the same the other way around. ;)

No. Siglent's Interval Trigger is a subset of Rigol's Delay Trigger functionality. So Delay Trigger can replace Interval Trigger, but not vice versa. -- Better get some sleep! (And so should I...)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 21, 2023, 11:11:53 pm
I didn't mean it that way either.
Good night John-Boy.. ;)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 21, 2023, 11:17:04 pm
Bed time for me.

Tautech can have this thread to himself for a while.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 21, 2023, 11:31:39 pm
Fist of all Interval trigger on Siglent supports two channels, it is equal to Rigol Delay trig.
Both have pulse trigger that is also same.  Pulse trigger can be achieved with Interval (Delay), pulse is really simply a quick shortcut.

Second in DHO800 datasheet I count 15 triggers including serial ones. 12 analog triggers and 3 serial ones.
Siglent SDS1104X-E has 9 analog triggers and 5 serial ones (because it supports 3 more serial protocols). 14 total.

DHO800 has additional Setup and hold, N-th edge and Duration (which is variation of Pattern) trigger.

Siglent has more versatile Dropout trigger (Timeout in Rigol) that support state in addition to edges.
It also have time setting in Runt. In a same manner it has time setting in Pattern trigger, which covers many options of Duration trigger.
And 2more serial triggers and protocols(CAN, LIN).

Only 2 triggers that SDS1000X-E does not have are Setup and hold and N-th edge. It has 2 more serial triggers and protocols(CAN, LIN).

As I said before Rigol likes to play checkbox in a datasheet game. In reality it is not that simple. If you need CAN and LIN it is Siglent that has advantage..

I would say both have very good trigger set.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 21, 2023, 11:42:54 pm
Second in DHO800 datasheet I count 15 triggers including serial ones. 12 analog triggers and 3 serial ones.
Siglent SDS1104X-E has 9 analog triggers and 5 serial ones (because it supports 3 more serial protocols). 14 total.

If you need CAN and LIN it is Siglent that has advantage..

Try looking in the DHO900 datasheet.  :popcorn:
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 21, 2023, 11:53:13 pm
Quote
I would say both have very good trigger set.

90% of which you only use the edge trigger anyway, even for serial decoding.

Quote
Tautech can have this thread to himself for a while.

Actually, I had started this thread to document as factual a comparison as possible.
Apropos, what is actually with your thread, did not you want to open its own with tests ?
Is it still coming ?

Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 22, 2023, 12:07:05 am
Apropos, what is actually with your thread, did not you want to open its own with tests ?
Is it still coming ?

That was just a joke to annoy my fan club.   :D
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: rpro on October 22, 2023, 02:47:07 am
Fist of all Interval trigger on Siglent supports two channels, it is equal to Rigol Delay trig.
Was the interval trigger working across 2 channels a feature added subsequent to the release of the 8/2021 manual? The siglentna.com manual description seems to convey that this trigger is defined on the same channel, referring to "the pulse time" of  "the [same?] input signal"... https://siglentna.com/wp-content/uploads/dlm_uploads/2021/08/SDS1000X-ESDS1000X-U_UserManual_EN05B.pdf . Page 82. Thanks.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 22, 2023, 07:09:52 am
Second in DHO800 datasheet I count 15 triggers including serial ones. 12 analog triggers and 3 serial ones.
Siglent SDS1104X-E has 9 analog triggers and 5 serial ones (because it supports 3 more serial protocols). 14 total.

If you need CAN and LIN it is Siglent that has advantage..

Try looking in the DHO900 datasheet.  :popcorn:

Sure, I can look at DS70000 datasheet too.

He's comparing DHO800  to SDS1104X-E.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 22, 2023, 07:20:49 am
Fist of all Interval trigger on Siglent supports two channels, it is equal to Rigol Delay trig.
Was the interval trigger working across 2 channels a feature added subsequent to the release of the 8/2021 manual? The siglentna.com manual description seems to convey that this trigger is defined on the same channel, referring to "the pulse time" of  "the [same?] input signal"... https://siglentna.com/wp-content/uploads/dlm_uploads/2021/08/SDS1000X-ESDS1000X-U_UserManual_EN05B.pdf . Page 82. Thanks.

No you are correct, my mistake. Sorry. I confused it with Delay trigger settings my scope has.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: tautech on October 22, 2023, 07:22:54 am
Second in DHO800 datasheet I count 15 triggers including serial ones. 12 analog triggers and 3 serial ones.
Siglent SDS1104X-E has 9 analog triggers and 5 serial ones (because it supports 3 more serial protocols). 14 total.

If you need CAN and LIN it is Siglent that has advantage..

Try looking in the DHO900 datasheet.  :popcorn:

Sure, I can look at DS70000 datasheet too.

He's comparing DHO800  to SDS1104X-E.
7 Mpts with all channels active.
500 MSa/s with all channels active
MSO capability.
AWG capability.

Is it a fair comparison ?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Performa01 on October 22, 2023, 08:35:40 am
7 Mpts with all channels active.
500 MSa/s with all channels active
MSO capability.
AWG capability.
To be more precise:

Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 22, 2023, 09:09:29 am
So you Siglent salesmen have nothing to worry about. Sit back and relax.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 22, 2023, 09:35:40 am
So you Siglent salesmen have nothing to worry about. Sit back and relax.

Only Tautech is making money selling Siglent... And does not hide it...
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 22, 2023, 09:38:33 am
Some other affiliations are less obvious, I guess.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 22, 2023, 10:12:36 am
Some other affiliations are less obvious, I guess.

I don't understand.

Topic introduced comparison between DHO800 and SDS1104X-E. I personally extricated myself from other DHOxxx/x topics, because I cannot contribute there to the current direction there ...

Despite all overhype DHO800 is extremely limited scope in it's capabilities. It seems it has rather low noise and 12 bit ADC, which despite thousands of stupid posts of hacking the PSU (because people want it to be portable or because Rigol screwed up such a basic thing as PSU) nobody really measured and characterized to see if that performance is really that good, or there are some hidden tricks there, which was hinted by some when tested.
It also have very decent list of triggers, I commended them for that, repeatedly.
FFT is half made and nobody can even prove it works well. Which means FFT is unusable in current state, unless you just want to gave something cool jumping on the screen, for visual effects.
Also not a SINGLE word about much hyped FastAcq. Is it simply a trick to hide fact it does not have real segmented mode that you can use for anything, like measurements or decoding.. Does anybody who bought these scopes actually plan to use them, or they just mean to twiddle PSU-s and hack them eternally?

OTOH SDS1104X-E is fully functional scope that was proven to work really well, it has 3 decode protocols more (no hacking necessary), better sampling rates with more channels, good front end, good FFT, fully functional segmented and history mode that work with full support of measurements.. Despite it being 8bit and no touch scope, it is much more advanced scope in ACTUAL measurement capabilities. It is not cutting edge, but very solid proven stable platform.

If I had to buy today inexpensive scope that I needed to do actual work and I could trust, and I had to choose between those two, I would choose SDS1104X-E today. For many reasons.

That is situation today. Cool facts, no Siglent propaganda. In fact there is huge hype about these DHO800 scopes that is simply not true and if anybody is misrepresenting facts that is Rigol fanbase..

It is in Rigols hands whether that changes.. They should step up and close the gap... Until then, my opinion and statement stay, substantiated with facts. Anybody that claims I'm wrong should present evidence to the contrary. In a format of actual measurement that they managed to do on DHO800 that cannot be done on SDS1104X-E.  Because I can demonstrate dozens type of work I know DHO800 cannot do and I use it all the time.

I don't care for ad hominem attacks. If anything they usually start when I proved my point and other side has no case and then the try to shut me up. It is usually a good sign I'm right...

Best,

Siniša
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Performa01 on October 22, 2023, 10:18:29 am
This is a test and compare thread. Martin72 has just started his tests, yet this thread already has more than 400 replies - most of them off topic or just noise.

Not everyone pointing out facts that are less favourable for Rigol is a "Siglent salesman".
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 22, 2023, 10:29:18 am
Some other affiliations are less obvious, I guess.
I don't understand.

I was not talking about you, and certainly don't mean to attack you. While it does come across that you generally like Siglent products, you tend to take a balanced and factual approach. Thanks for that!

By the way, I agree that the SDS1104X-E is a great scope in its class. If I had not bought a DS1054Z several years before the 1104X-E came out, I would probably own one of those today.

Not everyone pointing out facts that are less favourable for Rigol is a "Siglent salesman".

What is your link to Siglent? It does seem to go beyond "generally liking their products".
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 22, 2023, 10:30:14 am
Is it a fair comparison ?

DHO814 costs 499€(exc.VAT), SDS1104X-E 429€ (exc.VAT) so I think the comparison is logical.
Whether the SDS now has awg, LA and bodeplot and the DHO does not is irrelevant for the time being, as I am primarily comparing measurement situations.
If there are differences, this may be due to discrepancies in the hardware equipment according to the data sheet or the software still has errors.
But I haven't got that far yet. ;)
And next week I will be able to take a DS1054Z home with me, which is also one of the kombatants.
SDS1104X-E and DS1054Z (mostly hacked to 100Mhz) might be the most popular entry level scopes on the market at the moment, now a new generation is here and that's why I'm interested.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 22, 2023, 10:56:07 am
DHO814 costs 499€(exc.VAT), SDS1104X-E 429€ (exc.VAT) so I think the comparison is logical.

Not really because the 399€ DHO804 will outsell the DHO814 by an order of magnitude, see below.

SDS1104X-E and DS1054Z (mostly hacked to 100Mhz) might be the most popular entry level scopes on the market at the moment, now a new generation is here and that's why I'm interested.

Is the DS1054Z the only one that's allowed to be hacked?

People also hack their Siglents and a lot of people will hack their DHOs.

A DHO804 costs 100€ less than the Siglent and can be switched to Siglent-beating memory/bandwidth in under two minutes over Ethernet. An awful lot of hobbyists will do that (just like they did with the DS1054Z).

The only fly in the ointment is the Rigol's 1.25Ghz sample rate but I don't think that will deter people. Hackers gonna hack.

Besides, we only have 150Mhz probes so that will help to mitigate the problem.

Testing the DHO804 probes is definitely something that could usefully be tested by somebody who owns a better signal generator than me.

(Much more useful than going through all the trigger modes and making a list IMHO. Such a list will only feed the Rigol/Siglent wars...)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 22, 2023, 11:08:06 am
OTOH SDS1104X-E is fully functional scope that was proven to work really well

It's also big and ugly, not touch screen, won't run off a powerbank, twiddly knob user interface... and 100 Euros more expensive.

FFT is half made and nobody can even prove it works well. Which means FFT is unusable in current state, unless you just want to gave something cool jumping on the screen, for visual effects.

Dave had no problems using it in his review video. It outperformed the Siglent in terms of noise floor and completely destroyed it in terms of update rate.

He also found some weird distortions/anomolies/bugs on the Siglent FFT which nobody has explained yet.

See Dave's video at the 32 minute mark:
https://youtu.be/S8jrpCoZyx8?t=1920

Also check out the Rigol's pulse response which follows on from the FFT. Better than the Siglent.

Also not a SINGLE word about much hyped FastAcq. Is it simply a trick to hide fact it does not have real segmented mode that you can use for anything, like measurements or decoding.. Does anybody who bought these scopes actually plan to use them, or they just mean to twiddle PSU-s and hack them eternally?

It has real segmented mode with faster waveform capture rate than the Siglent.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 22, 2023, 11:15:13 am
Some other affiliations are less obvious, I guess.
I don't understand.

I was not talking about you, and certainly don't mean to attack you. While it does come across that you generally like Siglent products, you tend to take a balanced and factual approach. Thanks for that!

By the way, I agree that the SDS1104X-E is a great scope in its class. If I had not bought a DS1054Z several years before the 1104X-E came out, I would probably own one of those today.


I wasn't feeling being called out personally and even less attacked by you. We always had good, honest and respectful discussions.
I was simply asking for clarification in general.

Thank you for kind words. I try, all we do is always colored by our cognitive biases, so one has to be carefull.
But if science taught us something is that there are methods to ensure (more?) realistic results..

In case of instruments like oscilloscopes there are ways to look at things to ensure more balanced approach.

1. I don't look at "datasheet checklists" as direct comparisons. Nominaly same function can have such a different implementation so they could have vastly different capabilities.
2. So instead of questions like  "Does it have this trigger" right way to ask that question is "Can it trigger on this kind of event and how"
3 If it has "Feature XYZ" what can you actually do with it? So instead list of "Features" we should think in terms "It can do these types of measurements". Example: It is not about "Does this scope have BODE plot function" we should ask "Can we measure BODE plots with it and how and what we can measure"
4. This kind of thinking creates clarity. For instance if you need statistics one scope has statistics and other don't you have clear choice of one of them being inadequate. If both have the statistics, than you go into detail and look into quality of implementation.  But if one is better but other one is already adequate, then you decide on scope based on some other metric.
5. Basically you compare actual real word usage scenarios not datasheet checklists. Those are made by marketing in most companies and are there to paint it in good light. I do find Siglent's datasheets better written and more factual than Rigols though. Siglents manual for scopes are same quality as KEysight or R&S. Not that Rigol datasheets lie or misrepresent, but level of detail and how is written is different. It probably shows target market focus. Rigol is more oriented to hobby market and has a bit more consumer market approach in marketing. That is my impression.


Etc etc..

It is all about measure 3 time, cut once...

Best,
Siniša
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 22, 2023, 11:37:04 am
4. This kind of thinking creates clarity. For instance if you need statistics one scope has statistics and other don't you have clear choice of one of them being inadequate. If both have the statistics, than you go into detail and look into quality of implementation.

You also have to look at how fast/easy it is to use the feature. The Rigol's statistics shine in this area.

They're also better implemented (they use a sliding window and are always available - just unfold the stats area on the measurement of interest, no need to menu-dive and enable a special "stats" mode).

So it's horses for courses. You might be able to sit down and prove mathematically that the Siglent is somehow "best" but which is going to be nicer and more useful to most people?

eg. How do you assign weights to things like the way the statistics work? When you have little niceties like that all over the place then it starts to add up to something valuable.

The Rigol's windowing abilities, too. How will you factor that into the big equation?

etc., etc.

TLDR; Defining "better" isn't as easy as you seem to think.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 22, 2023, 11:46:31 am
OTOH SDS1104X-E is fully functional scope that was proven to work really well

It's also big and ugly, not touch screen, won't run off a powerbank, twiddly knob user interface... and 100 Euros more expensive.

FFT is half made and nobody can even prove it works well. Which means FFT is unusable in current state, unless you just want to gave something cool jumping on the screen, for visual effects.

Dave had no problems using it in his review video. It outperformed the Siglent in terms of noise floor and completely destroyed it in terms of update rate.

He also found some weird distortions/anomolies/bugs on the Siglent FFT which nobody has explained yet.

See Dave's video at the 32 minute mark:
https://youtu.be/S8jrpCoZyx8?t=1920

Also check out the Rigol's pulse response which follows on from the FFT. Better than the Siglent.

Also not a SINGLE word about much hyped FastAcq. Is it simply a trick to hide fact it does not have real segmented mode that you can use for anything, like measurements or decoding.. Does anybody who bought these scopes actually plan to use them, or they just mean to twiddle PSU-s and hack them eternally?

It has real segmented mode with faster waveform capture rate than the Siglent.

LOL.

Big and ugly... I'm not buying a girlfriend. And maybe I like them big and robust looking .. ??  :-DD Many people HATE touchscreen scopes.
Shitty type C connector and running of external (crappy) PSU is large put off.. That is my personal counter opinion. Who are you to judge me.
But comparison here would be: I'm buying a truck. Do I care first and foremost can it carry cargo I plan to transport, or I choose one with cool paint job? And I have limited money so I have to compromise on something...

Dave didn't show much. He twiddled knobs on some scopes without any plan (courtesy of unscripted videos). It was shown, many times , that FFT in its current state is this weird frequency related screen visualisation. It is fast but it shows questionable amplitudes and RBW info. At this moment it has same merit as spectrum analyser visualisation plugin on WinAmp. Yeah it reacts to signal and it is frequency and amplitude related but not a reliable instrument it should be.
Do us a favour. Prove me wrong. Make full characterization FFT and make sure it work really well. Post results, so we can put it to rest.

With segmented mode same as FFT. I asked dozens of times, pretty please, can someone try and make segmented capture and do measurements and decoding from that. Again, pretty please, would you be so kind and try it. I'm not even saying it cannot. But datasheet and manual does not claim it can, and there is no mention of anything like that in manual. Nobody tried it so far as I know.

To explain: many years ago, I bought DS1000Z that had Record mode (Segmented in Rigol parlance). Since I've seen many online screens how people were decoding from segments from DS2000A, I failed to check that DS1000Z has Record mode that you cannot do ANYTHING with, except replaying from screen to screen manually and look at waveforms. If I knew that that would be a big minus.

Please, could you test it and demonstrate it to all of us. If it cannot, than segmented mode is bulls**t marketing screen show with very limited usage.  If it does, that is GREAT news for you and other DHOxxx users and you get additional satisfaction that you proved me wrong...

Again, words like pretty, cool, like don't win an argument as to what can instrument be useful for.  Operational word here USEFULL.

Hard cold facts, testing, and measuring actual performance is the key here. Unless you need film prop for movie scene. In which case go for it, it does look cool I agree.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 22, 2023, 11:56:32 am
Big and ugly... I'm not buying a girlfriend. And maybe I like them big and robust looking .. ??  :-DD Many people HATE touchscreen scopes.
Shitty type C connector and running of external (crappy) PSU is large put off.. That is my personal counter opinion. Who are you to judge me.

This is good from somebody who claims to be 100% fact based.

Do us a favour. Prove me wrong.

Is it "us", or is it "me".

Get one of these yourself if you're so interested in it.

Why are you interested anyway? Surely you already found your holy grail, one that does everything you need.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 22, 2023, 12:01:01 pm
4. This kind of thinking creates clarity. For instance if you need statistics one scope has statistics and other don't you have clear choice of one of them being inadequate. If both have the statistics, than you go into detail and look into quality of implementation.

You also have to look at how fast/easy it is to use the feature. The Rigol's statistics shine in this area.

They're also better implemented (they use a sliding window and are always available - just unfold the stats area on the measurement of interest, no need to menu-dive and enable a special "stats" mode).

So it's horses for courses. You might be able to sit down and prove mathematically that the Siglent is somehow "best" but which is going to be nicer and more useful to most people?

eg. How do you assign weights to things like the way the statistics work? When you have little niceties like that all over the place then it starts to add up to something valuable.

The Rigol's windowing abilities, too. How will you factor that into the big equation?

etc., etc.

TLDR; Defining "better" isn't as easy as you seem to think.

You still speak EXCLUSIVELLY about graphic representation. Did you do verification that this scope calculates RMS properly. DS1000Z didn't...
It used highly decimated data that made RMS very inaccurate for complex waveforms. Does DHO800 use full memory or decimated data? If decimated how big buffer is (if implemented properly it can work quite OK). Can you choose decimated/full data.

To get back to truck analogy, drivers seat, position etc is VERY IMPORTANT for a professional drivers. I don't disagree with you on that. Scope's ergonomics is not unimportant, and given two equally capable scopes for same price I will also pick out one with better ergonomics.

But that is only after we verify my truck is capable of carrying 10 ton load I need. Coolest looking best cabin comfort truck with 5 ton capability is not on table at all.. An in inexpensive segment I might need to make a compromise and get a 10 ton truck that has less comfort... It will do the job though.

But if I only occasionally drive some furniture for friends and drive few friends to a day trip to some waterfalls 50km from home, I can buy a van, and make it a darn cool one... And if someone needs to transport 5 tons of something, you simply refuse it..

Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 22, 2023, 12:15:44 pm
Big and ugly... I'm not buying a girlfriend. And maybe I like them big and robust looking .. ??  :-DD Many people HATE touchscreen scopes.
Shitty type C connector and running of external (crappy) PSU is large put off.. That is my personal counter opinion. Who are you to judge me.

This is good from somebody who claims to be 100% fact based.

Do us a favour. Prove me wrong.

Is it "us", or is it "me".

Get one of these yourself if you're so interested in it.

Why are you interested anyway? Surely you already found your holy grail, one that does everything you need.

Ad hominem..

I was proving how whiny and unsubstantiated your arguments  sound. That was sarcastic reenactment of your statement. I guess it was too subtle. Not.

To US. Not to be confused with USA.
Us, the many Internet users who are reading this. You and I are not trading private mails here. Other people can see it too..

You are constantly saying I'm wrong about facts. I'm saying I'm not. So prove me wrong.
You (and anybody else who feels like it, thank you very much for your effort if you choose to contribute) can test and report.
Or stop refuting my information on basis of emotion. Facts please. Thank you for your effort, it is much appreciated.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: rpro on October 22, 2023, 12:17:41 pm
Also not a SINGLE word about much hyped FastAcq. Is it simply a trick to hide fact it does not have real segmented mode
It has fully segmented memory with recording and playback, as real as in any other DSO. (A trivial DSO capability these days).  Check the manual, pgs. 187-197.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 22, 2023, 12:24:25 pm
But that is only after we verify my truck is capable of...

Seems to me like you could keep on moving those goalposts forever.

Also not a SINGLE word about much hyped FastAcq. Is it simply a trick to hide fact it does not have real segmented mode
It has fully segmented memory with recording and playback, as real as in any other DSO. (A trivial DSO capability these days).  Check the manual, pgs. 187-197.

Case in point: He's already moved that one.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Performa01 on October 22, 2023, 12:26:03 pm
What is your link to Siglent? It does seem to go beyond "generally liking their products".
Most folks watching this forum got it by now. But it doesn't matter anyway - the only valid question would be: have I posted wrong facts anywhere? Or in this thread particularly?
Isn't it funny speculating about a possible link to Siglent instead of discussing the thread topic and the few facts about Siglent scopes that I'm throwing in?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 22, 2023, 12:37:06 pm
Also not a SINGLE word about much hyped FastAcq. Is it simply a trick to hide fact it does not have real segmented mode
It has fully segmented memory with recording and playback, as real as in any other DSO. (A trivial DSO capability these days).  Check the manual, pgs. 187-197.

Did you read it? Carefully?

In Playback mode you can animate frames visually. In navigate mode you can navigate bx Time OR Search Event (Edge or Pulse)  OR Frame segment number.
Frame segment mode is ONLY available in UltraAcq mode and in that mode ONLY Frame segment is available.

So Normal recording mode only allows manual animation in Playback mode.
UltraAck mode only suports Frame segment, visually only same as Playback mode. In UltraAcq no measurement or any kind of analysis is not available (it is disabled)

To cut on the fluff explaning this, here is simple and practical task:
Can you do this:

1. Capture 10 different I2C packets, with timebase made such that you capture each packet into each owns Frame/segment. Stop the scope.
2. Decode those 10 different packets while moving from segment to segment...

This is very common thing to do and, to most Keysight users primary reason to use segments.

Thanks!!
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 22, 2023, 12:39:04 pm
But that is only after we verify my truck is capable of...

Seems to me like you could keep on moving those goalposts forever.

Also not a SINGLE word about much hyped FastAcq. Is it simply a trick to hide fact it does not have real segmented mode
It has fully segmented memory with recording and playback, as real as in any other DSO. (A trivial DSO capability these days).  Check the manual, pgs. 187-197.

Case in point: He's already moved that one.
Ad hominem.
You are trolling in comparison thread sabotaging the comparison...

Be useful, do the test I asked for and report.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 22, 2023, 12:48:07 pm
What is your link to Siglent? It does seem to go beyond "generally liking their products".
Most folks watching this forum got it by now.

But you don't feel comfortable disclosing it when asked, let alone in your profile info? Well, you will have your reasons. But please be aware that it affects the reception of your posts once readers have realized that you have a hidden agenda or loyalty here.

Quote
the only valid question would be: have I posted wrong facts anywhere? Or in this thread particularly?

It's not about posting wrong facts, but about posting selectively picked facts which make "your" product look good, and glossing over aspects where the competing product has advantages. That's what decent salesmen do, and it is certainly what tautech and you have been doing here.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 22, 2023, 12:58:43 pm
1. Capture 10 different I2C packets, with timebase made such that you capture each packet into each owns Frame/segment. Stop the scope.
2. Decode those 10 different packets while moving from segment to segment...

I captured 1000, will that do?

https://www.youtube.com/watch?v=OxhKMkvBxtY (https://www.youtube.com/watch?v=OxhKMkvBxtY)

nb. That video was recorded using the DHO web control.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 22, 2023, 01:10:44 pm
1. Capture 10 different I2C packets, with timebase made such that you capture each packet into each owns Frame/segment. Stop the scope.
2. Decode those 10 different packets while moving from segment to segment...

I captured 1000, will that do?

https://www.youtube.com/watch?v=OxhKMkvBxtY (https://www.youtube.com/watch?v=OxhKMkvBxtY)

nb. That video was recorded using the DHO web control.

Excellent. Good work man.Thank you for that.

You are actually first one to publish that. That is good news for DHO users. DS1000Z could not do that.

Can you have measurements in a table with stats too? Enable some measurements and try. And if you enable statistics and play through these 1000 segments will it accumulate stats?

Thanks for helping.

Siniša
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 22, 2023, 01:12:37 pm
Can you have measurements in a table with stats too? Enable some measurements and try. And if you enable statistics and play through these 1000 segments will it accumulate stats?

There's some measurements on the right of that video.

If I unfold the stats the numbers also change in there.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 22, 2023, 01:13:45 pm
1. Capture 10 different I2C packets, with timebase made such that you capture each packet into each owns Frame/segment. Stop the scope.
2. Decode those 10 different packets while moving from segment to segment...

I captured 1000, will that do?

https://www.youtube.com/watch?v=OxhKMkvBxtY (https://www.youtube.com/watch?v=OxhKMkvBxtY)

nb. That video was recorded using the DHO web control.

And also, I presume you can have table view of decode too. Can table show only current segment or all of the segments?

Nice video capability. I like that.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 22, 2023, 01:15:35 pm
Can you have measurements in a table with stats too? Enable some measurements and try. And if you enable statistics and play through these 1000 segments will it accumulate stats?

There's some measurements on the right of that video.

Yeah sorry you're too quick. I meant in a table with stats. To see if stats is gathered across the segments.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ptluis on October 22, 2023, 01:20:56 pm
1. Capture 10 different I2C packets, with timebase made such that you capture each packet into each owns Frame/segment. Stop the scope.
2. Decode those 10 different packets while moving from segment to segment...

I captured 1000, will that do?

https://www.youtube.com/watch?v=OxhKMkvBxtY (https://www.youtube.com/watch?v=OxhKMkvBxtY)

nb. That video was recorded using the DHO web control.

This is the type of information that we future buyers seek to obtain to decide our purchases.  Not the wars of which brand is the best.  We have to pay to own the equipment, the brands don't offer it to us, so we as buyers have every interest in knowing whether the "X" equipment is competent in the features that the manufacturers say it has.  I've had several brands and there are no perfect brands, they all have their flaws.  My friends, make peace among yourselves!  Help in practice those who have to make decisions, by testing functionalities, bugs and the like.  Yes, that is useful.  Thank you for your time in reading my text :)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 22, 2023, 01:22:32 pm
Can table show only current segment or all of the segments?

Table view shows the packets on screen. If I capture three packets it shows three in the table.

Recording/playback updates the table perfectly.
(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1907964;image)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 22, 2023, 01:33:49 pm
Can table show only current segment or all of the segments?

Table view shows the packets on screen. If I capture three packets it shows three in the table.

Recording/playback updates the table perfectly.
(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1907964;image)

Excellent. So it does current segment. That is OK. Showing all segments would be to much for the screen.. It is small.

OK, as for decoding from segmented mode, that is way better than DS1000Z it replaces.  Good, good.

This is should be fixed in Rigol U.M. This should be shown and explained a bit. Looking at U.M. this does not exist.

Did you by any chance see a question about measurement with stats is a table. Can you play through 100 segments, will it collect stats for all of them?

Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Mechatrommer on October 22, 2023, 01:50:07 pm
sniff sniff i smell siglent fanboyism... this is DHO800 thread, not DHO900 MSO remember? i heard DHO800 FFT not good? i provided facts not fart talk, tell me what SA price has -120 to -140dB dynamic range? this is possible because Rigol proved themselve by providing API documentation and working PC SW example since DS1000E, and it got better and better. i havent seen one single sig-fanboy proved otherwise (siglent has better FFT? duh!) thats why i stick with Rigol brand... my Anritsu MS8609A cant reach -100dB let alone -140dB.. ignoring the fact by nitpick is of no use, try to prove its antialiasing weakness by eyeballing sine/repeating signal beyond nyquist sampling limit is unrealistic in real circuit debugging, if it is, why mourn entry level scope for that? get one of those 10GSa/s Lecroy DSO then you can be happy to probe your 500MHz at 20 points per cycle..

here again look carefully, open your eyes wide (attached image) and tell me what wrong with it? if you dont have clue, it proves you are the siglent fan boyism... this is only 5Mpts, i can push to 50Mpts now, and then do averaging to get even lower noise and smaller RBW. i know i know before you argue, DSO is no place for SA (same as LA is not for DSO to do imho), get the real SA. i did, but i know i have one extra tool at $400 to do redundant verification. now i have two actually, DS1000Z and DHO804 (err... or should is say DHO924? thanks to hubertyoung and friends) LA? serial decoding? i will venture DHO924 later when i need it, glad to know its there but so far my clone salae logic can do the job for my simple need.

(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1906533;image)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: rpro on October 22, 2023, 01:53:32 pm
Did you read it? Carefully?
Yes, I read it, and carefully. I own the scope, and have been using its segmented memory everyday since I've owned it. 

I suggest you either buy the scope, or borrow it, and perform and report on your own tests, before making preposterous statements about this or other scopes in reference to this thread (e.g., like interval trigger being the same as delay trigger). In the meantime, I am skipping your posts.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 22, 2023, 01:59:32 pm
Yeah sorry you're too quick. I meant in a table with stats. To see if stats is gathered across the segments.

Another goalpost move?

I couldn't find a way to reset stats at the moment I hit record but I set the stats window size to '4' and it seems to show the average of the last four segments. This seems more useful than a reset (and I think the window mode is more useful in general...)

https://www.youtube.com/watch?v=ob6dKf_WHlc (https://www.youtube.com/watch?v=ob6dKf_WHlc)

The signal was a pulse from an Arduino that changes width 255..0, 255..0.

I also connected a mouse and the video record function shows it nicely. :-)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 22, 2023, 02:04:07 pm
Yeah sorry you're too quick. I meant in a table with stats. To see if stats is gathered across the segments.

Another goalpost move?

I couldn't find a way to reset stats at the moment I hit record but I set the stats window size to four and it seems to show the average of the last four segments.

https://www.youtube.com/watch?v=ob6dKf_WHlc (https://www.youtube.com/watch?v=ob6dKf_WHlc)

The signal was a pulse from an Arduino that changes width 255..0, 255..0.

I also connected a mouse and the video record function shows it nicely. :-)

No it is not moving a goalpost. This is what I was saying for last 3 months...
I presume that it can be shown in a table..
Maybe a table have a way to reset stats..

It does not seem to update when playing segments.
What you can to is go to segment 1 and enable some other measurement (that was not enabled at capture time)
And see if that one gets updated..

Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 22, 2023, 02:05:55 pm
Quote
sniff sniff i smell siglent fanboyism.

So that's it for me here, I can do without this kindergarten stuff.
I'll get back to you with tests when the thread has regained a certain objectivity.

Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 22, 2023, 02:18:24 pm
No it is not moving a goalpost. This is what I was saying for last 3 months...
I presume that it can be shown in a table..
Maybe a table have a way to reset stats..

Yada yada. You're still adding more conditions. Can the revered Siglents do all this?

What you can to is go to segment 1 and enable some other measurement (that was not enabled at capture time)
And see if that one gets updated..

It does.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 22, 2023, 02:27:04 pm
Maybe a table have a way to reset stats..

Resetting stats can be done (of course) but it's not something you really need to do when you have a sliding-window function like this.

Stats simply update themselves in the background.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 22, 2023, 02:34:31 pm
Did you read it? Carefully?
Yes, I read it, and carefully. I own the scope, and have been using its segmented memory everyday since I've owned it. 

I suggest you either buy the scope, or borrow it, and perform and report on your own tests, before making preposterous statements about this or other scopes in reference to this thread (e.g., like interval trigger being the same as delay trigger). In the meantime, I am skipping your posts.

Yet you are too lazy to post a screenshot and fail to point where in the 270 page book it say so...
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Mechatrommer on October 22, 2023, 02:35:47 pm
Quote
sniff sniff i smell siglent fanboyism.
So that's it for me here, I can do without this kindergarten stuff.
I'll get back to you with tests when the thread has regained a certain objectivity.
just post if you have anything you think usefull for the cause, ignore the noises, we that reached the level of "Guardianship" will sometime have to counter-post noises just for fun ;D noises will make difficult to follow a thread, but it happened and there is really no way to get rid of them, new members keep coming..
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 22, 2023, 02:39:13 pm
No it is not moving a goalpost. This is what I was saying for last 3 months...
I presume that it can be shown in a table..
Maybe a table have a way to reset stats..

Yada yada. You're still adding more conditions. Can the revered Siglents do all this?

What you can to is go to segment 1 and enable some other measurement (that was not enabled at capture time)
And see if that one gets updated..

It does.

I'm not adding conditions, you silly rabbit.

I'm trying to actually find out what it can actually do.
So we can prove if it has or has not more function than competition.

I don't care who is "better". We lack good quality information about new Rigol scope beyond unpacking videos..
So far all the stuff that I had to FORCE you to do, was actually in favor of Rigol...
And I was the first one to ask those questions..

Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 22, 2023, 02:43:50 pm
Maybe a table have a way to reset stats..

Resetting stats can be done (of course) but it's not something you really need to do when you have a sliding-window function like this.

Stats simply update themselves in the background.

That is quite obviously wrong and false. You never used stats for actual measurements. Resetting the stats is basic thing you do all the time.
You setup some measurement, let it run to verify if all works well and then you reset stats to start actual gathering of data that will be your measurement propper. And sometimes you tweak something, rest stats and see how it does now....

There are other smart stuff that stats can benefit from but on a scope this cheap that is a stretch..
So far what I see is OK.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 22, 2023, 02:54:02 pm
That is quite obviously wrong and false. You never used stats for actual measurements.

And you never had a scope with sliding window (or are failing to understand what one is).

Resetting the stats is basic thing you do all the time.
You setup some measurement, let it run to verify if all works well and then you reset stats to start actual gathering of data

By the time you verified it's all working you already have the stats on these Rigols. You didn't need to reset them.

(assuming the trigger events are happening fast enough)

But as noted, you can reset the stats if you insist on it.

You can even reset stats individually instead of all at once.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 22, 2023, 03:06:16 pm
sniff sniff i smell siglent fanboyism... this is DHO800 thread, not DHO900 MSO remember? i heard DHO800 FFT not good? i provided facts not fart talk, tell me what SA price has -120 to -140dB dynamic range? this is possible because Rigol proved themselve by providing API documentation and working PC SW example since DS1000E, and it got better and better. i havent seen one single sig-fanboy proved otherwise (siglent has better FFT? duh!) thats why i stick with Rigol brand... my Anritsu MS8609A cant reach -100dB let alone -140dB.. ignoring the fact by nitpick is of no use, try to prove its antialiasing weakness by eyeballing sine/repeating signal beyond nyquist sampling limit is unrealistic in real circuit debugging, if it is, why mourn entry level scope for that? get one of those 10GSa/s Lecroy DSO then you can be happy to probe your 500MHz at 20 points per cycle..

here again look carefully, open your eyes wide (attached image) and tell me what wrong with it? if you dont have clue, it proves you are the siglent fan boyism... this is only 5Mpts, i can push to 50Mpts now, and then do averaging to get even lower noise and smaller RBW. i know i know before you argue, DSO is no place for SA (same as LA is not for DSO to do imho), get the real SA. i did, but i know i have one extra tool at $400 to do redundant verification. now i have two actually, DS1000Z and DHO804 (err... or should is say DHO924? thanks to hubertyoung and friends) LA? serial decoding? i will venture DHO924 later when i need it, glad to know its there but so far my clone salae logic can do the job for my simple need.



Ad hominem again... Call me what you want, I still have bought more Rigol than Siglent products in my life so far.

Could you please explain what are these images?
Are those screenshots from scope, or made on PC from data pulled.

If those are made on your PC from data pulled from scope, that is just funny.
We are arguing FFT implementation on a scope is half cooked, and to disprove me you post images of FFT that you made on PC because FFT on scope is crap...
What a great irony is that????

And again, you just hate whatever I say without reading or understanding what i meant.

I did not say ADC is bad, I did not say input is noisy. I repeatedly asked if someone could pull data on PC so we can see how well ADC performs, because on scope FFT is weird..
Same as Fungus, you guys fight so hard not to do the right thing... If I was not insistent we still would have no good data.

So despite your argumentative and rude post I thank you for data...
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Performa01 on October 22, 2023, 03:10:09 pm
sniff sniff i smell siglent fanboyism... this is DHO800 thread ...
You're wrong. This was intended as test and compare thread, not a Rigol DHO800 praising and worshipping thread.

i heard DHO800 FFT not good? i provided facts not fart talk, tell me what SA price has -120 to -140dB dynamic range?
So what is it if not "fart talk" if you make such claims, taking everyone as a fool?

The very best high end spectrum analyzers like R&S FSEA30 can have up to 115 dB dynamic range, while the average SA doesn't have more than 80. So it's not very plausible, that a bottom of the barrel entry level scope will beat that by some orders of magnitude :palm:

Do you even know how dynamic range is defined? And then for a SA in particular?

We get no clear information about the test conditions or the input signal, but even so there is not more than 50 dB dynamic range visible on these meaningless screenshots. And a lot of spurious signals.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 22, 2023, 03:18:13 pm
That is quite obviously wrong and false. You never used stats for actual measurements.

And you never had a scope with sliding window (or are failing to understand what one is).

Resetting the stats is basic thing you do all the time.
You setup some measurement, let it run to verify if all works well and then you reset stats to start actual gathering of data

By the time you verified it's all working you already have the stats on these Rigols. You didn't need to reset them.

(assuming the trigger events are happening fast enough)

But as noted, you can reset the stats if you insist on it.

You can even reset stats individually instead of all at once.

You seem to have limited knowledge of stats and how it is used... In your defense coming from Micsig you couldn't learn about it. Now that you have scope with stats, you will see you will use it more than you though.

I have plenty of scopes, and some of them have sliding window (and I knew about it long before you, more than 35 years ago), some have limited run stats (they capture number of samples and stop), some limited length sliding window, and on some you can choose.
As you may see by now, all of those are used in different occasions, for different purpose.

Resting stats is something that you do all the time. It went over your head that to get good measurements, you need to measure several time to assure all is right. You do that by keeping scope running, and resetting stats several times.

Again, instead of attacking and insulting me to prove you don't know much, you should have just answered with actual good information: It has stats reset and you can even reset individual measurement.
That is good. Point for team Rigol...
Thank you for good info.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 22, 2023, 03:29:10 pm
sniff sniff i smell siglent fanboyism... this is DHO800 thread ...
You're wrong. This was intended as test and compare thread, not a Rigol DHO800 praising and worshipping thread.

i heard DHO800 FFT not good? i provided facts not fart talk, tell me what SA price has -120 to -140dB dynamic range?
So what is it if not "fart talk" if you make such claims, taking everyone as a fool?

The very best high end spectrum analyzers like R&S FSEA30 can have up to 115 dB dynamic range, while the average SA doesn't have more than 80. So it's not very plausible, that a bottom of the barrel entry level scope will beat that by some orders of magnitude :palm:

Do you even know how dynamic range is defined? And then for a SA in particular?

We get no clear information about the test conditions or the input signal, but even so there is not more than 50 dB dynamic range visible on these meaningless screenshots. And a lot of spurious signals.

Some people confuse dynamic range with noise floor. I've seen that many times. And ignore SFDR metric..

A question to the public: what is theoretical dynamic range of 12 bit converter?  72,247dB
That is for ideal (nonexistent, spherical cow in a vacuum type) converter.
Quantization noise and nonlinearities will get in a way of that ideal.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: iMo on October 22, 2023, 03:33:32 pm
.. i heard DHO800 FFT not good? i provided facts not fart talk, tell me what SA price has -120 to -140dB dynamic range? this is possible because Rigol proved themselve by providing API documentation and working PC SW example since DS1000E, and it got better and better. i havent seen one single sig-fanboy proved otherwise (siglent has better FFT? duh!) thats why i stick with Rigol brand... my Anritsu MS8609A cant reach -100dB let alone -140dB..

How they do that -120 to -140dB dynamic range with a 12bit ADC?
PS: provided you mean the "noise floor" - how they could achieve such a low n.floor?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 22, 2023, 03:36:58 pm
Resting stats is something that you do all the time. It went over your head that to get good measurements, you need to measure several time to assure all is right. You do that by keeping scope running, and resetting stats several times.

Please provide a concrete example of when manual resetting is better than simply seeing (eg.) the RMS of the last 100 acquisitions on a 'scope that's constantly running.

I can easily think of when sliding window is much more useful, eg. when you're fiddling with a trim pot and don't want to keep reaching over to the 'scope to reset the stats every time you turn it to see what happens.

I'm struggling to think of an example where manual resetting is better.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 22, 2023, 03:45:32 pm
How they do that -120 to -140dB dynamic range with a 12bit ADC?
PS: provided you mean the "noise floor" - how they could achieve such a low n.floor?

That's just the way FFT math works.

It's like averaging of datapoints to get extra bits from the ADC but in the frequency domain.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 22, 2023, 03:46:31 pm
Resting stats is something that you do all the time. It went over your head that to get good measurements, you need to measure several time to assure all is right. You do that by keeping scope running, and resetting stats several times.

Please provide a concrete example of when manual resetting is better than simply seeing (eg.) the RMS of the last 100 acquisitions on a 'scope that's constantly running.

I can easily think of when sliding window is much more useful, eg. when you're fiddling with a trim pot and don't want to keep reaching over to the 'scope to reset the stats every time you adjust it.

I'm struggling to think of an example where manual resetting is better.

Don't be mad if I don't, I explained several times.
Just think about it more, you will understand.
Every scope I have, have reset button directly inside stat window.
LeCroy and Siglent also have Clear sweeps that flushes full acquisition memory for same reason..
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 22, 2023, 03:57:05 pm
.. i heard DHO800 FFT not good? i provided facts not fart talk, tell me what SA price has -120 to -140dB dynamic range? this is possible because Rigol proved themselve by providing API documentation and working PC SW example since DS1000E, and it got better and better. i havent seen one single sig-fanboy proved otherwise (siglent has better FFT? duh!) thats why i stick with Rigol brand... my Anritsu MS8609A cant reach -100dB let alone -140dB..

How they do that -120 to -140dB dynamic range with a 12bit ADC?
PS: provided you mean the "noise floor" - how they could achieve such a low n.floor?

Noise floor of scope is defined by ADC inherent noise (analog noise in input driving circuits that drive actual conversion circuitry) and quantization noise that is defined by resolution and sampling imperfections.
But on a scope you also have a front end before ADC, and that has a preamp that amplifies input signal for ADC.
Scope noise floor will be combination of those two.
So if you have a good, low noise preamp, your bottom can start from -140dBm but because dynamic range is 70db, top of scale will be -70dBm. Of course that would be ideal, tha cannot ever happen in prractice.

You can say that by using preamps/attenuators you have a 70dB window you can slide up and down: from -100 dBm to -30dBm. Or from -40dBm to +30dBm. But never from -100 dBm to +30dBm, cause that would mean 130dBm dynamic range...
That would mean 21,5 bit converter running at GHz speeds...
If you know how to make one, there is a Nobel prize waiting...
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 22, 2023, 03:57:59 pm
Resting stats is something that you do all the time. [...]
Please provide a concrete example of when manual resetting is better [...]

Gentlemen, I am confused now. I thought you had found that manually resetting the statistics is possible with the DHO800? The user manual seems to say that the operation can even be assigned to the Quick button on the front panel if you need to use it often.

If I got this right and the scope does offer the choice of manually resetting stats -- what is the debate about?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 22, 2023, 04:02:39 pm
Don't be mad if I don't, I explained several times.

All you explained is that you like to press reset, not that it's necessary.

Just think about it more, you will understand.
Every scope I have, have reset button directly inside stat window.

Argument from authority. Got it.

Anyway: You're avoiding the question. Can the Siglent do all this segmention/stats stuff?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 22, 2023, 04:06:03 pm
Resting stats is something that you do all the time. [...]
Please provide a concrete example of when manual resetting is better [...]

Gentlemen, I am confused now. I thought you had found that manually resetting the statistics is possible with the DHO800? The user manual seems to say that the operation can even be assigned to the Quick button on the front panel if you need to use it often.

If I got this right and the scope does offer the choice of manually resetting stats -- what is the debate about?

He said it has it and that is good enough for me. Fact that it can be added to quick button is great. Thank you for that data.
Argument, I don't know, Fungus seems to insisting resetting stats is not necessary because Rigol is doing sliding buffer stats.
I don't understand  how that is connected.

All in all Stats work, you can reset them, they work on segmented buffers...
 :-+
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 22, 2023, 04:11:29 pm
Don't be mad if I don't, I explained several times.

All you explained is that you like to press reset, not that it's necessary.

Just think about it more, you will understand.
Every scope I have, have reset button directly inside stat window.

Argument from authority. Got it.

Anyway: You're avoiding the question. Can the Siglent do all this segmention/stats stuff?

Are you deliberately provoking me today because I try to be polite even to you?
Argument from authority? You bet your ass it is. Are you saying you are smarter and know better than Kesight, R&S, LeCroy, Picoscope, Siglent and many more.... I know I wouldn't dare to say something like that for myself

If you don't understand why you would need to reset stats all the time while doing measurements, than I cannot explain you. It should be point of pure logic not a data point to learn by heart.
As I said, you will remember my words, once you actually learn how to use statistics to your benefit.

And I'm not avoiding the question I already said it before: it can.
That is why I'm asking, for COMPARISON...
If Rigol didn't do it it would be a minus for it.
Since it can that is good for Rigol.
Get it?

Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 22, 2023, 04:25:27 pm
.. i heard DHO800 FFT not good? i provided facts not fart talk, tell me what SA price has -120 to -140dB dynamic range? this is possible because Rigol proved themselve by providing API documentation and working PC SW example since DS1000E, and it got better and better. i havent seen one single sig-fanboy proved otherwise (siglent has better FFT? duh!) thats why i stick with Rigol brand... my Anritsu MS8609A cant reach -100dB let alone -140dB..

How they do that -120 to -140dB dynamic range with a 12bit ADC?
PS: provided you mean the "noise floor" - how they could achieve such a low n.floor?

Some literature to scratch the surface...

https://www.edn.com/dsos-and-noise/ (https://www.edn.com/dsos-and-noise/)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 22, 2023, 04:28:05 pm
If you don't understand why you would need to reset stats all the time while doing measurements, than I cannot explain

I don't see any difference between resetting and simply waiting 2 seconds for the window to slide along.

(apart from the physical movement of your arm)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 22, 2023, 04:43:23 pm
If you don't understand why you would need to reset stats all the time while doing measurements, than I cannot explain

I don't see any difference between resetting and simply waiting 2 seconds for the window to slide along.

(apart from the physical movement of your arm)
Two hints.
How deep is sliding window ?
What timebase?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Mechatrommer on October 22, 2023, 04:44:03 pm
If those are made on your PC from data pulled from scope, that is just funny.
We are arguing FFT implementation on a scope is half cooked, and to disprove me you post images of FFT that you made on PC because FFT on scope is crap...
What a great irony is that????
so you didnt see the picture of built-in FFT i posted?

(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1906593;image)

312K FFT points (625Ksamples) i'm providing both i'm not sure what siglent marketing hype refering to "points"? do you have any better siglent screenshot FFT? you asked people to do you favor by providing screenshots, but you didnt provide anything yourself. people are having hard time understanding what you want. in any case, i was showing that FFT of DHO800 is much much better than previous DS1000Z. i initially thought this thread is comparing new rigol vs older rigol, but it turn out differently, re-reading OP, maybe he want to compare between rigol and siglent, but his rigol hasnt arrived yet? so lets wait, i hope its going to be a thorough one including pulling data to PC, i havent seen that be done with siglent scope and its code example.

and to the rest replying i dont have time quoting each one... my point was, raw 16bit data can be pulled to PC from Rigol DHO800 scope, can this be done with Siglent? if not, dont bother claiming it has better built-in FFT, because it crap anyway compared to proper SA. i also pointed out, with higher data point count, cleaner FFT can be achieved, i dont know your theoritical formula for X bit scope's noise floor, but FFT i've shown has cleaner floor at -120dB although there are some spurious below -90dB, we should be able to see low level signal existence in -60 to -80dB range, since spurious are below that, and where there are no spurious in freq domain, we can see signal of much lower level, too bad my rfgen can only go -40dBm output and not the high end pure sine one. we can safely say imho anything above -90dB are real signal to be analyzed. even built-in FFT above also showing -120dB floor, does FFT algorithm lies?. and its lower RBW too with more datapoints only can be achieved by pulling data out of Rigol to PC, i believe even the holy grail siglent built in FFT is "blobby" (leaky) due to large RBW. and through VISA driver API, i can automate it into program instead of copying it into CSV in pendrive and then play math in Excel or Matlab, that is tedious and slow work. from some stand, i can say any entry level dso's built in FFT are useless anyway, so there is not much point highlighting it. thats why i developed my own SW, even 1Mpts siglent is not enough for me. i was looking its programming guide i believe i have it stored somewhere, but i havent seen a working SW/code example. ymmv.

.. i heard DHO800 FFT not good? i provided facts not fart talk, tell me what SA price has -120 to -140dB dynamic range? this is possible because Rigol proved themselve by providing API documentation and working PC SW example since DS1000E, and it got better and better. i havent seen one single sig-fanboy proved otherwise (siglent has better FFT? duh!) thats why i stick with Rigol brand... my Anritsu MS8609A cant reach -100dB let alone -140dB..
How they do that -120 to -140dB dynamic range with a 12bit ADC?
PS: provided you mean the "noise floor" - how they could achieve such a low n.floor?
Some literature to scratch the surface...
https://www.edn.com/dsos-and-noise/ (https://www.edn.com/dsos-and-noise/)
thats not literature... this is literature... https://dsp.stackexchange.com/questions/86124/units-of-6-02n-1-76-as-an-fft-noise-floor (https://dsp.stackexchange.com/questions/86124/units-of-6-02n-1-76-as-an-fft-noise-floor) and this https://www.eetimes.com/fft-plots-provide-insight-to-a-d-performance/ (https://www.eetimes.com/fft-plots-provide-insight-to-a-d-performance/) but i wont bother digging deep. i already have 10Mpts FFT, with markers system and zoom out zoom in feature. so thats what i will use.. what you need to prove to me now is why FFT algorithm lies?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: iMo on October 22, 2023, 05:02:43 pm
The FFT picture above tells me the real spectral lines of your signal (11 lines) are positioned in -30dB to -90dB band and they come from the FFT. All other spectral components you may see there is a math junk..
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 22, 2023, 05:12:05 pm
If those are made on your PC from data pulled from scope, that is just funny.
We are arguing FFT implementation on a scope is half cooked, and to disprove me you post images of FFT that you made on PC because FFT on scope is crap...
What a great irony is that????
so you didnt see the picture of built-in FFT i posted?

312K FFT points (625Ksamples) i'm providing both i'm not sure what siglent marketing hype refering to "points"?

I didn't, sorry.  But you don't understand what I'm asking you just seem to want to insult me because I dare to question your precious..

You say 312K FFT points (625Ksamples). OK. Where do those numbers come from? Where does it say on screen? It should otherwise those are just some squiggles..

And as for other response I provided a link to introductory text on topic of FFT on scope and implementations..
You provided links to what can be calculated with FFT if you dig deeper..

My link is relevant to his question, your link is relevant to what you are doing on your PC.. Good read and good articles but not on topic per se.. They are a bit too far down the rabbit hole...
I already told you, I admire what you can do with data on PC. Open separate topic and discuss it there in depth. But when FFT on scope as implemented is discussed, your offline PC analysis is off topic and only serves to confuse people.
I did mention several time that users (and that is you) reported that data transfer to PC i quite decent and that already some users are doing offline analysis on PC..



Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 22, 2023, 05:13:08 pm
How deep is sliding window ?

Whatever you want. (eg. In my segmentation test I set it to '4')

It remembers the setting, even across power cycles.

What timebase?

Doesn't matter. You can easily look at the number and see if it's still settling or not.

If it's taking its sweet time about settling down then feel free to manually reset it (or, more sensibly, adjust the window size so you don't need to reset it on the next change to your circuit).
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 22, 2023, 05:13:57 pm
The FFT picture above tells me the real spectral lines of your signal (11 lines) are positioned in -30dB to -90dB band and they come from the FFT. All other spectral components you may see there is a math junk..

Some of that grass will be spurious tones from ADC nonlinearities, and some are folded back signal that was aliased.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 22, 2023, 05:16:00 pm
If it's taking its sweet time about settling down then feel free to manually reset it (or, more sensibly, adjust the window size so you don't need to reset it on the next change to your circuit).

Also: If it never settles down then you know the system isn't stable.

Your manually-reset stats might hide that valuable information from you.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Mechatrommer on October 22, 2023, 05:18:03 pm
The FFT picture above tells me the real spectral lines of your signal (11 lines) are positioned in -30dB to -90dB band and they come from the FFT. All other spectral components you may see there is a math junk..
very good! now at least some people looked closer! ;) its possible i think to subtract dso's noise esp the larger one exist in three places there using some power combination formula, iirc its some form of  "pythagorean" or squared root rms formula, but i need to read paper and formulation again first to back this up and apply it in real application, but thats for later. with built-in scope's FFT, we can only "eyeball".

Some of that grass will be spurious tones from ADC nonlinearities, and some are folded back signal that was aliased.
same rule applied to any FFT calculating machine, siglent, rigol, tek, hp R&S whatever. is at the mercy of sampling HW system. to get rid aliasing entirely, you need brickwall filter, and that is a theoritical filter one cant achieve in real world. unless you are far crippling the sampling mechanism with much much lower BW filter. 8th order approximation also not that flat, how good front end filter for both rigol and siglent?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 22, 2023, 05:25:00 pm
How deep is sliding window ?

Whatever you want. (eg. In my segmentation test I set it to '4')

It remembers the setting, even across power cycles.

What timebase?

Doesn't matter. You can easily look at the number and see if it's still settling or not.

If it's taking its sweet time about settling down then feel free to manually reset it (or, more sensibly, adjust the window size so you don't need to reset it on the next change to your circuit).

Hehehe, grasshopper, set stat length of 1000 and then you'll get it..
4 averages are not stat, really... 
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 22, 2023, 05:26:44 pm
If it's taking its sweet time about settling down then feel free to manually reset it (or, more sensibly, adjust the window size so you don't need to reset it on the next change to your circuit).

Also: If it never settles down then you know the system isn't stable.

Your manually-reset stats might hide that valuable information from you.

You don't understand much do you?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 22, 2023, 05:32:05 pm
Some of that grass will be spurious tones from ADC nonlinearities, and some are folded back signal that was aliased.
same rule applied to any FFT calculating machine, siglent, rigol, tek, hp R&S whatever. is at the mercy of sampling HW system. to get rid aliasing entirely, you need brickwall filter, and that is a theoritical filter one cant achieve in real world. unless you are far crippling the sampling mechanism with uch uch lower BW filter.

Stop being rude and aggressive. I explained something, replying to his "math junk" comment to which I disagree. I didn't say it was "Rigol problem".
Of course every system has same. There are no ideal systems. We discussed this many times.
At his point I don't have any opinion on how well it performs. Thanks to your data I will take a look and then will comment.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: iMo on October 22, 2023, 05:39:38 pm
OK, "math junk" - I meant "none existent in the source signal, created artificially by any internal mechanism"..
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: TimFox on October 22, 2023, 05:41:34 pm
Otherwise known as "artifacts".
While studying physics at the University of Chicago, I had friends in the archaeology department who thought artifacts were a good thing (as opposed to rocks carved by natural processes).
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 22, 2023, 05:46:16 pm
Otherwise known as "artifacts".
While studying physics at the University of Chicago, I had friends in the archaeology department who thought artifacts were a good thing (as opposed to rocks carved by natural processes).

Usually called spurious tones in SA world... When in spectrum mode I call them so.. Seems appropriate..
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Mechatrommer on October 22, 2023, 05:46:56 pm
Some of that grass will be spurious tones from ADC nonlinearities, and some are folded back signal that was aliased.
same rule applied to any FFT calculating machine, siglent, rigol, tek, hp R&S whatever. is at the mercy of sampling HW system. to get rid aliasing entirely, you need brickwall filter, and that is a theoritical filter one cant achieve in real world. unless you are far crippling the sampling mechanism with uch uch lower BW filter.
Stop being rude and aggressive. I explained something, replying to his "math junk" comment to which I disagree. I didn't say it was "Rigol problem".
Of course every system has same. There are no ideal systems. We discussed this many times.
At his point I don't have any opinion on how well it performs. Thanks to your data I will take a look and then will comment.
and i'm also providing information relating to that. whether you already know it or not. i'm not being rude nor i say i disagree, infact i do agree i'm just adding fact to it. sorry if you got insulted too much ;)

Otherwise known as "artifacts".
While studying physics at the University of Chicago, I had friends in the archaeology department who thought artifacts were a good thing (as opposed to rocks carved by natural processes).
yes and every systems are not perfect, they have their own artifacts.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: iMo on October 22, 2023, 05:53:49 pm
When I messed with FFT (in the stone age w/ Z80/68k in asm) I did shoot a Dirac pulse into it to see the floor :)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 22, 2023, 05:55:59 pm
You don't understand much do you?

Aaaaand.... we're done here.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 22, 2023, 06:04:30 pm
You don't understand much do you?

Aaaaand.... we're done here.
Thank you!!
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: TimFox on October 22, 2023, 06:10:44 pm
Otherwise known as "artifacts".
While studying physics at the University of Chicago, I had friends in the archaeology department who thought artifacts were a good thing (as opposed to rocks carved by natural processes).

Usually called spurious tones in SA world... When in spectrum mode I call them so.. Seems appropriate..

Yes, spurious tones are a good example of artifacts in a system.
My professor at U Chicago was from Italy, and objected to my use of an incorrect Latin term "spuriae" for the plural of spurious for a system with multiple artifacts.
(Spuriae is a real word, meaning the feathers of the bastard wing of a bird.)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Mechatrommer on October 22, 2023, 06:15:33 pm
When I messed with FFT (in the stone age w/ Z80/68k in asm) I did shoot a Dirac pulse into it to see the floor :)
why play with theoritical signal that never existed? here FFT from computer generated sin wave (saved in CSV)... -280dB noise floor :palm: the -160dB harmonics are probably Double (64bits) FP precision artifacts (or Single 32bits? cant remember).
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 22, 2023, 06:21:51 pm
When I messed with FFT (in the stone age w/ Z80/68k in asm) I did shoot a Dirac pulse into it to see the floor :)
why play with theoritical signal that never existed? here FFT from computer generated sin wave... -280dB noise floor :palm: the -160dB harmonics are probably Double (64bits) FP precision artifacts.

Well, it would be interesting to quantize that sinewave to 16 bit and 12 bit level and then push those through FFT.......... Simulations are not useless if targeted.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 22, 2023, 06:23:43 pm
[Dirac pulse...]
why play with theoritical signal that never existed? here FFT from computer generated sin wave...

Spot the contradiction!  ;D
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Mechatrommer on October 22, 2023, 06:24:42 pm
When I messed with FFT (in the stone age w/ Z80/68k in asm) I did shoot a Dirac pulse into it to see the floor :)
why play with theoritical signal that never existed? here FFT from computer generated sin wave... -280dB noise floor :palm: the -160dB harmonics are probably Double (64bits) FP precision artifacts.
Well, it would be interesting to quantize that sinewave to 16 bit and 12 bit level and then push those through FFT.......... Simulations are not useless if targeted.
that need some work. but should be better than what i've shown from real 12bit DSO....
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 22, 2023, 06:26:42 pm
When I messed with FFT (in the stone age w/ Z80/68k in asm) I did shoot a Dirac pulse into it to see the floor :)
why play with theoritical signal that never existed? here FFT from computer generated sin wave... -280dB noise floor :palm: the -160dB harmonics are probably Double (64bits) FP precision artifacts.
Well, it would be interesting to quantize that sinewave to 16 bit and 12 bit level and then push those through FFT.......... Simulations are not useless if targeted.
that need some work. but should be better than what i've shown from real 12bit DSO....
Certainly. But it would show theoretical numbers to have baseline...
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Mechatrommer on October 22, 2023, 06:39:36 pm
[Dirac pulse...]
why play with theoritical signal that never existed? here FFT from computer generated sin wave...
Spot the contradiction!  ;D
right! new information. so what does it tells? dont feed it a pulse? what happen if we feed it to a real SA? will it see something?

edit: for fun i added dirac 100Vpp, not sure what use of this other than theoritical... so far the lesson is dont send SA a pulse, esp FFT ;)

edit: and dirac 300uVpp, the eyeball noise from DHO800... -120dB floor...
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: tautech on October 22, 2023, 09:38:05 pm
What is your link to Siglent? It does seem to go beyond "generally liking their products".
Most folks watching this forum got it by now.

But you don't feel comfortable disclosing it when asked, let alone in your profile info? Well, you will have your reasons. But please be aware that it affects the reception of your posts once readers have realized that you have a hidden agenda or loyalty here.

Quote
the only valid question would be: have I posted wrong facts anywhere? Or in this thread particularly?

It's not about posting wrong facts, but about posting selectively picked facts which make "your" product look good, and glossing over aspects where the competing product has advantages. That's what decent salesmen do, and it is certainly what tautech and you have been doing here.
You could of course research members posts and particularly their topics to seen how they fit into this forum.

AFAIK there are only a few resellers here, a couple each from the US and EU and myself from deep south in the Pacific.
Some have tried and represented many brands and due to their technical expertise only focussed on brands that fully meet their specs.

Beta testers are many more and from all parts and have extensive experience in the TE world and outstanding knowledge otherwise they would not be accepted as beta testers.
Clues to whom a few are is in their participation in various threads before equipment came to market.

Those that can be bothered to do the research can easy discover these members that for whatever reason chose to fly below the radar rather than be attacked for brand preferences.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 23, 2023, 05:23:39 am
AFAIK there are only a few resellers here [...]
Beta testers are many more [...]

It does not matter to me whether someone is making money from customers by selling Siglent products, or is getting money and/or free stuff from Siglent directly. If the result is that they feel loyal to Siglent, and hence don't give balanced advice here but act as Siglent advocates, that's what I need to know and what I refer to as salesman behavior.

Quote
You could of course research members posts and particularly their topics to seen how they fit into this forum. [...]

As a side note, one does not have to actually read the posts. It is sufficient to observe who's thanking whom on a regular basis to identify the members of the "Siglent mutual back-patting society".  ::)

Quote
Those that can be bothered to do the research can easy discover these members that for whatever reason chose to fly below the radar rather than be attacked for brand preferences.

Why would it be more desirable to be perceived as someone with a brand preference (and a material interest) who is not upfront about it?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 23, 2023, 06:45:31 am
As a side note, one does not have to actually read the posts. It is sufficient to observe who's thanking whom on a regular basis to identify the members of the "Siglent mutual back-patting society".  ::)

Also the fact that they're posting about Siglents in every single Rigol thread.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 23, 2023, 07:02:49 am
AFAIK there are only a few resellers here [...]
Beta testers are many more [...]

It does not matter to me whether someone is making money from customers by selling Siglent products, or is getting money and/or free stuff from Siglent directly. If the result is that they feel loyal to Siglent, and hence don't give balanced advice here but act as Siglent advocates, that's what I need to know and what I refer to as salesman behavior.

Quote
You could of course research members posts and particularly their topics to seen how they fit into this forum. [...]

As a side note, one does not have to actually read the posts. It is sufficient to observe who's thanking whom on a regular basis to identify the members of the "Siglent mutual back-patting society".  ::)

Quote
Those that can be bothered to do the research can easy discover these members that for whatever reason chose to fly below the radar rather than be attacked for brand preferences.

Why would it be more desirable to be perceived as someone with a brand preference (and a material interest) who is not upfront about it?

All of that is a moot point.
Problem is not who works for who or do they wear it on forehead.
Problem is staying on topic and dealing with facts.

For instance, I publicly say I prefer Siglent scopes because until now, trying all kinds of scopes, I prefer LeCroy type analytic scopes and Siglent makes something similar and is clearly more affordable. And they have excellent quality, and are decent company. I was Rigol user first, and I gave up. I was very interested in DS7000 at the time and eventually gave up, for instance. I also think Siglent is way better in bug fixes, adding features. Evidence is all there.

So yeah I'm biased towards Siglent because their "way" is closer to way I think.

Martin tried to make a comparison thread between cheaper SDS1104X-E and bit more expensive DHO800. They are in similar price bracket of entry level "not a toy" scopes, where DHO800 is sort of a "new generation DS1000Z".
And Rigol marketing and fanboys started victory lap of "game changers" etc etc.

But if you do cold fact based analysis it is not so clear cut. Especially because Rigol made spectacularly horrible release of what are basically release candidate products. Software for whole series was released in alpha stage, DHO900 violates Nyquist if not run in special combinations of channels/MSO etc...

So Martin being a scope person, buys a DHO800 (with his own money ) out of sheer curiosity. He also have access to dozen of other scopes (Siglents and LeCroys) so he can compare it.
And all we get is, well, you saw what we get..

In this topic it was not any of "Siglent fanboy club" that sabotaged the effort.

If I was not persistent, there would not be any good information about:

- segmented mode an its usage with measurements and decoding (note THERE IS NOT a word about it in manual. According to Rigol that is not possible)
- Details of statistics
- Some FFT data pulled from scope that circumvents closed and nontransparent "trust us there is a bump here" FFT on scope.

Martin also showed
- decoding in a table,
- statistics in a table,
- how you can arrange windows in all kinds of ways not only vertically (also not something you could learn from any Rigols docs).

All of that actually puts DHO800 in more positive light, better than what could be gleaned by looking at their own marketing and docs.

And all of that effort by "Siglent fanboy club" was actively disrupted by people who actually have DHO800.

Animosity and hate even if you say good things.

Which does not matter but facts. 
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: iMo on October 23, 2023, 07:51:34 am
Rigol is rather small company based on to me available info (530 FTEs and several subsidiaries w/ perhaps S&M only). Their product range is not small for that amount of core FTEs, however. Based on my own experience with 100xFTEs larger players (and w/ the actual number of knowledgeable doers related to a specific product) the number of R&D people dedicated to a single product series (like the 800/900) must be miniscule, imho. Like 2.5 FTEs max (1 sw, 1.5 hw) directly assigned to the product series till the product launch, with some shared support of course. There could be another small cross-team for their ASICs. They may have some small testing teams, perhaps abroad in their subsidiaries, but the bottleneck is their home staffing, imho. I can imagine myself there is a single person sitting in their office these days, reading these threads (and emails from their subsidiaries), laughing, and slowly debugging the sw issues of the 800/900/1000/4000 series in a pace the working hours allow :)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 23, 2023, 07:56:49 am
Problem is not who works for who or do they wear it on forehead.
Problem is staying on topic and dealing with facts.

I partially agree.

Some users here generally like Siglent products, but nevertheless take a balanced approach -- Martin and you are prime examples in my mind. Some others have a strong tendency to advocate for Siglent, rub in "pro Siglent" facts which are unrelated to the discussion at hand, dismiss Rigol design aspects in unobjective and insolent ways etc. Those are the ones I have referred to as "salesmen"  -- no need to name them here.

And there are a few users who push back. In contrast to the "Siglent circle", they don't seem to be affiliated with Rigol in any way, beyond having bought some equipment with their own money. I don't recall seeing them attacking Siglent in threads about Siglent TE, only pushing back against the undercurrent of Siglent advocates in the Rigol-related threads. And yes, sometimes their tone gets out of hand and becomes insolent as well.

I don't know why there is this imbalance of Siglent vs. no Rigol representatives on the forum. Maybe Rigol generally works with larger, multi-brand distributors, so none of those has been as motivated and committed to advocate for Rigol and use the forum to build a group of beta testers? But it is obvious that the imbalance exists. We can't force it to disappear, so the next best thing in my mind would be transparency -- which is why I would encourage people to disclose their ties to Siglent (and other brands), as e.g. tautech does.

[In the interest of transparency: I consider myself a brand-neutral hobbyist. I own (budget) equipment from Rigol, Siglent and a couple of other brands, and some old stuff from Philips and Hitachi, all bought with my own money.]
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: tautech on October 23, 2023, 08:46:02 am
We can't force it to disappear, so the next best thing in my mind would be transparency -- which is why I would encourage people to disclose their ties to Siglent (and other brands), as e.g. tautech does.
Some link their website and that should be enough IMO.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 23, 2023, 09:25:09 am
You don't understand much do you?

Aaaaand.... we're done here.
Thank you!!

Bottom  line: The Rigol can do everything.

You want sliding window? It does it.

You want to manually reset every time? Set the window size to 10000000 and it's the same thing.

Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 23, 2023, 09:49:07 am
Problem is not who works for who or do they wear it on forehead.
Problem is staying on topic and dealing with facts.

I partially agree.

Some users here generally like Siglent products, but nevertheless take a balanced approach -- Martin and you are prime examples in my mind. Some others have a strong tendency to advocate for Siglent, rub in "pro Siglent" facts which are unrelated to the discussion at hand, dismiss Rigol design aspects in unobjective and insolent ways etc. Those are the ones I have referred to as "salesmen"  -- no need to name them here.

And there are a few users who push back. In contrast to the "Siglent circle", they don't seem to be affiliated with Rigol in any way, beyond having bought some equipment with their own money. I don't recall seeing them attacking Siglent in threads about Siglent TE, only pushing back against the undercurrent of Siglent advocates in the Rigol-related threads. And yes, sometimes their tone gets out of hand and becomes insolent as well.

There will be those that that are overzealous.
And I could name few Rigolites(TM) (fans of Rigol :-DD) that were dropping in any discussion and when Siglent was mentioned they would simply just smash the party..  For instance whenever you mention that Siglent has always running segments (triggered capture memory) so you can always stop scope and go back if you wanted to, they would start attacking how that is stupid and useless. Because their favourite brand does not have it. Or when Siglent released 12 bit scope then it was all the rage how 12 bit is not important and that is just a elitistic bulshit to push expensive scopes. Then suddenly apparently 12 bit is all important. By same people. While now and then, 12 bit, like anything else, is important if you have use for it. If not you could be equally well served by 8 bit scope.. etc etc. And Rigol is here and reads it all..

And then you have users like Performa01. I understand him well. Like me, he sees all the nonsense and deflection being said. Like me he knows what is important in a scope. More BW is always better, unless you need low noise at low frequency, when suddenly more BW is your enemy. More memory is always better though. Lower noise is always better. More measurements is always better.

Many fresh, new, digital scope users think history started yesterday. While in fact it has been decades. There are many thing that are universal truth proven many times and then you have people that insist that "resetting stats is not needed, and if you set statistical sample to 4 on sliding windows stat that is all you need.. Ar you hyping reset because your Siglent has it?".... Hell yeah it has it, like ALL other 7 scopes I have... And than insist that I should prove that I'm right.. Because they reject "Argument from authority". While that is simply screaming ego that cannot admit they don't know something, combined with Kruger-Dunning and unhealthy ambition to win at any cost, including dirty play. If they don't like what I say, that is not because they are lacking knowledge (of any type and form required), no it is because I am .... Choose any type of derogative....
Worst thing is, not knowing something is not shameful. Not at all. Corpus of human knowledge is so wast, even full blown geniuses have fraction of a fraction of a fraction of knowledge in any given topic.

And since both Performa and myself are not spring chickens, with years you get weary of the noise....
Which shapes responses, tone, and how much you are ready to explain why.
I do it to the best of my abilities.
And when I'm wrong I own it.

Mind you this is not some apologetic statement or complaint or attack of any sort towards anybody.
It is just a heart to heart in our honest exchange here to explain a bit how I feel in all this.
I don't get paid for any of this. I like helping people when I can. It's nice to be nice.
I make recommendation that I genuinely think will benefit asking party.
Based on my experience. So I will preferentially suggest something that Siglent has that I tried and it is proven to work well.
Or I will (and had) recommend Keysight, Picoscope, Micsig and Rigol..
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 23, 2023, 10:10:50 am
You don't understand much do you?

Aaaaand.... we're done here.
Thank you!!

Bottom  line: The Rigol can do everything.

You want sliding window? It does it.

You want to manually reset every time? Set the window size to 10000000 and it's the same thing.

Yes, after Spanish inquisition torture treatment, you finally verified for us that does have it. I gave it a passing grade.

The comment is about 20 posts from you how that is not important, that is unnecessary, how I'm this and that,  instead of one simple yes for benefit of all.
And make note, not a single time I questioned you to show me any proof of it. I took your word for it.
You said you looked and confirmed it was there, was enough confirmation for me.

For all of the questions I asked there was a reason (hint: not Siglent related): these are important functions and in ALL of current Rigol documentation there is no explanation or even mention of it. There is some mention of how stats can be reset but not how and where and no image.
So images and answers you posted clarify that, and since they were positive, they actually benefit Rigol
And thanks to you now, potential buyers have better quality info, what it can and cannot do.
That would be even more important if those functions were not there.
It is shame it took so much effort from an "enemy" to enable you to be good an helpful and benefit Rigol community.
I must be worst Siglent fan ever....

Ruminate on that.

P.S. If we have to go all in in name calling, I would not be offended if called "Siglent compatible".... :-DD

Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 23, 2023, 11:56:52 am
There is some mention of how stats can be reset but not how and where and no image.

I searched for the word "reset" in the manual and got this as the first hit:
(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1909065;image)

This is the second hit:
(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1909053;image)

If you go to section 11.2.2 you get this:
(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1909059;image)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 23, 2023, 12:06:37 pm
This is the menu that pops up when you touch a measurement on the side bar:

You can reset the statistics for that measurement, enable an on-screen indicator (the orange lines above/below the signal when you're looking at Vpp), remove it, or go to the full measurement settings.

So... just two taps to reset the stats for any measurement.

(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1909071;image)

If you open the full measurement settings you see this popup wher you can configure all sorts of things. See the manual for details:
(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1909077;image)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 23, 2023, 01:33:23 pm
Edit, I just noticed another way to reset the stats!

This is for all the people who hate touch screens and don't want to dedicate the "Quick" button to resetting stats:

When you press "SINGLE" it resets the stats and captures a single event (it shows count=1 in the stats display).

Now you can press "RUN" and it continues counting up from 1.

Two button presses = stats reset.  :)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 23, 2023, 01:43:47 pm
I'm trying to figure out if my cheapo 150Mhz probes will keep me below Nyquist if I enable all 4 channels with 250Mhz bandwidth enabled. I just poked the probe into the BNC of my SigGen to see what I got.

This is my rise time with the crocodile clip:
(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1909143;image)

nb. The four pink lines aren't cursors, they're the overlay you get if you turn on the indicator for rise time.

This is my rise time with the little spring accessory:
(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1909149;image)

There's quite a big difference between the two!

Conclusions...

Crocodile clip: 163MHz=a tiny bit over.
Spring: 196MHz = nope.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 23, 2023, 02:45:37 pm
I'm trying to figure out if my cheapo 150Mhz probes will keep me below Nyquist if I enable all 4 channels with 250Mhz bandwidth enabled. I just poked the probe into the BNC of my SigGen to see what I got.

This is my rise time with the crocodile clip:

This is my rise time with the little spring accessory:

There's quite a big difference between the two!

Conclusions...

Crocodile clip... yes.
Spring... not so much.

First of all thank you for recent info. I did not find all of that in manual, thank you for that.

Also I like the probe test. When in doubt, measure.
Also if you remember previous topics about probes, by Perfoma01 and others, similar results to that.
If you have low enough source impedance, probe will have much higher BW than specced.

As I said, in order to be sure it won't alias with all 4ch , scope should be run in 100 MHz configuration.
With 1 or 2 ch it should not alias much (2ch) or at all (1ch).

Aliasing will be most visible as unstable edges or large overshoots on square wave , but you will generally see it more as spurious tones in FFT. They fold back, like in the mirror..

By using manual control of sampling on a scope we can simulate effects of aliasing so we can see how they look like.
Let me explain with images: same 20 MHz squarewave with 1ns edges (I deliberately stayed from faster edges, this should be similar to Arduino UNO I/O pins ).
It was sampled at 1.25 GS/s, then at 500MS/s and 250 MS/s. Sorry my scope cannot do 625 and 312.5 and this not supposed to be exactly the same, but to illustrate the effect so people can recognize it.. To simulate BW, I enable 200 MHz BW limit but on your scope it will be more like 250 Mhz so aliasing might be easier to show.

On 1.25 GS/s it  looks pretty much perfect. on two lower sampling rates it goes down the hill. Make note that repetition rate is only 20MHz and that edges are no very fast. 1ns edges or faster are pretty much guaranteed today in anything digital., unless you are working only on legacy TTL logic and retro computing...
 
Use this as baseline for comparison. Hope it helps with your evaluation.

Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 23, 2023, 03:15:48 pm
By using manual control of sampling on a scope we can simulate effects of aliasing so we can see how they look like. [...]
On 1.25 GS/s it  looks pretty much perfect. on two lower sampling rates it goes down the hill. [...]

Thanks for those screenshots! But they got me wondering: Is it really aliasing we see there, i.e. the presence of image frequencies, or just the effect of approximating the square wave with a limited number of harmonics? Would these look any different if you had a suitable analog low-pass at the input which blocks all frequency components above the Nyquist frequency?

Edit: For comparison, could you keep the high sample rate but add a digital low pass operation at Nyqist? Thanks!
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Performa01 on October 23, 2023, 03:36:20 pm
By using manual control of sampling on a scope we can simulate effects of aliasing so we can see how they look like. [...]
On 1.25 GS/s it  looks pretty much perfect. on two lower sampling rates it goes down the hill. [...]

Thanks for those screenshots! But they got me wondering: Is it really aliasing we see there, i.e. the presence of image frequencies, or just the effect of approximating the square wave with a limited number of harmonics? Would these look any different if you had a suitable analog low-pass at the input which blocks all frequency components above the Nyquist frequency?

Edit: For comparison, could you keep the high sample rate but add a digital low pass operation at Nyqist? Thanks!
The answer to all these questions as well as the requested screenshots (and many more) can be found in the document at the end of the first posting in the following thread.

https://www.eevblog.com/forum/testgear/sds2000x-plus-bandwidth-aliasing-application-note/msg3919544/#msg3919544 (https://www.eevblog.com/forum/testgear/sds2000x-plus-bandwidth-aliasing-application-note/msg3919544/#msg3919544)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 23, 2023, 03:47:18 pm
The answer to all these questions as well as the requested screenshots (and many more) can be found in the document at the end of the first posting in the following thread.

https://www.eevblog.com/forum/testgear/sds2000x-plus-bandwidth-aliasing-application-note/msg3919544/#msg3919544 (https://www.eevblog.com/forum/testgear/sds2000x-plus-bandwidth-aliasing-application-note/msg3919544/#msg3919544)

Thank you! That document deserves time to work through properly...

Upon quickly skimming it, I could not find screenshots which compare the effect of capturing a square wave with aliasing (due to a limited sampling rate 2F) with the effect of limited bandwidth (high sampling rate, but lowpass at cutoff frequency F). Could you point me to the right figures please?

Edit: Ok, I think I got it in principle. The "wiggles" on 2N3055's screenshots can be explained by bandwith limitations, while the jitter is the effect of aliasing, right? If there are direct comparisons of the two effects in your document, I would still appreciate a pointer.

And if there is an explanation how aliasing translates into the jitter effect, please direct me to that one too -- I can't seem to get my head around that effect...

Edit Edit: Ah, saw your new response only after I had hit "save". Reading now, thanks!
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Performa01 on October 23, 2023, 03:56:04 pm
The answer to all these questions as well as the requested screenshots (and many more) can be found in the document at the end of the first posting in the following thread.

https://www.eevblog.com/forum/testgear/sds2000x-plus-bandwidth-aliasing-application-note/msg3919544/#msg3919544 (https://www.eevblog.com/forum/testgear/sds2000x-plus-bandwidth-aliasing-application-note/msg3919544/#msg3919544)

Thank you! That document deserves time to work through properly...

Upon quickly skimming it, I could not find screenshots which compare the effect of capturing a square wave with aliasing (due to a limited sampling rate 2F) with the effect of limited bandwidth (high sampling rate, but lowpass at cutoff frequency F). Could you point me to the right figures please?

Title: Re: Rigol DHO804 Test and Compare Thread
Post by: asmi on October 23, 2023, 06:34:58 pm
And I could name few Rigolites(TM) (fans of Rigol :-DD) that were dropping in any discussion and when Siglent was mentioned they would simply just smash the party.. 
I don't remember a single Siglent thread where that would be the case - but maybe I haven't noticed because I admit I don't have time to read them all. But ANY Rigol thread is always swarming full of Siglent shills. What business to they have to be there at all? When I read such threads, I want to get an objective information, not endless shilling and holy wars.

For instance whenever you mention that Siglent has always running segments (triggered capture memory) so you can always stop scope and go back if you wanted to, they would start attacking how that is stupid and useless. Because their favourite brand does not have it. Or when Siglent released 12 bit scope then it was all the rage how 12 bit is not important and that is just a elitistic bulshit to push expensive scopes. Then suddenly apparently 12 bit is all important. By same people. While now and then, 12 bit, like anything else, is important if you have use for it. If not you could be equally well served by 8 bit scope.. etc etc. And Rigol is here and reads it all..
Again, didn't see that. But I do see Siglent shills preaching how 12 bit is not important at all :-DD

And then you have users like Performa01.
Do you mean shills like Performa01, who don't disclaim their affiliation and try to pass up their shilling as "unbiased" opinion? Sorry, but I despise such folks. At least tautech has guts to openly admit his affiliation, and I respect him for that.

Based on my experience. So I will preferentially suggest something that Siglent has that I tried and it is proven to work well.
Having biases is OK as long as they are known by people you talk too, so that they can keep it in mind when deciding if they should take your advice on a purchase or not. Because things one doesn't say are just as important (and telling) as things one does say.
And to me as someone fairly unbiased (I have exactly one Rigol and one Siglent TM, so they are even in my eyes :D ), you do come across as being excessively negaitive towards these Rigol scopes, and constantly comparing them to devices from significantly higher price bracket, which is not helpful at all for potential buyers - we all know that Lexus is better than Toyota, but if you've only got a budget for a barebones lowest trim of Corolla, reading comparisons between Toyota Corolla and Lexus ES are not going to provide you with anything useful.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Mechatrommer on October 23, 2023, 07:33:41 pm
And I could name few Rigolites(TM) (fans of Rigol :-DD) that were dropping in any discussion and when Siglent was mentioned they would simply just smash the party.. 
I don't remember a single Siglent thread where that would be the case - but maybe I haven't noticed because I admit I don't have time to read them all. But ANY Rigol thread is always swarming full of Siglent shills. What business to they have to be there at all? When I read such threads, I want to get an objective information, not endless shilling and holy wars.
look at the bright side! they are trying to help $400 scope to push boundary of $4000 scope ;D i really wish them success.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: asmi on October 23, 2023, 07:53:56 pm
look at the bright side! they are trying to help $400 scope to push boundary of $4000 scope ;D i really wish them success.
I don't know - to me in sounds like a guy who comes into topic about Toyota Corolla and goes on and on about his new Lexus ES. Not helpful nor interesting. If $400 scope will get all features of $4000 one, it won't be a $400 scope anymore. Everything has a price.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 23, 2023, 08:34:36 pm
What business to they have to be there at all?

Dude, it is a comparison thread...  :palm: With Siglent scope....  :-//
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 23, 2023, 08:39:26 pm
look at the bright side! they are trying to help $400 scope to push boundary of $4000 scope ;D i really wish them success.
I don't know - to me in sounds like a guy who comes into topic about Toyota Corolla and goes on and on about his new Lexus ES. Not helpful nor interesting. If $400 scope will get all features of $4000 one, it won't be a $400 scope anymore. Everything has a price.

Go back and read.. If made a critique of anything it was bugs and stuff that needs to fixed..
Nobody said they should add features..
Actually, in this very topic we documented all the good stuff that DHO800 has and is not very well documented or obvious.
And it is actually quite good feature wise, just needs a good debug..

So your complaints are unfounded. If you go and read you will find out I have Rigol DM3068, DP831, DG1064Z and used to have DS1074Z.. Also have Micsig, Keysight, Picoscope..
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: asmi on October 23, 2023, 08:39:35 pm
Dude, it is a comparison thread...  :palm:
Dude, I don't care. I want to hear opinions of normal users, not shills. They don't add anything useful to conversation.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: asmi on October 23, 2023, 08:41:09 pm
Go back and read.. If made a critique of anything it was bugs and stuff that needs to fixed..
Nobody said they should add features..
Actually, in this very topic we documented all the good stuff that DHO800 has and is not very well documented or obvious.
And it is actually quite good feature wise, just needs a good debug..
But the only way to find this out is to spend ungodly amount of time going through flame wars and shilling, so that they can find 10-15 posts which are actually useful and informative. Nobody has time for that.

So your complaints are unfounded.
Yes they are and you know it. Don't even predend otherwise.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 23, 2023, 08:50:15 pm
Go back and read.. If made a critique of anything it was bugs and stuff that needs to fixed..
Nobody said they should add features..
Actually, in this very topic we documented all the good stuff that DHO800 has and is not very well documented or obvious.
And it is actually quite good feature wise, just needs a good debug..
But the only way to find this out is to spend ungodly amount of time going through flame wars and shilling, so that they can find 10-15 posts which are actually useful and informative. Nobody has time for that.

So your complaints are unfounded.
Yes they are and you know it. Don't even predend otherwise.

You are wrong. I responded to trolling and shilling. Realtime scope that has nominal 200MHz+ BW and samples at 156,25 MSPS/s is crap and you know it (DHO900). I had argument about that.
I also had argument here about facts.

Yet you would want me not to react when somebody writes complete nonsense.
Why didn't you react and point out inaccuracies? And nonsensical things?

But you come after me because I dare to argue about facts..?
Your post alone just proves exactly my point...
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 23, 2023, 08:51:21 pm
Quote
But the only way to find this out is to spend ungodly amount of time going through flame wars and shilling, so that they can find 10-15 posts which are actually useful and informative. Nobody has time for that.

I think it would be good if people here would finally get back to the subject and not to themselves and other people.
That fills pages here and then complains about the fact that you can hardly find the useful posts in it...Something bizarre. ::)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: asmi on October 23, 2023, 09:04:44 pm
You are wrong. I responded to trolling and shilling. Realtime scope that has nominal 200MHz+ BW and samples at 156,25 MSPS/s is crap and you know it (DHO900). I had argument about that.
I also had argument here about facts.
This thread is about DHO804 - it's right there in the title! What the hell are you doing here talking about different device? Why is it even here?

Yet you would want me not to react when somebody writes complete nonsense.
Why didn't you react and point out inaccuracies? And nonsensical things?

But you come after me because I dare to argue about facts..?
Your post alone just proves exactly my point...
Your posts has already proven to me everything I needed to know. Now they add exactly zero new information. So please save us all from this noise and let's see if we can increase S/R ratio of this thread.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: asmi on October 23, 2023, 09:06:02 pm
I think it would be good if people here would finally get back to the subject and not to themselves and other people.
That fills pages here and then complains about the fact that you can hardly find the useful posts in it...Something bizarre. ::)
I only have 4 or 5 posts here, other 22 pages are not mine, and yet their SNR is so low that even the best SA won't be able to make out of all the noise.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Mechatrommer on October 23, 2023, 10:27:12 pm
Yet you would want me not to react when somebody writes complete nonsense.
yet when people react to you with informations/facts, you call them rude?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: nctnico on October 23, 2023, 10:35:08 pm
Quote
But the only way to find this out is to spend ungodly amount of time going through flame wars and shilling, so that they can find 10-15 posts which are actually useful and informative. Nobody has time for that.

I think it would be good if people here would finally get back to the subject and not to themselves and other people.
That fills pages here and then complains about the fact that you can hardly find the useful posts in it...Something bizarre. ::)
It could also be due to lack of real content  8) Perhaps it is better to collect a lot of data + measurements + images, write text in a text editor (go over it a few times) and once you are done, create 1 or more big posts with all your findings bundled together. That is how I typically approach posting equipment reviews / bigger projects. And these threads tend to stay very on-topic. Maybe consider starting a new thread.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 23, 2023, 10:53:31 pm
You are wrong. I responded to trolling and shilling. Realtime scope that has nominal 200MHz+ BW and samples at 156,25 MSPS/s is crap and you know it (DHO900). I had argument about that.

Yes, but it DOESN'T sample at that rate, not when you use it sensibly.

Going into every single thread and telling people that it does that isn't helping anybody.

It especially doesn't help people who just arrived and don't yet know who the EEVBLOG "personalities" are.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 23, 2023, 10:55:26 pm
I only have 4 or 5 posts here, other 22 pages are not mine, and yet their SNR is so low that even the best SA won't be able to make out of all the noise.

Not even 12 bits is enough to pick out the signal.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 24, 2023, 07:31:27 am
You are wrong. I responded to trolling and shilling. Realtime scope that has nominal 200MHz+ BW and samples at 156,25 MSPS/s is crap and you know it (DHO900). I had argument about that.
Yes, but it DOESN'T sample at that rate, not when you use it sensibly.

Apparently that sensible use can only be expected from the more advanced users of more expensive oscilloscopes. Tautech explained this with reference to the SDS2000X plus series once:  ;)

Most buyers of this class of scope (low mid range) will understand the tradeoff of sampling rate vs frequency (aliasing) and select sufficient a sampling rate for their frequencies of interest or be quite aware to use just one channel on each ADC.

Granted, the SDS2000X plus is an edge case (500 MHz bandwidth at 1 GSa/s), while Rigol is pushing things much further with the DHO924. Rigol should at the very least state clearly in the specs that using the LA costs you half the sampling rate in the analog channels. Very unusual to my knowledge, since in other DSOs the ADC is the bottleneck, while in the DHO800/900 it's apparently the FPGA's capacity to handle digital data streams.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: iMo on October 24, 2023, 08:00:35 am
That FPGA could do happily 200-300MHz LA sampling with the 16(32) bits width. The issue/bottleneck is somewhere between the FPGA and the shared external memory (shared with o'scope channels) attached to the FPGA, imho. A dirty hack could be to use the internal bram for the LA, but with much smaller data amount sampled (like XX kBytes), none sampling rate decrease needed with the LA "on" then..
My 15y old openbench-logic-sniffer ($50) can do 200MHz sampling w/ 16bit (24kB bram).
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 24, 2023, 08:10:33 am
That FPGA could do happily 200-300MHz LA sampling with the 16(32) bits width.

It even handles 625 MSa/s LA sampling in the DHO900. But then only a total of another 625 MSa/s is available for 1..4 analog channels.

I agree that we don't know which exact part of the digital section constitutes the bottleneck. It might well be the external RAM. There are those two extra RAMs which are only populated on the DHO900 series mainboard, which could be either for LA or AWG use -- I don't think that has been determined?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: tautech on October 24, 2023, 08:11:28 am
Most buyers of this class of scope (low mid range) will understand the tradeoff of sampling rate vs frequency (aliasing) and select sufficient a sampling rate for their frequencies of interest or be quite aware to use just one channel on each ADC.

Granted, the SDS2000X plus is an edge case (500 MHz bandwidth at 1 GSa/s), while Rigol is pushing things much further with the DHO924. Rigol should at the very least state clearly in the specs that using the LA costs you half the sampling rate in the analog channels. Very unusual to my knowledge, since in other DSOs the ADC is the bottleneck, while in the DHO800/900 it's apparently the FPGA's capacity to handle digital data streams.
Bold is incorrect.

SDS2000X Plus while a 500 MHz design uses two 2GSa/s ADCs however when 3 channels are activated automatic BW limiters are engaged to ensure Nyquist remains met with sufficient sampling rates.

However SDS2000X Plus can support 2 channels at 500 MHz BW and its -3dB point is ~600 MHz IIRC. Some say 580 others 620 MHz.
This is described in the datasheet:
Sample rate (Max.) 2 GSa/s (interleaving mode),1 GSa/s (non-interleaving mode)
Where in interleaved mode 4x the rated BW is supported with 2 GSa/s to comfortably meet Nyquist.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: iMo on October 24, 2023, 08:27:46 am
That FPGA could do happily 200-300MHz LA sampling with the 16(32) bits width.

It even handles 625 MSa/s LA sampling in the DHO900. But then only a total of another 625 MSa/s is available for 1..4 analog channels.

I agree that we don't know which exact part of the digital section constitutes the bottleneck. It might well be the external RAM. There are those two extra RAMs which are only populated on the DHO900 series mainboard, which could be either for LA or AWG use -- I don't think that has been determined?

Thus it seems the max r/w bandwidth into those external drams is those ~625Mwords/sec (or the twice when interleaved r/w). That is somehow in sync with the ~667MHz max clock of the Zynq FPGA there (assuming the lowest grade FPGA).

The other DSOs I saw have got usually 4x drams where you can share the r/w bandwidth even better.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 24, 2023, 08:32:56 am
SDS2000X Plus while a 500 MHz design uses two 2GSa/s ADCs however when 3 channels are activated automatic BW limiters are engaged to ensure Nyquist remains met with sufficient sampling rates.

Ah, thanks for pointing that out. That is a clean solution; I wish Rigol did the same in the DHO900. Maybe they will add it in a future firmware update; the required lowpass filter settings are probably all on board.

Hey, maybe that's the real reason why they have a 70 MHz entry model -- that happens to be the Nyqist bandwidth in the worst case of using all DHO900 channels.  ::)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: tautech on October 24, 2023, 08:50:22 am
SDS2000X Plus while a 500 MHz design uses two 2GSa/s ADCs however when 3 channels are activated automatic BW limiters are engaged to ensure Nyquist remains met with sufficient sampling rates.

Ah, thanks for pointing that out. That is a clean solution;
No it's the only proper solution when insufficient sampling is available for 4 channel operation.
These auto BW limiters get clearly displayed in each channel tab when applied just like the manually engaged 20 MHz BW filter.
SDS1204X-E & SDS5104X don't use this solution as they provide sufficient sampling to meet Nyquist when all channels are active.
OTOH SDS2504X Plus and SDS2504X HD do use this solution for 350 MHz max when 4 channels are active.

SDS1204X HD will use a similar solution to maintain sufficient sampling rates whereas SDS1104X HD provides sufficient sampling rates to not need BW limiters.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 24, 2023, 09:32:50 am
Yes, but it DOESN'T sample at that rate, not when you use it sensibly.

Apparently that sensible use can only be expected from the more advanced users of more expensive oscilloscopes. Tautech explained this with reference to the SDS2000X plus series once:  ;)

Rubbish. Most people simply won't be connecting that much stuff to it. Not connecting stuff doesn't take knowledge.

Besides: It will only be a problem if the incoming signals are over Nyquist, which they won't be if they're coming from Arduinos and/or breadboards with dupont cables.

To me the biggest limitation will be the small screen for showing all that stuff. Anybody looking to connect that many wires should probably go for an MSO5000 which costs about the same.

I can tell you're not going to let this go though so let's not argue that.

I also predict that an awful lot of DHO900 sales will be for a couple of channels with 250Mhz analog bandwidth and/or the built-in AWG, NOT for the LA.

(especially given the price of the LA probes)

Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 24, 2023, 10:34:05 am
Apparently that sensible use can only be expected from the more advanced users of more expensive oscilloscopes. Tautech explained this with reference to the SDS2000X plus series once:  ;)
Rubbish.

I realize that this topic is close to your heart, but please calm down a bit. The yellow thing in my comment is a smiley, ya know?

Quote
Besides: It will only be a problem if the incoming signals are over Nyquist, which they won't be if they're coming from Arduinos and/or breadboards with dupont cables.

Sampling of the digital channels at 625 MSa/s is perfectly fine. To look at analog signals in parallel -- whether analog I/O of the system under test or digital signals that need close scrutiny -- I would use proper analog probes, and then the scope's violation of the Nyquist limit may become a problem.

Especially for the use case of scrutinizing a digital signal to look for overshoots, runt pulses etc., I do see the low sampling rate on the analog inputs as a real limitation. What good is this if you have a much lower sampling rate on the analog channels than on the digital inputs? You could only do this on a single analog channel -- which is better than nothing though.

Still, the sampling rate limitations would not be a total show stopper for me. As mentioned earlier, a DHO914 including Rigol's rather nice logic probe is still significantly less expensive than e.g. a Saleae Logic Pro 16, and has better specs in the digital and analog domain.

Quote
I can tell you're not going to let this go though so let's not argue that.

As mentioned a couple of times: The thing I really resent Rigol for is that they don't disclose the sampling rate impact on the analog channels when using the LA. Let's assume it is just an oversight and they will come out with a corrected data sheet quickly. Umm, right...  :P
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: UK on October 24, 2023, 11:58:43 am
Haven't you found that it's a bit weird that most of Rigol's threads here look more like advertising of Siglent than a strict topic discussion?
Why in Siglent threads not always talking about Rigol?! :-DD
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: TurboTom on October 24, 2023, 12:39:58 pm
...

Thus it seems the max r/w bandwidth into those external drams is those ~625Mwords/sec (or the twice when interleaved r/w). That is somehow in sync with the ~667MHz max clock of the Zynq FPGA there (assuming the lowest grade FPGA).

The other DSOs I saw have got usually 4x drams where you can share the r/w bandwidth even better.

That's actually not quite correct: The speed is valid for the two ARM Cortex A9 cores which don't shovel the raw ADC data to the sample memory. The FPGA logic (Artix7-equivalent with 74k logic cells) with its parallel architecture can perform much faster than that. The RAM that's used is specified at 2.133 GT/s, which at the utilized 16 bit wide interface will easily match the 1.25GSa/s data rate of the ADC plus some overhead. All of this, combined with the 3.3MB block RAM contained inside the FPGA makes me wonder if the two additional RAM foorprints are actually populated in the DHO900 series, considering the observation of the sample rate loss when enabling the digital inputs...

This wouldn't be the first time that the BOM of production versions of test gear has been significantly "economized" compared to pre-production units which afterwards limits performance and expandability considerably (SDG6000X...). And Rigol was "Clever" enough not to publish any MSO-related performance data ::)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 24, 2023, 01:01:39 pm
[...] makes me wonder if the two additional RAM foorprints are actually populated in the DHO900 series

They are, at least in @hubertyoung's DHO924 unit: https://www.eevblog.com/forum/testgear/rigols-new-dho800-oscilloscope-unbox-teardown/msg4976278/#msg4976278 (https://www.eevblog.com/forum/testgear/rigols-new-dho800-oscilloscope-unbox-teardown/msg4976278/#msg4976278)

That is an early unit from July though. It is also the donor of the vendor.bin which has been used by various '804 owners to upgrade their scopes, by the way.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 24, 2023, 01:16:38 pm
Haven't you found that it's a bit weird that most of Rigol's threads here look more like advertising of Siglent than a strict topic discussion?
Why in Siglent threads not always talking about Rigol?! :-DD

You are in the wrong thread.

This is a comparison thread.

But apparently there should be no comparison or even discussing features and capabilities of different equipment ..
 :-//
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: TurboTom on October 24, 2023, 02:34:48 pm
[...] makes me wonder if the two additional RAM foorprints are actually populated in the DHO900 series

They are, at least in @hubertyoung's DHO924 unit: https://www.eevblog.com/forum/testgear/rigols-new-dho800-oscilloscope-unbox-teardown/msg4976278/#msg4976278 (https://www.eevblog.com/forum/testgear/rigols-new-dho800-oscilloscope-unbox-teardown/msg4976278/#msg4976278)

That is an early unit from July though. It is also the donor of the vendor.bin which has been used by various '804 owners to upgrade their scopes, by the way.

Yes I'm aware of that. And the relatively early time that Hubert got his specimen makes it very likely that his was a pre-production unit. Just like Shariar's (Signalpath) SDG6000X that he reviewed and that contained the four dedicated sample memory chips while mine doesn't: https://www.eevblog.com/forum/testgear/siglent-sdg6000-series-awg_s/msg3545119/#msg3545119 (https://www.eevblog.com/forum/testgear/siglent-sdg6000-series-awg_s/msg3545119/#msg3545119)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 24, 2023, 03:37:08 pm
Haven't you found that it's a bit weird that most of Rigol's threads here look more like advertising of Siglent than a strict topic discussion?
Why in Siglent threads not always talking about Rigol?! :-DD

You are in the wrong thread.

This is a comparison thread.

But apparently there should be no comparison or even discussing features and capabilities of different equipment ..
 :-//

He's talking about Rigol threads in general.

I don't remember a single Rigol thread ever which was any different.

Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 24, 2023, 04:17:47 pm
Haven't you found that it's a bit weird that most of Rigol's threads here look more like advertising of Siglent than a strict topic discussion?
Why in Siglent threads not always talking about Rigol?! :-DD

You are in the wrong thread.

This is a comparison thread.

But apparently there should be no comparison or even discussing features and capabilities of different equipment ..
 :-//

He's talking about Rigol threads in general.

I don't remember a single Rigol thread ever which was any different.

And Siglent related threads are no different. Instead of comparing notes to be better educated and demand more from all manufacturers for benefit of all..

And even if in that case this should still be the wrong thread. For facts about thread post in that thread... Or open a complaint thread...

But I simply refuse those accusations, at least on my part.
How many posts I have in DHO hacking thread ?
How many posts in any (non comparison) DHo based thread where I mention Siglent (if it was not to answer the question)...
How many times in this very thread I said something about DHO800 was good and right once I saw how it was done?
Have I ever said that DHO800 was crap because it did not have as many function as SDS2000X HD for instance?
Or did I repeatedly said that being a simple scope and in that price range is quite OK?

Really, go look... I might be abrasive sometimes, but facts are facts.

It is not even about brands anymore, it's simply lynch mob mentality... No facts needed....
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 24, 2023, 04:32:34 pm
[...] makes me wonder if the two additional RAM foorprints are actually populated in the DHO900 series
They are, at least in @hubertyoung's DHO924 unit
Yes I'm aware of that. And the relatively early time that Hubert got his specimen makes it very likely that his was a pre-production unit.

Would that imply that @hubertyoung's DHO924 can possibly sustain its analog sampling rate even when the LA is activated? (Provided that its current firmware and FPGA configuration can still detect and use the extra RAMs, which may be a long shot.)

I'll send him a PM and ask, in case he does not monitor all those DHO threads...
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Mechatrommer on October 24, 2023, 04:55:23 pm
Why in Siglent threads not always talking about Rigol?! :-DD
if every Rigol owners are like me... i have to admit Siglent spec is somewhat better than Rigol, except some minor aspects (such as me insist on downloadable data through usb cable), so we cant argue in their thread otherwise we just shooting our own foot...but since Siglent are more expensive, because of the price alone, we tend stick to Rigol, or there is no real need to switch (upgrade) to Siglent because we can manage with our existing Rigol dso. to get a picture of what we (i) feel when i see new siglent dso model appearing is like... oh this scope is sooooo good, but when i look at the price... oooh ok, no wonder why that scope is soo good. when we look at new Rigol, ok this rigol is much better than previous one, and it cheapest bang per buck! lets go get it! and hack it to maximum spec it can be hacked to. i bought 804 is for a reason, 814 is just few dollar more expensive, i can afford if i want to but.... we know rigol's "tradition" since dave made this forum, and it seems it hasnt changed.

edit: fair enough siglent is designed properly. not to mention its 2-10X the price.. but it will never see oscillating hi bw opamp with excessive feedback capacitance. If you havent seen it in its aliased form, you wont love rigol ;D
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: TurboTom on October 24, 2023, 08:12:33 pm
...

Would that imply that @hubertyoung's DHO924 can possibly sustain its analog sampling rate even when the LA is activated? (Provided that its current firmware and FPGA configuration can still detect and use the extra RAMs, which may be a long shot.)

I'll send him a PM and ask, in case he does not monitor all those DHO threads...

Well to be honest, I don't know  ;). All I can tell that when applying logic and common sense, tripling the memory and data rate available to the Zynq as seen on the pre-production DHO900 vs. the DHO800 and still having to cut sampling rate by half when enabling the digital channels doesn't make much sense. My take was that the two additional ram chips identical to the main sample memory chip were there to provide storage for sampling the 16 digital channels (would be a good fit since the GDP2BFLM-CA DDR3 RAM is organized 16 bits wide) and for the AWG to store arbitrary waveforms (14 bit DAC, hence also a good fit...).

But when looking at the cuts Rigol made regarding analog sample rate when using the digital channels makes me believe that all the sampled data (analog/digital) has to be transfered via the same memory bus. The meagre arbitrary waveform size of 16kSa that the AWG can actually process can easily be placed in the Zynq's internal block ram and so won't affect sampling performance at all. A single GDP2BFLM-CA provides storage for 256M x 16 bits so it would be easily possible to put there 2x50MSa of data plus double buffering / buffer switching. So my educated guess is that Rigol could actually have arranged the DHO800/900 with just a single DHO800 hardware configuration and only add the AWG piggyback board for the (S) versions. Certainly, the engineers at Rigol had a different concept in mind, but very likely, the bean counters got in their way...  :-// I may be wrong tough, in which case the engineers didn't do their work properly.  ::)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 25, 2023, 01:55:31 am
My take was that the two additional ram chips identical to the main sample memory chip were there to provide storage for sampling the 16 digital channels

That's still unknown.

Are those two chips installed in production DHO900s?

A Google image search for "Rigol DHO900 teardown" comes up blank.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: asmi on October 25, 2023, 02:46:07 am
The RAM that's used is specified at 2.133 GT/s
RAM can work that fast, but memory controller in lower-end Zynqs can not. DDR3 can only go up to 533 MHz on a PS side (hard IP), and 400 or 533 MHz on PL (fabric) side (depending on the speed grade and if it's ran at 1.5 or 1.35 V).
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: iMo on October 25, 2023, 04:05:26 pm
The RAM that's used is specified at 2.133 GT/s
RAM can work that fast, but memory controller in lower-end Zynqs can not. DDR3 can only go up to 533 MHz on a PS side (hard IP), and 400 or 533 MHz on PL (fabric) side (depending on the speed grade and if it's ran at 1.5 or 1.35 V).

There is a single dram populated (see the teardown thread) at the Zynq.
2 dram pads are empty.
How they push 1.25Gsa/s into it then?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: asmi on October 26, 2023, 01:02:43 am
There is a single dram populated (see the teardown thread) at the Zynq.
2 dram pads are empty.
How they push 1.25Gsa/s into it then?
You direct the question to the wrong person. How would I know? I'm not the one who designed it. 16 bit DDR interface at 533 MHz can theorerically push 533 * 2 * 16 = 17056 Mbit/s, while 1.25 GS/s @12 bit requires 15000 Mbit/s, so it looks to have enough margin for overhead. I wonder what kind of connection does it have to application processor, Zynq-015 has 4 multi-gigabit transceivers which allow implementing up to PCIE 2.0 x4 link, which should provide for 20 Gbps of link bandwidth.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ballsystemlord on October 26, 2023, 02:13:16 am
If @Martin72 is still accepting requests, do you have the capability to test how close the Oscilloscope is to an NIST calibrated DMM on a DC signal and AC sine wave?

Thanks!

EDIT: To be clear I'm asking for 2 separate tests. *Not* an AC sine wave imposed on a DC signal.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 26, 2023, 06:13:22 pm
I am just warming up the siglent sdm3065X, the rigol scope and the dmm ref.plus source...
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 26, 2023, 06:18:33 pm
Place your bets:
(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1911828;image)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 26, 2023, 06:36:00 pm
Can you also measure difference between min/max voltage to eliminate offset errors?

(It should show min/max/delta in stats)

Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 26, 2023, 06:56:58 pm
Too late...
No, can repeat it, but first the measures I´ve already made.
The results are really good for a scope...
And it makes a difference when measuring dcv what scale you have set. At 200mV/div. it´s more precise than when setting 1V/div.
I´ve added DVM and counter, the counter was set to maximum digits (6).
The sdm3065x was simultaneously connected to the reference, here are the results(left sdm3065x/right rigol (no DVM):

DCV: 4.99937V/4.9980V(-0.03%)
ACV 100Hz: 4.99351V/4.9939V(+0.008%)
ACV 10khz: 4.99277V/5.0104V(+0.35%)

Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 26, 2023, 08:22:53 pm
Here is another picture with the fancy table.
First I was surprised that the counts stop at 1000.
But a look in the manual has then given the all-clear, you can set the counter from 2 to 100000. :phew: ;)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 26, 2023, 09:26:16 pm
The results are really good for a scope...

 :-+ 8)

Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ballsystemlord on October 26, 2023, 11:30:07 pm
That's not an AC sine wave, but thanks! That was informative.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ballsystemlord on October 26, 2023, 11:41:42 pm
I am just warming up the siglent sdm3065X, the rigol scope and the dmm ref.plus source...
Just for the sake of my own sanity, the SDM3065X, was it NIST calibrated like I had asked or not?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: tautech on October 26, 2023, 11:50:23 pm
I am just warming up the siglent sdm3065X, the rigol scope and the dmm ref.plus source...
Just for the sake of my own sanity, the SDM3065X, was it NIST calibrated like I had asked or not?
Official statement:
https://siglentna.com/service-and-support/calibration-certificate/
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Mechatrommer on October 26, 2023, 11:58:22 pm
i see tea'ism comes to the party now, after siglenism... ;D find Dave's video in the early age... DSO is not for Vdc accuracy... why this has to happen so many times? why? :palm:
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: asmi on October 27, 2023, 12:40:18 am
Official statement:
https://siglentna.com/service-and-support/calibration-certificate/
"We swear on the Bible that our calibration is good! (since we're not Christians we can say whatever we want :box: )"
"Oh, actually, it's soooo goood that it's not only good on delivery, but also for up to 180 days". :-/O
"Hmm, nevermind 180 days - 18 months sounds even better! (it's still mostly BS but now we can sell even super-old crap for pennies that nobody wants to buy, so it collects the dust in the warehouse)."
 :-DD  :-DD  :-DD
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: tautech on October 27, 2023, 12:44:17 am
Official statement:
https://siglentna.com/service-and-support/calibration-certificate/
"We swear on the Bible that our calibration is good! (since we're not Christians we can say whatever we want :box: )"
"Oh, actually, it's soooo goood that it's not only good on delivery, but also for up to 180 days". :-/O
"Hmm, nevermind 180 days - 18 months sounds even better! (it's still mostly BS but now we can sell even super-old crap for pennies that nobody wants to buy, so it collects the dust in the warehouse)."
::)
Such are the realities of worldwide distribution chains or is that too complex to get your head around.  :-//
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: asmi on October 27, 2023, 01:06:07 am
Such are the realities of worldwide distribution chains or is that too complex to get your head around.  :-//
Wouldn't it be easier to perform calibration before sending out units to the end users? Most places which care about calibration will not accept any manufacturer's calibration anyway because who knows what happens to the unit during transport, storage, handling, etc, and will want to do a proper calibration anyway - and at some place which is independent of manufacturer. And for the rest of the buying public it doesn't matter anyway, so manufacturer can write whatever.
At the end of the day cars to undergo a pre-delivery inspections, and some of the scopes cost in the same ballpark as cars - so why not?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: tautech on October 27, 2023, 01:18:30 am
Such are the realities of worldwide distribution chains or is that too complex to get your head around.  :-//
Wouldn't it be easier to perform calibration before sending out units to the end users?
No.
To do so would mean every reseller worldwide would require a Cal lab.

Quote
Most places which care about calibration will not accept any manufacturer's calibration anyway because who knows what happens to the unit during transport, storage, handling, etc, and will want to do a proper calibration anyway - and at some place which is independent of manufacturer. And for the rest of the buying public it doesn't matter anyway, so manufacturer can write whatever.
Dunno what other brands do but every Siglent unit Cal sheet specifies the factory calibration equipment used, the model and SN# and its Cal expiry date.
Is that not enough to convey accurate calibration that meets datasheet spec ?
Quote
At the end of the day cars to undergo a pre-delivery inspections, and some of the scope cost in the same ballpark as cars - so why not?
Every end seller is different and may not do PD checks, but we do.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: asmi on October 27, 2023, 01:28:01 am
To do so would mean every reseller worldwide would require a Cal lab.
Or have a contract with one.

Dunno what other brands do but every Siglent unit Cal sheet specifies the factory calibration equipment used, the model and SN# and its Cal expiry date.
Is that not enough to convey accurate calibration that meets datasheet spec ?
It doesn't guarantee that nothing happens to it between factory cal and actual delivery to the end user. And you should know better than most how shipping goes sometimes.

Every end seller is different and may not do PD checks, but we do.
If I would be the manufacturer I would require resellers to do it. Because I do care that my customers get what I advertise. Here in Canada we have an official Rigol rep which does all of this, but to my knowledge there is no Siglent rep in the country at all. Which is kind of annoying, and part of the reason why I opted for a Rigol scope many-many years ago (I think it was in 2016 or something like that) when I bought my MSO2022A, which still works to this day btw!
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: tautech on October 27, 2023, 02:15:50 am
To do so would mean every reseller worldwide would require a Cal lab.
Or have a contract with one.
To add additional cost and delay to equipment supply ?

Dunno what other brands do but every Siglent unit Cal sheet specifies the factory calibration equipment used, the model and SN# and its Cal expiry date.
Is that not enough to convey accurate calibration that meets datasheet spec ?
It doesn't guarantee that nothing happens to it between factory cal and actual delivery to the end user. And you should know better than most how shipping goes sometimes.
Don't have such issue here, however I trust border Customs far less.
OTOH I have a 26.5 GHz VNA to deliver 1500km away which I will be doing in person where in some effort to minimise risk, airline baggage handlers are the only unknown.

Every end seller is different and may not do PD checks, but we do.
If I would be the manufacturer I would require resellers to do it.
Of any/all brands ?
Fail to see advantage of such when gear has been tested to remain within spec for a considerable period post manufacture.

Because I do care that my customers get what I advertise.
So do we however we have no reason to distrust Siglent Cal anymore than a Cal from any other TE producer.

Here in Canada we have an official Rigol rep which does all of this, but to my knowledge there is no Siglent rep in the country at all.
You need update your knowledge.

From the US 'Partners' map:
Canada
ACA TMetrix
800-665-7301
 www.tmetrix.com (http://www.tmetrix.com)
 info@tmetrix.com

RCC Electronics
800-668-6053
 www.rcce.com (http://www.rcce.com)
 sales@rcce.com

Techno-Test
 450-681-5777
 www.Techno-Test.com (http://www.Techno-Test.com)
 info@techno-test.com
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: asmi on October 27, 2023, 03:04:54 am
To add additional cost and delay to equipment supply ?
That depends on your organization of this process. You can forecast a demand and have some units pre-caled within a week let's say.

Don't have such issue here, however I trust border Customs far less.
I've seen it all - from light damage all the way to near full destruction.

OTOH I have a 26.5 GHz VNA to deliver 1500km away which I will be doing in person where in some effort to minimise risk, airline baggage handlers are the only unknown.
Unfortunately they are known. And not in a good way.

Of any/all brands ?
Of my brand. Why would I care what they do to other products?

Fail to see advantage of such when gear has been tested to remain within spec for a considerable period post manufacture.
I know how testing works all to well too believe that. Statistics don't work when we talk about one specific unit.

So do we however we have no reason to distrust Siglent Cal anymore than a Cal from any other TE producer.
Those who care don't accept any mfg's cal for the same reason.

You need update your knowledge.

From the US 'Partners' map:
Canada
ACA TMetrix
800-665-7301
 www.tmetrix.com (http://www.tmetrix.com)
 info@tmetrix.com

RCC Electronics
800-668-6053
 www.rcce.com (http://www.rcce.com)
 sales@rcce.com

Techno-Test
 450-681-5777
 www.Techno-Test.com (http://www.Techno-Test.com)
 info@techno-test.com
This is what representative looks like: https://www.rigolcanada.com/ (https://www.rigolcanada.com/)
Note branding, localized prices, support (which has been superb even with my relatively cheap unit BTW! they loaned me much more expensive unit for free until the unit I ordered arrived from mfg), lack of stuff from other brands, etc.
What you linked are resellers, not representatives.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: tautech on October 27, 2023, 03:08:31 am
What you linked are resellers, not representatives.
Then Siglent NA in Ohio are your reps.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: asmi on October 27, 2023, 05:00:20 pm
Then Siglent NA in Ohio are your reps.
Now you see the problem. Apparently Siglent is not interested in our market enough, unlike Rigol.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 27, 2023, 07:45:55 pm
Just for the sake of my own sanity, the SDM3065X, was it NIST calibrated like I had asked or not?

It is calibrated(June 2023), I was a little disappointed with the one sheet of paper that came with the meter and explained that the meter had been calibrated and everything was fine - anyone can write that.
But since the serial number of my meter was listed, it occurred to me that Siglent might have a database with the calibration values of each device.
And I was right... ;)
I got this data and so it is clear that the explanation on this one sheet of paper can actually be trusted.
Calibration intervals are usually 12 months (e.g. ISO), for higher calibration methods (e.g. DAkks) the intervals can be extended to e.g. 24 months.
As mentioned, the calibration of my meter was about 4 months ago, so I'm still "full" in it.
What actually does not matter with the tolerance of an oscilloscope, so "bad" the meter can not become, unless it is defective.
Nevertheless, it must be said that the Rigol has made a very good figure, in the comparison measurement.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: nctnico on October 27, 2023, 08:39:41 pm
i see tea'ism comes to the party now, after siglenism... ;D find Dave's video in the early age... DSO is not for Vdc accuracy... why this has to happen so many times? why? :palm:
Agreed. A DMM is the wrong tool to measure oscilloscope accuracy anyway. For that you need a calibrated signal (AC) source which can also output tens to several hundred Volts.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: tautech on October 27, 2023, 08:48:25 pm
Then Siglent NA in Ohio are your reps.
Now you see the problem. Apparently Siglent is not interested in our market enough, unlike Rigol.

Have you worked with your Canada ppl ?
Is their support substandard or something ?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 27, 2023, 09:32:57 pm
Agreed. A DMM is the wrong tool to measure oscilloscope accuracy anyway. For that you need a calibrated signal (AC) source which can also output tens to several hundred Volts.

I cannot imagine that it just happened to fit so well in this case(it was a comparison of the measured values, not more).
The levels of the sine signals from the fluke calibrators often used in calibration laboratories go just above 5V(squarewaves up to 200Vpp).
Depending on the frequency, you can also use an ac signal that has not been calibrated, as long as the measuring device used to determine the level is much more accurate than the specifications of the scope.

Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 28, 2023, 01:51:51 am
It seems pointless to measure "AC accuracy" on a 'scope. If the DC accuracy is good then "AC accuracy" is down to the user settings.

On a DMM it makes sense because they have TRMS converter chips inside them and they don't work the same way oscilloscopes do.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 28, 2023, 09:22:29 am
It seems pointless to measure "AC accuracy" on a 'scope. If the DC accuracy is good then "AC accuracy" is down to the user settings.

On a DMM it makes sense because they have TRMS converter chips inside them and they don't work the same way oscilloscopes do.

What you say might hold in some very low frequency range close to DC.

You do realize scope has a BW of DC-100 MHz. Or DC-1GHz. Or DC-100GHz... ?

It's frequency response will be complex curve..

BW is specified at -3dB point.  So scope with 100MHz -3dB response, will at 100MHz have amplitude error of 29 %
And in between DC and -3dB point it will be some falloff.

So yeah, scope needs to be checked for AC accuracy.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 28, 2023, 12:06:29 pm
The DMMref plus reference has two calibrated ac signals, 100hz and 10khz.
"Low enough" to be measured accurately with any good multimeter and therefore I think you can still compare, but of course this says nothing about the scope accuracy as a whole.
A nice comparison, nothing more.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: KedasProbe on October 28, 2023, 12:09:18 pm
Some IR view compare DHO914S (top) vs Hameg HMO1022 (bottom)
The hot part behind it is the USB power adapter

Looks like it's even heating up the Hameg next to it.

zip file is the same 3 pictures but original .bmp with extra info in it from UTi260B
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 28, 2023, 12:40:52 pm
Heating up the Hameg next to it from the inside? That seems counter-intuitive, to say the least... Is the Hameg powered off?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: KedasProbe on October 28, 2023, 12:45:33 pm
They are both on for a while, in the front image you see the left side of the Hameg to be warmer receiving heat from the rigol. (but would need to test it with rigol off to be sure.)

edit: The hameg has an USB stick in the front, the rigol USB mouse.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ballsystemlord on October 28, 2023, 12:53:36 pm
i see tea'ism comes to the party now, after siglenism... ;D find Dave's video in the early age... DSO is not for Vdc accuracy... why this has to happen so many times? why? :palm:
The selling point of 12bit DSOs is that they're more accurate than 8 bit DSOs. IIRC, Rigol marketing said 60%. So, it seemed to me that testing the accuracy would be interesting. I sought to determine if the DSO was truly accurate or just had improved dynamic range.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: mawyatt on October 28, 2023, 03:15:34 pm
i see tea'ism comes to the party now, after siglenism... ;D find Dave's video in the early age... DSO is not for Vdc accuracy... why this has to happen so many times? why? :palm:
The selling point of 12bit DSOs is that they're more accurate than 8 bit DSOs. IIRC, Rigol marketing said 60%. So, it seemed to me that testing the accuracy would be interesting. I sought to determine if the DSO was truly accurate or just had improved dynamic range.

Gave a quick look at our clients 824 (we haven't delivered yet, as client is tied up) using our in-house derived squarewave generator (precision duty-cycle and amplitude squarewave derived from precision 5 volt reference).

https://www.eevblog.com/forum/testgear/ac-rms-dmm-tests/msg3940957/#msg3940957 (https://www.eevblog.com/forum/testgear/ac-rms-dmm-tests/msg3940957/#msg3940957)

Results were very good wrt using a precision squarewave from above at 250Hz. Reference source confirmed with our latest KS34465A (we have 3) and our DMM6500. We periodically use this reference source to quickly check each DMM (also SDM3065X, HP34401A, AG34401A) to make sure that one isn't issuing rouge rogue readings.

DHO824 measured with 1000 averages.

Vavg = 2.5001VDC
Vrms = 2.5092Vrms

BTW why is this important for us? We often employ a DSO to view & measure complex waveforms and often these waveforms are beyond the frequency range where one would expect the DMMs to render a decent measurement, so we employ the built-in DSO measurements. This all boils down to KTI (Know Thy Instruments) and where and how to apply such. For our work having measurements, statistics and such that "One Can Rely On" is a great asset these modern DSOs possess, same goes for the FFT and Bode Functions :-+

Stated before these are complex data acquisition systems, disguised as scopes, that can do so much more within the hands of experienced users  ;)

Side Note: When we acquired our 1st DSO here at the Labs a few years back, it was a Siglent. One of the first things we did was evaluate the measurement capabilities, and how they behaved. Needless to say we were impressed then as we are now with the Rigol DHO824 measurement capabilities, altho the FFT needs some polish, however our client isn't interested in the FFT (nor Bode Function) so for us a moot point in that respect.

Best,
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: nctnico on October 28, 2023, 03:17:15 pm
i see tea'ism comes to the party now, after siglenism... ;D find Dave's video in the early age... DSO is not for Vdc accuracy... why this has to happen so many times? why? :palm:
The selling point of 12bit DSOs is that they're more accurate than 8 bit DSOs.
No, resolution isn't accuracy.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 28, 2023, 03:26:06 pm
No, resolution isn't accuracy.

It is when it's doing self-cal.  :popcorn:
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Mechatrommer on October 28, 2023, 04:14:04 pm
i see tea'ism comes to the party now, after siglenism... ;D find Dave's video in the early age... DSO is not for Vdc accuracy... why this has to happen so many times? why? :palm:
The selling point of 12bit DSOs is that they're more accurate than 8 bit DSOs.
No, resolution isn't accuracy.
true, but probably he's not talking about 12bit is being accurate. he probably talk about self-cal algorithm and voltage/frequency reference used.

i see tea'ism comes to the party now, after siglenism... ;D find Dave's video in the early age... DSO is not for Vdc accuracy... why this has to happen so many times? why? :palm:
The selling point of 12bit DSOs is that they're more accurate than 8 bit DSOs.
if its that important, then need to plot dso's frequency respond as well, it may accurate at DC but wobbly respond in frequency domain. if you get that kind of scope, i great you congratulation! ;D
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 28, 2023, 04:22:14 pm
Needless to say we were impressed then as we are now with the Rigol DHO824 measurement capabilities, altho the FFT needs some polish, however our client isn't interested in the FFT (nor Bode Function) so for us a moot point in that respect.

If you disregard FFT and the missing Bode, this is also a really nice entry-level scope.
Firmware-wise, FFT can be improved and Bode could at least be implemented with an external source to help, but I don't believe that rigol will change much in this regard.
But as you wrote, if there are people who do not need that, that can be the purchase decision in this price range.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: mawyatt on October 28, 2023, 04:57:12 pm
Needless to say we were impressed then as we are now with the Rigol DHO824 measurement capabilities, altho the FFT needs some polish, however our client isn't interested in the FFT (nor Bode Function) so for us a moot point in that respect.

If you disregard FFT and the missing Bode, this is also a really nice entry-level scope.
Firmware-wise, FFT can be improved and Bode could at least be implemented with an external source to help, but I don't believe that rigol will change much in this regard.
But as you wrote, if there are people who do not need that, that can be the purchase decision in this price range.

Agree the 800 series is a good entry level DSO!! Since the 800 series has no AWG, nor Bode capability, won't discount it for that. Rigol could implement an external AWG control and enable Bode Feature in the 800 series, but from what's been shown with the 900 series wrt the Bode Capability, doubt that's going to happen.

The FFT isn't that bad, and with some work could become a nice usable feature IMO. Again that's up to Rigol if they want to invest any resources ($) into improving the FFT capability.

Or clients intended 824 use involves viewing various complex waveforms for comparison purposes, and the measurement capability could yield an easier Go/NoGo decision for end users wrt to waveform interpretations.

Best,
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 28, 2023, 09:54:24 pm
Agree the 800 series is a good entry level DSO!!

Yep, I'll say it's a bargain for that price. Very capable and much nicer to use than a twisty-knob 'scope.

The screen is a bit small but it goes with the overall size which I really like. I don't have any problem using it and the text is really legible - more legible than my Micsig with its bigger screen

Mine hasn't crashed on me even once and there's only one bug that really affects me and it has an easy workaround (the serial decoder reference voltage bug, set probes to 1x mode to fix it).

The 12 bits and low noise really shows in actual use.

It's also been fun to hack around with and explore via ADB.  :)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 28, 2023, 09:57:35 pm
Quote
Mine hasn't crashed on me even once

I had a few crashes in the beginning, but after the firmware update not a single one - Except for the incompatibility of plugging in the usb-hub during operation.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 28, 2023, 10:07:12 pm
Features everybody needs to try:

I'm really liking the "Indicator" feature on the measurements, eg. here I'm indicating the preshoot on a pulse:
(https://www.eevblog.com/forum/testgear/split-from-rigols-new-dho800-oscilloscope-unbox-amp-teardown/?action=dlattach;attach=1913781;image)

It moves around when you touch the measurement boxes in the panel. After using it for a while I've left it permanently turned on.  :)

Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 28, 2023, 10:09:07 pm
Ah, you mean the dash-dot line, right ?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 28, 2023, 10:09:56 pm
Ah, you mean the dash-dot line, right ?

Yes. That's not a cursor, it moves around with the signal.

Edit: It would be better if they disappeared when the measurement panel is off. I'll add that to the wish list thread...
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 28, 2023, 10:37:34 pm
Quote
Edit: It would be better if they disappeared when the measurement panel is off. I'll add that to the wish list thread...

I know these "auxiliary lines" from the lecroy scopes with MAUI.
There they are displayed only as long as one is directly at the parameter in the measuring menu, when leaving then only the corresponding measured value is displayed.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 28, 2023, 11:22:21 pm
Quote
Mine hasn't crashed on me even once

I had a few crashes in the beginning, but after the firmware update not a single one - Except for the incompatibility of plugging in the usb-hub during operation.

If it does crash there's a daemon that starts it right back up again in the state it was at.

You can test it by killing the man task with ADB.   ;D

adb root
adb shell kill -9 $(pidof com.rigol.scope)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: asmi on October 29, 2023, 01:24:58 am
If it does crash there's a daemon that starts it right back up again in the state it was at.
That's an Android thing. All apps should be ready to be suspended/killed at any time, and then restore themselves to the way they were once re-launched. Because that's how OS works on cell phones when it starts running low on memory - it kills oldest used apps, and when you switch back to them, they are supposed to restore itself to whatever state they were when they were last interacted with.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 29, 2023, 06:21:31 pm
Two Tone tests...
I wanted to try the other method of combining 2 signals instead of using the "wave combine" function of my generator.
There the rigol came as called... ;)
As with the dho4204 there are a few oddities regarding FFT, but if you ignore that you get good "pictures".
The little jewel is doing quite well, at 100Mhz I got nothing more, but that's not really dramatic.
Oh well, I just don't like the color of the math channel, a selection palette would be a great thing.
So, here are some pictures of various frequencies.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 29, 2023, 06:50:04 pm
I like this one best:
(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1914726;image)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 29, 2023, 06:50:41 pm
Two Tone tests [...]
So, here are some pictures of various frequencies.

Nice to see that the peak search can produce meaningful results!  :-+

In your early exploration of the DHO800, I seem to recall that you got a very messy list of apperently random peaks which the DHO had selected. It did not seem to prioritize them by peak height at all. Have you explored that any further? Is there a (higher than expected) minimum peak/background contrast required for reliable peak identification, or some other constraint?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 29, 2023, 06:57:42 pm
Oh well, I just don't like the color of the math channel, a selection palette would be a great thing.

You have four to choose from:
(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1914774;image)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 29, 2023, 07:04:07 pm
In your early exploration of the DHO800, I seem to recall that you got a very messy list of apperently random peaks which the DHO had selected. It did not seem to prioritize them by peak height at all. Have you explored that any further? Is there a (higher than expected) minimum peak/background contrast required for reliable peak identification, or some other constraint?

No, I hadn't paid attention to that, I might try that again.
Here again the former post:
https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/msg5122722/#msg5122722 (https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/msg5122722/#msg5122722)
But that was also a bit "unfair", as noisy as the fundamental wave was and the rigol no FFT averaging function got.
The siglent had set most of the peaks there, but did not "forget" the other two harmonics.
I'll test this again.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 29, 2023, 07:04:29 pm
In your early exploration of the DHO800, I seem to recall that you got a very messy list of apperently random peaks which the DHO had selected. It did not seem to prioritize them by peak height at all. Have you explored that any further? Is there a (higher than expected) minimum peak/background contrast required for reliable peak identification, or some other constraint?

Yes, you can order peaks by amplitude/frequency, set maximum number of peaks, set threshold and excursion values.
(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1914780;image)

Edit: It's not very obvious how to get there. The trick is to either read the manual or to press the up-arrow at the bottom of the FFT parameter page.  :)
(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1914786;image)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 29, 2023, 07:05:08 pm
Quote from: Fungus
You have four to choose from:

No, I want my palette ! (*footstomping*)  ;D
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 29, 2023, 07:22:24 pm
Here again the former post:
https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/msg5122722/#msg5122722 (https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/msg5122722/#msg5122722)
But that was also a bit "unfair", as noisy as the fundamental wave was and the rigol no FFT averaging function got.
The siglent had set most of the peaks there, but did not "forget" the other two harmonics.
I'll test this again.

Yes, that's the post I was thinking of, thanks! Looking at the first picture there -- even with the noise shown, I would have expected that the scope can pick out the fundamental and the harmonics and list those first.

Agree that Rigol would do themselves a big favor by introducing an option to average over the FFT spectra. From the Siglent comparisons I saw somewhere, that has so much more impact than FFT'ing over averaged traces.

Or is there an "Average" function in the Math menu, which one could set up in a second Math channel and apply to the FFT results? Couldn't find anything in the manual.

Yes, you can order peaks by amplitude/frequency, set maximum number of peaks, set threshold and excursion values.

In Martin's early measurement (link above), it looks like they are sorted by frequency, but only in a very narrow range around the fundamental. Why would the scope do that?

Edit: Typos...
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 29, 2023, 07:49:37 pm
Can your Siglents do four simultaneous FFTs each with a different window function and peak search?

(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1914819;image)

Ok, that's a bit silly but you could easily show different areas of an FFT, expand one part, etc., by having multiple windows open.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 29, 2023, 07:55:44 pm
That is quite neat (also the fact that it does not slow down the scope, as you mentioned in the other thread)! It does highlight the limitations of the small display though.

Hopefully, in a future software release Rigol gives some thought to proper rounding in tables, and to the choice of meaningful increments and decimal places for the axis labels. Especially with the limited space on the display, it hurts to see all those "4.9..99 kHz" table entries and the awkward values on the vertical axes.  ::)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 29, 2023, 07:59:05 pm
Yes, you can order peaks by amplitude/frequency, set maximum number of peaks, set threshold and excursion values.

In Martin's early measurement (link above), it looks like they are sorted by frequency, but only in a very narrow range around the fundamental. Why would the scope do that?

I don't know but the default number of peaks is five so he obviously fiddled with the peak detection settings.

Maybe he set a very low value for "excursion" (the amount a peak has to stick out for it to be added to the table).
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 29, 2023, 07:59:58 pm
Hi,

Tried again, the menu Fungus showed I already knew, it makes no differece between frequency or amplitude order.
But there´s the excursion button...Excursion, what´s this ?
Manual do not describe it in a manner I could understand it.
But google do:

Quote
Press Excursion to specify the amplitude above the FFT waveform's noise floor necessary to be recognized as a peak.

Aha...
Now you don't know where the noise carpet starts for the excursion, at the bottom, in the middle, rather at the top....
It is also very "thick", so the only thing that helps is to try it out.
With 35dB I "caught" at least 3 peaks, better than nothing.
But an averaging function for the FFT would be really desirable.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 29, 2023, 08:07:35 pm
That is quite neat (also the fact that it does not slow down the scope, as you mentioned in the other thread)! It does highlight the limitations of the small display though.

Hopefully, in a future software release Rigol gives some thought to proper rounding in tables, and to the choice of meaningful increments and decimal places for the axis labels. Especially with the limited space on the display, it hurts to see all those "4.9..99 kHz" table entries and the awkward values on the vertical axes.  ::)

I think the firmware was developed on the big-screen DHO40000.  :popcorn:

Color graded FFTs... oooh!
(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1914873;image)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 29, 2023, 08:09:19 pm
This is a nice colorful picture. ;)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 29, 2023, 08:20:53 pm
I think the firmware was developed on the big-screen DHO40000.  :popcorn:

Yes, obviously it was. They made limited tweaks for the small screen, e.g. compressing the math channel button in the bottom to the small four-up, where the DHO4000 has individual fields similar to those for the analog channels.

So they should at least stop wasting space for stupidly long (and hard-to-interpret) axis labels and badly rounded tabulated values.  |O

Regarding the vertical axes: For the FFT result, I understand the scope chooses the grid on its own -- so it could easily put the grid lines on even 10 or 20 dBV increments and label them accordingly with even numbers, right?

For the trace window, I see that the the signal's offset is adjusted by the user, and that drives the awkward odd values on the vertical axis. How do other scopes handle this? Is there a "snap to grid" option when adjusting the offset, say by pushing some button during or after offset adjustment?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 29, 2023, 08:34:16 pm
Quote
so it could easily put the grid lines on even 10 or 20 dBV increments and label them accordingly with even numbers, right?

If you enter "clean" values(Setup), you will also get a clean result(Scale).
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: tautech on October 29, 2023, 08:34:42 pm
For the trace window, I see that the the signal's offset is adjusted by the user, and that drives the awkward odd values on the vertical axis. How do other scopes handle this? Is there a "snap to grid" option when adjusting the offset, say by pushing some button during or after offset adjustment?
Offset = Reference position.
When there is need to have accurate measurements engage a table, that might display frequency or amplitude or both. < that's how other brands do it.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 29, 2023, 08:43:09 pm
That is quite neat (also the fact that it does not slow down the scope, as you mentioned in the other thread)! It does highlight the limitations of the small display though.

New game: Who can open the most windows on a Rigol DHO800...?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 29, 2023, 08:46:16 pm
For the trace window, I see that the the signal's offset is adjusted by the user, and that drives the awkward odd values on the vertical axis. How do other scopes handle this? Is there a "snap to grid" option when adjusting the offset, say by pushing some button during or after offset adjustment?
Offset = Reference position.
When there is need to have accurate measurements engage a table, that might display frequency or amplitude or both. < that's how other brands do it.

Thanks. I was referring to the labels the scope (optionally) puts on the vertical axes of the main trace display -- one value per grid line. And maybe I should have written "vertical position" instead of "offset"? I mean the value one adjusts via the fine adjustment knob in the vertical controls.

So what is the common way of letting these interact? Do all scopes show you odd values on the axis labels, unless you carefully adjust the position to an even grid line?

(I very often use the vertical position knob just to space signals apart on the screen. On my stupid old scope which does not label the grid lines at all, I typically try to roughly align the signal's 0V value with one of the grid lines, so I can use the grid to estimate amplitudes. But I would find it annoying to have to adjust the position very precisely, lest I see "2.004V", "3.004V" etc. as the axis labels. Is there a convenient way to get nice round label values -- besides setting the position to 0V by pushing the control knob, of course?)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: tautech on October 29, 2023, 09:02:15 pm
For the trace window, I see that the the signal's offset is adjusted by the user, and that drives the awkward odd values on the vertical axis. How do other scopes handle this? Is there a "snap to grid" option when adjusting the offset, say by pushing some button during or after offset adjustment?
Offset = Reference position.
When there is need to have accurate measurements engage a table, that might display frequency or amplitude or both. < that's how other brands do it.

Thanks. I was referring to the labels the scope (optionally) puts on the vertical axes of the main trace display -- one value per grid line. And maybe I should have written "vertical position" instead of "offset"? I mean the value one adjusts via the fine adjustment knob in the vertical controls.

So what is the common way of letting these interact? Do all scopes show you odd values on the axis labels, unless you carefully adjust the position to an even grid line?

(I very often use the vertical position knob just to space signals apart on the screen. On my stupid old scope which does not label the grid lines at all, I typically try to roughly align the signal's 0V value with one of the grid lines, so I can use the grid to estimate amplitudes. But I would find it annoying to have to adjust the position very precisely, lest I see "2.004V", "3.004V" etc. as the axis labels. Is there a convenient way to get nice round label values -- besides setting the position to 0V by pushing the control knob, of course?)
Martin explains it well....the operators settings have the most influence on this.
However unless competent in using FFT and instead using auto setup then all bets are off.   :horse:
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 29, 2023, 09:07:47 pm
Martin explains it well....the operators settings have the most influence on this.
However unless competent in using FFT and instead using auto setup then all bets are off.   :horse:

Martin explained how the FFT windows are formatted, and that was helpful, thanks.

But I asked about the trace window, where the grid is fixed via the vertical V/div setting, and the traces can be shifted continuously via the vertical position knob. How do I ensure that I get "clean" numbers labelling the vertical axis there? Is tweaking the vertical position knob very carefully the only way?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: tautech on October 29, 2023, 09:18:17 pm
Martin explains it well....the operators settings have the most influence on this.
However unless competent in using FFT and instead using auto setup then all bets are off.   :horse:

Martin explained how the FFT windows are formatted, and that was helpful, thanks.

But I asked about the trace window, where the grid is fixed via the vertical V/div setting, and the traces can be shifted continuously via the vertical position knob. How do I ensure that I get "clean" numbers labelling the vertical axis there? Is tweaking the vertical position knob very carefully the only way?
Probably if you must have axis values displayed.
Like I mentioned, better measurements should be available from a FFT marker table or from a trace display, just the correct selection of measurements required.
Trouble is, on a little display things get crowded real quick.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 29, 2023, 09:28:01 pm
Probably if you must have axis values displayed.
Like I mentioned, better measurements should be available from a FFT marker table or from a trace display, just the correct selection of measurements required.
Trouble is, on a little display things get crowded real quick.

That's a valid point; switching the labels off might be the solution. ;)

I guess I was fascinated by this "shiny new (for me) feature" and wondering how scope manufacturers make it really useful. Maybe the answer is they don't...

Still, a "snap vertical position to grid" option might be neat. Say, a short press on the vertical position knob snaps the channel's zero position to the nearest grid line, and a slightly longer press or a second press puts it to 0V?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 29, 2023, 09:30:33 pm
Quote
How do I ensure that I get "clean" numbers labelling the vertical axis there? Is tweaking the vertical position knob very carefully the only way?

With the Siglent scopes, you can select whether the scale moves with or not.
Then the labeling remains "clean" and you must then orient yourself at the infobox, where the offset is numerically located (or, siglent also shows it directly on the screen, as long as you turn the vertical knob).
I have not yet found this function in the rigol, there you can only switch the labeling on or off.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 29, 2023, 09:39:37 pm
With the Siglent scopes, you can select whether the scale moves with or not.
Then the labeling remains "clean" and you must then orient yourself at the infobox, where the offset is numerically located (or, siglent also shows it directly on the screen, as long as you turn the vertical knob).
I have not yet found this function in the rigol, there you can only switch the labeling on or off.

Thanks! And thank you for nicely illustrating the problem in the second screenshot. Those labels on the vertical axis really make me gnash my teeth...

Do they get just as awkward on the horizontal axis once you shift the trigger time? Edit: Oh yes, they do, as seen in various earlier screenshots. Not quite as painful since they don't take up that much space down there, but still difficult to interpret.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 29, 2023, 09:44:20 pm
Yepp, but not too harsh to read..

EDIT : Ah, edit... ;)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: tautech on October 29, 2023, 09:47:02 pm
Do they get just as awkward on the horizontal axis once you shift the trigger time?
Not when you place it directly on a grid.

Not that it matters much for us oldies that come from CRO days when all we had for measurements were graticules.  :horse:
Decision time = turn axis labels ON or engage the measurements required OR continue eyeballing what we need take from a scope display.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 29, 2023, 09:53:45 pm
Do they get just as awkward on the horizontal axis once you shift the trigger time?
Not when you place it directly on a grid.

Not that it matters much for us oldies that come from CRO days when all we had for measurements were graticules.  :horse:
Decision time = turn axis labels ON or engage the measurements required OR continue eyeballing what we need take from a scope display.

Sure, I have lived happily with my simple DS1054Z which can't label the axes at all. And found that a big step up from a few decades with hobbyist CROs which would not even display the V/div on screen.  ;)

Still -- couldn't pushing the fine-position knob (on either the horizontal or the vertical axis) first do a "snap to grid", and then only do a "snap to 0V" or "snap to 0µs" when you hold it a bit longer or press it a second time? Seems useful to me, even in eyeballing mode.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 29, 2023, 09:54:22 pm
Quote from: ebastler
Those labels on the vertical axis really make me gnash my teeth...

If you had seen this on the siglent sds2000xplus when they introduced the axis labeling, your teeth would have fallen out.... ;)
Values with up to six digits after the comma, really great...
But:
Siglent had corrected this to a tolerable level with one of the next firmware updates.
That's what I like about them, they often listen to the wishes of their users.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Mechatrommer on October 29, 2023, 10:01:39 pm
That is quite neat (also the fact that it does not slow down the scope, as you mentioned in the other thread)! It does highlight the limitations of the small display though.

Hopefully, in a future software release Rigol gives some thought to proper rounding in tables, and to the choice of meaningful increments and decimal places for the axis labels. Especially with the limited space on the display, it hurts to see all those "4.9..99 kHz" table entries and the awkward values on the vertical axes.  ::)

I think the firmware was developed on the big-screen DHO40000.  :popcorn:

Color graded FFTs... oooh!
(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1914873;image)

do this and glue it on top of built-in LCD and nobody can dick wave about small screen anymore.. you have $400+$100 scope with lcd larger than any $10K scope on earth.

https://www.youtube.com/watch?v=r_BYYgCqScE (https://www.youtube.com/watch?v=r_BYYgCqScE)

i can see some model sold at $100 or less. but heck, i dont buy scope for entertainment... the built-in one is enough for me. only whats missing in those multiple windows is resizable tab. when like 2 windows side by side, i wish i can make larger one windows than the other by tap and move the tab on corner between windows...
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 29, 2023, 10:08:31 pm

Still -- couldn't pushing the fine-position knob (on either the horizontal or the vertical axis) first do a "snap to grid", and then only do a "snap to 0V" or "snap to 0µs" when you hold it a bit longer or press it a second time? Seems useful to me, even in eyeballing mode.

The horizontal/vertical axis knobs don't move the FFT around, they still move the waveform.

The two multipurpose knobs change FFT center and span when an FFT is on screen.

If you push them they center and span to 1MHz. That doesn't seem useful.  ???

Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 29, 2023, 10:08:58 pm
Quote
, i dont buy scope for entertainment...

Exactly. ;)

Quote
btw whats missing in those multiple windows is resizable tab. when like 2 windows side by side, i wish i can make larger one windows than the other...

Yes, that would be my wish too.
The window function is a good thing in itself, but not consistently thought through to the end and brought.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 29, 2023, 10:12:57 pm

Still -- couldn't pushing the fine-position knob (on either the horizontal or the vertical axis) first do a "snap to grid", and then only do a "snap to 0V" or "snap to 0µs" when you hold it a bit longer or press it a second time? Seems useful to me, even in eyeballing mode.

The horizontal/vertical axis knobs don't move the FFT around, they still move the waveform.

The two multipurpose knobs change FFT center and span when an FFT is on screen.

If you push them they center and span to 1MHz. That doesn't seem useful.  ???

Not talking about FFT here, just regular display of waveforms. The grid labels (µs on the horizontal and V/mV on the vertical axis) take on these awkward, odd values as soon as you move the trigger delay or the channel's vertical position around.  :rant:
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 29, 2023, 10:16:06 pm
do this and glue it on top of built-in LCD and nobody can dick wave about small screen anymore..

You don't get more stuff on screen though, just higher-res UI.

Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 29, 2023, 10:17:56 pm
Not talking about FFT here, just regular display of waveforms. The grid labels (µs on the horizontal and V/mV on the vertical axis) take on these awkward, odd values as soon as you move the trigger delay or the channel's vertical position around.  :rant:

Oh, yeah... they do that. I don't really pay much attention to them myself. I wish I could turn them off.

Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 29, 2023, 10:32:00 pm
Quote
I wish I could turn them off.

Do it...
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 29, 2023, 10:35:03 pm
Quote
I wish I could turn them off.

Do it...

Pheww... Fungus had me scared for a moment. You found it quicker than I did in the manual.  :phew:
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 29, 2023, 10:37:21 pm
I have not yet found this function in the rigol, there you can only switch the labeling on or off.

How do you switch it off?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 29, 2023, 10:45:38 pm
I have not yet found this function in the rigol, there you can only switch the labeling on or off.

How do you switch it off?

See reply #649 from Martin just above, in response to your previous comment.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 29, 2023, 11:01:51 pm
How do you switch it off?
See reply #649 from Martin just above, in response to your previous comment.

Nice.

But it turns it off on the FFT as well.  :scared:

Oh, well. At least I have the option.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 29, 2023, 11:07:51 pm
Quote
But it turns it off on the FFT as well.

Not with Siglent scopes, which I find inconsistent.
Although it is actually logical that the scaling is then also missing with the FFT, because scale is scale...
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: rpro on October 30, 2023, 02:26:05 am
Not talking about FFT here, just regular display of waveforms. The grid labels (µs on the horizontal and V/mV on the vertical axis) take on these awkward, odd values as soon as you move the trigger delay or the channel's vertical position around.  :rant:
For a Multipurpose Knob to become associated with a vertical channel offset, etc., you first have to open the respective channel menu window. E.g., by default, knob 2 becomes associated with Offset once the window opens (as indicated by the small yellow "2" hexagon), and you can just press the knob to set it to 0V. (Also, from there, by tapping the up/down buttons adjacent to the input field, you can quickly change it by integer values as needed...)...I am also getting used to just entering 0-OK quickly on the keypad for this purpose.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 30, 2023, 07:27:50 am
Not talking about FFT here, just regular display of waveforms. The grid labels (µs on the horizontal and V/mV on the vertical axis) take on these awkward, odd values as soon as you move the trigger delay or the channel's vertical position around.  :rant:
For a Multipurpose Knob to become associated with a vertical channel offset, etc., you first have to open the respective channel menu window. [...] I am also getting used to just entering 0-OK quickly on the keypad for this purpose.

Oh, I was not talking about the multipurpose knobs. Rather about the dedicated "single purpose knobs" for controlling the horizontal and vertical position of traces on the screen.

I use these all the time to position traces on the screen such that I can tell them apart, see correlations between them, see the relevant section. While my current scope does not have a touch screen at all, I would still expect to use these knobs a lot with the DHO800 or another touch-enabled scope.

But as soon as you move your trace and trigger positions to odd values (i.e. practically all the time if you use these "analog" knobs), the on-screen scale labels for the horizontal and vertical grid will turn into rather messy, odd numbers. Hence my suggestion that there should be a quick way to snap these continuous position adjustments back to the grid.

Not a bug, just a feature or usability suggestion. As it stands, it seems to me that the axis labels do more harm than good in most situations, by taking up screen space and confusing the user with odd values. So switching them off is the workaround of choice, I guess.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 30, 2023, 08:19:10 am
Not talking about FFT here, just regular display of waveforms. The grid labels (µs on the horizontal and V/mV on the vertical axis) take on these awkward, odd values as soon as you move the trigger delay or the channel's vertical position around.  :rant:
For a Multipurpose Knob to become associated with a vertical channel offset, etc., you first have to open the respective channel menu window. [...] I am also getting used to just entering 0-OK quickly on the keypad for this purpose.

Oh, I was not talking about the multipurpose knobs. Rather about the dedicated "single purpose knobs" for controlling the horizontal and vertical position of traces on the screen.

I use these all the time to position traces on the screen such that I can tell them apart, see correlations between them, see the relevant section. While my current scope does not have a touch screen at all, I would still expect to use these knobs a lot with the DHO800 or another touch-enabled scope.

But as soon as you move your trace and trigger positions to odd values (i.e. practically all the time if you use these "analog" knobs), the on-screen scale labels for the horizontal and vertical grid will turn into rather messy, odd numbers. Hence my suggestion that there should be a quick way to snap these continuous position adjustments back to the grid.

Not a bug, just a feature or usability suggestion. As it stands, it seems to me that the axis labels do more harm than good in most situations, by taking up screen space and confusing the user with odd values. So switching them off is the workaround of choice, I guess.

On my scopes one brand have two display modes. In one you move grid and static numbers... In other mode grid stays static and then you get these fractional numbers.
On other it you get only fractional numbers.

I prefer moving grid and static numbers. That one is intuitive to me because that is how you plot data in math...
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 30, 2023, 08:30:07 am
Axis labeling is a good thing, but I had gotten by for 20 years before that.
You don't have to count boxes anymore, that makes the scope for you. ;)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Mechatrommer on October 30, 2023, 08:53:21 am
Axis labeling is a good thing, but I had gotten by for 20 years before that.
You don't have to count boxes anymore, that makes the scope for you. ;)
it wont help much if your signal offset is like 1.054887V try it and look at label and your signal is in between. if you familiar with interpolation, you'll have fun finding "points in between", esp for metrologists and tea'ism.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 30, 2023, 09:10:24 am
Axis labeling is a good thing, but I had gotten by for 20 years before that.
You don't have to count boxes anymore, that makes the scope for you. ;)
it wont help much if your signal offset is like 1.054887V try it and look at label and your signal is in between. if you familiar with interpolation, you'll have fun finding "points in between", esp for metrologists and tea'ism.

On scopes I have here, offsets are not completely "analog", but in some discrete steps. It won't be completely bonkers like your example.
More likely "1.09V"  with a step of 10mV... But still confusing a bit. That is why I said I like the moving grid better. There scale stays fixed, nice round numbers and you move the whole thing up and down.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 30, 2023, 09:25:20 am
On my scopes one brand have two display modes. [...]

On scopes I have here, offsets are not completely "analog", but in some discrete steps.

I appreciate the effort to avoid triggering people. But I hope we are back on a healthy track where we can mention "the brand which must not be named (in a Rigol thread)".  ;) 

Right -- having the position control work on an even sub-division of the grid, say steps of 1% or 2% of a division, would already help. Then one can adjust the position to an exact grid line with limited knob-tweaking, and the numbers on odd settings inbetween do not look too messy.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 30, 2023, 09:39:43 am
On my scopes one brand have two display modes. [...]

On scopes I have here, offsets are not completely "analog", but in some discrete steps.

I appreciate the effort to avoid triggering people. But I hope we are back on a healthy track where we can mention "the brand which must not be named (in a Rigol thread)".  ;) 

Right -- having the position control work on an even sub-division of the grid, say steps of 1% or 2% of a division, would already help. Then one can adjust the position to an exact grid line with limited knob-tweaking, and the numbers on odd settings inbetween do not look too messy.

 8)

A hint...
Rigol imitates Keysight in concept how they implemented this feature.
But they didn't pay attention to how Keysight display numbers.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 30, 2023, 09:42:55 am
Not a bug, just a feature or usability suggestion. As it stands, it seems to me that the axis labels do more harm than good in most situations, by taking up screen space and confusing the user with odd values. So switching them off is the workaround of choice, I guess.

Yep. I've never had them on other 'scopes and they don't add much IMHO.

They're useful on the FFT so I guess I have to enable them manually there. It would be nice if they could fix that.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: tautech on October 30, 2023, 09:46:14 am
On my scopes one brand have two display modes. [...]

On scopes I have here, offsets are not completely "analog", but in some discrete steps.

I appreciate the effort to avoid triggering people. But I hope we are back on a healthy track where we can mention "the brand which must not be named (in a Rigol thread)".  ;) 
::)
2N3055 also own HPAK, would you take offence if he told you all he thinks about it ?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 30, 2023, 09:55:00 am
Not a bug, just a feature or usability suggestion. As it stands, it seems to me that the axis labels do more harm than good in most situations, by taking up screen space and confusing the user with odd values. So switching them off is the workaround of choice, I guess.

Yep. I've never had them on other 'scopes and they don't add much IMHO.

They're useful on the FFT so I guess I have to enable them manually there. It would be nice if they could fix that.

Scales are very big improvement if done right. I would not buy a scope without it anymore once I got used to it.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 30, 2023, 10:15:29 am
Rigol imitates Keysight in concept how they implemented this feature.
But they didn't pay attention to how Keysight display numbers.

Just using proper rounding would go a long way...

In the screenshot below (courtesy of Fungus), I think we can ignore the scales in the FFT windows, since these are set by the user via the FFT dialog. Just look at the table entries and the vertical scale of the yellow trace. ::) 
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 30, 2023, 10:29:52 am
Rigol imitates Keysight in concept how they implemented this feature.
But they didn't pay attention to how Keysight display numbers.

Just using proper rounding would go a long way...

In the screenshot below (courtesy of Fungus), I think we can ignore the scales in the FFT windows, since these are set by the user via the FFT dialog. Just look at the table entries and the vertical scale of the yellow trace. ::)

Example of how it looks. On Keysight it is same as Fixed, including number formatting.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 30, 2023, 10:54:05 am
Example of how it looks. On Keysight it is same as Fixed, including number formatting.

Yes, that looks about right. It's really not so difficult and I hope Rigol can get it right in an upcoming firmware release:
Hmm, this might be a pet peeve of mine. I'll shut up now.  ::)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Mechatrommer on October 30, 2023, 11:47:23 am
On my scopes one brand have two display modes. [...]
On scopes I have here, offsets are not completely "analog", but in some discrete steps.
I appreciate the effort to avoid triggering people. But I hope we are back on a healthy track where we can mention "the brand which must not be named (in a Rigol thread)".  ;) 
::) 2N3055 also own HPAK, would you take offence if he told you all he thinks about it ?
we admit drawbacks and bugs in rigol, thats why we very out loud on bug and wish lists. do you believe i wish all this bashings and complaints from you people will reach rigol? so they can do something about it to improve. we very welcome "constructive critisicm" (as long as its within "academic sanity"), there are many good things in siglent if you still remember my post, in fact i believe in this compare siglent vs rigol, siglent will win in most aspects, they have very good color grading, manual sampling rate etc. now rigol opted to enforce Sinc is a bad thing imho. and with this new android multi windows thing, there are certain things still can be improved, surely hope they listen. if only they have the spirit of "aeronautic engineering" that everything automatic must be able to switch back to "manual" (by default everything automatic for education/newbie purpose).

imagine if Rigol enforce "proper design" according to our friend's definition, that requires probing at 1MSps need to cutoff analog BW to 500kHz, that will be a total screw up imho. we have things to go back to "manual" such as Peak Detect feature, dots etc. anyway to cut short, we are certain new rigol cheap 12bit provide much improvement compared to its predecessor, except the things that we cant do anymore. the more things we cant do the more hate we will have. comparison thread, be it old vs new rigol, or siglent vs rigol should be seen by manufacturers themselves for improvement to take place. we dont have much hope rigol will see. we just wait, maybe they only care about sales figure and dave's review. if they not see this thread, we are just mumbling around. we love toys, any brand of toys, but our pocket limited so we choose based on what we really need based on reviews made. cheers.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 30, 2023, 12:35:45 pm
we admit drawbacks and bugs in rigol, thats why we very out loud on bug and wish lists. do you believe i wish all this bashings and complaints from you people will reach rigol? so they can do something about it to improve. we very welcome "constructive critisicm" (as long as its within "academic sanity"), there are many good things in siglent if you still remember my post, in fact i believe in this compare siglent vs rigol, siglent will win in most aspects, they have very good color grading, manual sampling rate etc. now rigol opted to enforce Sinc is a bad thing imho. and with this new android multi windows thing, there are certain things still can be improved, surely hope they listen. if only they have the spirit of "aeronautic engineering" that everything automatic must be able to switch back to "manual" (by default everything automatic for education/newbie purpose). imagine if Rigol enforce "proper design" according to our friend's definition, that requires probing at 1MSps need to cutoff analog BW to 500kHz, that will be a total screw up imho. we have things to go back to "manual" such as Peak Detect feature, dots etc. anyway to cut short, we are certain new rigol cheap 12bit provide much improvement compared to its predecessor, except the things that we cant do anymore. the more things we cant do the more hate we will have. comparison thread, be it old vs new rigol, or siglent vs rigol should be seen by manufacturers themselves for improvement to take place. we dont have much hope rigol will see. we just wait, maybe they only care about sales figure and dave's review. if they not see this thread, we are just mumbling around. we love toys, any brand of toys, but our pocket limited so we choose based on what we really need based on reviews made. cheers.

Could you please try and add the occasional paragraph break (two carriage returns)?

It would make your posts much easier to read, by indicating where one train of thought ends and the next one begins, and also by giving the eye some orientation marks. Otherwise it's hard to do your posts justice and read them diligently.

Oh, and for even better orientation: Capitalizing the first letter of each sentence does help the reader too.  8)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: dmulligan on October 30, 2023, 01:00:10 pm
Just using proper rounding would go a long way...

This!  What human can really see the difference between the scales we are taking about.  The slight reduction in displayed, not recorded, accuracy can't be seen and would be much easier to read.

Wait.  What is proper rounding?  There are so many choices!  Round up, round down, half up, half down, even up... What about negatives, which way is up?  It wasn't that many years ago that my mind was blown when reading a Javadoc which listed and explained the available rounding options.  See https://en.wikipedia.org/wiki/Rounding
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 30, 2023, 01:20:26 pm
imagine if Rigol enforce "proper design" according to our friend's definition, that requires probing at 1MSps need to cutoff analog BW to 500kHz, that will be a total screw up imho.

I presume this was addressed to me. This is again you saying something completely invented and then blatantly lie I said that..

I will repeat again what I said:
While any scope can be made to undersample by user driving it wrong/ without proper knowledge, there is no 4 ch + MSO scope out there (including Hanteks and Owon and UNI-T) that will try to sell you 200Mhz scope that samples at maximum of 156.25 MS/s when all channels are on.

My problem is not that DHO900 will sometimes undersample (like the rest of the scopes). Problem is that unless you use it like you have bought 2 ch scope, it CANNOT satisfy Nyquist at any setting of memory and time base.

That is either bad design (which it cannot be because Rigol does know better) or deliberate, very unsavoury, marketing scam.
You know ones that tell you something with big letters on first page, followed by 3 pages of disclaimers explaining how it applies in only certain special cases...

EDIT: This undersampling problem does not apply to DHO800 in it's factory form 100 MHz. They did that one right as far as sampling goes. It is still a bit marginal with more than 150MHz front end BW, but that is probably OK. It should work OK. Except short memory in 4ch mode that will also drop sampling rate very quickly as you go longer timebases.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Mechatrommer on October 30, 2023, 01:52:22 pm
...
My problem is not that DHO900 will sometimes undersample (like the rest of the scopes). Problem is that unless you use it like you have bought 2 ch scope, it CANNOT satisfy Nyquist at any setting of memory and time base.

That is either bad design (which it cannot be because Rigol does know better) or deliberate, very unsavoury, marketing scam.
...
nope! there is no one in the sky telling it must satifies Nyquist at 4 channels, its even mentioned in datasheet (4 channels 312.5MSps) and we have no problem with that, sometime we need 4 channels for low freq debugging, for max freq, turn them all off like 1 channel. the fact that there is no telling much about the 16ch LA, prepare for anything, get used to that, thats how china's metric works in general. cheers. ;)
https://beyondmeasure.rigoltech.com/acton/attachment/1579/f-c2b704a4-c02c-4b09-9748-7e41815c1fa9/0/-/-/-/-/DHO900_DataSheet_EN.pdf
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 30, 2023, 01:55:49 pm
Just using proper rounding would go a long way...

This!  What human can really see the difference between the scales we are taking about.  The slight reduction in displayed, not recorded, accuracy can't be seen and would be much easier to read.

Wait.  What is proper rounding?  There are so many choices!  Round up, round down, half up, half down, even up... What about negatives, which way is up?  It wasn't that many years ago that my mind was blown when reading a Javadoc which listed and explained the available rounding options.  See https://en.wikipedia.org/wiki/Rounding

Appropriate rounding here would be rounding away from zero, with 2 decimal places. And no switching of units on same display. Those are only axis values for visual orientation.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Mechatrommer on October 30, 2023, 02:07:09 pm
Could you please try and add the occasional paragraph break (two carriage returns)?

It would make your posts much easier to read, by indicating where one train of thought ends and the next one begins, and also by giving the eye some orientation marks. Otherwise it's hard to do your posts justice and read them diligently.

Oh, and for even better orientation: Capitalizing the first letter of each sentence does help the reader too.  8)
You could be a good Language Teacher ;) no offense, but thanks for advice.

Sometime i'm lazy arse on capitalizing, except tech short term.

I break paragraph when i change subject.

Anyhow i separated them for your eyes. I think you are not going to read all that through anyway all my mumbling above.

Savvy? ;)

Just using proper rounding would go a long way...
you cannot satisfy everybody...
Is there possibility to show freq like 4.43361875 Mhz, my dho804 only shows like rounded to 4.4444 - only 4 digits after dot :(
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 30, 2023, 02:14:20 pm
...
My problem is not that DHO900 will sometimes undersample (like the rest of the scopes). Problem is that unless you use it like you have bought 2 ch scope, it CANNOT satisfy Nyquist at any setting of memory and time base.

That is either bad design (which it cannot be because Rigol does know better) or deliberate, very unsavoury, marketing scam.
...
nope! there is no one in the sky telling it must satifies Nyquist at 4 channels, its even mentioned in datasheet (4 channels 312.5MSps) and we have no problem with that, sometime we need 4 channels for low freq debugging, for max freq, turn them all off like 1 channel. the fact that there is no telling much about the 16ch LA, prepare for anything, get used to that, thats how china's metric works in general. cheers. ;)
https://beyondmeasure.rigoltech.com/acton/attachment/1579/f-c2b704a4-c02c-4b09-9748-7e41815c1fa9/0/-/-/-/-/DHO900_DataSheet_EN.pdf

That is your problem. There are industry standards. Way how things are being called for decades.
World don't care that you, in your head live in different universe and have your own definition.
There is certain "code of conduct" between manufacturers for at least basic decency.
Otherwise it's would be Wild West out there.

If I buy 4ch scope I expect it to be VALID 4ch scope at least in basic requirements.
Not some scope with 3 pages of disclaimer.
In my country we call that "I bought a cat in a bag".
People in general don't analyze datasheets in detail. Target market for these scopes are not professionals.

They will read on EEVBLOG how this "game changer" DHO900 stellar super duper hypersonic miracle for the money is so great.........
By the time they realize it is not, they won't be able to return it.

I will tell you my prediction in a year or two. DHO800 will be good seller. It is cheap. And they will debug a thing or two, but not everything. But it will generally be brought to be working scope and will become DS1000Z of 12 bit world.
OTOH DHO900 is going to bring lots of headache to Rigol.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: voltsandjolts on October 30, 2023, 02:26:27 pm
200Mhz scope that samples at maximum of 156.25 MS/s when all channels are on.

I think 156.25 MS/s is a mistake and should be 312.5 MSa/s, unless I am misunderstanding something?

Datasheet for DHO800 & 900 series states:
Code: [Select]
1.25 GSa/s (single-channel[1]), 625 MSa/s (dual-channel[2]), 312.5 MSa/s (full-channel[3])
Note:
[1]: Single-channel mode: If any one of the channels is enabled, it is called single-channel mode.
[2]: Dual-channel mode: For four-channel models, if any two of the channels are enabled, it is called dual-channel mode.
[3]: Full-channel mode: For two-channel models, if all of the two channels are enabled, it is called full-channel mode; for four-
channel models, if any three channels or all of the four channels are enabled, it is called full-channel mode.

Some dealer websites mistakingly state "1.25 GSa/s (divided by number of active hannels)"
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 30, 2023, 02:45:26 pm
200Mhz scope that samples at maximum of 156.25 MS/s when all channels are on.

I think 156.25 MS/s is a mistake and should be 312.5 MSa/s, unless I am misunderstanding something?

Datasheet for DHO800 & 900 series states:
Code: [Select]
1.25 GSa/s (single-channel[1]), 625 MSa/s (dual-channel[2]), 312.5 MSa/s (full-channel[3])
Note:
[1]: Single-channel mode: If any one of the channels is enabled, it is called single-channel mode.
[2]: Dual-channel mode: For four-channel models, if any two of the channels are enabled, it is called dual-channel mode.
[3]: Full-channel mode: For two-channel models, if all of the two channels are enabled, it is called full-channel mode; for four-
channel models, if any three channels or all of the four channels are enabled, it is called full-channel mode.

Some dealer websites mistakingly state "1.25 GSa/s (divided by number of active hannels)"

With MSO drops to 156.25 MS/s
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 30, 2023, 03:09:25 pm
With MSO drops to 156.25 MS/s

And that is, very unfortunately, not mentioned in Rigol's datasheet.  :--
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 30, 2023, 03:21:27 pm
200Mhz scope that samples at maximum of 156.25 MS/s when all channels are on.

I think 156.25 MS/s is a mistake and should be 312.5 MSa/s, unless I am misunderstanding something?

It's 156.25 MS/s if you have HDO900 and you turn all channels and logic analyzer on.

Back here in HDO800 world (the subject of the thread) it's 312.5 MSa/s.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Mechatrommer on October 30, 2023, 03:21:45 pm
That is your problem. There are industry standards. Way how things are being called for decades.
World don't care that you, in your head live in different universe and have your own definition.
There is certain "code of conduct" between manufacturers for at least basic decency.
this goes back to you. Rigol will make sales and we dont return it.. whether you like it or not ;)

In my country we call that "I bought a cat in a bag".
when we want to buy a cat, we expect a cat, no bag no problem, if we got bag, we are thankful. we bought NanoVNA and things thats not in conduct. you can buy industrial stuffs, free world..

People in general don't analyze datasheets in detail. Target market for these scopes are not professionals.
another insult again. but i wont comment, just to let you know it is an insult, if you not already know. Rigol got ASICs :P

They will read on EEVBLOG how this "game changer" DHO900 stellar super duper hypersonic miracle for the money is so great.........
By the time they realize it is not, they won't be able to return it.
yes it is game changer, miracle on the price. and we wont return it whether you like it or not. World don't care that you, in your head live in different universe and have your own definition.

I will tell you my prediction in a year or two. DHO800 will be good seller. It is cheap. And they will debug a thing or two, but not everything. But it will generally be brought to be working scope and will become DS1000Z of 12 bit world. OTOH DHO900 is going to bring lots of headache to Rigol.
you prediction seems inline with me (if you can allow prediction (suspicion) as not an insult) but not because DHO900 is not properly designed, but because DHO800 is highly hackable to DHO900. similar to their predecessor.

are we still friend? friends do fight right? ;D

just to let this on topic, i checked the vertical labels are indeed rounded off, i was exaggerating... but still 200 on graticule is better than 272.. i can live with that by ignoring.. or simply switch it off, the option is there, thats the most important part. ymmv
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 30, 2023, 03:26:15 pm
With MSO drops to 156.25 MS/s

And that is, very unfortunately, not mentioned in Rigol's datasheet.  :--

I see it like one of those hatchback cars with fold-down rear seats.

Either you carry passengers in the back or you carry cargo. Not both at the same time.

I believe there's a lot of them out there and everybody thinks they're a good compromise. Thanks to them we don't all have to buy crew-cab pickup trucks or seven seat minivans.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Mechatrommer on October 30, 2023, 03:33:46 pm
Thanks to them we don't all have to buy crew-cab pickup trucks or seven seat minivans.
or buy cheaper DHO800, and cloned LA, or even legit one, still not hit £2K thanks to "them".
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 30, 2023, 03:42:23 pm
With MSO drops to 156.25 MS/s

And that is, very unfortunately, not mentioned in Rigol's datasheet.  :--

I see it like one of those hatchback cars with fold-down rear seats.
Either you carry passengers in the back or you carry cargo. Not both at the same time.

I believe there's a lot of them out there and everybody thinks they're a good compromise. Thanks to them we don't all have to buy crew-cab pickup trucks or seven seat minivans.

I did not say that the sharing of sampling rate is an unacceptable compromise. (Although I think it is a very unfortunate one: Rigol have this neat low-cost 12 bit ADC, and then they throttle it down by skimping on the FPGA or RAM bandwidth.)

In any case it is a very unusual compromise, not found in any other MSO. And as such, it needs to be stated in the datasheet. The dishonesty is what annoys me, much more than the design tradeoff itself.

Even the car manufacturers state that the maximum trunk volume is only available when you fold down the rear seats. And that is a compromise which is clear and obvious to everyone, rather than a total surprise. If you enjoy car analogies: How would you like a car where the top speed is reduced by 50% when you turn on the lights or the air conditioning, and where that is not mentioned in the specs?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 30, 2023, 04:10:02 pm
I will tell you my prediction in a year or two. DHO800 will be good seller. It is cheap. And they will debug a thing or two, but not everything. But it will generally be brought to be working scope

It's a working 'scope right now.

I only know of two bugs so far in the DHO800 that affect usage (ie. make me have to take an action). Neither is a showstopper, both seem easy to fix.

One of them needs fixing right away to avoid confusion but it seems like an easy fix in the firmware.

I will tell you my prediction in a year or two. DHO800 will be good seller. It is cheap. And they will debug a thing or two, but not everything. But it will generally be brought to be working scope and will become DS1000Z of 12 bit world.

This thing blows away the DS1054Z in every possible way. It's great looking, it doesn't take up much space and it's fun to use! No twisty knob!!

It's exactly what hobbyists need. It already IS the "DS1000Z of 12 bit world"*

(*) Right now it's creating a 12 bit world. 8 bits is dead, and it's something the unmentionable brand has no answer for right now.

OTOH DHO900 is going to bring lots of headache to Rigol.

Maybe. I think a lot of people will buy it for the signal generator, and a lot of those for the Bode plot. They need to fix the Bode plot ASAP.

I don't think the LA will be a big selling point simply because of the price of the probes.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 30, 2023, 04:17:29 pm
I don't think the LA will be a big selling point simply because of the price of the probes.

Well, if all you want to probe is 3.3V and 5V signals, you can buy a cheap probe on ebay for $80, including (equally cheap) clips.

Personally I am still not ruling out a DHO900 with the official Rigol probes, since the large +-40V input range would be useful for working on vintage computers. As mentioned before, that combination would still be significantly cheaper than a Saleae Logic Pro 16, and beat it on all specs. (Although maybe not on usability.)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 30, 2023, 04:25:58 pm
Thanks to them we don't all have to buy crew-cab pickup trucks or seven seat minivans.
or buy cheaper DHO800, and cloned LA, or even legit one, still not hit £2K thanks to "them".

I think this might eventually create a bunch of Chinese LA probe clones but I don't think many people will be modifying their DHO800 into a DHO900. It just seems too risky/messy and will need skillz/toolz if the PCB needs modding more than just soldering in a connector.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 30, 2023, 05:03:07 pm
I will tell you my prediction in a year or two. DHO800 will be good seller. It is cheap. And they will debug a thing or two, but not everything. But it will generally be brought to be working scope

It's a working 'scope right now.

I only know of two bugs so far in the DHO800 that affect usage (ie. make me have to take an action). Neither is a showstopper, both seem easy to fix.

One of them needs fixing right away to avoid confusion but it seems like an easy fix in the firmware.

I will tell you my prediction in a year or two. DHO800 will be good seller. It is cheap. And they will debug a thing or two, but not everything. But it will generally be brought to be working scope and will become DS1000Z of 12 bit world.

This thing blows away the DS1054Z in every possible way. It's great looking, it doesn't take up much space and it's fun to use! No twisty knob!!

It's exactly what hobbyists need. It already IS the "DS1000Z of 12 bit world"*

(*) Right now it's creating a 12 bit world. 8 bits is dead, and it's something the unmentionable brand has no answer for right now.

OTOH DHO900 is going to bring lots of headache to Rigol.

Maybe. I think a lot of people will buy it for the signal generator, and a lot of those for the Bode plot. They need to fix the Bode plot ASAP.

I don't think the LA will be a big selling point simply because of the price of the probes.

LeCroy created 12 bit world decade ago..
Rigol is bringing in to the masses.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 30, 2023, 05:14:06 pm

People in general don't analyze datasheets in detail. Target market for these scopes are not professionals.
another insult again. but i wont comment, just to let you know it is an insult, if you not already know. Rigol got ASICs :P


It is not. It is statement confirmed by thousands posts here in EEVBLOG. It is an observation.
Target market for DHO800/900 is hobby/entry level.
It is not an insult it is Rigols own market strategy.

I have no idea what does statement about ASIC mean and has to do ANTHING with previous sentence and why are you insulted by it...
Or at this point if you are insulted by something I said or by the fact that Rigol has ASIC:

If you feel insulted by me, that was not my intention. I'm sorry that you are.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 30, 2023, 05:15:55 pm
The bracket was attached earlier and somehow you can also understand this as a statement about what I think of this scope. 8)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 30, 2023, 05:23:27 pm
LeCroy created 12 bit world decade ago..
Rigol is bringing in to the masses.

I think that's what Fungus meant -- bringing 12 bit to entry-level scopes.

You have to grant it to Rigol that they are good at pushing the envelope in the low-cost segment: To my knowledge they were the first ones to bring TDS210-style compact DSOs to the low-cost market; then to bring 4 channels and "digital phosphor" intensity grading with the DS1054Z; now to bring 12 bits with the DHO800 and 900.

Yes, they have a tendency to rush things to the market. But looking at the major benefits they have had from being "first to market", I can understand their approach. It looks like the DS1054Z is still a very good seller, despite the fact that Siglent came out with an arguably better competing instrument a couple of years later. But the DS1054Z had made its name, got a lot of publicity and recommendations by that time. Heck, even the DS1052E is still available, so some people who follow old recommendations must still buy it...

It looks like Siglent is more closely on Rigol's tracks now with the SDS1000X HD (at least as a competitor for the DHO900). But they might be missing the window of opportunity again, while the DHOs establish themselves in people's minds as "the 12-bit scope I can afford".
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 30, 2023, 05:38:42 pm
LeCroy created 12 bit world decade ago..

By that definition we all live in an 8-channel, 10Ghz "world".  :-DD

(or higher (https://www.teledynelecroy.com/oscilloscope/labmaster-10-zi-a-oscilloscopes)!)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 30, 2023, 05:49:23 pm
It looks like Siglent is more closely on Rigol's tracks now with the SDS1000X HD

But can they compete on price? I doubt it. Not without an ASIC.

Does anybody have a price prediction or possible feature set yet? I don't follow Siglent threads...
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Antonio90 on October 30, 2023, 06:00:34 pm
It will not compete in price with the DHO800, but with the DHO1000 AFAIK.
We will see, but Tautech predicts a 800-900 price for the DSO1104X-HD. The prices in China, already published, are closer to 1k but the 2104X-Plus is more expensive in Siglent China than it's base price in Europe.

They are really not in the same class, I think. It doesn't look like Siglent is competing in the "true" entry level range with 12 bits. If it really costs close to 800€ it could fill a gap in the low-cost range, as almost all sensible offerings jump from 500 to 1000+ without any steps in between.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 30, 2023, 06:09:06 pm
They are really not in the same class, I think. It doesn't look like Siglent is competing in the "true" entry level range with 12 bits. If it really costs close to 800€ it could fill a gap in the low-cost range, as almost all sensible offerings jump from 500 to 1000+ without any steps in between.

Seems to me like they'll mainly be competing with their own SDS2000 series.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 30, 2023, 06:11:55 pm
Quote
I don't follow Siglent threads...


You can tell, but in this case make an exception and check out the appropriate thread, otherwise this is getting too offtopic.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 30, 2023, 06:13:03 pm
Quote
I don't follow Siglent threads...
You can tell, but in this case make an exception and check out the appropriate thread, otherwise this is getting too offtopic.

OK, I just noticed this in the second post of the "SDS1000X HD coming" thread.

(https://www.eevblog.com/forum/testgear/siglent-sds1000x-hd-coming/?action=dlattach;attach=1751303;image)

Let's see... 200Mhz bandwidth, 250MSa/sec .... doesn't that break Nyquist?   :-//

ENOB 8.4???  :scared:
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on October 30, 2023, 06:15:35 pm
Does anybody have a price prediction or possible feature set yet? I don't follow Siglent threads...

The expected feature set of the SDS1000X HD is well-known and quite desirable: https://www.eevblog.com/forum/testgear/siglent-sds1000x-hd-coming/ (https://www.eevblog.com/forum/testgear/siglent-sds1000x-hd-coming/)

Regarding the price, there is a lot of speculation. Translating the pricing of the version which is already available in China into US or European pricing (using the price tag of scopes available in both markets as an indicator) puts it at below 1000$ or 1000€.

So it is above the DHO900 both in specs and price, but not so far that it would be out of consideration for hobbyists.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Antonio90 on October 30, 2023, 06:15:44 pm
They are really not in the same class, I think. It doesn't look like Siglent is competing in the "true" entry level range with 12 bits. If it really costs close to 800€ it could fill a gap in the low-cost range, as almost all sensible offerings jump from 500 to 1000+ without any steps in between.

Seems to me like they'll mainly be competing with their own SDS2000 series.

It won't have AWG and LA hardware built in, and the frontend is 200 MHz. Maybe the additional harware, along with more than twice the bandwith separates them well enough, but I really don't know.

It seems to be following the last few years trend. A direct competitor to Rigol products, with worse headline specs, quite a bit more expensive, and also more polished. We'll see I guess.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Mechatrommer on October 30, 2023, 06:16:12 pm
LeCroy created 12 bit world decade ago..
Rigol is bringing in to the masses.
thats why its game changer. we can talk about siglent and owon? 14bits? that came earlier. the game changer (to hobbiests community) is actually the price tag.

I have no idea what does statement about ASIC mean and has to do ANTHING with previous sentence and why are you insulted by it...
just for fun... you are a stiff one (we call here "straight" people with no sense of humor) ;D

If you feel insulted by me, that was not my intention. I'm sorry that you are.
no offense taken. its only for public benefit and some parts are personal preferences. nothing personal really. and the same to my conclusions are general view by many people. if you feel insulted, then i'm sorry too. just next time dont call people babbon, babbon dont know how to read literatures carefully and dont remember what he said or people said to him before. and again i'm not insulted i'm all too familiar with this. cheers.

Heck, even the DS1052E is still available, so some people who follow old recommendations must still buy it...
just few days ago someone PM me here asking how to fix his DS1052E, he bought it 2nd hand. unfortunately even my DS1052E cant be turned on anymore. i think it reached its service life where data in its ic/mcu/rom start to disintegrate.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: csuhi17 on October 30, 2023, 07:59:12 pm
Quote
I don't follow Siglent threads...
You can tell, but in this case make an exception and check out the appropriate thread, otherwise this is getting too offtopic.

OK, I just noticed this in the second post of the "SDS1000X HD coming" thread.

(https://www.eevblog.com/forum/testgear/siglent-sds1000x-hd-coming/?action=dlattach;attach=1751303;image)

Let's see... 200Mhz bandwidth, 250MSa/sec .... doesn't that break Nyquist?   :-//

ENOB 8.4???  :scared:

These data do not seem real!
Based on the pictures in the topic linked above, 2Gs/s.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 30, 2023, 08:02:18 pm
It looks like Siglent is more closely on Rigol's tracks now with the SDS1000X HD

But can they compete on price? I doubt it. Not without an ASIC.

Does anybody have a price prediction or possible feature set yet? I don't follow Siglent threads...

You have no data at what prices Siglent buys parts.. Just saying...

There is another consideration here.. Is Siglent really so eager to sell cheapest possible stuff..
We already said that SDS1000X HD will be at least a level up from HDO1000...

Comparing it to DHO900 is just not correct.


Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on October 30, 2023, 08:04:47 pm
Quote
I don't follow Siglent threads...
You can tell, but in this case make an exception and check out the appropriate thread, otherwise this is getting too offtopic.

OK, I just noticed this in the second post of the "SDS1000X HD coming" thread.

(https://www.eevblog.com/forum/testgear/siglent-sds1000x-hd-coming/?action=dlattach;attach=1751303;image)

Let's see... 200Mhz bandwidth, 250MSa/sec .... doesn't that break Nyquist?   :-//

ENOB 8.4???  :scared:

These data do not seem real!
Based on the pictures in the topic linked above, 2Gs/s.

That data is not correct. Incoming SDS1000X HD will have better specs.  It is all there in topic for it.
No need for poluting thread here with different models (Rigol and Siglent)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on November 05, 2023, 12:15:08 pm
I may have overlooked it -- has anyone tested serial decoding with the DHO800/900 yet? I was wondering whether it does a better job than the old DS1000Z series, which always uses only the data on the screen for decoding.

The two attached DS1054Z screenshots illustrate the limitation I am concerned about: Even in Zoom mode, when the beginning of the message is outside of the zoomed-in window, it will not be decoded and the decoder struggles to get in sync. The decoder ignores the available data just before the zoomed-in region, never mind that they are right there, displayed in the upper part of the screen.

Does the DHO800 handle this properly? And out of interest, does the MSO5000, if anyone happens to know?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on November 05, 2023, 02:00:56 pm
I may have overlooked it -- has anyone tested serial decoding with the DHO800/900 yet? I was wondering whether it does a better job than the old DS1000Z series, which always uses only the data on the screen for decoding.

In non-zoom mode it works like the DS1054Z. In zoomed mode it seems to do a full memory decode. If you enable a lot of memory then the screen update starts to get really slow (the first time I've noticed these slow down...)

Here's some data on screen in non-zoom mode:
(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1919928;image)

Here's what happens if you scroll it off screen:
(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1919934;image)

This is zoom mode - going off screen isn't a problem.  Edit: If you look closely you can see that "B1" is shown in miniature in the top part of the screen, ie. it's definitely doing a full memory decode when zoomed.
(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1919940;image)

You also get a full-memory event table in zoom mode. Scroll up/down to see it all...
(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1919946;image)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on November 05, 2023, 02:18:03 pm
In non-zoom mode it works like the DS1054Z. In zoomed mode it seems to do a full memory decode. If you enable a lot of memory then the screen update starts to get really slow (the first time I've noticed these slow down...)

Great -- thank you very much for testing this! Seems like a decent implementation, offering the user both options: Fast interactive navigation in non-zoom mode (but with possible decoding glitches at the left edge); and proper, robust decoding in zoom mode.

If any MSO5000 users happen to follow along: Is it the same there, or is the MSO5000 as limited as the DS1054Z (i.e. without the robust decoding in zoom mode)?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on November 05, 2023, 03:04:54 pm
Great -- thank you very much for testing this! Seems like a decent implementation, offering the user both options: Fast interactive navigation in non-zoom mode (but with possible decoding glitches at the left edge); and proper, robust decoding in zoom mode.

It's worth noting that using a mouse* works really well in zoomed mode. You can scroll up/down the table using the mouse wheel and drag the zoom box around to areas of interest.

https://www.youtube.com/watch?v=eucBKU-ls_g (https://www.youtube.com/watch?v=eucBKU-ls_g)

(*) Or stylus. Seriously, people, get a stylus...

Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on November 05, 2023, 04:02:35 pm
If any MSO5000 users happen to follow along: Is it the same there, or is the MSO5000 as limited as the DS1054Z (i.e. without the robust decoding in zoom mode)?

Maybe this could help:
https://www.eevblog.com/forum/blog/new-rigol-scope/msg2034745/#msg2034745 (https://www.eevblog.com/forum/blog/new-rigol-scope/msg2034745/#msg2034745)

Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on November 05, 2023, 04:42:01 pm
Maybe this could help:
https://www.eevblog.com/forum/blog/new-rigol-scope/msg2034745/#msg2034745 (https://www.eevblog.com/forum/blog/new-rigol-scope/msg2034745/#msg2034745)

Thanks! That suggests that the MSO5000 does use the deeper memory for decoding, not just the screen buffer. On the DS1054Z, decoding falls apart as soon as you can't make out the individual bits on the screen anymore.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on November 05, 2023, 06:39:09 pm
Decoding table export:
Only what is currently on the screen is decoded and displayed in the table.
If you then export the table, only what was displayed is included and rigol could also think again about the correct formatting.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on November 05, 2023, 06:55:08 pm
Decoding table export:
Only what is currently on the screen is decoded and displayed in the table.
If you then export the table, only what was displayed is included and rigol could also think again about the correct formatting.

Try it in zoom mode...

In zoom mode you should be able to set maximum memory depth then capture/decode a LOT of data.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on November 05, 2023, 06:59:00 pm
I guess you live in one of the countries where Microsoft decided the "Comma" part of "CSV" shouldn't be taken literally.

(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1920306;image)

I think Excel has a special import option to fix it but don't ask me where.

Microsoft  :palm:
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on November 05, 2023, 07:06:08 pm
I guess you live in one of the countries where Microsoft decided the "Comma" part of "CSV" shouldn't be taken literally.
I think Excel has a special import option to fix it but don't ask me where.
Microsoft  :palm:

Yeah, can't use a comma here to separate fields, because we use that to separate decimal places... Can't blame Microsoft, I guess; it's a German thing. ::) 

Micrososoft either lets you switch this stuff globally, or specifically when importing a file. But both options are annoying...
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on November 05, 2023, 07:20:19 pm
Try it in zoom mode...
In zoom mode you should be able to set maximum memory depth then capture/decode a LOT of data.

To be able to zoom in, you had extended your time base to 20ms/div.
This means that several packets can be seen on the screen and are also decoded.
And the table is then also filled accordingly.
Wait, I have to look at something (Webcontrol is great, the scope is running in the other room and I don't have to go there...)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on November 05, 2023, 07:21:35 pm
Yeah, can't use a comma here to separate fields, because we use that to separate decimal places...

Yes you can. The original CSV standard says to put quotes around fields that have a comma in them.

Can't blame Microsoft

Yes you can.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on November 05, 2023, 07:23:23 pm
I set horizontal to 2s/div and did a big capture.

It decodes OK but there's a limit...
(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1920330;image)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on November 05, 2023, 07:30:47 pm
It decodes OK but there's a limit

But... I exported a CSV file and there's 3000 values in it.

Maybe the limit is only in the display.

Edit: I did one at 5s/div and it still exported 3000 values.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on November 05, 2023, 07:40:41 pm
It decodes OK but there's a limit

But... I exported a CSV file and there's 3000 values in it.

Maybe the limit is only in the display.

Is there a way to search in the results table (for a specific data value), and then jump to that position in the trace by clicking the table entry? Or scroll through the table, click a line, and go to the right trace position that way?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on November 05, 2023, 07:44:42 pm
Quote
I exported a CSV file and there's 3000 values in it.

From the table, right ?

Quote
but there´s a limit..

Sounds familar to me, siglent specifies the maximum number of packets in its data sheets, depending on the decoder.

Title: Re: Rigol DHO804 Test and Compare Thread
Post by: csuhi17 on November 05, 2023, 07:47:35 pm
https://www.copytrans.net/support/how-to-open-a-csv-file-in-excel/ (https://www.copytrans.net/support/how-to-open-a-csv-file-in-excel/)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on November 05, 2023, 08:00:07 pm
Is there a way to search in the results table (for a specific data value)

No.

and then jump to that position in the trace by clicking the table entry? Or scroll through the table, click a line, and go to the right trace position that way?

No, but the times are shown in both windows so it's not hard to find:
(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1920351;image)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on November 05, 2023, 08:19:26 pm
Thank you for checking!

Not having the link from the data table back to the trace seems like a usability miss -- it would be such an obvious thing to do on the touch screen. And I can certainly see the use, when e.g. you see an unexpected byte in the table and want to check whether it's due to corruption of the signal.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on November 06, 2023, 12:09:27 pm
A quick UI question -- don't think I saw this mentioned anywhere:

Do the two "general purpose" encoders have detents? If not, do they suffer from the "Rigol disease" of liking to slip to the next position the moment you push down on the encoder knob?

(Or do you simply not push these knobs anymore, but rather tap somewhere on the touch screen to confirm data entry?)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on November 06, 2023, 01:33:50 pm
Do the two "general purpose" encoders have detents?

No.

(Or do you simply not push these knobs anymore, but rather tap somewhere on the touch screen to confirm data entry?)

You don't really push them. They just change numbers on screen when you turn them, no need to confirm anything.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on November 06, 2023, 03:10:32 pm
You don't really push them. They just change numbers on screen when you turn them, no need to confirm anything.

Thanks! Thinking about it, you probably hardly use the encoders for "discrete" selections -- menu entries or virtual keyboards -- at all, since these are more easily available on the touch screen. So they really are largely "analog" controls, in which case detents don't make much sense. And even if, say, a cursor moves by one pixel when you push the knob, that would not cause much harm.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on November 06, 2023, 05:26:09 pm
Thanks! Thinking about it, you probably hardly use the encoders for "discrete" selections -- menu entries or virtual keyboards -- at all,

I just tried it and you CAN use them in drop-down selections. You can even push them to confirm the choice.

I'd never even noticed that before.  ;D
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on November 07, 2023, 09:52:26 pm
Just tested the XY mode with the batronix demo board.
It looks really good and I would like to have this split screen with my other scopes as well.
Nice effect:
Ch1 yellow, Ch2 blue, what is the conclusion?
Right, green for the XY representation...
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on November 07, 2023, 10:44:51 pm
That looks nice and clean!
But can you play Asteroids on it?  8)

Actually, the resolution looks like it might be good enough for Asteroids' 10-bit X/Y DACs. And the DHO manual states you can even map a Z (blanking) input to one of the remaining analog channels! So maybe the answer is "yes".  :)

Edit: Does it support intensity grading in XY mode?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on November 07, 2023, 10:54:10 pm
Quote
Edit: Does it support intensity grading in XY mode?

Will check this tomorrow..
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: mawyatt on November 08, 2023, 01:41:50 am
Well we've been able to hang on to this 824 longer than expected (client has much more pressing issues to resolve, so doesn't need any distractions at this time), and decided to try and give the XY mode a whirl.

Here's a couple characteristic curve 2N3904 plots utilizing XY mode with an external AWG (OMG we utilized the forbidden "S" brand AWG!!!).

For those not familiar with silicon bipolar transistors, these are plots created by sweeping the collector emitter voltage Vce, while stepping the base current and plotting collector current.

The 2N3904_CTR0 curve shows the NPN bipolar operating in reverse (backwards, or upside down) mode as it's often called, where the collector and emitter are effectively interchanged by allow a negative Vce for the NPN type (also shows the forward direction, centered around 0 volts). Note the lower Beta (current gain) and breakdown (steeper collector current slope) in the reverse direction wrt to the forward normal operation mode. This reverse mode was often utilized way back due to the very low Vcesat voltage at low to modest currents.

Anyway, seems the little 824 can produce some nice XY plots!!

Best,

Title: Re: Rigol DHO804 Test and Compare Thread
Post by: blargg on November 08, 2023, 05:47:28 am
Not sure which Rigol thread to post this in. Just unboxed my DHO804 and trying a basic task, triggering off clocked data. I've got it in Normal trigger mode, on the clock line. Data comes in a burst, then nothing for a couple of seconds. I'd expect the scope to keep triggering on clocks until they stop, showing the last capture on trigger. Instead of overlays several captures on screen. In Gear->Display->Persistence I've got it set on Min (there's no Off). Is there no way to have it just show the most recent capture?

EDIT: I tried the same on my 1054Z and it worked as I expected, always showing only a single capture on screen at any given moment (there Persistence was also set to min., which is apparently off on that model).
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on November 08, 2023, 06:40:41 am
Not sure which Rigol thread to post this in. Just unboxed my DHO804 and trying a basic task, triggering off clocked data. I've got it in Normal trigger mode, on the clock line. Data comes in a burst, then nothing for a couple of seconds. I'd expect the scope to keep triggering on clocks until they stop, showing the last capture on trigger. Instead of overlays several captures on screen. In Gear->Display->Persistence I've got it set on Min (there's no Off). Is there no way to have it just show the most recent capture?

EDIT: I tried the same on my 1054Z and it worked as I expected, always showing only a single capture on screen at any given moment (there Persistence was also set to min., which is apparently off on that model).

Do you press "STOP"?

Maybe you want the "freeze" setting at the bottom of the display settings.
(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1922433;image)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: blargg on November 08, 2023, 07:44:54 am
Not sure which Rigol thread to post this in. Just unboxed my DHO804 and trying a basic task, triggering off clocked data. I've got it in Normal trigger mode, on the clock line. Data comes in a burst, then nothing for a couple of seconds. I'd expect the scope to keep triggering on clocks until they stop, showing the last capture on trigger. Instead of overlays several captures on screen. In Gear->Display->Persistence I've got it set on Min (there's no Off). Is there no way to have it just show the most recent capture?

EDIT: I tried the same on my 1054Z and it worked as I expected, always showing only a single capture on screen at any given moment (there Persistence was also set to min., which is apparently off on that model).

Do you press "STOP"?

Maybe you want the "freeze" setting at the bottom of the display settings.

Freeze only affects the display when it's stopped. In Run mode it still overlays multiple traces; the freeze switch has no effect there. I made a short video demonstrating. https://files.catbox.moe/jzlpc0.mp4 (https://files.catbox.moe/jzlpc0.mp4)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on November 08, 2023, 07:58:43 am
Freeze only affects the display when it's stopped. In Run mode it still overlays multiple traces; the freeze switch has no effect there. I made a short video demonstrating. https://files.catbox.moe/jzlpc0.mp4 (https://files.catbox.moe/jzlpc0.mp4)

Thanks for the video. The DHO800 captures all look strange to me, including the initial Single capture. What happened to the intensity grading??  ???
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: blargg on November 08, 2023, 08:11:28 am
Freeze only affects the display when it's stopped. In Run mode it still overlays multiple traces; the freeze switch has no effect there. I made a short video demonstrating. https://files.catbox.moe/jzlpc0.mp4 (https://files.catbox.moe/jzlpc0.mp4)

Thanks for the video. The DHO800 captures all look strange to me, including the initial Single capture. What happened to the intensity grading??  ???

It's there, there just isn't much overlap. Screenshot attached.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on November 08, 2023, 08:20:35 am
What happened to the intensity grading??  ???

You mean like this (https://www.eevblog.com/forum/testgear/split-from-rigols-new-dho800-oscilloscope-unbox-amp-teardown/msg5156568/#msg5156568)?

(https://www.eevblog.com/forum/testgear/split-from-rigols-new-dho800-oscilloscope-unbox-amp-teardown/?action=dlattach;attach=1922070;image)

Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on November 08, 2023, 08:32:26 am
What happened to the intensity grading??  ???

It's there, there just isn't much overlap. Screenshot attached.

Thanks, the still screenshot looks better. In the video it appeared like all pixels were on at full intensity on the DHO800, while the DS1054Z showed dim lines at the fast vertical edges vs. brighter lines for the high and low states. Probably just a camera exposure artefact, with the DHO traces set to a higher brightness than on the DS1054Z?

Still, the contrast between the edges and the steady logic states is not very pronounced at all on the DHO screenshot. But the root cause of the overlaid traces doesn't seem to be in a persistence or saturation setting or something along those lines.

@Fungus -- sure, I know that the DHO scope can do intensity grading. I just couldn't see any of it happening in the video.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on November 08, 2023, 08:34:04 am
Freeze only affects the display when it's stopped. In Run mode it still overlays multiple traces; the freeze switch has no effect there. I made a short video demonstrating. https://files.catbox.moe/jzlpc0.mp4 (https://files.catbox.moe/jzlpc0.mp4)

Maybe it's just that the capture rate is much higher on the DHO. Try setting set trigger holdoff so it triggers less often...

Technically speaking: The DHO is showing something closer to what you'd see on an analog 'scope. "Min" persistance doesn't mean there's no persistence.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on November 08, 2023, 08:46:19 am
It's there, there just isn't much overlap. Screenshot attached.
Regardless of everything, I would choose Auto memory, you still have 10k fixed as a setting(according to the screenshot)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on November 08, 2023, 08:50:35 am
[I made a short video demonstrating. https://files.catbox.moe/jzlpc0.mp4 (https://files.catbox.moe/jzlpc0.mp4)

I have one more question -- although it is probably unrelated to the effect under discussion: In the video, what are you doing to set the DHO to Single and Run mode, respectively? I see your hand operating the DS1054Z, and the status indicators on the DHO just seem to follow along "magically". What am I missing there?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on November 08, 2023, 09:04:42 am
[I made a short video demonstrating. https://files.catbox.moe/jzlpc0.mp4 (https://files.catbox.moe/jzlpc0.mp4)

I have one more question -- although it is probably unrelated to the effect under discussion: In the video, what are you doing to set the DHO to Single and Run mode, respectively? I see your hand operating the DS1054Z, and the status indicators on the DHO just seem to follow along "magically". What am I missing there?

I think he's pressing a "send some data" button somewhere off-camera.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on November 08, 2023, 09:09:04 am
I think he's pressing a "send some data" button somewhere off-camera.

Yes, that obviously is happening too, to actually start the triggering and sweep. But how does the "Single" LED on the DHO light up at 0:07 in the video, and how does the "Run/Stop" LED turn green at 0:12?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: blargg on November 08, 2023, 09:31:43 am
Freeze only affects the display when it's stopped. In Run mode it still overlays multiple traces; the freeze switch has no effect there. I made a short video demonstrating. https://files.catbox.moe/jzlpc0.mp4 (https://files.catbox.moe/jzlpc0.mp4)

Maybe it's just that the capture rate is much higher on the DHO. Try setting set trigger holdoff so it triggers less often...

Technically speaking: The DHO is showing something closer to what you'd see on an analog 'scope. "Min" persistance doesn't mean there's no persistence.

Fair point. The DHO is freezing what the analog scope would have last shown (before it fades out during the couple of seconds of no activity for the test signal in the video).

I looked around and enabled UltraAcquire mode and for it gives what I wanted (and what the 1054Z does), but that's a new can of worms because it seems like this should not work and I can't figure out why it's not making multiple captures stacked/in perspective etc. as this mode should (I played around for a while and couldn't get consistent results, will have to dig into this another day).

[I made a short video demonstrating. https://files.catbox.moe/jzlpc0.mp4 (https://files.catbox.moe/jzlpc0.mp4)

I have one more question -- although it is probably unrelated to the effect under discussion: In the video, what are you doing to set the DHO to Single and Run mode, respectively? I see your hand operating the DS1054Z, and the status indicators on the DHO just seem to follow along "magically". What am I missing there?

Sorry about that, was just off the top of the camera. For the first test I hit Single on the '804, then hit Run (same buttons I press on DS1054Z except the latter also requires setting the mode to Normal as it switches to Auto).

The test signal has a bunch of pulses for about 4ms, then nothing for a couple of seconds.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on November 08, 2023, 10:07:38 am
Actually, I still like the intensity grading of the DS1000Z series better, not to speak of the higher models of this heritage...

I just revisited the older posts on DHO intensity grading, prompted by the observed difference to the DS1054Z in blargg's video. There were some earlier comments that the DHO's grading does not look as convincing as on other scopes, including Rigol scopes.

It looks to me like the DHO800/900 varies the pixel intensity only based on how often a pixel was redrawn. In contrast, the DS1054Z (and many other scopes) also take into account how fast the "beam" was moving when drawing the trace. I.e. if there is a lower density of actual acquisition points, say on the fast edge of a signal, the interpolated line is rendered dimmer on the DS1054Z, but not on the DHO.

Visible in TurboTom's photo (re-attached here) along the envelope of the modulated signal, which is brighter only on the DS1054Z. (Because the carrier frequency "takes a slow turn" at its peaks.) And visible in blarrg's video, a few posts above, where the DS1054Z shows a marked contrast between the fast edges vs. the high/low logic states of the signal, but the DHO does not. (Except for the low state in some areas, which occurs more often.)

Does this make sense? Maybe a DHO owner can specifically confirm or refute this theory by looking at suitable test signals?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on November 08, 2023, 12:29:08 pm
I've got it in Normal trigger mode, on the clock line. Data comes in a burst, then nothing for a couple of seconds. I'd expect the scope to keep triggering on clocks until they stop, showing the last capture on trigger. Instead of overlays several captures on screen. In Gear->Display->Persistence I've got it set on Min (there's no Off). Is there no way to have it just show the most recent capture?

EDIT: I tried the same on my 1054Z and it worked as I expected, always showing only a single capture on screen at any given moment (there Persistence was also set to min., which is apparently off on that model).

I just tried this on the DS1054Z (with a different signal and timing), and can get the same qualitative effect. I used a modulated signal from a function generator which comprises a sequence of different bursts; the Single capture in the first picture gives an idea. When I set the scope to Run mode with Normal trigger, let it aquire for a moment and then switch the generator output off, the DS1054Z also shows an overlay of multiple sweeps, see the second picture. Persistence is at "minimum" here as well.

So the behavior you observed is not unique to the DHO. I think Fungus is right: The fact that the DS1054Z only shows a single sweep in your setting, while the DHO shows multiple, is due to a higher waveform update rate on the DHO. If one deliberately wants to isolate a single sweep, a trigger holdoff time is requred.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on November 08, 2023, 01:41:16 pm
This little persistence bug  is not a show stopper but just one of  the little quirks that Rigol is known to do sometimes.

Just a note.

While it seems you guys figured out what is happening, that is still not really correct behavior.
It should show only data from last trigger event, if persistence is disabled.

Looking for workarounds is wrong approach. File a bug report.
Fact that DS1000Z also did it wrong is not excuse  for anything.

Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on November 08, 2023, 01:59:58 pm
This little persistence bug  is not a show stopper but just one of  the little quirks that Rigol is known to do sometimes.

Turns out that this has been discussed four years ago with respect to the DS1000Z: https://www.eevblog.com/forum/testgear/rigol-ds1054z-persistance-in-stopwait-mode/ (https://www.eevblog.com/forum/testgear/rigol-ds1054z-persistance-in-stopwait-mode/)

I would argue that the real limitation (or bug if you want) is that the persistence time can't really be set to 0, but only to "minimum". According to a comment by PeDre in the linked thread, that seems to mean 20 ms for the D1000Z -- not sure whether that number applies independent of the selected time base.

Pressing Stop or no longer providing triggers (in Normal triggering mode) will just freeze the last display, which is what I would expect from a DSO. But since there is always a bit of persistence "happening" while in Run mode, that last display will show multiple sweeps overlaid, if the sweep time is less than the persistence time.

Hence, if we submit a bug report, it should be "persistence time cannot be set to zero" in my understanding.

I have no idea what the DHO800's "Waveform Freeze" option does in this mix. Does it somehow override the persistence setting and force it to zero -- but only when entering Stop mode?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on November 08, 2023, 03:41:52 pm
I have no idea what the DHO800's "Waveform Freeze" option does in this mix. Does it somehow override the persistence setting and force it to zero -- but only when entering Stop mode?

Yes.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on November 08, 2023, 03:46:47 pm
I have no idea what the DHO800's "Waveform Freeze" option does in this mix. Does it somehow override the persistence setting and force it to zero -- but only when entering Stop mode?

Yes.

So, when the scope is waiting for a trigger in RUN mode, and showing the most recently acquired set of persistent traces on the screen -- can you press STOP, and it redraws the screen content from the acquisition buffer, showing just a single trace?

That would be another workaround for the "can't have zero persistence" limitation. But it seems that allowing a "persistence: none" setting would be the cleaner way from a UI perspective. I wonder whether there is some deep division-by-zero type limitation in the rendering engine for the intensity-graded display which does not allow this?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on November 08, 2023, 04:08:06 pm
So, when the scope is waiting for a trigger in RUN mode, and showing the most recently acquired set of persistent traces on the screen -- can you press STOP, and it redraws the screen content from the acquisition buffer, showing just a single trace?

Yes.

That would be another workaround for the "can't have zero persistence" limitation. But it seems that allowing a "persistence: none" setting would be the cleaner way from a UI perspective. I wonder whether there is some deep division-by-zero type limitation in the rendering engine for the intensity-graded display which does not allow this?

It simply doesn't make sense on a fast 'scope.

Imagine it's updating a byte of random serial data 60 times a second on screen. All the bits are going to be flickering between 0 and 1 at full frame rate. How does "persistence=0" help with that? All it does is move the persistence to your eyes.

Now imagine they're not completely random. Maybe they're 25% zeros. A bit of little bit of persistence will help you see the bias more clearly..


Where the DHO destroys the DS1054Z is in segmented memory mode. In this mode you can record all the bytes and play them back with "persistence=0".
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on November 08, 2023, 05:43:36 pm
(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1922553;image)

I haven't played much with that asapect of the DHO but the DS1054Z is famous for having impossibly good intensity grading. It's as good as any 'scope at any price...

Why is that? I don't know. Maybe a quirk of it's "everything on screen" architecture or something.  :-//
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on November 08, 2023, 06:15:51 pm
Maybe a DHO owner can specifically confirm or refute this theory by looking at suitable test signals?

This is about the best I could get:
(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1922796;image)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on November 08, 2023, 06:52:39 pm
I made some too:
https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/msg5106300/#msg5106300 (https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/msg5106300/#msg5106300)

Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on November 08, 2023, 07:32:32 pm
Thank you both! The intensity grading looks alright on the DHO800, but not as convincing as on the good ol' DS1000Z... The large inner area of the modulated envelope is rendered pretty homogeneous -- despite the fact that the "beam" sweeps the central areas, where the carrier amplitude is high, much faster. So real phosphor would get excited less in those areas, and the DS1000Z mimics that nicely.

Ah well; not a tragedy for DHO800 usefulness. But always a bit disappointing when a modern, more powerful product falls behind its predecessor.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on November 08, 2023, 07:39:24 pm
Quote
Edit: Does it support intensity grading in XY mode?

Will check this tomorrow..

Yes and No... ;)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on November 08, 2023, 07:50:15 pm
Quote
Edit: Does it support intensity grading in XY mode?
Will check this tomorrow..
Yes and No... ;)

Pity -- no brightly glaring shots when playing Asteroids on this. ::)
Well, Mike has shown us in reply #730 what XY mode is really useful for in electronics, and the DHO800 handles those plots very nicely indeed!
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: iMo on November 08, 2023, 07:56:33 pm
..But always a bit disappointing when a modern, more powerful product falls behind its predecessor.

Hmm, not sure about that.. While looking at the DS1054Z mobo I can see an ADC FPGA with two rams (16b and 32b width) attached, then an FPGA for the display processing, a linux MCU with ram and the 3rd FPGA for the LA..
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on November 08, 2023, 08:00:15 pm
Quote
But always a bit disappointing when a modern, more powerful product falls behind its predecessor.

I don't think rigol knows how they managed that either.
The grading is the best I've ever seen on a DSO, on the 1054Z - but also on the DS2072, which I also had.
Both had Ultravision I technology.
MSO5000/7000 was UV II and today's have UV III.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: iMo on November 08, 2023, 08:08:12 pm
The DHO's display data are processed inside the android MCU, the DS1054Z display data are processed in a separate FPGA, afaik.. It seems to me the tricks with the persistance shading simply do not fit the android MCU performance (or data bandwidths somewhere)..
PS: the DS1054Z could be more performant than the DHO800 - the 1000Z's FPGA/MCU clocks might be slower (?), on the other hand it does "a distributed processing", with less bottlenecks, kind of..

..But always a bit disappointing when a modern, more powerful product falls behind its predecessor.

Hmm, not sure about that.. While looking at the DS1054Z mobo I can see an ADC FPGA with two rams (16b and 32b width) attached, then an FPGA for the display processing, a linux MCU with ram and the 3rd FPGA for the LA..
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on November 08, 2023, 08:38:05 pm
The DHO's display data are processed inside the android MCU, the DS1054Z display data are processed in a separate FPGA, afaik.. It seems to me the tricks with the persistance shading simply do not fit the android MCU performance (or data bandwidths somewhere)..

PS: the DS1054Z could be more performant than the DHO800 - the 1000Z's FPGA/MCU clocks might be slower (?), on the other hand it does "a distributed processing", with less bottlenecks, kind of..

I don't know about "more performant" in general. The UI response seems much smoother on the DHO800/900, FFT calculations have not only higher dynamic range but happen at a much faster rate, the waveform update rate is significantly improved too.

But they probably had to cut corners somewhere to meet the cost target. The memory (?) bandwidth being shared between analog and digital channels was one major surprise (and disappointment); maybe a simplified grading implementation is another, more minor one.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: TurboTom on November 08, 2023, 10:11:31 pm
What I painfully missed on the DHO914S that I had the opportunity to evaluate vs. Rigol's mature oscilloscopes is the measurement history, and especially their graphic display. This was so comfortable to document trends of measured parameters like a phase walk-through or the like. To the best of my knowledgle, this function was only present on these "legacy" Rigol 'scopes (DS1000Z, DS2000(A) and DS4000 and the corresponding MSO versions). Maybe Rigol could add this function on the DHO in a firmware down the line, but I wouldn't bet on it...



Edit: For those who are not familiar with what I mean, you may want to have a look here -- the fourth attached screenshot shows this function (https://www.eevblog.com/forum/testgear/new-rigol-16-bit-function-generators-dg800900-series/msg2424708/#msg2424708).
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: mawyatt on November 09, 2023, 05:02:37 am
Well we've been able to hang on to this 824 longer than expected (client has much more pressing issues to resolve, so doesn't need any distractions at this time), and decided to try and give the XY mode a whirl.

Here's a couple characteristic curve 2N3904 plots utilizing XY mode with an external AWG (OMG we utilized the forbidden "S" brand AWG!!!).

For those not familiar with silicon bipolar transistors, these are plots created by sweeping the collector emitter voltage Vce, while stepping the base current and plotting collector current.

The 2N3904_CTR0 curve shows the NPN bipolar operating in reverse (backwards, or upside down) mode as it's often called, where the collector and emitter are effectively interchanged by allow a negative Vce for the NPN type (also shows the forward direction, centered around 0 volts). Note the lower Beta (current gain) and breakdown (steeper collector current slope) in the reverse direction wrt to the forward normal operation mode. This reverse mode was often utilized way back due to the very low Vcesat voltage at low to modest currents.

Anyway, seems the little 824 can produce some nice XY plots!!

Best,

Had a little time this evening to play around with the DHO824 some more.

Some folks may be wondering how we created these XY Curve Trace plots on the DHO824. A proper Curve Trace for a bipolar transistor requires a +- ramp voltage with variable amplitude and offset for sweeping the collector to emitter, or Vce, and sensing the collector current Ic. A +- step base current Ib is required for the base, and the Vce and Ic are plotted as X and Y respectively on the DSO. All this requires quite a bit of circuitry, current sensing amplifiers, variable ramp +- voltage generators with variable offset, and synchronized variable step base +- current source with variable offset. Just take a look at the old Tek 577, it's huge and chocked full of all sorts of electronics (sure it's much more versatile and has much larger ranges in voltage and current as it's a dedicated Curve Tracing Instrument, pretty good one at that!!). So this can be a complex undertaking, or maybe one can just use whats at hand, like a AWG, a couple resistors and a DSO with XY plotting capability and get a crude Curve Tracing ::)

Guess which path we chose  ;)

Anyway, we also utilized our old Tek 577 to see just how crude these plots were relative to a proper Curve Tracing Instrument, judge for yourself.

Best,
 
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on November 09, 2023, 06:52:42 am
Pity -- no brightly glaring shots when playing Asteroids on this. ::)

You can enable a Z channel... :-)

(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1923063;image)

I doubt it will do the flare around the bright dots though.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: blargg on November 09, 2023, 10:28:18 am
I have no idea what the DHO800's "Waveform Freeze" option does in this mix. Does it somehow override the persistence setting and force it to zero -- but only when entering Stop mode?

Yes.

So, when the scope is waiting for a trigger in RUN mode, and showing the most recently acquired set of persistent traces on the screen -- can you press STOP, and it redraws the screen content from the acquisition buffer, showing just a single trace?

That would be another workaround for the "can't have zero persistence" limitation. But it seems that allowing a "persistence: none" setting would be the cleaner way from a UI perspective. I wonder whether there is some deep division-by-zero type limitation in the rendering engine for the intensity-graded display which does not allow this?

After a good while experimenting with test signals (Audacity to draw repeating waveforms played over the headphone jack), I've made more sense of how the virtual phosphors (persistence) and acquisition buffer(s) interact. After doing this I tried the same on the 1054Z and what do you know, it seems to behave the same way though I didn't test it as extensively as the DHO804. This is what I found:

Normal operation of persistence is to add each sweep to a buffer and slowly fade out the buffer between sweeps. On an analog scope once the signal stops triggering (and it's in normal not auto mode), everything will fade out. But the Rigol will keep drawing the last sweep at full intensity, which is more useful IMO than just fading to black.

The issue I had occurs when when memory depth is set to a lower value (e.g. 10k). In this case it keeps *multiple* sweep buffers saved in memory as it is successively triggered. The displayed sweep is ALL of these drawn on top of each other. So when the signal stops triggering, all these buffers stay at full intensity on screen, not just the most recent buffer. This behavior with smaller buffers acts like a secondary persistence system that keeps recent previous sweeps from fading out.

So the fix for my case is to increase the memory depth to 10M or 25M, which seems to ensure only one buffer is kept in memory at a time and thus only the last sweep persists on screen.

Something different happens when you stop capture with the Run/Stop button. If Waveform Freeze is on, it basically just freezes the screen, persistence and all. If Waveform Freeze is off, it displays only the most recent (single) sweep buffer, without any persistence of anything previous. Contrast this with what happens when the signal stops triggering, where it keeps displaying the multiple sweep buffers in memory.

For a test signal I had pulses of increasing width one after the other. This allowed me to easily see how many were being displayed overlaid at once, by the falling edges appearing in a row across the screen.

I'm enjoying using this scope with the mouse on its own screen (though it locks out the touch screen). I thought I would be hooking this up to a monitor but the screen is quite readable despite the small fonts (and over HDMI mouse movement was very lagged and choppy, which was unbearable to use).
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on November 09, 2023, 11:16:50 am
I'm enjoying using this scope with the mouse on its own screen (though it locks out the touch screen).

It's fun to use, right? No twisty knob!

You could also try one of those $1 phone stylus things instead of a mouse (the rubber-tip ones, not the fancy electronic ones).
(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1923156;image)

This frees up the USB port for WiFi and you can grab screenshots over the 'net (HTTP or FTP).

I thought I would be hooking this up to a monitor but the screen is quite readable despite the small fonts

Yep, the font rendering is excellent, very easy to read. YMMV but the "small screen" really hasn't bothered me at all.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on November 09, 2023, 11:22:38 am
I've just been messing around playing youtube videos into the 'scope in XY mode:
https://www.youtube.com/watch?v=Pg7tY__Y_BA (https://www.youtube.com/watch?v=Pg7tY__Y_BA)

(video recorded in web browser using the built-in web server's screen record function  :)  )

Original video:
https://www.youtube.com/watch?v=ywdRQ3zU6Uc (https://www.youtube.com/watch?v=ywdRQ3zU6Uc)

Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on November 09, 2023, 11:30:44 am
Another one:

https://www.youtube.com/watch?v=ouAr389sw8M (https://www.youtube.com/watch?v=ouAr389sw8M)

I'm not sure how much distortion is from Youtube's lossy audio compression.  :-//

Original video:
https://www.youtube.com/watch?v=5WBWIKnr0Os (https://www.youtube.com/watch?v=5WBWIKnr0Os)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: rpro on November 09, 2023, 01:43:56 pm
In case this has been missed, you can enable the XY "Advanced Settings" switch on the XY setup window by turning on "Test Mode" first (3 taps on Utility/About). 
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on November 09, 2023, 04:49:24 pm
In case this has been missed, you can enable the XY "Advanced Settings" switch on the XY setup window by turning on "Test Mode" first (3 taps on Utility/About).


I wondered about that! :-DD

The XY mode has a load of "Advanced Settings" that appear if you click the hamburger on the XY window, but they're all greyed out.
(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1923378;image)

The only way to get to them is through a secret trick? Nice one!

(FWIW they don't seem to improve these videos...)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on November 09, 2023, 05:13:46 pm
In case this has been missed, you can enable the XY "Advanced Settings" switch on the XY setup window by turning on "Test Mode" first (3 taps on Utility/About).

Are there any other secret passageways which get unlocked in "Test Mode"?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on November 09, 2023, 05:16:28 pm
In case this has been missed, you can enable the XY "Advanced Settings" switch on the XY setup window by turning on "Test Mode" first (3 taps on Utility/About).

Are there any other secret passageways which get unlocked in "Test Mode"?

Only in places that make sense.

(AFAIK)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on November 09, 2023, 05:33:01 pm
Are there any other secret passageways which get unlocked in "Test Mode"?

Only in places that make sense.
(AFAIK)

I would certainly hope so. ;)

My question was, where are these places? Any pleasant surprises -- like full control over FFT acquisition details, more control over the number format in axis labels, or such?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on November 09, 2023, 07:33:27 pm
My question was, where are these places? Any pleasant surprises -- like full control over FFT acquisition details, more control over the number format in axis labels, or such?

I'd class that as "unexpected".

AFAIK: It only shows more system info, a self-test menu, an extended self-cal.

ie. Stuff you'd expect a "debug" mode to do.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on November 09, 2023, 07:36:02 pm
Quote
AFAIK: It only shows more system info, a self-test menu, an extended self-cal.

Confirmed, I called up all the menus in test mode earlier and nothing was different than usual.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on November 09, 2023, 07:52:29 pm
AFAIK: It only shows more system info, a self-test menu, an extended self-cal.
ie. Stuff you'd expect a "debug" mode to do.

... plus extended, surprisingly detailed controls for XY mode, right? Which I would not necessarily consider "stuff I expect a debug mode to do"; hence my question.

Anyway, thank you both for checking!
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on November 09, 2023, 08:00:07 pm
Quote
plus extended, surprisingly detailed controls for XY mode, right?

No,
This "Mode" is available in the "Add window" menu under XY - but not in the horizontal menu, where you can only switch XY on or off.
Somewhat stupidly done, if Fungus hadn't shown this, I still wouldn't have known.
Either way, the rigol is ahead of the siglent scopes, because you can't do anything there, you don't even have the split screen with XY and the two channels.
Siglent should change that.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on November 09, 2023, 08:12:36 pm
That's interesting, at least I hadn't noticed that until just now:
In the web server, the screen has a different resolution, 1280x800, as you can see in the two pictures from my previous post.
A direct screenshot saved on a usb stick has the resolution of the installed screen.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: iMo on November 09, 2023, 08:13:05 pm
I've just been messing around playing youtube videos into the 'scope in XY mode:
How do you modulate (switch on/off, etc) the beam?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on November 09, 2023, 08:13:11 pm
... plus extended, surprisingly detailed controls for XY mode, right?

They're not easy to find.

Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on November 09, 2023, 08:15:16 pm
I've just been messing around playing youtube videos into the 'scope in XY mode:
How do you modulate (switch on/off, etc) the beam?

I didn't. I just got a wire with a stereo jack plug on the end and played the audio of the Youtube video into my 'scope.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on November 09, 2023, 08:32:58 pm
That's interesting, at least I hadn't noticed that until just now:
In the web server, the screen has a different resolution, 1280x800, as you can see in the two pictures from my previous post.
A direct screenshot saved on a usb stick has the resolution of the installed screen.

But the 1280x800 pictures don't look great -- more blurry fonts and some jagged edges. Looks like they don't get the benefit of proper rendering from scratch (as the scope allegedly does on the external HDMI screen), but are upscaled 1024*600 images?

Edit: Or is it just my browser handling the pictures differently? I have plenty of screen resolution on the computer, so it's not the PC being forced to rescale. How do the 1280*800 captures look to others?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: dmulligan on November 09, 2023, 08:50:31 pm
Are there any other secret passageways which get unlocked in "Test Mode"?
There are some HDMI settings IIRC.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on November 09, 2023, 09:16:46 pm
Are there any other secret passageways which get unlocked in "Test Mode"?
There are some HDMI settings IIRC.

Yes, that, too... you can set HDMI resolution manually in debug mode.

Normally it reads the monitor's native definition and uses that. I'm not sure why you're want to use other resolutions but I guess that's why it's a "debug" feature.

But the 1280x800 pictures don't look great -- more blurry fonts and some jagged edges.

Yep, I reported that as a bug. 1280x800 is 1000/4000 series screen resolution.

It should be an easy fix, the resolution is hard-coded in the HTML of the web page that it serves up.
(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1923552;image)

(I wonder if I can find/edit that file with ADB  :) )

Edit: It's buried in "webcontrol.apk" and I don't know how to modify .apk files.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: DaneLaw on November 10, 2023, 03:34:52 am
Maybe a DHO owner can specifically confirm or refute this theory by looking at suitable test signals?

This is about the best I could get:
(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1922796;image)

Weird - as it does not look like it has much detail in those inner-modulated signals,- what amount of EXIF metadata do screen dumps from Rigol-scopes contain.?

I wondered if it was the high amount of grading levels, that made the step-grading less pronounced on the DHO800/900 series, and why you see a faster transition to dark on scopes with a low amount of grading levels., like fx scopes with 64-levels - but usually, you can decipher that, if you step a few feet back, and look to see if there are details (depth) in that uniform inner-mass, just with very fine grading/transition from all the grading levels, but that doesn't look to be the case on your example.

On the Micsig it also got pretty high grading levels to the point that it at times can look uniform, but it does carry depth, even signals that at first glance look'ed uniform.
Both in CCT-mode, and in native channel-colors. (256)

- Ch3 with a few grading steps (SG FY6900) picture 5 & 6 are with CCT. (temp)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: KedasProbe on November 10, 2023, 02:58:04 pm
I compared the signal generator accuracy, set to 10MHz (DHO914S)
Compared to Leo Bodnar mini GPSDO via DG4102 Counter and scope phase change.

Start up about 40Hz too high dropping fast
After about 6 minutes it hits 10MHz exactly
After 10 minutes it's 6 Hz too low
Long time: 16-17Hz too low

It is possible to fine tune the generator setting to hit 10Mhz but doesn't stay there very long. (screenshot)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on November 10, 2023, 09:51:36 pm
Tried it out earlier with the batronix board spi 4-channel(Mosi, Miso, CS,CLK), works very well with the 804.
What is absolutely annoying is this "waveform freeze"... ::)
If you stop the scope, you can't recognize the waveform because it is superimposed.
Freeze off is the solution and it will stay with me permanently.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on November 11, 2023, 08:20:31 am
What is absolutely annoying is this "waveform freeze"... ::)
If you stop the scope, you can't recognize the waveform because it is superimposed.

Just to be crystal clear for users of other brands: It's a user option.

Freeze off is the solution and it will stay with me permanently.

It depends what you're looking at.

If it's data packets then it's bad. Analog signals? Not so much.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on November 11, 2023, 09:51:01 am
What is absolutely annoying is this "waveform freeze"... ::)
If you stop the scope, you can't recognize the waveform because it is superimposed.

Just to be crystal clear for users of other brands: It's a user option.

Freeze off is the solution and it will stay with me permanently.

It depends what you're looking at.

If it's data packets then it's bad. Analog signals? Not so much.

It is good that you can shut it off.
It is equally useless for digital and analog signals.

Unless used with persistence. Which is why that option should be in persistence settings.
And should be coupled with persistence, and if persistence is off it should be automatically off.

That is logical, consistent and how it should have been done.
And to make it worse, it is not something that is problem with scope hardware.
Just a poor choice of function grouping and lack of understanding how it should be done.

It is obvious that it was added as an afterthought, probably someone complained and instead of realizing WHY it was wrong and fixing the problem in concept itself, they made a checkbox fix and just planted it somewhere. It is, unfortunately, a consequence of modern software development  practice, of shipping "approximation" of product and counting on fixing it later.
Then a fix is made 1 year later by someone who was not in primary team, and is pretty much given directive "just fix this and close the ticket"...

So you get this "it can do it but you need to know this trick.." kind of result.

But as I said as long as it achieve the task, no matter how illogical it is, I guess it is going to be OK..

But so far, they didn't show any institutional advances to their software process. Brand new platform, same development process so far.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: TurboTom on November 11, 2023, 12:14:11 pm
The "Freeze" function can be useful if an intensity graded display of an (analog) signal is desired for duocumentation. The legacy instruments had this always enabled, still it didn't bother (me) at all: If one wants the "frozen" trace, press "Stop/Run", if a single scan is desired, press "Single". No function switching required...
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on November 11, 2023, 08:49:01 pm
I have now started to display and save the signals from the demo board step by step on the 804.
Then another scope, another one.
And to upload the data sets for comparison.
But first the 804 and then the decoder signals from the board.
This worked quite well, but it is a bit annoying that you can only get back to the decoder menu via the menu button at the bottom left - unless you have activated the table, from there you can go directly to the menu.
A bit confusing and illogical.
RS232, I²C and SPI no problems, but the "parallel decoding" function leaves me somewhat perplexed.
The demoboard provides 8bit in parallel, so I thought, ok, then I'll just decode 4 bit, whatever.
But that didn't work, it was worth a try. ;)
I didn't quite understand the point of the parallel bus decoder.
If you go to the menu, you can first define whether you have a clock and if so, on which channel.
Then which channel the bus is on - Hm?
I'm not a bus expert, but parallel decoding on a single channel sounds strange.
However, you can select one of the four channels under "bus", but there is also "user".
If you select this, you can assign a bit to each channel and specify the bit width (maximum 4, logically).
Otherwise not...
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: nctnico on November 11, 2023, 09:03:41 pm
What is absolutely annoying is this "waveform freeze"... ::)
If you stop the scope, you can't recognize the waveform because it is superimposed.

Just to be crystal clear for users of other brands: It's a user option.

Freeze off is the solution and it will stay with me permanently.

It depends what you're looking at.

If it's data packets then it's bad. Analog signals? Not so much.

It is good that you can shut it off.
It is equally useless for digital and analog signals.

Unless used with persistence. Which is why that option should be in persistence settings.
And should be coupled with persistence, and if persistence is off it should be automatically off.

That is logical, consistent and how it should have been done.
And to make it worse, it is not something that is problem with scope hardware.
Just a poor choice of function grouping and lack of understanding how it should be done.
Let me stop you right there... This is one of the typical situations where a feature is handy or gets in the way. Tektronix DSOs (at least the older ones) operate in this way and that is where Rigol likely copied it from. It can be handy when dealing with slow signals so you can see the difference between the old and the new signal without needing slow or infinite persistence. On the Tektronix scopes you can press one of the channel buttons to make the previous acquisition dissapear.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on November 11, 2023, 09:10:41 pm
I have now started to display and save the signals from the demo board step by step on the 804.

Thanks for these! 

Fungus had found a few days ago that, if one wants the scope to also "look back" beyond the time window visible on-screen, one has to decode from Zoom mode. (In order to decode messages which are not fully shown on screen, but started earlier.) https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/msg5152266/#msg5152266 (https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/msg5152266/#msg5152266)

Reassuringly, your I2C_tab.png screenshot suggests that the decoder always works from deeper memory, not from the screen buffer like in the DS1054Z. It might only look at the time interval visible on-screen, but it can still decode data which are not resolved on the screen. That's good!

Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on November 11, 2023, 09:28:52 pm
Ah, I think I understand what that means, because until now I thought, ok, it always shows what you can see.
E.g. seven data packets visible, seven data packets are displayed in the table.
But I seem to remember that it wasn't like that with the 1054Z... crap, I already had it in the bag yesterday and then didn't feel like taking it home with me.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on November 11, 2023, 09:44:48 pm
In the situation shown in the I2C_tab.png screenshot, the DS1054Z would not be able to decode anything. As soon as the individual bits are no longer resolvable on-screen, they can't be decoded either.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on November 11, 2023, 09:59:12 pm
Ah, ok.
So a screen-only decoding would not be able to do something like the following picture?
But only when it can be seen in full resolution (second picture), I think I have understood it now.
But only when it can be seen in full resolution (second picture), I think I have understood it now.
The third image shows the same word, but with an additional table.
It's a pity that the value is no longer displayed on the screen, it seems to be compressed when you have a window next to it.


Title: Re: Rigol DHO804 Test and Compare Thread
Post by: nctnico on November 11, 2023, 10:03:35 pm
I have now started to display and save the signals from the demo board step by step on the 804.
Then another scope, another one.
Just wondering: how is the 7" screen in terms of operator comfort?

And does the DHO804 decode full memory or only the part of the signal shown on screen?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on November 11, 2023, 10:11:00 pm
Ah, ok.
So a screen-only decoding would not be able to do something like the following picture?
But only when it can be seen in full resolution (second picture), I think I have understood it now.

Yep, that's right. No way to decode something like your first screenshot on the DS1054Z; you have to zoom in until you can resolve the bits like in the second screenshot. Good to see that the DHO800 does it properly.

I wonder whether (and very much hope that!) there is similar progress in the "measurements" department. Again, the DS1054Z does these from the screen data: As soon as the relevant details are no longer resolved on screen, measurements show wrong values or indicate that they are unable to measure anything ('*****'). Does the DHO800 handle this better?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on November 11, 2023, 10:12:59 pm
And does the DHO804 decode full memory or only the part of the signal shown on screen?

As mentioned earlier (referencing Fungus' findings), it seems to be "ful memory" when you are in Zoom mode, while it's only the part shown on the screen (but with the full resolution from memory!) in normal view.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: nctnico on November 11, 2023, 10:16:35 pm
And does the DHO804 decode full memory or only the part of the signal shown on screen?

As mentioned earlier (referencing Fungus' findings), it seems to be "ful memory" when you are in Zoom mode, while it's only the part shown on the screen (but with the full resolution from memory!) in normal view.
So basically it decodes only what is on screen which is not full memory.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on November 11, 2023, 10:19:02 pm
How can you determine for sure whether it is from the complete memory?
This is a fundamental question.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on November 11, 2023, 10:25:39 pm
And does the DHO804 decode full memory or only the part of the signal shown on screen?

As mentioned earlier (referencing Fungus' findings), it seems to be "ful memory" when you are in Zoom mode, while it's only the part shown on the screen (but with the full resolution from memory!) in normal view.
So basically it decodes only what is on screen which is not full memory.

It decodes from memory over the time interval defined by the screen view. Makes sense?
Or, to say it another way: Only "the part" which is on the screen, but not only "the data" (or "the detail") visible on screen.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on November 11, 2023, 10:29:05 pm
I wonder whether (and very much hope that!) there is similar progress in the "measurements" department. Again, the DS1054Z does these from the screen data: As soon as the relevant details are no longer resolved on screen, measurements show wrong values or indicate that they are unable to measure anything ('*****'). Does the DHO800 handle this better?

Example, 10khz sine wave...
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on November 11, 2023, 10:37:03 pm
Example, 10khz sine wave...

Progress never stops!  :-+   ;)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on November 11, 2023, 10:40:11 pm
Just wondering: how is the 7" screen in terms of operator comfort?
Hard on the edge for people with thick sausage fingers... ;)
The arrows in the top right corner are impossible to hit without a mouse or stylus.
But it has to be said that the UI fits together pretty well in terms of the touchscreen and how the individual menus are structured.
With a little practice, operation is much faster than with the SDS1104X-e or DS1054Z, for example.
But they should rework the window function, which is a good idea in itself, but somewhat sloppily implemented.
You cannot determine the size and the number of positions on the screen is also fixed (top/bottom/sideways).
Changing the position is like a little game of patience.

Title: Re: Rigol DHO804 Test and Compare Thread
Post by: rpro on November 11, 2023, 11:33:27 pm
The arrows in the top right corner are impossible to hit without a mouse or stylus.
One can just swipe that ribbon left/right (with momentum), without tapping on the arrows...

(I've also noticed the utility menu opens up with a single tap on the LXI logo, bottom right. I also like navigating from within the timebase/acquire menu to the vertical/tab menus and from there to the trigger or measurement menus, etc. Lots of entry points to all menus...)   
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on November 12, 2023, 12:04:11 am
And does the DHO804 decode full memory or only the part of the signal shown on screen?

As mentioned earlier (referencing Fungus' findings), it seems to be "ful memory" when you are in Zoom mode, while it's only the part shown on the screen (but with the full resolution from memory!) in normal view.
So basically it decodes only what is on screen which is not full memory.

Read that again...

When you're in zoom mode it does full memory.

How can you determine for sure whether it is from the complete memory?
This is a fundamental question.

You can see it in this image (the line "B1" in the zoom area):
(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1919940;image)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: nctnico on November 12, 2023, 12:11:54 am
Now try the same without needing the zoom window that A) takes a lot of space and B) has a better purpose than selecting which part of the acquisition you want to decode. The screen is already tiny, you'll want to waste as little as possible (keep in mind that in a real world use case you'll have meaningfull analog traces on screen as well). In addition, with a full memory decode as a table, you can keep track of where you are within a set of messages IF the contents remains the same regardless of any other setting. If the contents of the decode table changes by what is on the display, it is impossible to make a correlation between messages while inspecting the analog signals in detail using your oscilloscope as the message index changes.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on November 12, 2023, 12:13:57 am
You also get a long event table, although it seems to be limited to 1000 entries.

Here's a decode of some data captured at 2s/div. It decodes correctly.
(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1920330;image)

There's 1000 entries in the event table but when I exported a .csv I got more than 3000 lines.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on November 12, 2023, 12:15:25 am
Now try the same without needing the zoom window that ...

We went through all this last week...

Start here: https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/msg5152266/#msg5152266 (https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/msg5152266/#msg5152266)

A) takes a lot of space and B) has a better purpose than selecting which part of the acquisition you want to decode

Don't knock 'til you've tried it. The zoom window is a great way to navigate a lot of data when you have a touch screen.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on November 12, 2023, 12:17:37 am
Quote
You can see it in this image (the line "B1" in the zoom area):

What I can see is that what is visible in the zoom is decoded.
Furthermore, the DHO804 behaves in the same way as the MSO5000, the SDS2000xplus and the SDS2000X HD.
This means that either all these models decode from the memory or not, hence my question as to how this can be determined.

Title: Re: Rigol DHO804 Test and Compare Thread
Post by: nctnico on November 12, 2023, 12:18:11 am
Now try the same without needing the zoom window that ...

We went through all this last week...

Start here: https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/msg5152266/#msg5152266 (https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/msg5152266/#msg5152266)
So my assertion is correct: the DHO804 decodes only what is on screen (which is in line with previous / other Rigol scopes).
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on November 12, 2023, 01:02:00 am
So my assertion is correct: the DHO804 decodes only what is on screen (which is in line with previous / other Rigol scopes).

Nope.

The DS1054Z works with screen PIXELS (ie. 1200 data points). If you zoom out the decoding will break.

On these DHOs you can zoom out and you still get a decode. Here's almost 10Mpts of data "on screen" being decoded.

On screen you just see little vertical lines where the bytes are but the table has the decoded data.

(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1925760;image)

Or flip it around and zoom out some more:
(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1925766;image)

As noted earlier: The table shows max 1000 lines but if I export the decoded data as a .csv file I get much more.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on November 12, 2023, 01:29:28 am
And, yes, if you scroll left/right the first few characters of those 1000 lines can be garbage:
(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1925778;image)

Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on November 12, 2023, 01:35:46 am
I also like navigating from within the timebase/acquire menu to the vertical/tab menus and from there to the trigger or measurement menus, etc. Lots of entry points to all menus...)   

Yes, there's lots of links to related functions in the UI. Many ways to get to other places:

eg.
(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1925784;image)

(...and yes, you can touch the little switches in the diagram to flip them, you don't have to use (eg.) the AC/DC dropdown, just touch the switch where it says "AC")
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: csuhi17 on November 12, 2023, 04:56:18 am
Did those who replaced the original memory card experience an improvement in operation or boot time?
What card was it originally?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on November 12, 2023, 07:11:41 am
Now try the same without needing the zoom window that ...

So my assertion is correct: the DHO804 decodes only what is on screen (which is in line with previous / other Rigol scopes).

Are you just not listening/reading, or are you actively trying to troll this thread?

We explain twice that the scope decodes the full buffer in Zoom mode (which takes a noticeable time), or decodes the time section visible on the screen, but with full resolution, in regular view (which is nice for interactive work). And then you come back with your passive-aggressive "now try the same again without needing zoom".  :palm:

Fungus explains it to you a third time -- and you come back with a summary that is still plain wrong, regarding both (!) modes. The DHO804 already goes beyond DS1000Z capabilities in regular view mode, because it accesses the deep memory to resolve and decode details not visible on-screen.

What's next? Are we going to get GW Instek recommendations from you?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: iMo on November 12, 2023, 08:28:27 am
How do you know the "measure" results (the sine wave in the replay #802) are made a) from all data in the memory, or, b) from the data visible on the screen only?

PS: in order to check that you would need a more complex modulated signal, like 100mV sine for say 300ms and then 1V sine for 300ms, etc. Moving with the zoom inside that signal will show how the measurement is made then..
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on November 12, 2023, 08:39:58 am
How do you know the "measure" results (the sine wave in the replay #802) are made a) from all data in the memory, or, b) from the data visible on the screen only?

What we know is that measurements are made on the data in deep memory (with full time resolution), rather than on the screen buffer data themselves (like the DS1000Z does). That's clear since the measurements can quantify details which are not resolved on screen.

I have not seen your (a) vs. (b) scenarios discussed for measurements. But I strongly assume it is (b), at least while not viewing in Zoom mode. Otherwise the measurements would be much slower than they are.

So it is "limited time span, but full time resolution". And you can easily define which time span you want covered by going to a slower time base, so you can control the tradeoff between statistical precision and measurement speed. I quite like that approach.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on November 12, 2023, 10:08:43 am
The DHO804 already goes beyond DS1000Z capabilities in regular view mode, because it accesses the deep memory to resolve and decode details not visible on-screen.

...and that's without going into segmented mode decodes, etc. (which have all been discussed here)

Bottom line: The decoding on this is orders of magnitude better than the DS1054Z.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on November 12, 2023, 10:16:24 am
This worked quite well, but it is a bit annoying that you can only get back to the decoder menu via the menu button at the bottom left - unless you have activated the table, from there you can go directly to the menu.
A bit confusing and illogical.

If you're going in/out of the decode dialog a lot then you can scroll a shortcut into view at top-right...  :)
(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1925982;image)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on November 12, 2023, 10:30:31 am
Aha.. :D
It would be cleverer if it were right at the position, because you have the mode active.
But good to know.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on November 12, 2023, 10:34:17 am
Topic decode from memory or not:
If it can only decode what is visible on the screen, then this(attached pic in run mode) shouldn't work at all...or should it?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: nctnico on November 12, 2023, 10:49:00 am
Now try the same without needing the zoom window that ...

So my assertion is correct: the DHO804 decodes only what is on screen (which is in line with previous / other Rigol scopes).

Are you just not listening/reading, or are you actively trying to troll this thread?
No. I just wanted to have something clarified beyond any doubt about decoding behaviour through a very simple question which actually was not answered before.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: nctnico on November 12, 2023, 10:50:55 am
Topic decode from memory or not:
If it can only decode what is visible on the screen, then this(attached pic in run mode) shouldn't work at all...or should it?
Try to figure how to drive the number of messages in that table display and you'll know it.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on November 12, 2023, 11:01:17 am
Quote
Try to figure how to drive the number of messages in that table display and you'll know it.

Just tried it out, you can only change the number of decoded packages displayed via the time base.
If you set it to 50ms, you have 15 packages. 37 packages
If you set it to 10ms, you get 7.
If you now use the manual allocation of the memory and set it to e.g. 10Mpts, the number of packages displayed remains at 7, although the memory is now much more than in auto mode.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on November 12, 2023, 11:09:29 am
Which is all consistent with what we said all the time, right? The sweep time defines the time window which gets decoded.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on November 12, 2023, 11:49:45 am
I added the siglent, which does exactly the same thing.
Here 100ms with both scopes, both show 75 lines in the table, the packages can only be recognised as dashes - I can't imagine that the scopes can decode this if they don't decode from memory.
(By the way: I like the table colour of rigol much better, have I said that before? ;)  )

Edit: Traces are hided on the siglent, forgot to set it back. Edit2: Why does the rigol shows "too many results" but still decode correctly..
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on November 12, 2023, 11:58:53 am
Hi,

See #825 and yes I've also tried with max memory (25Mpts because of 2 channels active).
Look at the amount of memory the siglent got(Automode), it doesn't matter at all.

Edit: Post was erased...
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on November 12, 2023, 12:10:36 pm
See #825 and yes I've also tried with max memory (25Mpts because of 2 channels active).
Look at the amount of memory the siglent got(Automode), it doesn't matter at all.

Try disabling roll mode and set it to 1s/div or something like that. You can grab several seconds of data.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: nctnico on November 12, 2023, 03:12:45 pm
Quote
Try to figure how to drive the number of messages in that table display and you'll know it.

Just tried it out, you can only change the number of decoded packages displayed via the time base.
If you set it to 50ms, you have 15 packages. 37 packages
If you set it to 10ms, you get 7.
If you now use the manual allocation of the memory and set it to e.g. 10Mpts, the number of packages displayed remains at 7, although the memory is now much more than in auto mode.
If you zoom out (if there is off-screen data), you should be able to see more packets in the decoding table (up to the limit). And what happens with the number of packets in the decode table when you zoom in? Both in stop mode BTW so the acquisition record is fixed.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on November 12, 2023, 03:27:25 pm
(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1926249;image)

Yes, because you didn't record for longer time, you only increased the sample rate.

The amount of serial data you recorded stayed the same, ie. 100ms (7 packets).
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on November 12, 2023, 03:53:38 pm
@nctnico:

https://www.youtube.com/watch?v=BxseQOIIXxE (https://www.youtube.com/watch?v=BxseQOIIXxE)

Something like this will happen.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: nctnico on November 12, 2023, 04:07:52 pm
That answers my question! Thanks for taking the trouble to show it in a video  :-+
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on November 12, 2023, 04:12:07 pm
No problem, its better than posting pics - But now to the interesting part:
Does it decode from the memory in the last part of the video ?  :D
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: nctnico on November 12, 2023, 04:16:31 pm
No problem, its better than posting pics - But now to the interesting part:
Does it decode from the memory in the last part of the video ?  :D
Yes. There is (acquired) data outside the visible area when you pressed stop. By zooming out, you increased the timespan and brought the packets which where invisible before into the visual 'range' so the DHO804 decided to try and decode that part of the acquisition as well.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on November 12, 2023, 04:21:25 pm
But now to the interesting part:
Does it decode from the memory in the last part of the video ?  :D

The I²C code shows with approx. 70 bits/div in your last scope setting. Even at an ideal 2 pixels/bit, it would take 2*70*10 pixels to resolve these on the screen, which is more than what the screen provides even in full-screen mode. So it can't be decoding from the screen buffer, right?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on November 12, 2023, 04:36:46 pm
The same scenario again, only with the siglent hd.
It has memory management on board, so I was able to set it to 100Mpt* and zoom out accordingly.

https://www.youtube.com/watch?v=h8FUwxvQUK8 (https://www.youtube.com/watch?v=h8FUwxvQUK8)

*) 200Mpts if I had used channel 3, but that doesn't matter in this case.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on November 14, 2023, 09:39:05 pm
Hi,
Got the rigol DS1054Z out of the cupboard at work today to try out this decoder thing on it (unfortunately forgot the usb stick with pics at work).
It's true, for the one I2C test you set the time base to 1ms, then the DS1054Z decodes one word.
If you set it to 2ms, then it decodes nothing...
But what I found really "scary" was that I took the scope out of the cupboard for the first time in a while - and compared to the DHO, it seems downright "antique" to me. 8)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on November 14, 2023, 10:58:18 pm
But what I found really "scary" was that I took the scope out of the cupboard for the first time in a while - and compared to the DHO, it seems downright "antique" to me. 8)

Yep.

I bet the non-touch Siglents aren't much different either.

I'm going to get my Micsig out this week and see which one I want to keep.  :)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on November 14, 2023, 11:01:38 pm
Quote
I bet the non-touch Siglents aren't much different either.

Exactly.
Once you've experienced the benefits of a touchscreen, you're dead to the other way of operating devices.

Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on November 14, 2023, 11:21:43 pm
In the next few days I will show you an example of how drastic the difference can be, even with things as ordinary as choosing the right divisor factor.
With the DHO and the siglent touch models this is a matter of a few seconds, with the DS1054Z and the 1104X-E you first have to call up the menu and then scroll through the divisions with the action button.
This is no longer up to date, but you can forgive them, they are a bit older. ;)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on November 15, 2023, 12:22:14 am
This is no longer up to date, but you can forgive them, they are a bit older. ;)

Yes, but if you're going out to buy today... not even on the shortlist, right?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on November 15, 2023, 08:22:01 am
This is no longer up to date, but you can forgive them, they are a bit older. ;)

Yes, but if you're going out to buy today... not even on the shortlist, right?

Like we said before many times, there are still many things DS1104X-E can do that DHO800 cannot.
It is only a question if that matters to you or not.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on November 15, 2023, 09:01:39 am
there are still many things DS1104X-E can do that DHO800 cannot.

You mean things that require more hardware?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on November 15, 2023, 09:19:12 am
there are still many things DS1104X-E can do that DHO800 cannot.

You mean things that require more hardware?

And when people call you a troll and Rigol apologist and shill you seem to get offended.

But all you ever offer is never ending innuendos and spreading of vague denialism.

Facts are out there. Go back and read again.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on November 15, 2023, 10:20:08 am
Like we said before many times, there are still many things DS1104X-E can do that DHO800 cannot.
It is only a question if that matters to you or not.

Since I just decided to spend the money for an SDS2104X plus, which punches one weight class above, I consider myself impartial in the "DHO800/900 vs. SDS1104X-E" debate now. ;) Early bugs aside, here's my take -- purely a summary of what I have learned from the forum, I don't have first-hand experience with either scope:
Did I forget anything major?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on November 15, 2023, 11:20:06 am
Facts are out there. Go back and read again.

Fact: The DHO800 can do many things the SDS1000X-E cannot.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on November 15, 2023, 12:28:13 pm
Facts are out there. Go back and read again.

Fact: The DHO800 can do many things the SDS1000X-E cannot.

That is PARTIAL fact.

FULL Fact is that it is true both ways...

Ebastler  nicely quickly summarized it. There are few more details but those are details.

EVERY device, even 1M USD 100 GHz scopes have pros and cons. It is a list.
Which people look at and decide what is important to them or not.

You should start adding a new phrases to your vocabulary. It is :"to me." and "for me".

Example of use in sentence: "The DHO800 can do many things for me that SDS1000X-E cannot."
or: "Yes, but if you're going out to buy today... for me not even on the shortlist, right?"

And I would not have said a word.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Mechatrommer on November 15, 2023, 12:36:01 pm
If you want Bode plots and/or MSO functionality, the DHO800 does not offer these at all. You would have to buy the DHO900, spending several hundred USD or EUR more.
i hope soon DHO800 will be upgradable (hackable) to bode plot capable... hopefully at less than $100 cost...

You We should start adding a new phrases to your our vocabulary. It is :"to me." and "for me".
here corrected for you ;) cheers.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on November 15, 2023, 12:52:05 pm
If you want Bode plots and/or MSO functionality, the DHO800 does not offer these at all. You would have to buy the DHO900, spending several hundred USD or EUR more.
i hope soon DHO800 will be upgradable (hackable) to bode plot capable... hopefully at less than $100 cost...

You We should start adding a new phrases to your our vocabulary. It is :"to me." and "for me".
here corrected for you ;) cheers.

Yeah, you are the one with moral right to claim so.... :-+
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on November 15, 2023, 10:43:55 pm
Yes, but if you're going out to buy today... not even on the shortlist, right?

As a main device, not a single 7" scope would be on my list, the small screen would be too tiring for me in the long run.
If that weren't the case and I had a tight budget and no scope yet, the SDS1104X-E and the DHO804 would remain.
However, since I need Bodeplot and the Rigol doesn't offer one, I would have to opt for the siglent.
That's quite a shame, because I like the DHO804 better in some areas (what exactly will follow).
And even if I had more money to spare, a DHO900S would be out of the question for me, as I consider it a rather superfluous model.
What can it do better than the 800, almost nothing.
If you don't need an LA, the device is a more expensive 800.
As things stand, I think the 800 series is the best of all the new Rigol scopes, no joke.
The "oddities" and the sometimes rather meager features can be forgiven for the cheap 800, as the owner of a DHO1000 or even 4000 I would feel a bit stultified in view of the fact that most of the hardware used there is also available for a quarter or eighth of the price with the 800 and the software and thus the operation is the same anyway.



Title: Re: Rigol DHO804 Test and Compare Thread
Post by: nctnico on November 16, 2023, 12:05:13 am
Yes, but if you're going out to buy today... not even on the shortlist, right?

As a main device, not a single 7" scope would be on my list, the small screen would be too tiring for me in the long run.
If that weren't the case and I had a tight budget and no scope yet, the SDS1104X-E and the DHO804 would remain.
However, since I need Bodeplot and the Rigol doesn't offer one, I would have to opt for the siglent.
That's quite a shame, because I like the DHO804 better in some areas (what exactly will follow).
And even if I had more money to spare, a DHO900S would be out of the question for me, as I consider it a rather superfluous model.
What can it do better than the 800, almost nothing.
If you don't need an LA, the device is a more expensive 800.
As things stand, I think the 800 series is the best of all the new Rigol scopes, no joke.
The "oddities" and the sometimes rather meager features can be forgiven for the cheap 800, as the owner of a DHO1000 or even 4000 I would feel a bit stultified in view of the fact that most of the hardware used there is also available for a quarter or eighth of the price with the 800 and the software and thus the operation is the same anyway.
I agree. If you could modify the DH800 to have a bigger display, it would be more or less equal to the way more expensive DHO models.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on November 16, 2023, 01:02:44 am
However, since I need Bodeplot and the Rigol doesn't offer one, I would have to opt for the siglent.
And even if I had more money to spare, a DHO900S would be out of the question for me, as I consider it a rather superfluous model.

With the Siglent you have to add the cost and extra bench space of a signal generator. A DHO900 could compare very favorably to that.

What can it do better than the 800, almost nothing.
If you don't need an LA, the device is a more expensive 800.

If you're not going to use the LA then the DHO900 makes no sense at all. Some people might think it has a higher bandwidth but that's not really true and it's just more opportunity for aliasing.

The DHO900 is a sweet deal for Rigol though. $200 higher sticker price could maybe make them three times the profit, all for the cost of a $1 edge connector.

(I think this is the reason they so massively underrate the official bandwidth of the DHO800)

As things stand, I think the 800 series is the best of all the new Rigol scopes, no joke.

Yep. The DHO804 is amazing value.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on November 16, 2023, 01:14:58 am
Quote
With the Siglent you have to add the cost and extra bench space of a signal generator.

I wouldn't have the "problem" with the Rigol, of course.
But then I wouldn't have a bode plot either. ;)
This is a good opportunity to buy yourself a nice generator.
And Rigol could of course also implement Bodeplot and then design it so that you can use external (Rigol) generators for it.
But I don't think that will ever happen.
That's just a point for me, if you don't need a Bodeplot, you can live very well with the 800.

Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on November 16, 2023, 01:28:02 am
I wouldn't have the "problem" with the Rigol, of course.
But then I wouldn't have a bode plot either. ;)

Was the Siglent Bode plot 100% perfect on launch?  :popcorn:

(I'm still waiting for an explanation of the Siglent's FFT problems shown in Dave's review of the DHO800...)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on November 16, 2023, 01:36:55 am
Quote
Was the Siglent Bode plot 100% perfect on launch?

I didn't follow that back then, I just know that when I got to know it (2018), it was really good.
You can't compare that with what rigol almost reluctantly pushed after the MSO5000 via firmware update.
And that was years ago and what you can see with the 900S is exactly the same - they have no desire to make something good out of it.

Quote
I'm still waiting for an explanation of the Siglent's FFT problems shown in Dave's review of the DHO800...

What problem ?
That would be good if you could name it, because I have access to the scope at work.
This is also interesting in that the FFT performance of rigol is the biggest weakness for me, apart from the lack of a bodeplot function.

Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Mechatrommer on November 16, 2023, 04:56:28 am
You people dont look dave's video arent you people? siglent has wobbly fft and dho800/900 can be connected to 99" tv with touch if you wish to :palm: btw.. going to sending 'less small sparrow afg' board to jlcpcb tonight after final checking stage... fwiw..
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on November 16, 2023, 06:49:53 am
Quote
I'm still waiting for an explanation of the Siglent's FFT problems shown in Dave's review of the DHO800...

What problem ?
That would be good if you could name it, because I have access to the scope at work.

See the video at 32:15:

https://www.youtube.com/watch?v=S8jrpCoZyx8&t=1935s (https://www.youtube.com/watch?v=S8jrpCoZyx8&t=1935s)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on November 16, 2023, 07:33:30 am
I didn't follow that back then, I just know that when I got to know it (2018), it was really good.

I don't follow Siglent threads much either but their firmware has release notes and it's
quite long:

https://www.siglenteu.com/wp-content/uploads/dlm_uploads/2018/02/SDS1000X-Firmware-Revise-History.pdf (https://www.siglenteu.com/wp-content/uploads/dlm_uploads/2018/02/SDS1000X-Firmware-Revise-History.pdf)

I know the Bode plot can glitch if it does one of its little internal recalibrations half way through:

https://www.eevblog.com/forum/testgear/siglent-sds1204x-e-bode-plot-glitches (https://www.eevblog.com/forum/testgear/siglent-sds1204x-e-bode-plot-glitches!)!/


You probably don't remember Siglent mailing little bags of capacitors to people to install in their new 'scopes either?

https://www.eevblog.com/forum/testgear/siglent-sds1202x-e-compensation-issue/msg1350586/#msg1350586 (https://www.eevblog.com/forum/testgear/siglent-sds1202x-e-compensation-issue/msg1350586/#msg1350586)

Imagine if Rigol did that? We'd never hear the last of it.

Title: Re: Rigol DHO804 Test and Compare Thread
Post by: tautech on November 16, 2023, 07:43:48 am
Fuck off Fungus
https://www.eevblog.com/forum/projects/project-yaigol-fixing-rigol-scope-design-problems/ (https://www.eevblog.com/forum/projects/project-yaigol-fixing-rigol-scope-design-problems/)

Shit PLL lock also:
https://www.youtube.com/watch?v=K1IJH9aJvgE (https://www.youtube.com/watch?v=K1IJH9aJvgE)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on November 16, 2023, 07:52:01 am
Fuck off Fungus
https://www.eevblog.com/forum/projects/project-yaigol-fixing-rigol-scope-design-problems/ (https://www.eevblog.com/forum/projects/project-yaigol-fixing-rigol-scope-design-problems/)

Come on, man, get a grip. What kind of tone is that?

Regarding early scope issues: Sure, the "Yaigol" bug was disconcerting. But it was fixed within six weeks by a firmware update (improving the PLL settings). In contrast, Siglent's SDS1202X-E had an actual hardware issue. And they chose to address this not by a clean and simple "we'll send you a replacement scope, then you return your buggy scope to us", but by shipping DIY capaycitor kits. Not something to be proud of.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: tautech on November 16, 2023, 07:54:51 am


Regarding early scope issues: Sure, the "Yaigol" bug was disconcerting.
DS2000

Quote
But it was fixed within six weeks by a firmware update (improving the PLL settings).
DS1054Z
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on November 16, 2023, 08:12:15 am
DS2000
DS1054Z

The PLL issue was quickly addressed via firmware updates for both scopes, to my knowledge. I did not follow the DS2000 thread back then, but skimming it now it seems to me that Bud went off on a tangent. Which scope performance metric needed further improvement exactly?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: RoGeorge on November 16, 2023, 08:44:42 am
The PLL jitter bug was fixed with a firmware update, after Dave showed the bug.  Since then (~8 years ago) the PLL is working just fine on my Rigol DS1054Z.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: tautech on November 16, 2023, 09:00:39 am
Fuck off Fungus
your sale hurts?
Not at all, quite busy actually.

Those that throw dirt should expect some to be thrown back.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on November 16, 2023, 10:01:22 am
@Fungus:

https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/msg5171130/#msg5171130 (https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/msg5171130/#msg5171130)

I don't know where you're going with this... :-//
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on November 16, 2023, 10:07:56 am
@Fungus:
https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/msg5171130/#msg5171130 (https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/msg5171130/#msg5171130)
I don't know where you're going with this... :-//

I think this whole digression is based on a misunderstanding. When you wrote,

I wouldn't have the "problem" with the Rigol, of course.
But then I wouldn't have a bode plot either. ;)

Fungus assumed you were claiming that the DHO900 "does not have a Bode plot" since that functionality is not working properly yet. So he felt compelled to point out that other scopes had bugs upon their release as well.

Whereas I understood that you were focusing on the DHO800, which obviously does not have a Bode plot at all. -- Maybe Rigol wil eventually implement Bode plots using external Rigol function generators, now that they have announced function generators (and DMMs) in a DHO-style package? Would be a nice incentive to collect them all...
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: nctnico on November 16, 2023, 12:23:02 pm
Fuck off Fungus
https://www.eevblog.com/forum/projects/project-yaigol-fixing-rigol-scope-design-problems/ (https://www.eevblog.com/forum/projects/project-yaigol-fixing-rigol-scope-design-problems/)

Come on, man, get a grip. What kind of tone is that?
Trouble in kindergarten test equipment land  :popcorn: The toddlers are having a diaper fight.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on November 16, 2023, 03:47:52 pm
Fungus assumed you were claiming that the DHO900 "does not have a Bode plot" since that functionality is not working properly yet.

Yep.

I was just pointing out that most other 'scopes don't "work" on launch day either.

(maybe even "none of them"...  :-// )
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on November 16, 2023, 04:21:17 pm
They had nearly four years time to polish the function since it cames out for the MSO5000.
So please forgive my scepticism that something bigger is happening.
I would be delighted if I were wrong, you can take my word for it. ;)

Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on November 16, 2023, 05:10:30 pm
So please forgive my scepticism that something bigger is happening.
I would be delighted if I were wrong, you can take my word for it. ;)

I don't pretend to understand Rigol internally. If you've just spent 100 million (or whatever) on developing a chipset and bringing these new devices to market then it seems a no-brainer to put a couple of people on EEVBLOG to gather info and do a monthly firmware update for the first few months.

The few bugs that we've found in the DHO800 seem to me like they could be fixed with a couple of morning's work.

It's a mystery.  :-//
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on November 16, 2023, 05:22:27 pm
Today I tested the waveform updaterate.
Based on the first table of rf-loop measurements, with a sine of 600mVpp and frequencies from 1khz up to 40Mhz.
As you know, with rigol you can't make any settings regarding vector/dots or lin / sinx/x, it only works as it is.
Memory mode is set to Auto, beforehand I made sure that the aux output is actually set to trigger out.
The trigger out signal has an amplitude of 3.3V and a single pulse width of 100ns.
The updaterates appear as bursts with pauses in between, which was to be expected.

(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1929924;image)

Things worth noting:
from 5ns to 500ns the rate remains almost constant, between 1µs and 5µs it drops only slightly and between 5µs and 20µs it shows the halving at every timebase change that I know of.
But then from 50µs it drops drastically from 4 digits to 2 digits, for whatever reason.
The early minimisation of the sample rate is also interesting, it is already reduced from 100µs.
The memory points remain constant at 625 kpts from 50 µs - only at 500 µs does it rise again to 781.25 kpts and then drop again to 625 - whatever triggers this, especially as 781.25 is a rather crooked number.
I will have a look at the ultra acquiremode, how to use it and then create a table from it.
First attempt was "unsuccessful", I also had max 20000wfms/s in ultra mode.
Can't be right, so I'll look for what went wrong.

Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on November 16, 2023, 05:27:01 pm
Quote
The few bugs that we've found in the DHO800

Whereby the emphasis is on found.
And on bugs, there are also things that could be done better.
And how easy it is to fix things, I have no idea, but the scope is still very young, there's still something to come.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on November 16, 2023, 07:17:55 pm
Quote from: Me
I will have a look at the ultra acquiremode, how to use it and then create a table from it.
First attempt was "unsuccessful", I also had max 20000wfms/s in ultra mode.
Can't be right, so I'll look for what went wrong.

I'm beginning to understand what this mode is supposed to represent and how to adjust it, I also wrote down the values earlier, but I still have to transfer them to a table.
From 5ns to 20ns it is a constant 42000 wfms/s.
At 50ns something happens, the numbers shoot up to actually 1 million, fluctuates a bit.
Between 50ns and 500ns it remains in descending 6 digits and between 50µs and 100µs there is this dramatic drop again.
And the strange 781.25Kpoints are also present again at 500µs.
More of this soon.

Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on November 16, 2023, 11:47:35 pm
See the video at 32:15:

I just did, it doesn't look nice, but I don't know the settings, nor are they revealed there.
And I switched off the video at the latest when the bodnar pulser is attached to the results and its comments. ;)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: rpro on November 17, 2023, 12:54:28 am
Between 50ns and 500ns it remains in descending 6 digits and between 50µs and 100µs there is this dramatic drop again.
You are probably well aware of this, but in case it helps others, keep in mind that the capture rate is limited by the time it takes to display the waveform on the screen. For example at 100µs/div and 10div, the capture rate can not be any faster than 1/(1000µs) or 1000 wfms/sec; at 1ms/div it can be at most 100 wfms/sec, etc. 
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on November 17, 2023, 01:08:48 am
Hi,
This hard drop down I didn´t noticed on any other scope before, including the DHO4204.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: rpro on November 17, 2023, 02:17:15 am
Hi,
This hard drop down I didn´t noticed on any other scope before, including the DHO4204.
However, it may be of interest to note that, whereas at 20ns/div, 42K wfms/sec captures only 0.84% of the 5M/sec max available; at 1ms/div, the 36 wfms/sec you've measured in normal mode captures 36% of the 100/sec max available...

(Also, at 50ns/div, the 1M wfms/sec you've measured covers 50% of the 2M max avail., which is very nice.)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on November 17, 2023, 07:07:44 am
I just did, it doesn't look nice, but I don't know the settings, nor are they revealed there.

Send Dave a PM.

This hard drop down I didn´t noticed on any other scope before, including the DHO4204.

I recall seeing similar hings in a few videos.

I can't mathematically do 1M at all settings. There's only 50M memory and it has to capture at least a screen-width of data for each "wave". If it can do it at half a dozen different settings then that seems good enough.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: core on November 17, 2023, 09:10:58 am
It seems that a Black Friday for DHO1000 will start soon :

https://www.rigol.eu/NEWS/news/58.html (https://www.rigol.eu/NEWS/news/58.html)

with 40% discount it sounds interesting vs DHO800 ...
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on November 17, 2023, 12:29:31 pm
It seems that a Black Friday for DHO1000 will start soon :

https://www.rigol.eu/NEWS/news/58.html (https://www.rigol.eu/NEWS/news/58.html)

with 40% discount it sounds interesting vs DHO800 ...

DHO1074 costs $899. With 40% off that's $539.

You get a bigger screen, 200MHz, 2GSa/sec., 100Mpts.  (assuming a hack)

Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Antonio90 on November 17, 2023, 12:33:57 pm
It seems that a Black Friday for DHO1000 will start soon :

https://www.rigol.eu/NEWS/news/58.html (https://www.rigol.eu/NEWS/news/58.html)

with 40% discount it sounds interesting vs DHO800 ...

DHO1074 costs $899. With 40% off that's $539.

You get a bigger screen, 200MHz, 2GSa/sec., 100Mpts.  (assuming a hack)
It costs 999, I think, It already has a 10% discount.
The price will be €599 most likely, which is still pretty good. You also get internal 50 Ohm termination.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Mechatrommer on November 17, 2023, 12:38:31 pm
It seems that a Black Friday for DHO1000 will start soon :

https://www.rigol.eu/NEWS/news/58.html (https://www.rigol.eu/NEWS/news/58.html)

with 40% discount it sounds interesting vs DHO800 ...
DHO1074 costs $899. With 40% off that's $539.
You get a bigger screen, 200MHz, 2GSa/sec., 100Mpts.  (assuming a hack)
damned i bought dho800 too early :palm: as dave simply put it, they are going to play the market by themselves. someone must be "fuck me off" by this "die veneris nigrum" thing...
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: core on November 17, 2023, 12:46:22 pm
For sure I will get one even if I already have enough oscilloscopes. I don't have a 12 bit one  :-DD

We'll see if the offer will be worldwide.

DHO800 it's OK as functionality, but the effective screen size is very small. The all-time active menus takes a lot of space. 10 inch is much better for this interface.

Also, the USB-C power supply connector it's not on my taste.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on November 17, 2023, 12:51:39 pm
You also get internal 50 Ohm termination.

Are you sure? I don't think the DHO1000 has that; the DHO4000 might.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: core on November 17, 2023, 12:56:15 pm
Hardware it's the same as HDO4000.
I think it's a matter of hacking.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on November 17, 2023, 01:00:09 pm
Hardware it's the same as HDO4000.

I don't think so. The DHO4000 has dual ADCs twice the sample rate too, and active probe interfaces.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: core on November 17, 2023, 01:02:13 pm
Hardware it's the same as HDO4000.

I don't think so. The DHO4000 has dual ADCs too, and active probe interfaces.


There is a teardown on Dave's Youtube channel, the input stage is the same. Even the 50 ohm path is there.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Antonio90 on November 17, 2023, 01:02:34 pm
You also get internal 50 Ohm termination.

Are you sure? I don't think the DHO1000 has that; the DHO4000 might.

Well, not really, as I haven't read the datasheet or manuals, but the images on Rigol.eu say so.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on November 17, 2023, 01:11:35 pm
You also get internal 50 Ohm termination.

Are you sure? I don't think the DHO1000 has that; the DHO4000 might.

Well, not really, as I haven't read the datasheet or manuals, but the images on Rigol.eu say so.

It looks like they have dropped this feature late in the game. There's no mention of 50 Ohm inputs in the datasheet. And while the manual has a section on "Selecting the input impedance", all that section says is that there's a fixed 1 MOhm impedance only. (But then there is a leftover sentence in the section on AC/DC setting stating that 50 Ohm impedance always forces DC coupling...)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on November 17, 2023, 05:12:52 pm
Who's going to be brave enough to buy one and find out if it has 50 Ohm when you change it to a DHO4000?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on November 17, 2023, 05:51:27 pm
We already have a DHO1000/4000 Thread... ;)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: bobxyz on November 17, 2023, 06:02:42 pm
Can anyone comment on the web browser interface of the DHO814 versus the Siglent SDS1104X-E?
- Does it behave exactly the same as using the scope's touchscreen (or mouse) directly?
- What resolution does it support - just 1024x600 (or 800x480 for the Siglent) or is higher resolution available?
- Does it run at full speed, or is the update rate noticeably slower?

[background: I'm looking for a small quiet desktop scope for hobbyist use - generally 2-layer PCB debug, mostly digital with small amounts of analog conditioning circuits.  I have a couple old LeCroy scopes in the closet if I need high bandwidth, but the LeCroys are big and noisy.  Most of my debug time is spent in front of the PC on my bench - updating code, taking notes, viewing documentation, etc.  Having good web based control of the scope makes the debug and documentation (screenshots) faster and easier.]
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on November 17, 2023, 06:08:15 pm
Can anyone comment on the web browser interface of the DHO814 versus the Siglent SDS1104X-E?
- Does it behave exactly the same as using the scope's touchscreen (or mouse) directly?

Yes.

- What resolution does it support

The same as the 'scope.

Does it run at full speed, or is the update rate noticeably slower?

Pretty much full speed.

[background: I'm looking for a small quiet desktop scope for hobbyist use - generally 2-layer PCB debug, mostly digital with small amounts of analog conditioning circuits.  I have a couple old LeCroy scopes in the closet if I need high bandwidth, but the LeCroys are big and noisy.  Most of my debug time is spent in front of the PC on my bench - updating code, taking notes, viewing documentation, etc.  Having good web based control of the scope makes the debug and documentation (screenshots) faster and easier.]

It's also very easy to take screenshots and record videos via the web interface.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: skander36 on November 17, 2023, 07:07:36 pm
We already have a DHO1000/4000 Thread... ;)
Indeed, and there has been said that the 50 ohm cand be activated with vendor.bin method as so the 800 MHz BW. But no real use without 2 ADC as the signal is halved and processed weird. 
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on November 17, 2023, 11:28:44 pm
Can anyone comment on the web browser interface of the DHO814 versus the Siglent SDS1104X-E?
1- Does it behave exactly the same as using the scope's touchscreen (or mouse) directly?
2- What resolution does it support - just 1024x600 (or 800x480 for the Siglent) or is higher resolution available?
3- Does it run at full speed, or is the update rate noticeably slower?

1: Yes
2: 1280x800 (Rigol)
3: Slower, I´m having a kind of lagging sometimes although my DHO is directly conecting via LAN cable.
But it´s not a kind of showstopper, I like to control the DHO while I´m sitting in my livingroom.. ;)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: voltsandjolts on November 18, 2023, 10:38:07 am
It seems that a Black Friday for DHO1000 will start soon :
https://www.rigol.eu/NEWS/news/58.html (https://www.rigol.eu/NEWS/news/58.html)
with 40% discount it sounds interesting vs DHO800 ...

RIGOL DHO1074 £620 on sale now it seems...
https://www.amazon.co.uk/DHO1074-Digital-Oscilloscope-channel-warranty/dp/B0BJ31PHLN (https://www.amazon.co.uk/DHO1074-Digital-Oscilloscope-channel-warranty/dp/B0BJ31PHLN)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on November 18, 2023, 10:41:11 am
It seems that a Black Friday for DHO1000 will start soon :
https://www.rigol.eu/NEWS/news/58.html (https://www.rigol.eu/NEWS/news/58.html)
with 40% discount it sounds interesting vs DHO800 ...

RIGOL DHO1074 £620 on sale now it seems...
https://www.amazon.co.uk/DHO1074-Digital-Oscilloscope-channel-warranty/dp/B0BJ31PHLN (https://www.amazon.co.uk/DHO1074-Digital-Oscilloscope-channel-warranty/dp/B0BJ31PHLN)

Somebody's dumping inventory.

I wonder what's in the pipeline?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on November 18, 2023, 12:36:26 pm
See my post in the suitable thread, this is a sale of the old designations, I don't think it means anything more.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: voltsandjolts on November 18, 2023, 03:03:51 pm
See my post in the suitable thread, this is a sale of the old designations, I don't think it means anything more.

I concur, there was likely some legal agreement with the HDO trademark owner that all Rigol HDO branded scopes be removed from the market by a certain date, perhaps end of this year.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on November 18, 2023, 03:05:50 pm
You could say that, Thank you Lecroy  ;D
Title: Noise characterization
Post by: zrq on November 18, 2023, 03:47:06 pm
I did some characterization of the input voltage noise of my DHO914S (250 M BW unlocked) at the full sampling rate (1.25 Gsps). Input shorted and scope is warmed up for ~1 hour.
[attach=1]
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: DaneLaw on November 19, 2023, 12:41:39 am
DHO800 it's OK as functionality, but the effective screen size is very small. The all-time active menus takes a lot of space. 10 inch is much better for this interface.

Also, the USB-C power supply connector it's not on my taste.
Yep. the DHOxxx vertical-screen aspect is undermined quite a bit by menus & info boxes..

From users-screenshots, it looks to be up around 35%?  That's a lot of your precious" vertical screen when you're dealing with a 7" that is in a 16/9 ratio that is already vertically cramped if you can't remove some of these top & bottom boxes.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on November 19, 2023, 12:48:18 am
DHO800 it's OK as functionality, but the effective screen size is very small. The all-time active menus takes a lot of space.

It's easy to imagine that but I bet you won't even think about it after you use one for a few weeks.

You really have to see one in person to appreciate the tiny size.

From users-screenshots, it looks to be up around 35%?

Ditto.

That's a lot of your precious" vertical screen when you're dealing with a 7" that is in a 16/9 ratio that is already vertically cramped if you can't remove some of these top & bottom boxes.

But this 'scope does a lot of things horizontally.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on November 19, 2023, 01:09:14 am
The DS1000Z wastes more space in the display, so in general you can either get by with the 7" or not.

Quote
t's easy to imagine that but I bet you won't even think about it after you use one for a few weeks.

Exactly that.
I've often said elsewhere that it makes a difference whether you try something out yourself or just read about it, look at pictures and watch videos... ;)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Mechatrommer on November 19, 2023, 03:44:12 am
screen is small if you want read pdf with it, but its not a pdf reader. once you try to debug a real circuit, even 4" screen is better than none at all.most reviews are imho only aeshetic or try to compare it with 27" screen entertainment machine.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: NE666 on November 19, 2023, 08:58:58 am
See my post in the suitable thread, this is a sale of the old designations, I don't think it means anything more.

Plausible but I'd be more secure in that belief if it were not for the announcement of the 1000U model.

Might it not be the case that lower than expected sales revenue from the 1000 series has forced Rigol to look at its BOM cost, being just a DAC short of the considerably more expensive 4000, the result being the cost-reduced 1000U which will ultimately replace it in the product line?

Just a theory but the product line is starting to look very crowded already without yet another low-end 12-bit.  FWIW the signal generator range seems to be suffering the same, with the 800/900 Pro announcement.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on November 19, 2023, 10:12:27 am
800/900 Pro? Would you have a link?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: bulba99 on November 19, 2023, 10:33:06 am
800/900 Pro? Would you have a link?

https://www.rigol.com/products/products/waveform-generators (https://www.rigol.com/products/products/waveform-generators)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on November 19, 2023, 11:15:33 am
Ah, thank you. I had misunderstood and thought you were talking about the internal signal generators in the scope, and an upcoming change in their voltage or frequency range.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on November 19, 2023, 09:32:35 pm
I have just had another go at decoding, this time feeding in the signal(SPI) from the competitor's demoboard. >:D
After a few attempts, I managed to get a super-stable signal.
First with 3 channels, so CS included.
I used the "Pulse" trigger.
Then I looked to see if I could do the same with 2 channels and timeout.
Yes, but a few letters were missing, the solution was that the default timeout is 1µs, 8µs was then enough.
Finally I tried it with the SPI trigger.
This also enabled me to create a rockstable trigger with a timeout of 8µs.
Interesting:
In the SPI trigger menu you can only select MISO, but I had previously deactivated MISO in the decoder menu because it is not available on the demo board (only MOSI).
Conclusion:
The decoder signals on the siglentboard are also "bitchy"(like on the batronix board), but with the right settings the DHO achieves super stable decoding - very good. :-+
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on November 19, 2023, 09:48:49 pm
Hi @Martin72, I came across a thread in the German mikrocontroller.net forum (https://www.mikrocontroller.net/topic/539674) a while ago which discusses I²C decoding on the MSO5000. It is claimed there that the MSO5000 can only decode reliably when it does a surprisingly high amount of oversampling: Sampling at 50x the I²C bit rate is supposedly not enough for reliable decoding, 100x works.

That observation seems very surprising to me, and I am not sure it is correct. The modest DS1054Z -- while being very limited by the fact that it only decodes from screen memory -- can at least do that nicely as soon as it can resolve the bits in the I²C signal. Could you try with the DHO800 which degree of oversampling it needs, by either limiting the memory size or zooming out to a very slow time base? Thanks!
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on November 19, 2023, 10:04:41 pm
Can do it tomorrow with the batronix demoboard (I²C does not work on the siglent demoboard).
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: tautech on November 19, 2023, 10:52:37 pm
Can do it tomorrow with the batronix demoboard (I²C does not work on the my siglent demoboard).
FTFY  ;)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on November 19, 2023, 10:55:37 pm
Hehehe.... ;)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on November 20, 2023, 07:05:40 pm
I tested it with 20kbit data rate.
20KSa/s is too low, nothing is decoded.
It has to be 50Ksa/s to display anything meaningful.
However, you can't always play with the manual memory, everything under 1Mpt is dropped from 200ms/s.
Since the batronix board offers different data rates, I will probably test another, higher speed.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on November 20, 2023, 07:09:10 pm
I tested it with 20kbit data rate.
20KSa/s is too low, nothing is decoded.

Well, obviously...

20kbit data rate means the clock signal is changing 40k times per second.

How will you capture that with 20kSa/s?

It has to be 50Ksa/s to display anything meaningful.

Working at 50kSa/s is quite impressive. It's only 20% above the minimum requirement.

(and the "minimum" still means you have to get lucky with the sample alignment)

Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on November 20, 2023, 07:15:50 pm
It has to be 50Ksa/s to display anything meaningful.

Working at 50kSa/s is quite impressive. It's only 20% above the minimum requirement.
(and the "minimum" still means you have to get lucky with the sample alignment)

Agreed, that's a pretty convincing implementation.  :-+
Thank you for testing, Martin!
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on November 20, 2023, 08:39:42 pm
Quote
How will you capture that with 20kSa/s?

It was only for demonstration... ;)
See the previous question from ebastler.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on November 20, 2023, 09:01:43 pm
Now the data rate has been increased from 20kbits to 200kbits.
It needs 500KSa/s to decode this properly, very good.
I noticed this briefly when I was playing around earlier(with the lower datarate), but didn't go into it.
Now I noticed it again:
2.5MSa/s flawless decoding
1.25MSa/s NO decoding
500KSa/s flawless decoding again.
Interesting....
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on November 20, 2023, 09:12:54 pm
Now the data rate has been increased from 20kbits to 200kbits.
[...]
2.5MSa/s flawless decoding
1.25MSa/s NO decoding
500KSa/s flawless decoding again.
Interesting....

I'd say that is another entry for the bug thread.  :-BROKE

Some of the addresses are still decoded correctly at 1.25 MSa/s (but most of them are not). But not a single letter? What does it look like if you zoom in, so that individual characters can be displayed on the decoder trace?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on November 20, 2023, 09:46:41 pm
Nothing gets better, I think because of the scarce 100Kpts.
But:
As usual, 1.25MSa/s, 5ms/div. nothing is displayed correctly.
Then press stop and increase to 10ms/div - now it is displayed correctly.
It gets even better, back to 5ms nothing displayed, then to 2ms...it is displayed correctly.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on November 20, 2023, 10:04:47 pm
:o
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on November 23, 2023, 07:11:45 pm
An old friend has found his way here. ;)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on November 23, 2023, 07:18:50 pm
An old friend has found his way here. ;)

Looks a bit yellowish-stained in comparison... And I guess it will look old in many other ways too.  ;)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on November 23, 2023, 08:18:30 pm
Quote
Looks a bit yellowish-stained in comparison

In "real" it is even more yellowish looking.
In the group photo with all the scopes I currently have, the shiny display of the 804 stands out clearly.
When switched on, you notice the 7 (8?) years difference between the two UIs (804/DS1054Z).
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on November 23, 2023, 09:28:11 pm
Seems like the DHO800 screen is much brighter than the DS1054Z.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on November 23, 2023, 09:57:53 pm
The camera makes it look brighter, but yes, the display is also slightly brighter in "real life" at the same setting.
And, above all, clearer.
I don't have to compare much to realize that this is simply no longer a fair comparison.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on November 23, 2023, 10:14:19 pm
Bodnar pulse...Rigol doesn't seem to have always been so particular about bandwidth, if you look at the risetime of the 50Mhz scope. ;)
Otherwise, the respective display speaks for itself.
Speaking of the risetime measure, that's something I don't like about the new model.
This display of the measured value could be solved just as discreetly as with the 1054Z.
Or at least transparent without the whole rectangular "strip" on the side.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on November 23, 2023, 10:36:48 pm
Yes, the DHO800 is a bit wasteful with screen real estate. That's a general theme, I think -- UI elements that work well on the 10" screen (with 1280*800 pixels) still take up the same number of pixels, and hence a larger percentage of the screen.

By the way: In DHO1000 videos, I see that the curve display area is compressed horizontally when the results display pops up on the right. But your screenshot shows the results bar overlapping the grid area. Is there a switch somewhere where you can select the desired behavior?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on November 23, 2023, 10:48:49 pm
Quote
UI elements that work well on the 10" screen (with 1280*800 pixels) still take up the same number of pixels, and hence a larger percentage of the screen.

I can't remember what it was like with the 4204...I should still have screenshots though.

Quote
Is there a switch somewhere where you can select the desired behavior?

Good question, I´ll look for it.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on November 24, 2023, 06:21:53 pm
I took the 1104X-E home with me today, so I have a total of 5 different scopes here.
Well, the 2104X+ has to go back on Monday, but I can use the two smaller ones a bit longer.
Let's see what I can manage this weekend.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on November 24, 2023, 07:04:56 pm
What's left to test?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on November 24, 2023, 07:17:40 pm
I think I'm done with decoding, I would have to go through triggers again, then I would test the display of more complex signals, pass/fail test, then I wanted to test the menu navigation/user-friendliness again, see where the feature differences are between old and new scope, compare FFT, noise test I still wanted to do...
Oh, and go through the acquisitions, especially the ultra acquire mode, which I still haven't fully understood, except that it can produce beautiful graphics.
Just a few things like that.
I will compare it with the two other small ones as far as the equipment is concerned and then only "internally" for me, as long as nothing noticeable comes out of it.


Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on November 24, 2023, 07:18:48 pm
Quote
Is there a switch somewhere where you can select the desired behavior?
Good question, I´ll look for it.

There is nothing about this in the settings or in the manual.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on November 24, 2023, 07:43:05 pm
Quote
Is there a switch somewhere where you can select the desired behavior?
Good question, I´ll look for it.

There is nothing about this in the settings or in the manual.

Thanks for checking! Then either Rigol have chosen different ways to show the measurements + traces on the DHO800 vs 1000 -- which would make some sense given the different screen sizes. Or maybe the DHO800 version is the newer one and will show up on the 1000 with an upcoming formware update. (Or it has already and I was looking at older screenshots and videos.)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on November 24, 2023, 10:00:45 pm
Quote
which would make some sense given the different screen sizes.

I had looked at my "old" screenshots from February, I think that's exactly why.
You simply have enough screen width, with the 800 the boxes were not compressed and instead the window with the measurement results was made transparent.
But it's true, that could be taken over from the small model.
Something for the wish list...

@others : Here (starting at appx 1:15) you can clearly see the compression when activating the sidebar:

https://www.eevblog.com/forum/testgear/rigol-hdo1000-and-hdo4000-12bit-oscilloscopes-launched-in-china/msg4717715/#msg4717715 (https://www.eevblog.com/forum/testgear/rigol-hdo1000-and-hdo4000-12bit-oscilloscopes-launched-in-china/msg4717715/#msg4717715)

Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on November 26, 2023, 11:20:35 pm
The ultra acquire mode still leaves me baffled.
You can conjure up impressive images on the screen with it, but somehow that's about it.
I had sent various glitch signals to the scope, but they were more noticeable in normal mode and with the appropriate triggers than in ultra acquire mode.
On the contrary, the glitch is not visible in this mode.
If no one can provide me with a corresponding picture/test to the contrary, I will check off this mode as a gimmick.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on November 26, 2023, 11:35:09 pm
The ultra acquire mode still leaves me baffled.
You can conjure up impressive images on the screen with it, but somehow that's about it.

I think the idea is to see events "in context", ie. you can see the event and what came before/after it all on the same screen (in 3D or whatever).
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on November 26, 2023, 11:49:44 pm
The ultra acquire mode still leaves me baffled.
You can conjure up impressive images on the screen with it, but somehow that's about it.

I think the idea is to see events "in context", ie. you can see the event and what came before/after it all on the same screen (in 3D or whatever).

But in most time domain applications, you can also do that paging through conventional memory segments one at a time, and get a much better view of the signal in each segment.

I would agree that UltraAquire is mostly a gimmick, although you can certainly find specific use cases where the visual correlation of the neighbouring events is helpful. Analog TV images might look nice as a 3D landscape, or topographical scans or the like.  :)

EDIT: Once I get to actually use my new DHO1000, I will dig out my old homebuilt scanning tunneling micoscope! I was always too lazy to write proper PC software to visualize the acquired scanned profile, but UltraAquire should handle that job nicely.  8)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Neutrion on November 27, 2023, 01:55:38 pm
Today I tested the waveform updaterate.
Based on the first table of rf-loop measurements, with a sine of 600mVpp and frequencies from 1khz up to 40Mhz.
As you know, with rigol you can't make any settings regarding vector/dots or lin / sinx/x, it only works as it is.
Memory mode is set to Auto, beforehand I made sure that the aux output is actually set to trigger out.
The trigger out signal has an amplitude of 3.3V and a single pulse width of 100ns.
The updaterates appear as bursts with pauses in between, which was to be expected.

(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1929924;image)

Things worth noting:
from 5ns to 500ns the rate remains almost constant, between 1µs and 5µs it drops only slightly and between 5µs and 20µs it shows the halving at every timebase change that I know of.
But then from 50µs it drops drastically from 4 digits to 2 digits, for whatever reason.
The early minimisation of the sample rate is also interesting, it is already reduced from 100µs.
The memory points remain constant at 625 kpts from 50 µs - only at 500 µs does it rise again to 781.25 kpts and then drop again to 625 - whatever triggers this, especially as 781.25 is a rather crooked number.
I will have a look at the ultra acquiremode, how to use it and then create a table from it.
First attempt was "unsuccessful", I also had max 20000wfms/s in ultra mode.
Can't be right, so I'll look for what went wrong.

Hi Martin!
Thanks for the waveform update test, but the problem with it is, that the memory depth what you got
set is much lower then the advertised aviable memory of the scope, so these numbers do not
allow a real comparison with other scopes in the same price range, or similar mem depth.
To not to talk about allowing more than one channel which would be obvious with a four channel scope.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on November 28, 2023, 07:08:27 am
Setting was auto-memory management.
If I wanted to make a direct comparison, I would have to have the same circumstances, otherwise it makes no sense.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Randy222 on November 28, 2023, 05:35:21 pm
Been watching lots of write-ups and vids on DHO800 series.

Am I correct on this, getting the 804 to the 814 via "upgrades" is easy?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Neutrion on November 28, 2023, 05:56:22 pm
Setting was auto-memory management.
If I wanted to make a direct comparison, I would have to have the same circumstances, otherwise it makes no sense.
Yes I know, but the point was to know how does it work with the advertised memory enabled. I think with a few kpoints the 1104x-e could also get to some astronomical numbers.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on November 28, 2023, 06:15:46 pm
Been watching lots of write-ups and vids on DHO800 series.

Am I correct on this, getting the 804 to the 814 via "upgrades" is easy?

Yes...Look into the hack thread.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on November 28, 2023, 10:29:26 pm
Working with the DS1054Z is like traveling backwards in time. ;)
I hadn't noticed this before, but now, with the DHO804 in direct comparison, I have to say:
Farewell and thank you for once arousing my interest in a private scope and fulfilling my wish to own one.
But your time is simply up, no one should buy you anymore, given the DHO800.
A small example of how it could not be more drastic.
50mV/div, then stop, then enlarged to 20mv/div.
As I said, time's up.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Randy222 on November 29, 2023, 07:14:29 pm
Sorry if I missed it, what is the -3db of the 804 when brought up to 814 100MHz level? Is it near 185MHz?

Also, if ch1 triggers from ch4, can you still get full 1.25Gsa/s on ch1 ?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on November 29, 2023, 09:48:03 pm
Hi Randy,

Measured -3dB point lies on 200Mhz.

Quote
Also, if ch1 triggers from ch4, can you still get full 1.25Gsa/s on ch1 ?

Just tested it - samplerate will be then reduced to half although only one channel is active..
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on November 29, 2023, 10:31:34 pm
Sorry if I missed it, what is the -3db of the 804 when brought up to 814 100MHz level? Is it near 185MHz?

It's exactly 199Mhz.

Also, if ch1 triggers from ch4, can you still get full 1.25Gsa/s on ch1 ?

No.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: tautech on November 29, 2023, 10:34:43 pm
I'm still waiting for an explanation of the Siglent's FFT problems shown in Dave's review of the DHO800...
It has been revealed Dave can't drive FFT properly.
https://www.eevblog.com/forum/testgear/siglent-sds1104x-e-in-depth-review/msg5195079/#msg5195079 (https://www.eevblog.com/forum/testgear/siglent-sds1104x-e-in-depth-review/msg5195079/#msg5195079)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on November 29, 2023, 11:10:06 pm
I'm still waiting for an explanation of the Siglent's FFT problems shown in Dave's review of the DHO800...
It has been revealed Dave can't drive FFT properly.
https://www.eevblog.com/forum/testgear/siglent-sds1104x-e-in-depth-review/msg5195079/#msg5195079 (https://www.eevblog.com/forum/testgear/siglent-sds1104x-e-in-depth-review/msg5195079/#msg5195079)

Why are you telling me? Take it up with Dave.

All I know is that Dave got it working on the Rigol, he got it working on the R&S, if he failed on the Siglent then there's a problem with the Siglent. Either in the UI or the implementation.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Randy222 on November 30, 2023, 02:00:04 pm
Hi Randy,

Measured -3dB point lies on 200Mhz.

Quote
Also, if ch1 triggers from ch4, can you still get full 1.25Gsa/s on ch1 ?

Just tested it - samplerate will be then reduced to half although only one channel is active..
Arrrrg.

I assume then if the device does 1/2 on sample rate you will get 2x the record length when capturing for any given memory depth?

Does the 2ch w/ ext have the same issue when using ext as the trigger?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on November 30, 2023, 08:07:25 pm
Quote
Why are you telling me? Take it up with Dave.

Dave wasn't the one crowing all over the place that the siglent had a problem with the FFT...
This has now been readjusted three times with three different 1104X-Es, without any problems.
Speaking of problems, I had another hitch with the rigol after a long time, this time a "half".
Happened when I had the FFT function active to recreate the gimmicks, with FM mod and so on.
Suddenly the FFT display disappeared and didn't come back.
The signal itself was strangely discolored and you couldn't resolve it any further, the time base setting was out of order.
Very strange.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: gf on November 30, 2023, 08:20:11 pm
12.5 MSa/s implies a 0...6.25MHz maximum span, therefore the 10MHz center is out of range.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on November 30, 2023, 08:24:24 pm
Yes, that's right - But that was displayed when the crash occurred, before that it was much more, or rather, I had taken the picture at that point by chance - It was 12.5MSa/s everywhere when the scope "froze".
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on November 30, 2023, 09:08:54 pm
I think I've figured it out.
At 5ms/div the FFT disappears, correctly because the sample rate is then too low.
But it comes back when enough sample rate is available - from 2ms.
But earlier it didn't come back and the scope was permanently stuck at 12.5MSsa/s.
So don't play around with it too much... ;)
Otherwise, the FFT function behaves in the same way as its big brother, the 4204.
In other words, hardly anything can be set, no different modes, which is a particular pity that there is no averaging.
And what I already noticed in February with the 4204 is also present here.
Generator with wavecombine function, 10Mhz frequency, ch1 10Vpp, ch2 1mVpp 10.1Mhz frequency, 50Ohm termination.
I have done this with another scope with a "flattop" window and it works perfectly.
With Rigol it looks different when you switch from Hanning to Flattop.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on December 01, 2023, 08:48:36 am
hardly anything can be set, no different modes, which is a particular pity that there is no averaging.

The absence of averaging is clearly a gap. Makes the FFT output so much cleaner, and makes signals clearly visible that you otherwise have to guess at -- and it should be easy to implement. I think it's catching up with Rigol here that they implemented Averaging as an acquisition mode (only), not as a math function. That's a nice solution when you want to use Averaging on time-domain signals: no overhead and conveniently activated. But it means that averaging is not available post-FFT. A dedicated option would be needed there.

Besides that, I am struggling with the "hardly anything can be set" complaint. Span and Center are set directly in the FFT dialog; sampling rate and record length are set via the time base and memory size in my understanding. Are there critical parameters which can't be adjusted at all? Or is the complaint that the settings are not as clear and direct as one would like? -- Not aiming to defend the Rigol scopes here; I would like to better understand what is missing (or awkward). Thanks!

Quote
With Rigol it looks different when you switch from Hanning to Flattop.

Looks like the Flat-top window function is plainly broken on the Rigol. It is just that particular window function which gives the unexpected results, right? Maybe they don't deal with the negative weights properly? Looks like a bug.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on December 01, 2023, 08:53:36 am
FFT center and span are really easy to set on a touch screen...

Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on December 01, 2023, 09:44:54 am
Quote
Besides that, I am struggling with the "hardly anything can be set" complaint.

Deepl translation error..
There is nothing to complain about in the menu operation, on the contrary, I think it is one of the most successful menu structures at the moment.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on December 01, 2023, 09:53:51 am
Quote
Besides that, I am struggling with the "hardly anything can be set" complaint.

Deepl translation error..
There is nothing to complain about in the menu operation, on the contrary, I think it is one of the most successful menu structures at the moment.

I didn't understand it as "it is hard to set anything", but as "there are not enough things which can be set". Is there something in the FFT which you would like to adjust but can't?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: iMo on December 01, 2023, 10:15:48 am
Working with the DS1054Z is like traveling backwards in time. ;)
I hadn't noticed this before, but now, with the DHO804 in direct comparison, I have to say:
Farewell and thank you for once arousing my interest in a private scope and fulfilling my wish to own one.
But your time is simply up, no one should buy you anymore, given the DHO800.
A small example of how it could not be more drastic.
50mV/div, then stop, then enlarged to 20mv/div.
As I said, time's up.

Hmm, what I see is the 1054Z shows the raw voltage (60 points with the steps), the DHO shows the sinc interpolation (through the 64 points). You cannot judge on the resolution based on that pictures, imho..
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: TurboTom on December 01, 2023, 11:15:28 am
I guess the engineers at Rigol confused the Flattop window function with the Tukey window which actually has a flat top in the time domain, maybe a language thing... Wouldn't worry too much about this since the most relevant window functions von Hann, Blackman-Harris and rectangular are available and appear to work correctly. A hint for using FFT on DHO scopes: don't use auto sampling depth but rather choose a fairly high number (at least at 1MPts the FFT still utilizes the full memory). Only if very fast FFT update rate is required at reduced available RBW, it makes sense to select less sample memory since Rigol's FFT engine is pretty fast anyway.

True, it's a pity that FFT avaraging isn't available (yet) -- Rigol should have included this instead of this color-grading FFT display nonsense (available on DHO1000 series, don't know if it's included in the DHO800 as well), but otherwise I don't find the FFT U/I too troublesome or unlogical to use. It's possible to get pretty decent results easily. And since sales for the anticipated high-quantity instrument range just started, we may actually see some reasonable firmware-polishing in future. At least I've still got some hope for this...  ;)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on December 01, 2023, 12:09:47 pm
A hint for using FFT on DHO scopes: don't use auto sampling depth but rather choose a fairly high number (at least at 1MPts the FFT still utilizes the full memory). Only if very fast FFT update rate is required at reduced available RBW, it makes sense to select less sample memory since Rigol's FFT engine is pretty fast anyway.

I assume the DHO1000 has the same somewhat haphazard "RBW" indication as the DHO800 -- did you manage to figure out what it means?

I am not concerned with the precise naming (should it be "RBW", "resolution", "frequency interval" or whatever). But can you tie it back to the sampling rate and number of FFT data points in a systematic way? Does it depend on the choice of window function too? And what is the missing unit -- is it always Hz?

Thanks for your insights!
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on December 01, 2023, 12:51:46 pm
Quote
Is there something in the FFT which you would like to adjust but can't?

Number of points for example, I'm used to being able to manually set the number of memory points (which are also not displayed on the rigol).
And RBW means resolutionbandwith, and the unit Hz is omitted on the rigol, depending on the situation, I didn't pay close attention to when this happens.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on December 01, 2023, 12:57:57 pm
color-grading FFT display nonsense (available on DHO1000 series, don't know if it's included in the DHO800 as well),

It is, and you can do it in multiple windows.  :)

(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1914873;image)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on December 01, 2023, 01:02:48 pm
It is, and you can do it in multiple windows.  :)

But it still is just a color banding depending on the vertical position, right? Reminds me of those old video games with a transparent, colored screen overlay, before color monitors became affordable. 8)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Performa01 on December 01, 2023, 01:22:51 pm
The absence of averaging is clearly a gap. Makes the FFT output so much cleaner, and makes signals clearly visible that you otherwise have to guess at -- and it should be easy to implement. I think it's catching up with Rigol here that they implemented Averaging as an acquisition mode (only), not as a math function. That's a nice solution when you want to use Averaging on time-domain signals: no overhead and conveniently activated. But it means that averaging is not available post-FFT. A dedicated option would be needed there.
Average acquisition mode and/or math function are something completely different than averaging of an FFT trace.

Full featured DSOs have Average as
1.   Acquisition mode, yet with reduced max. memory depth
2.   Math function
3.   Substitute for VBW setting of an SA for the FFT traces.

All three could be used at the same time, yet the value of this would be questionable.

The SDS1104X-E provides 1 and 3 from the list above.


Besides that, I am struggling with the "hardly anything can be set" complaint.
I do not know what can be set in the DHO, maybe Martin will enlighten us. Yet there are other maybe even more important things.

For instance, am I the only one who wonders how the “RBW” can always be “100” (without dimension), regardless of the window function?

From the sparse info on the screen we get that the FFT sample rate is 62.5 MSa/s. We don’t know the number of FFT points, so we can only assume it’s the same as the record length, which is displayed as 625.00 kpts. What a coincidence that the frequency step happens to be exactly 100 Hz in this case. And of course the frequency step is independent of the window function. The RBW on the other hand can be anything from 90 Hz to 380 Hz, hence the info on the FFT is not only misleading but plain wrong. Hardly a professional touch…


Looks like the Flat-top window function is plainly broken on the Rigol. It is just that particular window function which gives the unexpected results, right? Maybe they don't deal with the negative weights properly? Looks like a bug.
Who cares? As long as you can browse the web and play doom on it. You just need to get aware of the real priorities in T&M…

Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on December 01, 2023, 01:34:06 pm
Average acquisition mode and/or math function are something completely different than averaging of an FFT trace.

Full featured DSOs have Average as
1.   Acquisition mode, yet with reduced max. memory depth
2.   Math function
3.   Substitute for VBW setting of an SA for the FFT traces.

But if a Math function 2. were available which averages over successive sweeps, couldn't it be be applied to the FFT to obtain 3.?

Quote
For instance, am I the only one who wonders how the “RBW” can always be “100” (without dimension), regardless of the window function?

From the sparse info on the screen we get that the FFT sample rate is 62.5 MSa/s. We don’t know the number of FFT points, so we can only assume it’s the same as the record length, which is displayed as 625.00 kpts. What a coincidence that the frequency step happens to be exactly 100 Hz in this case. And of course the frequency step is independent of the window function. The RBW on the other hand can be anything from 90 Hz to 380 Hz, hence the info on the FFT is not only misleading but plain wrong. Hardly a professional touch…

As stated in my questions to TurboTom, a few posts above, I have been wondering that too. If the only flaw in the displayed "RBW" is that it is not actually an RBW but a frequency step, I can live with that (although Rigol should fix it, of course, and add a unit while they are at it). But I did see some screenshots or videos earlier where unexpected "RBW" values were displayed, which did not seem to make sense even as a frequency step and assuming a Hz unit. Maybe Tom or Martin can shed some light onto whether and when this happens?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on December 01, 2023, 01:41:05 pm
Quote
Besides that, I am struggling with the "hardly anything can be set" complaint.

Deepl translation error..
There is nothing to complain about in the menu operation, on the contrary, I think it is one of the most successful menu structures at the moment.

I didn't understand it as "it is hard to set anything", but as "there are not enough things which can be set". Is there something in the FFT which you would like to adjust but can't?

FFT settings:

Parameter | Factory Settings

Operation | OFF
Source | CH1
X | Span-Center
Unit | dBm/dBV
Center Frequency | 5 MHz
Frequency Range | 10 MHz
Vertical Scale | 20 dB
Offset | 0 dBV
Window Function | Hanning
Color Grade | OFF

Peak Search | OFF
Peak Number | 5
Threshold | 5.5 dBV
Excursion | 1.8 dB
Order | Amp Order


This is not FFT. This is some kind of simplified Spectrum view.
There are no settings for :

1. FFT mode : Normal, Average, Max Hold (at least)
2. Number of points/bins
3. RBW cannot be set. It is displayed in window title (which by the way is not visible if you do multiple windows, negating the benefit) and is some kind of  function of timease. You twiddle timebase left and right until you like how it looks.

Problems with flattop window are not irrelevant. It is used for best amplitude accuracy, when trying to measure peaks amplitude.

Taking into account this simple cheap scope, I will not talk about  markers and all the stuff connected to it.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on December 01, 2023, 01:42:30 pm
Quote
Is there something in the FFT which you would like to adjust but can't?

Number of points for example, I'm used to being able to manually set the number of memory points (which are also not displayed on the rigol).

I thought that's set via the acquisition memory setting (up to 1 MPts)? Is the issue that it's not in the FFT dialog, or that the available steps are too coarse? Or does that setting not actually set the number of FFT points at all?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on December 01, 2023, 01:47:35 pm
1. FFT mode : Normal, Average, Max Hold (at least)
2. Number of points/bins
3. RBW cannot be set. It is displayed in window title (which by the way is not visible if you do multiple windows, negating the benefit) and is some kind of  function of timease. You twiddle timebase left and right until you like how it looks.

1. I think we all agree that lacking Average mode is an annoying omission, as discussed separately above. I don't know about the relevance of Max Hold mode, but that's probably due to my lack of knowledge about some applications (regulatory/EMC maybe?).

2. As discussed, it's set via the acquisition memory size in my understanding. That way of doing it may be lacking something; see my questions to Martin just above.

3. Now I am confused. If you choose the window function, record length and sampling rate -- how can you set the RBW independently?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on December 01, 2023, 01:51:57 pm

As stated in my questions to TurboTom, a few posts above, I have been wondering that too. If the only flaw in the displayed "RBW" is that it is not actually an RBW but a frequency step, I can live with that (although Rigol should fix it, of course, and add a unit while they are at it). But I did see some screenshots or videos earlier where unexpected "RBW" values were displayed, which did not seem to make sense even as a frequency step and assuming a Hz unit. Maybe Tom or Martin can shed some light onto whether and when this happens?

Basic problem is that this is a measurement instrument but nobody knows what it shows.

If it measures and shows kilobananas then say that so user knows.

If RBW is RBW in a SA sense then it should be configurable and documented how it does rescaling.
If they use RBW for frequency bin width, that is simply wrong.

Also since real FFT parameters are not shown, and RBW is aparently dimensionless number, how you know it is correct in what it shows. And since you can see how the rest of the scope is tested, at this point I would not trust FFT for any measurements.
Until this is untangled, FFT is simply a graphical visualization, like Fungus nicely shows in his multi window image. You have 3 spectrum windows without basic parameters shown. You know the window function used and resampled sample rate. nothing else.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on December 01, 2023, 01:57:14 pm
1. I think we all agree that lacking Average mode is an annoying omission, as discussed separately above. I don't know about the relevance of Max Hold mode, but that's probably due to my lack of knowledge about some applications (regulatory/EMC maybe?).

2. As discussed, it's set via the acquisition memory size in my understanding. That way of doing it may be lacking something; see my questions to Martin just above.

3. Now I am confused. If you choose the window function, record length and sampling rate -- how can you set the RBW independently?

1. Max hold is as much used as averaging. For instance frequency sweep..
2. Number of bins can be separate from sample rate and acquistion length.
3. I apologize for confusion. I mentioned RBW as it is now only thing they have. If they have RBW then it should be configurable like in a propper SA. In which case by setting RBW, scope changes number of bins to get close and then recalculates FFT bins to RBW bins taking into consideration used window.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on December 01, 2023, 02:04:55 pm
Basic problem is that this is a measurement instrument but nobody knows what it shows.

If it measures and shows kilobananas then say that so user knows.

If RBW is RBW in a SA sense then it should be configurable and documented how it does rescaling.
If they use RBW for frequency bin width, that is simply wrong.

Also since real FFT parameters are not shown, and RBW is aparently dimensionless number, how you know it is correct in what it shows.

Sorry, but I feel this did not add anything to the prior discussion besides negative emotions. Can we please keep separate matters separate, and be specific about them?

(a) What Rigol displays is apparently not RBW but frequency step, so they should fix either the label or the way the calculate it. Already said more than once.
(b) Of course it should always be displayed with a unit. Already said more than once.
(c) Which "real FFT parameters" are you missing? The number of FFT points, as already said more than once; what else?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on December 01, 2023, 02:09:39 pm
2. Number of bins can be separate from sample rate and acquistion length.

How would that be done? Doesn't the time resolution and length of the transformed time series define the spectral resolution and range of the FFT? Unless you do a piecewise FFT of partial segments of the time series, or preprocess the time series by averaging etc., of course.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on December 01, 2023, 02:21:14 pm

Unless you do a piecewise FFT of partial segments of the time series, or preprocess the time series by averaging etc., of course.


Exactly like that....
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: rf-loop on December 01, 2023, 02:22:56 pm
Just for satisfy some peoples curiosity, not compete with any,. Here one poor sample using SDS1204XHD (at this time it is China only model)
Around same kind of signals but need run low level LSB peak instead of USB  and 10MHz for keep generator high peak level around 20Vpp (because >10MHz can not this level) (Looks like this is bit too challenging for generator what I use  and it somehow produce also USB peak etc...  )

FFT F1  normal, and Hanning
FFT F2  Max Hold, Hanning
FFT F3  Average 16, Hanning
Eta: do not care Trigger setting in image. it is Auto and other things there do not matter anything here.

(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1941756;image)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Performa01 on December 01, 2023, 02:37:15 pm
Average acquisition mode and/or math function are something completely different than averaging of an FFT trace.

Full featured DSOs have Average as
1.   Acquisition mode, yet with reduced max. memory depth
2.   Math function
3.   Substitute for VBW setting of an SA for the FFT traces.

But if a Math function 2. were available which averages over successive sweeps, couldn't it be be applied to the FFT to obtain 3.?
I’m not sure if I understand correctly what you mean. Of course there is a difference whether we average the records, i.e. the waveform in the time domain, which are the basis for the FFT, or the converted math result (FFT) which is now in the frequency domain.

If you mean an advanced scope with math on math, where you want to apply averaging on the FFT result, either by two math traces where one acts as input for the other, or defined in a formula in a single channel. I’ve never tried it, but would not be surprised if FFT (which delivers a frequency domain result after all) would be about the only math function that cannot act as a source for other (time domain) functions.

Since Averaging is included in the FFT package anyway, why bother.


As stated in my questions to TurboTom, a few posts above, I have been wondering that too. If the only flaw in the displayed "RBW" is that it is not actually an RBW but a frequency step, I can live with that (although Rigol should fix it, of course, and add a unit while they are at it). But I did see some screenshots or videos earlier where unexpected "RBW" values were displayed, which did not seem to make sense even as a frequency step and assuming a Hz unit. Maybe Tom or Martin can shed some light onto whether and when this happens?
Yes, you can live with it – once you know what it actually means. It’s annoying nevertheless – and up to now, you only know what I have found out by accident. Rght now you’re expressing doubts what this dimensionless number actually is. I can only tell what I see in a few screenshots, so others will have to verify it.


Quote
Is there something in the FFT which you would like to adjust but can't?

Number of points for example, I'm used to being able to manually set the number of memory points (which are also not displayed on the rigol).

I thought that's set via the acquisition memory setting (up to 1 MPts)? Is the issue that it's not in the FFT dialog, or that the available steps are too coarse? Or does that setting not actually set the number of FFT points at all?
Yes, this is one possibility, but can’t you imagine situations, where you have to capture long records, exceeding 1 Mpts, yet want a shorter FFT, maybe to get a wider RBW?


1. FFT mode : Normal, Average, Max Hold (at least)
2. Number of points/bins
3. RBW cannot be set. It is displayed in window title (which by the way is not visible if you do multiple windows, negating the benefit) and is some kind of  function of timease. You twiddle timebase left and right until you like how it looks.

1. I think we all agree that lacking Average mode is an annoying omission, as discussed separately above. I don't know about the relevance of Max Hold mode, but that's probably due to my lack of knowledge about some applications (regulatory/EMC maybe?).

2. As discussed, it's set via the acquisition memory size in my understanding. That way of doing it may be lacking something; see my questions to Martin just above.

3. Now I am confused. If you choose the window function, record length and sampling rate -- how can you set the RBW independently?
Ad 2: see above.

Ad 3: Max Hold is at least as important as Averaging. It allows the scope to do frequency response plots. Other then Bode Plot, this can use the full bandwidth up to half the sample rate and it can plot the frequency response of the scope itself. The attached screenshot shows an example of a measurement graph demonstrating the frequency response of an SDS2000X Plus in 10 bit mode, that could not be produced otherwise.

(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1941765)
SDS2354X Plus_FR_BFull_1GSa_500MHz_10bit
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: TurboTom on December 01, 2023, 03:14:53 pm
RBW value that gets displayed on DHO1000 FFT screen is 3dB reolution bandwidth in units kHz. To me it appears that on the DHO800 screen, the RBW value is in units Hz but I may wrong.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: rf-loop on December 01, 2023, 03:29:09 pm
RBW value that gets displayed on DHO1000 FFT screen is 3dB reolution bandwidth in units kHz. To me it appears that on the DHO800 screen, the RBW value is in units Hz but I may wrong.

In DHO800 image by @Martin72 (Reply #956)  it looks that it is simply sample frequency / FFT length.  (62500000/625000=100)
And then there read just plain RBW:100   and also then same RBW even for Hanning and Flattop..  They did not use  window factor but print only Bin interval as RBW. RBW we normally think as Resolution Band Width.
Of course it can say it is RBWBins  but more commonly with spectrum analyzers etc we use RBW3dB  and for some purposes RBW6dB (example EMI measurements). But tightly speaking it is not absolute error to tell RBWBin but why then not tell it using example  Δf as example Siglent use what do not leave anything unclear. Also then can tell "normal" RBW also and its width depending used window. As can see example in my last image.

Well, if someone names it RBW, shame on him (Rigol) and even without a unit... well, what about the units of measurement... this is just a measuring device where guessing is part of the game. (sarc.)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: gf on December 01, 2023, 04:07:11 pm
Of course there is a difference whether we average the records, i.e. the waveform in the time domain, which are the basis for the FFT, or the converted math result (FFT) which is now in the frequency domain.

I'm just wondering: When does it make sense to average in the time domain instead of averaging the spectral power of the FFT bins?
I would always prefer the latter.
The former suffers from trigger jitter due to noise, which slightly misaligns the traces to be averaged.
OTOH, the sampling phase (or IOW the trigger point of the traces) does not matter at all for spectral power averaging.

Quote
The attached screenshot shows an example of a measurement graph demonstrating the frequency response of an SDS2000X Plus in 10 bit mode, that could not be produced otherwise.

(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1941765)
SDS2354X Plus_FR_BFull_1GSa_500MHz_10bit

What is the blue "Ref" trace?

In DHO800 image by @Martin72 (Reply #956)  it looks that it is simply sample frequency / FFT length.  (62500000/625000=100)

I agree with that. It is obviously just the FFT bin spacing, not the -3dB bandwidth of the corresponding spectrum analysis filter.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on December 01, 2023, 04:07:32 pm
If you mean an advanced scope with math on math, where you want to apply averaging on the FFT result, either by two math traces where one acts as input for the other, or defined in a formula in a single channel. I’ve never tried it, but would not be surprised if FFT (which delivers a frequency domain result after all) would be about the only math function that cannot act as a source for other (time domain) functions.

Since Averaging is included in the FFT package anyway, why bother.

Yes, that's what I meant. Agree, if there is a dedicated averaging mode in the FFT, nothing else is needed. I just wanted to confirm my understanding what Averaging FFT mode does, and whether a secondary math averaging function is equivalent (if it can be applied to the FFT result, of course). Thanks!

Quote
[...] can’t you imagine situations, where you have to capture long records, exceeding 1 Mpts, yet want a shorter FFT, maybe to get a wider RBW?

But what would the FFT operation do then? Split the long record into multiple segments, Fourier-transform them individually, and combine them via Averaging or Max Hold? If so, isn't that equivalent to setting a shorter record length in the first place and keeping the operation running?

(Honest question; I might be missing something.)

Quote
Ad 3: Max Hold is at least as important as Averaging. It allows the scope to do frequency response plots. Other then Bode Plot, this can use the full bandwidth up to half the sample rate and it can plot the frequency response of the scope itself. The attached screenshot shows an example of a measurement graph demonstrating the frequency response of an SDS2000X Plus in 10 bit mode, that could not be produced otherwise.

OK, thanks. So Max Hold would be used in scenarios where you sweep the input signal, as 2N3055 also suggested? It's a bit counter-intuitive to me that you would always do a full FFT during such a scan, rather than a Bode-plot style detection of the known fundamental frequency. If a system has strong distortion, say due to clipping, at a low input frequency, that might appear as an apparent response at a higher harmonic?

Anyway -- if it's a feature that is commonly available, it seems like an omission on Rigol's part not to implement it. Like averaging mode, it should be relatively low-hanging fruit.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Performa01 on December 01, 2023, 04:44:35 pm
I'm just wondering: When does it make sense to average in the time domain instead of averaging the spectral power of the FFT bins?
I would always prefer the latter.
The former suffers from trigger jitter due to noise, which slightly misaligns the traces to be averaged.
OTOH, the sampling phase (or IOW the trigger point of the traces) does not matter at all for spectral power averaging.
Of course it makes no sense to average the acquisitions before an FFT is applied. It kills all modulation and other dynamic effects.

Yet I think I need not stress how important Average acquisition mode and/or math function can be when we do not intend to do the FFT processing. This mode even allows the scope to act as an autocorrelator to clearly display weakest signals deeply buried in noise, if only we have a synchronous reference signal for the trigger available.

And no, trigger jitter absolutely isn’t a concern on these machines, thanks to the incorporation of a fully digital trigger system with proper trigger point interpolator. It is measured in the picoseconds...

What is the blue "Ref" trace?
That is the frequency response in the 2nd Nyquist zone, i.e. from 1 GHz – 500 MHz 😉

Title: Re: Rigol DHO804 Test and Compare Thread
Post by: dmulligan on December 01, 2023, 05:47:19 pm
The discussion about FFT has been very interesting and made me fire up my DHO804 to see what it can do.  I was disappointed when I couldn't select any of the math operations as a source.  I checked and according to the manual FFT on the DHO800 only works with one of the 4 channels as the source.  It doesn't work from either a math or reference source.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Performa01 on December 01, 2023, 06:12:38 pm
Quote
[...] can’t you imagine situations, where you have to capture long records, exceeding 1 Mpts, yet want a shorter FFT, maybe to get a wider RBW?

But what would the FFT operation do then? Split the long record into multiple segments, Fourier-transform them individually, and combine them via Averaging or Max Hold? If so, isn't that equivalent to setting a shorter record length in the first place and keeping the operation running?

(Honest question; I might be missing something.)
Don’t make it more complicated than it is. We can of course just select the record length so that it makes for the desired FFT length.
We can also take the freedom to select the record length using one criterion and a different criterion for the FFT length. What’s wrong with that?

Of course the record length cannot be shorter than the FFT length. But it could be way longer.
As to the question what happens then – the same what happens whenever we capture e.g. 10 Mpts but have only 1 Mpts FFT available. The data gets decimated before FFT processing.


OK, thanks. So Max Hold would be used in scenarios where you sweep the input signal, as 2N3055 also suggested? It's a bit counter-intuitive to me that you would always do a full FFT during such a scan, rather than a Bode-plot style detection of the known fundamental frequency. If a system has strong distortion, say due to clipping, at a low input frequency, that might appear as an apparent response at a higher harmonic?
Just because we can always find a scenario where something might not work well, this doesn’t make a certain feature less valuable. In my example it worked just perfect.

Of course we don’t have a frequency synchronous measurement and yes, because of the very high dynamic range of the FFT we can see the harmonics as false signals even from sources with low distortion – but these spurious signals get overwritten in most wideband measurements anyway – except for the cases where we want to measure the stop band of a LP filter of all things.

If we stick to a decent signal source (AWG or signal generator) the harmonic level shouldn’t be much of a problem.  And if it still is, we can do a separate scan for the stop band alone - there are so many ways to solve a problem. Finding solutions is the main job of engineers, by the way. But for this, they need reliable tools and the knowledge how to use them properly – which includes a clear judgement what is going to work and what is not.

Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on December 01, 2023, 06:14:19 pm
Hi,
I just wanted to go through various time bases and capture the displayed values in the FFT window via screenshot, once with automemory, once with max memory.
But there are already inconsistencies at the beginning...
I started with 2µs/div., was over at 10µs, went back to 10µs/div.
And I have 2 different resolutions (RBW)
How does that work... ???
Oh yes, the unit Hz is not displayed at any time.
Instead, there are decimal numbers such as 19.99k, and a sample rate of 1.26GSa/s was also displayed...
I'll continue, but here are two pictures with the different RBW with the same time base
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Performa01 on December 01, 2023, 06:23:27 pm
The discussion about FFT has been very interesting and made me fire up my DHO804 to see what it can do.  I was disappointed when I couldn't select any of the math operations as a source.  I checked and according to the manual FFT on the DHO800 only works with one of the 4 channels as the source.  It doesn't work from either a math or reference source.
It cannot do an FFT on reference traces, because these are heavily decimated (maybe even screen) data. You would need so called Memory Traces for this, which are similar to Reference traces, but with the the original data, hence original sample rate.

It's similar for math traces. Math channels as a source for math (aka math on math) is an advanced feature, and makes mostly sense in scopes that work on undecimated data for the math.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: gf on December 01, 2023, 07:25:59 pm
Wouldn't worry too much about this since the most relevant window functions von Hann, Blackman-Harris and rectangular are available and appear to work correctly.

I would. A flattop window is important to get good amplitude accuracy for frequencies that are not integer multiples of the bin spacing. The maximum amplitude error of the flattop window 1) is only 0.016 dB. Hann, Blackman and various others still have significant scalopping loss for frequencies that fall in the middle between two bins. Blackman-Harris has also ~0.83 dB. And a rectangular window leaks as hell if the frequency is not an integer multiple of the bin spacing.

1) I consider the Matlab variant here, but there exist several other variants too
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on December 01, 2023, 08:02:45 pm
Don’t make it more complicated than it is. We can of course just select the record length so that it makes for the desired FFT length.
We can also take the freedom to select the record length using one criterion and a different criterion for the FFT length. What’s wrong with that?

Nothing wrong with that, of course. But on the other hand, I can't see where the serious omissions in adjustable parameters are in Rigol's FFT implementation. That's what I was trying to understand, after hearing that complaint many times from the Siglent crew.

It seems to me that you can adjust all relevant parameters on the Rigol: Record length and sampling interval (and hence FFT frequency step) via the scope's regular acquisition and horizontal controls; center frequency and span via the FFT dialog (and the touch screen too).

I get the impression that there is mainly a difference in approach here: Rigol sees this as a regular time series acquisition, with its standard controls, followed by a specific math operation -- while Siglent pulls all parameters together in an FFT-specific menu, to make FFT mode behave similar to a spectrum analyzer.

Having said that -- yes, Rigol's displayed "RBW" is not an RBW and lacks a unit, and Rigol really should implement Averaging and Max Hold modes! I hope they do that sooner rather than later...
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on December 01, 2023, 09:04:36 pm
Quote
I hope they do that sooner rather than later...

Just had a look, even the MSO8000A does not offer more than what the DHO800 offers in terms of FFT.
But at least the unit is given with RBW, although I know this from the MSO5000 as well.
Apart from that, if you can't set the number of points, it would be great if the rigol could at least show how many points are currently available.
"Max. 1Mpt" (from the manual)doesn't say anything at first.

Apropos, It's been a long week, it's evening, you can have a bit of a mental block...
Like me right now, operating the rigol from the living room. ;)
Span= half of the current samplerate
RBW= 1/capturetime
If the timebase ist set to say 50µs/Div, capturetime should be 500µs, so RBW should be 1/500µs  = 2000Hz.
With the Rigol, I have an RBW of 5000(Hz) precisely under these parameters.
What else does the RBW depend on?
And:
Span is currently 625Mhz, which makes sense if the sample rate is 1.25GSa/s.
I know from siglentscopes that the FFT sample rate is equal to the sample rate of the time domain if the number of FFT points is greater than the number of points of the current memory points.
Since the FFT sample rate is the same, I assume that rigol "has" more than 625kpts for the FFT (unfortunately it is not displayed).
If I now set the memory from auto to manual and let's say 10Mpts, the FFT sample rate should go down.
But it doesn't, Instead, the RBW is now reduced to 2000Hz - i.e. to the value actually to be expected at 50µs/div.
And that's where my mental block is, I must be missing something. ;)

Edit: Forget it, the rigol drives me crazy...
While typing this post, the rigol shows 5K RBW until I´ve set the memory 10 Mpt as mentioned above.
So I make a pic from it, then I want to make a pic from the state before, switch back to Automemory and 625kpts - RBW remains 2K...
And it´s getting better:
OK, let´s change the timebase and go back to 50µs/Div.
Now I have 1K RBW....
::)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on December 01, 2023, 09:48:34 pm
OK, it´s a bug... ;)
When changing the timebase, the scope "forget" (often but not everytime) to refresh the RBW value.
If you then move the position (vertical offset) of the FFT, the RBW value is updated. :phew:
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Mechatrommer on December 02, 2023, 07:28:16 am
Apart from that, if you can't set the number of points, it would be great if the rigol could at least show how many points are currently available.
istr when i ordered my dho804 few weeks ago, someone keep complaining about dho800/900, how 900 (same HW as 800) can easily aliased (by struggling hard enough to show gibbs effect phenomenon as aliasing etc)  how bad things including its fft, so i let him find the formula by himself. usually if people think he is clever i'll let him find the formula himself... not sure if he already figure that out... the formula is very simple..

number of FFT point (bins you saw plotted on screen) = FFT frequency range / rbw
FFT frequency range = DC - sampling rate / 2.

both frequency range and rbw can be seen on screen..
working example: sampling rate: 1.25GSps, hence FFT range = DC - 625MHz (sampling rate / 2), RBW (shown) = 2K (Hz).... so number of FFT bins = 625MHz / 2KHz = 312500 points (bins).

since FFT only use/show half of calculated points (another half is only mirror image), number of sampled points used to generate FFT is twice bins number. you are right what you have figured, dho800 has some bug on showing RBW, i reported in bug thread but not sure if people understood when i reported it.. i figure when you increase time/div and then back down/ reduce it again, it will show correct rbw, but not when you increase time/div.

so in conclusion, we can indirectly change how many FFT or sampled points used by dho800 by changing time/div and use formula above to figure how many points currently used for FFT, ymmv.
and btw, if you have traditional real/sweeping SA, you'll know you only have freq range and RBW figure, you wont have sampled/fft points count anywhere there is no such thing, so rigol is being traditious ymmv.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Performa01 on December 02, 2023, 08:03:42 am
When trying to sound smart, people should at least post correct information.

That includes not using points and bins as synonym first, and making contradicting statements later by (accidentally?) stating something that sounds right, namely that FFT bins are half the FFT points.

One should also not confuse frequency step (df) with resolution bandwidth (RBW).

One should also understand the vast difference between a traditional swept SA and the FFT on a DSO – or even a combination of both to form a powerful realtime SA…

When in doubt, one can always look up the fundamentals in this old post (reply #23):

https://www.eevblog.com/forum/testgear/rohde-schwarz-rtb2002-vs-siglent-sds2104x-plus/msg3239832/#msg3239832 (https://www.eevblog.com/forum/testgear/rohde-schwarz-rtb2002-vs-siglent-sds2104x-plus/msg3239832/#msg3239832)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: gf on December 02, 2023, 08:17:00 am
Quote
number of FFT point (bins you saw plotted on screen)

In common terminology, the "number of FFT points" usually refers to the number of points in the time domain from which the FFT is computed, not to the subset of frequency bins which happen to be displayed.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: gf on December 02, 2023, 09:52:24 am
When I see screenshots showing 62.5MSa/s, 625000 points, and RBW 100 (assuming that 100Hz is not really the -3dB RBW, but actually the frequency bin spacing), then I get the impression that the FFT size is the full record length of 625000 points, which would also imply that this FFT implementation can handle sizes that are not a power of two. Of course, there has to be a limit to the maximum FFT size, so the question remains what happens if the acquired records are longer than the limit. What subset of samples is selected? Start of the record? Center? Or are long records even split into multiple chunks of the maximum FFT size?

If we distrust the numbers displayed on the screen, ist it possible to export the FFT math trace to a text file? If yes, how many points does it export if full span (0...fs/2) is selected? The number of saved points and the difference between adjacent frequencies should give an indication for the actual FFT size and frequency bin spacing (unless only decimated screen data are saved :( - that's useless, of course).
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on December 02, 2023, 10:09:30 am
You wouldn't be so much in the dark if there was something like this - and it can't be difficult to implement.
But so far I haven't seen a Rigol that does it, neither expensive nor cheap.

(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1942365;image)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Mechatrommer on December 02, 2023, 10:18:43 am
When trying to sound smart, people should at least post correct information.

That includes not using points and bins as synonym first, and making contradicting statements later by (accidentally?) stating something that sounds right, namely that FFT bins are half the FFT points.

One should also not confuse frequency step (df) with resolution bandwidth (RBW).

One should also understand the vast difference between a traditional swept SA and the FFT on a DSO – or even a combination of both to form a powerful realtime SA…

When in doubt, one can always look up the fundamentals in this old post (reply #23):

https://www.eevblog.com/forum/testgear/rohde-schwarz-rtb2002-vs-siglent-sds2104x-plus/msg3239832/#msg3239832 (https://www.eevblog.com/forum/testgear/rohde-schwarz-rtb2002-vs-siglent-sds2104x-plus/msg3239832/#msg3239832)

i may mixed up / confusing what a specific DSO brand refering to "FFT points" (sampled points? or bin points? i dont own "THAT brand" DSO) but... what a waste lengthy talk about -3dB points of FFT Windowing function that looks like smart but in fact a "more than necessary" a complicated misinformation... better refer to "known brand"'s definition, than one guys' own definition from an unknown location ;) cheers...

https://www.analog.com/en/design-center/glossary/frequency_bin.html (https://www.analog.com/en/design-center/glossary/frequency_bin.html)
https://dsp.stackexchange.com/questions/26927/what-is-a-frequency-bin (https://dsp.stackexchange.com/questions/26927/what-is-a-frequency-bin)
https://www.ap.com/technical-library/more-about-ffts/ (https://www.ap.com/technical-library/more-about-ffts/)
https://www.ni.com/docs/en-US/bundle/ni-rfsa/page/nirfsa/resolution-bandwidth.html (https://www.ni.com/docs/en-US/bundle/ni-rfsa/page/nirfsa/resolution-bandwidth.html)

there is NONE talking about WINDOWING function relating to this...

https://googlethatforyou.com?q=fft%20bins (https://googlethatforyou.com?q=fft%20bins)
https://googlethatforyou.com?q=resolution%20bandwidth%20fft (https://googlethatforyou.com?q=resolution%20bandwidth%20fft)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: gf on December 02, 2023, 10:25:51 am
i may mixed up / confusing what a specific DSO brand refering to "FFT points" (sampled points? or bin points? i dont own "THAT brand" DSO) but... what a waste lengthy talk about -3dB points of FFT Windowing function that looks like smart but in fact a "more than necessary" a complicated misinformation... better refer to "known brand"'s definition, than one guys' own definition from an unknown location ;)

FFT and window functions are pure math - nothing brand spacific. The term "RBW" comes from spectrum analyzers, and there it means the -3dB bandwidth of the spectrum analysis filter. Anyone familar with spectrum analyzers associates RBW with this bandwidth.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on December 02, 2023, 10:32:54 am
Quote
If we distrust the numbers displayed on the screen, ist it possible to export the FFT math trace to a text file?

Directly from the FFT menu not, only the peak/marker table.
But I'll try another thing, maybe that works.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Mechatrommer on December 02, 2023, 10:33:37 am
You wouldn't be so much in the dark if there was something like this - and it can't be difficult to implement.
But so far I haven't seen a Rigol that does it, neither expensive nor cheap.

(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1942365;image)
if you are depending on that figure, then good for you, you dont have to know formula... (my program also provides such figure) i know rigol is a bit behind in this, but now its catching up... "the traditional way", which somehow bring back nostalgic emotion.. but please dont argue smart like some people.. only providing own's definition without being backed up by industrial name's definition. cheers.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Mechatrommer on December 02, 2023, 10:58:43 am
When I see screenshots showing 62.5MSa/s, 625000 points, and RBW 100 (assuming that 100Hz is not really the -3dB RBW, but actually the frequency bin spacing), then I get the impression that the FFT size is the full record length of 625000 points, which would also imply that this FFT implementation can handle sizes that are not a power of two. Of course, there has to be a limit to the maximum FFT size, so the question remains what happens if the acquired records are longer than the limit. What subset of samples is selected? Start of the record? Center? Or are long records even split into multiple chunks of the maximum FFT size?

If we distrust the numbers displayed on the screen, ist it possible to export the FFT math trace to a text file? If yes, how many points does it export if full span (0...fs/2) is selected? The number of saved points and the difference between adjacent frequencies should give an indication for the actual FFT size and frequency bin spacing (unless only decimated screen data are saved :( - that's useless, of course).

you people maybe right about bin size vs RBW, but that probably due to some advanced feature of FFT that may not accessible to normal people, such as spectrum leakage and varying window function effect on actual spectrum power, until you people can provide more reliable materials to read, i think rigol refering RBW as bin spacing as defined by link i provided. if rigol implementing your peole's definition of RBW, then there is no way of knowing how many points. but then... what practical benefit to know how many points? other than swinging dick contest this brand is lower points than the other. just read the goat damned FFT/SA the like old people did it... no need number of pts or question this brand is more reliable than others... ymmv.

(attached image is for illustration or amusement only, dont be too serious! life is short. name erased to avoid swinging dick contest, source: https://www.youtube.com/watch?app=desktop&v=S8jrpCoZyx8&t=1953s (https://www.youtube.com/watch?app=desktop&v=S8jrpCoZyx8&t=1953s)) i cannot erase voice sorry ;D
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on December 02, 2023, 11:14:22 am
Quote
If we distrust the numbers displayed on the screen, ist it possible to export the FFT math trace to a text file?

Directly from the FFT menu not, only the peak/marker table.
But I'll try another thing, maybe that works.

Unfortunately this (save/recall-->save-->from memory, after this from screen) did not work, everything is recorded and the maths display is probably not included.
What I also noticed is that if you call up such system functions while maths (FFT) is active, the scope starts to sweat a bit and is paralysed by the processing of the inputs.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: rf-loop on December 02, 2023, 03:38:57 pm
When I see screenshots showing 62.5MSa/s, 625000 points, and RBW 100 (assuming that 100Hz is not really the -3dB RBW, but actually the frequency bin spacing), then I get the impression that the FFT size is the full record length of 625000 points, which would also imply that this FFT implementation can handle sizes that are not a power of two. Of course, there has to be a limit to the maximum FFT size, so the question remains what happens if the acquired records are longer than the limit. What subset of samples is selected? Start of the record? Center? Or are long records even split into multiple chunks of the maximum FFT size?

If we distrust the numbers displayed on the screen, ist it possible to export the FFT math trace to a text file? If yes, how many points does it export if full span (0...fs/2) is selected? The number of saved points and the difference between adjacent frequencies should give an indication for the actual FFT size and frequency bin spacing (unless only decimated screen data are saved :( - that's useless, of course).

you people maybe right about bin size vs RBW, but that probably due to some advanced feature of FFT that may not accessible to normal people, such as spectrum leakage and varying window function effect on actual spectrum power, until you people can provide more reliable materials to read, i think rigol refering RBW as bin spacing as defined by link i provided. if rigol implementing your peole's definition of RBW, then there is no way of knowing how many points. but then... what practical benefit to know how many points? other than swinging dick contest this brand is lower points than the other. just read the goat damned FFT/SA the like old people did it... no need number of pts or question this brand is more reliable than others... ymmv.

(attached image is for illustration or amusement only, dont be too serious! life is short. name erased to avoid swinging dick contest, source: https://www.youtube.com/watch?app=desktop&v=S8jrpCoZyx8&t=1953s (https://www.youtube.com/watch?app=desktop&v=S8jrpCoZyx8&t=1953s)) i cannot erase voice sorry ;D

Not perfectly to you even when I quote you.

1st.

Bins are intervals between samples in frequency domain.
Frequency domain include fact that there need be 2 samples.
All know that if we have example 1GSa/s (sampling frequency 1GHz)  FFT full scale in not  1GHz. It is 0-500MHz...   2 samples  means frequency interval in frequency domain... 1 Bin, one Δf.  One FFT bin need two sample (in time domain)
(example for carify: 1GSa/s and 524288pts Δf=1.9073kHz. Siglent display Δf 1.91kHz) (If you use FFT full span frequency  for Δf (for Bin) you need use FFTpts/2)

Spectrum analyzers, old analog... normally RBW mean filter 3dB width.
 
This RBW is so commonly used like it in many places just for meaning filter width as it is used tens of years in many instruments. It is confusing if some use RBW as Bin frequency interval. Better way imho, is to tell Δf and example Siglent have selected this way.

But as can see in my previous one image (https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/msg5198817/#msg5198817) some Siglent oscilloscope may tell both,  Δf  and RBW  and my opinion is that this is good way to avoid confusion. In this case RBW change when user change FFT window, because RBW3dB really change depending filter parameters. It looks like also one filter type, example  Hanning may have bit different filter factor in different implements depending some deeper details. Example Siglent hanning RBW3dB is not just 1.44 x Δf (bin).

My opinion is that if use RBW  as RBWBin it need also tell somehow for avoid confusion.

Least I have default in my mind after tens of years using many kind of instruments that when I see frequency domain and there RBW I will automatically asume it is RBW3dB until specially noted exception. Because this have been so common practice. And it is same also in these SA what have full digital IF  and  example FFT (more or less wide realtime or step swept FFT) instead of analog filters. Newer seen there RBW is FFT bin).


One maestro for this mess is National (NI) (https://www.ni.com/docs/en-US/bundle/ni-rfsa/page/nirfsa/resolution-bandwidth.html) when they simply say: "The resolution bandwidth (RBW) determines the fast-Fourier transform (FFT) bin size, or the smallest frequency that can be resolved."


In this Keysight page (https://rfmw.em.keysight.com/wireless/helpfiles/89600b/webhelp/Subsystems/gui/content/windows_shapefactor_and_equiv_noisebw.htm) there is some good example about different FFT window and RBW3dB and RBWNoise

GW Instek is one example about good information in this matter.

MDO2000A data sheet have nice detail. 

FFT Windows,  FFT Factor:
Hanning 1.44 ; Rectangular 0.89 ; Hamming 1.30 ; Blackman 1.68
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on December 02, 2023, 09:32:25 pm
Yeah, I was just playing around, this time with my flir i60... ;D
...The scope after about 2 hours of operation.

(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1942920;image)

(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1942926;image)

(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1942932;image)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on December 02, 2023, 10:20:23 pm
FFT again, going through several times/div.

Timebase Samplerate Memory FFT-SR RBW

10µs        1.25G        125Kpt   1.25G 10K
20µs        1.25G        250Kpt   1.25G 5K
50µs        1.25G        625Kpt   1.25G 2K
100µs      625M         625Kpt    625M 1K
200µs     312.5M       625Kpt  312.5M 500
500µs   156.25M   781.25Kpt 156.4M 199.9
1ms         62.5M        625Kpt   62.5M 100
2ms       31.25M        625Kpt  31.25M 50
And so on.
I don't understand the values at 500µs, these "crooked" values in the FFT, nor the memory, which is 625Kpt before and after, but 781.25kpt in this time base.
Rigol specifies the maximum number of FFT points as "up to 1Mpt".
But how could you find out how many points are currently being used if this value is not displayed?
BTW,
Not only is the RBW not updated at times, the graphically displayed span is not updated either.
Both can be refreshed by moving the vertical offset.


Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on December 02, 2023, 10:39:07 pm
But how could you find out how many points are currently being used if this value is not displayed?

Seems like the number of data points listed in your "memory" column is also used for the FFT. With that assumption, the listed "RBW" (which is really delta_f) is consistent with the sample rate and number of data points given, delta_f = samplerate / memory.

Quote
I don't understand the values at 500µs, these "crooked" values in the FFT, nor the memory, which is 625Kpt before and after, but 781.25kpt in this time base.

Bit strange indeed. It looks like they wanted to maintain the systematic 500/200/100 cadence for delta_f. If delta_f = 200 Hz and sampling rate = 156.25 MHz are given, you land at that odd number of data points.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: gf on December 02, 2023, 11:36:19 pm
FFT again, going through several times/div.

Have you ever seen a FFT sample rate different from the acquisition sample rate?
What happens if you increase the memory depth beyond 1M points (i.e. beyond the maximum FFT size)?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on December 02, 2023, 11:45:34 pm
Right here and now, just shooting from the hip:
500µs Auto Memory, 500µs 10Mpts.
Note the FFT sampling rate.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on December 02, 2023, 11:54:10 pm
Right here and now, just shooting from the hip:
500µs Auto Memory, 500µs 10Mpts.
Note the FFT sampling rate.

The 156.4 can't be right; as gf said, how could it be different from the acquisition rate? Must be a rounding error, which also results in the awkward 199.9 bandwidth figure. We have seen in other places (axis scales and table entries) that Rigol struggles with proper rounding...
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: gf on December 03, 2023, 08:37:54 am
10Mpts.png

Seems that it down-samples*) if the record length is larger than the maximum FFT size.
And "RBW: 200" suggests that we got 625000 FFT points @125MSa/s.

So eventually it seems to do both here:
1) 10x down-sampling, which reduces 10M points to 1M points
2) Truncate the 1M points to 625k FFT points

*) And since the noise fllor does not roll off sharply a little bit below Nyquist (62.5 MHz), it's likely down-sampling w/o decimation filtering.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: TurboTom on December 03, 2023, 02:28:35 pm
Wouldn't worry too much about this since the most relevant window functions von Hann, Blackman-Harris and rectangular are available and appear to work correctly.

I would. A flattop window is important to get good amplitude accuracy for frequencies that are not integer multiples of the bin spacing. The maximum amplitude error of the flattop window 1) is only 0.016 dB. Hann, Blackman and various others still have significant scalopping loss for frequencies that fall in the middle between two bins. Blackman-Harris has also ~0.83 dB. And a rectangular window leaks as hell if the frequency is not an integer multiple of the bin spacing.

1) I consider the Matlab variant here, but there exist several other variants too

Whatsoever, it shouldn't be too difficult to correct this: In the scope's directory /rigol/resource/window/ there are all the window functions as binary arrays of 2^20 single precision (float32, little endian) numbers stored. Obviously, the file "flatTop_1048576.hex" (https://easyupload.io/i6erni) is defective since it starts and ends with some value of -0.853 while it should be something very close to 0.

But since it isn't too complicated to generate a correct file, those who need the proper flattop window shape could easily modify it and replace the file. Nevertheless, this should have been Rigol's job.  :-//
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on December 03, 2023, 03:51:44 pm
Quote
Nevertheless, this should have been Rigol's job.

That's exactly what it should be.
If you're still wondering how easy it is to hack the new generation scopes....
These are evaluation boards with a screen and a basic software framework and if something is wrong, you can fix it yourself. :P
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: TurboTom on December 03, 2023, 07:53:42 pm
I just generated a new Flat Top window file as per the formula described here (https://www.mathworks.com/help/signal/ref/flattopwin.html). The result looks much better than the original but there's still some side lobes emerging from the noise. I cannot tell for sure how flat the top actually is, but if someone wants to try, here's the download link (https://easyupload.io/4ayorp).  :D



Edit: Sorry I had to update the download link since I found a small error in my math... Now it's corrected and the FFT with the FlatTop window looks really nice  ;D
See attached screenshot: UR - FlatTop; LL - Blackman-Harris; LR - von Hann

P.S. I could just barely control myself not to use an AM signal.  >:D

Edit: Download link updated. Alternativeley, you can download a windows EXE file that will generate the window file here. (https://www.eevblog.com/forum/testgear/hacking-the-hdo1khdo4k-rigol-12-bit-scope/msg5202903/#msg5202903)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: gf on December 03, 2023, 08:36:23 pm
Here is the frequency response of the spectrum analysis filter corresponding to Matlab's flattopwin().
The flatness in the range -0.5...+0.5 is important.
Stopband rejection is > 68 dB. I'm surprised that you seem to get more :-//
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on December 03, 2023, 08:51:17 pm
I just generated a new Flat Top window file as per the formula described here (https://www.mathworks.com/help/signal/ref/flattopwin.html). The result looks much better than the original but there's still some side lobes emerging from the noise. I cannot tell for sure how flat the top actually is, but if someone wants to try, here's the download link (https://easyupload.io/sd8t6v).  :D

Very nice work, both finding the file and fixing it -- thank you!

Is it possible that this messed-up Flat Top window has been a Rigol tradition forever? My old DS1054Z shows very similar "leaky" spectral lines when using the Flat Top window. No easy way to swap out the window function on that scope, I'm afraid...
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on December 03, 2023, 09:15:56 pm
Oops, forget to switch off my DHO804, now it´s (nearly)24h burn-in proofed... ;)

Earlier I took the 1khz reference signal as the source and went through all the windows.
Then I did the same with the Siglent SDS1104X-E, but of course I checked the 1khz reference again to see if there were any differences.
Here are the pictures.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on December 03, 2023, 09:17:46 pm
Continued, rigol got triangle, siglent not.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on December 03, 2023, 10:31:58 pm
So, the scope is now switched off, this time I haven't forgotten it. ;)
Finally, three more things:
One picture where the scope "forgot" to change the scale.
Then the thing with the pop-up menu regarding Peaksearch, am I the only one who thinks the respective arrow direction is wrong? ;D
I would do it the other way around.
And it's no longer a secret that I think the visual display of the tables is great.
But...
Too much space is taken up, e.g. the index column could be much narrower, and there is no need for 3 or even more decimal places for the other values.
So you would have a little more space for the signal, which brings me back to saying that the window function is great if you could influence it more in terms of position and size.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on December 03, 2023, 10:43:27 pm
The FFT results look pretty nasty in comparison. Is there a general problem, maybe with the non-power-of-two number of data points?

I share your feelig that too much space is wasted for frames, decorations, long numbers etc., give the small size of the display. I have posted a small rant in the bugs & wishlist thread a couple of weeks ago (or did I just mean to do that?).

The upward/downward arrow is not meant to indicate an action, but a current status of the collapsible window, I guess. I have seen this elsewhere quite often (on websites and also in Windows or MS Office?). But I guess you could argue either way. Just like I prefer to change the "touchpad scrolling direction" on every laptop I use for more than a few minutes...
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on December 03, 2023, 11:19:47 pm
See attached screenshot: UR - FlatTop; LL - Blackman-Harris; LR - von Hann

Wait a second...von Hann....2GSa/s....What scopemodel do you have... ;)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: TurboTom on December 03, 2023, 11:38:46 pm
See attached screenshot: UR - FlatTop; LL - Blackman-Harris; LR - von Hann

Wait a second...von Hann....2GSa/s....What scopemodel do you have... ;)

Of course, it's a DHO1k, but the flattop window is equally broken as on DHO800 / 900 instruments. Moreover, I simply don't call the "Hanning" window function this way since the man behind this mathematics was the Austrian meteorologist Julius von Hann, so the window function should be correctly called "von Hann" or "Hann" window. Maybe I'm pathetic but IMO we don't need to "americanize" every scientist's name...  ;)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: gf on December 03, 2023, 11:40:31 pm
Earlier I took the 1khz reference signal as the source and went through all the windows.

Looks broken on your Rigol. And not just Flattop, the others look weird, too.

In order to show maximum leakage, don't choose exactly 1kHz, but rather 997.5 Hz in conjunction with your Rigol settings, and 998.97 Hz with your Siglent settings. IOW, us a frequency f = (N+0.5)*delta_f, where N is an integer. Calculate with enough decimal places, i.e. delta_f = 4.76837 and not just 4.77 for your Siglent settings.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on December 04, 2023, 12:06:56 am
This was taken from the calibrate signalsource of the scopes, but yes, I could use my generator for this.
Tomorrow. ;)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on December 04, 2023, 08:11:09 am
See attached screenshot: UR - FlatTop; LL - Blackman-Harris; LR - von Hann

Wait a second...von Hann....2GSa/s....What scopemodel do you have... ;)

Of course, it's a DHO1k, but the flattop window is equally broken as on DHO800 / 900 instruments. Moreover, I simply don't call the "Hanning" window function this way since the man behind this mathematics was the Austrian meteorologist Julius von Hann, so the window function should be correctly called "von Hann" or "Hann" window. Maybe I'm pathetic but IMO we don't need to "americanize" every scientist's name...  ;)

It's not even "americanizing".. It is just wrong.  "Von Hann" or "Hann" is the name.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Mechatrommer on December 04, 2023, 10:27:04 am
Maybe I'm pathetic but IMO we don't need to "americanize" every scientist's name...  ;)
https://www.youtube.com/watch?v=Zc-tZ8Y7MO0 (https://www.youtube.com/watch?v=Zc-tZ8Y7MO0)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on December 04, 2023, 12:31:03 pm
Stopband rejection is > 68 dB. I'm surprised that you seem to get more :-//

Well, it rolls off to -80 dB or a bit better in your MatLab plot as you move further away from the peak. And that's about what TurboTom's screenshot also shows, right?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: gf on December 04, 2023, 01:12:55 pm
Stopband rejection is > 68 dB. I'm surprised that you seem to get more :-//

Well, it rolls off to -80 dB or a bit better in your MatLab plot as you move further away from the peak. And that's about what TurboTom's screenshot also shows, right?

That's not the reason. But my fault for not seeing immediately what was happening. Yes, the first side lobe is about -68dB. But the frequency response of the window function has zeros at +/-N*delta_f, where N is an integer >= 5. If the signal frequency is an integer multiple of delta_f, then the side lobes don't show up because the signal frequency hits the zeros between the lobes, so outside the main lobe, we only see the noise floor in the discretely sampled frequency spectrum. For signal frequencies which do hit the side lobes, we'll see the resulting "leakage".

Btw, the Siglent flattop window is possibly a different variant, having lower side lobes (handbook sais -93 dB; due to lack of the hardware I can't verify). This would also imply a wider main lobe.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Performa01 on December 04, 2023, 01:30:35 pm
Earlier I took the 1khz reference signal as the source and went through all the windows.

Looks broken on your Rigol. And not just Flattop, the others look weird, too.

In order to show maximum leakage, don't choose exactly 1kHz, but rather 997.5 Hz in conjunction with your Rigol settings, and 998.97 Hz with your Siglent settings. IOW, us a frequency f = (N+0.5)*delta_f, where N is an integer. Calculate with enough decimal places, i.e. delta_f = 4.76837 and not just 4.77 for your Siglent settings.

FOr the SDS2000X Plus, this has already been done a while ago (reply #3561):

https://www.eevblog.com/forum/testgear/siglent-sds2000x-plus-coming/msg4318822/#msg4318822 (https://www.eevblog.com/forum/testgear/siglent-sds2000x-plus-coming/msg4318822/#msg4318822)

Since the FFT core implementation is identical, I expect quite similar results from the SDS1104X-E.


Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Performa01 on December 04, 2023, 01:36:14 pm
Btw, the Siglent flattop window is possibly a different variant, having lower side lobes (handbook sais -93 dB; due to lack of the hardware I can't verify). This would also imply a wider main lobe.
Indeed. The RBW of the Flattop window is 3.73 times the frequency step.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: gf on December 04, 2023, 01:39:11 pm
FOr the SDS2000X Plus, this has already been done a while ago (reply #3561):
https://www.eevblog.com/forum/testgear/siglent-sds2000x-plus-coming/msg4318822/#msg4318822 (https://www.eevblog.com/forum/testgear/siglent-sds2000x-plus-coming/msg4318822/#msg4318822)

Very nice!  :-+
[ I obviously had a peek at it at the time, but I did not remember. ]
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: core on December 04, 2023, 02:27:31 pm
Oops, forget to switch off my DHO804, now it´s (nearly)24h burn-in proofed... ;)

Earlier I took the 1khz reference signal as the source and went through all the windows.
Then I did the same with the Siglent SDS1104X-E, but of course I checked the 1khz reference again to see if there were any differences.
Here are the pictures.


I have replicated them on MSO5000, they are absolutely the same as HDO800. It seems that Rigol have no interest regarding FFT, no improvement after all these years.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Mechatrommer on December 04, 2023, 03:40:42 pm
Oops, forget to switch off my DHO804, now it´s (nearly)24h burn-in proofed... ;)
i recommend you need to work more and have enough sleep to get better view/comparison... cheers.

(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1944648;image) (https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1944054;image)

(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1944654;image) (https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1944066;image)

(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1944660;image) (https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1944078;image)

(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1944666;image) (https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1944090;image)

(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1944672;image) (https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1944102;image)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on December 04, 2023, 08:31:28 pm
In order to show maximum leakage, don't choose exactly 1kHz, but rather 997.5 Hz in conjunction with your Rigol settings, and 998.97 Hz with your Siglent settings.

Did it with 997.5Hz.
Additional with 10ms/div = 6.25MSa/s.

Siglent will follow with 998.97Hz.


Title: Re: Rigol DHO804 Test and Compare Thread
Post by: voltsandjolts on December 04, 2023, 09:04:27 pm
Is this the broken Rigol Flat Top or the fixed Flat Top?  ;D
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on December 04, 2023, 09:25:03 pm
Btw flat top...
Here a  siglent flat top pic with drastically reduced FFT-points.
I find the similarity with rigol's amazing.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: TurboTom on December 04, 2023, 09:27:07 pm
Is this the broken Rigol Flat Top or the fixed Flat Top?  ;D

@Martin72's flattop window function is still the broken (original) one, the repaired one (albeit on a DHO1000, hence a different sampling rate) is shown in the screenshot.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on December 04, 2023, 09:39:22 pm
To me, looking at (original) Rigol FFT windows, it looks like Flattop and Rectangular windows look pretty much the same.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on December 04, 2023, 09:42:23 pm
Btw flat top...
Here a  siglent flat top pic with drastically reduced FFT-points.
I find the similarity with rigol's amazing.

So -- is the assumption that the Rigol uses the full duration of the record, to get to the indicated small frequency step -- but reduces that dataset by undersampling (using only every n.th data point) or some similar scheme?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on December 04, 2023, 09:43:39 pm
Quote
To me, looking at (original) Rigol FFT windows, it looks like Flattop and Rectangular windows look pretty much the same.

Argh, I have to check, not that I made a mistake.
Thank you!
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on December 04, 2023, 09:53:00 pm
@2N3055:

No, not a mistake...

Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on December 04, 2023, 10:08:30 pm
Note that you can set the channel labels to show the FFT window function in screenshots, it's what I did here:
(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1914873;image)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on December 04, 2023, 10:12:20 pm
Good hint, hadn't had that in mind until then.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Randy222 on December 07, 2023, 09:35:39 pm
My 804 just arrived from Aliexpress, it has firmware v00.01.02 dated Nov 9 2023.
It's not available as download on Rigol site.

What's new and/or fixed in 01.02 ?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on December 07, 2023, 09:40:23 pm
My 804 just arrived from Aliexpress, it has firmware v00.01.02 dated Nov 9 2023.
It's not available as download on Rigol site.

What's new and/or fixed in 01.02 ?

Not much.

Code: [Select]

v00.01.02.00.00  2023/11/2

1. Self calibration optimization update
2. Solve the problem of UltraLab startup connection failure
3. Solve the problem of failure to save waveform in wfm format
4. Add education model equivalent settings
5. Solve the problem of unresponsive touch on startup screen

v00.01.01.00.02 2023/09/12

1. Self calibration optimization update
2. Update Help Documents

v00.01.01.00.01  2023/08/10

1. Remove all time-related displays on the instrument
2. To modify the vertical interface, click the wiring diagram to modify the AC coupling function
3. Modify the delayed scan Chinese display as Zoom
4. Modify the order of the menu in the upper right corner, put the measurement in the front and Default in the back
5. The probe ratio interface is removed, and the probe ratio option is added to the vertical first-level menu


v00.01.00.00.19  2023/07/24

1. The first version is released
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Serg65536 on December 07, 2023, 09:46:00 pm
I use firmware 1.02, it's not available for download now. Nothing critical was fixed in this version.
See more here: https://www.eevblog.com/forum/testgear/hacking-the-rigol-dho800900-scope/msg5173176/#msg5173176 (https://www.eevblog.com/forum/testgear/hacking-the-rigol-dho800900-scope/msg5173176/#msg5173176)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Randy222 on December 07, 2023, 10:19:20 pm
My 804 just arrived from Aliexpress, it has firmware v00.01.02 dated Nov 9 2023.
It's not available as download on Rigol site.

What's new and/or fixed in 01.02 ?

Not much.

Code: [Select]

v00.01.02.00.00  2023/11/2

1. Self calibration optimization update
2. Solve the problem of UltraLab startup connection failure
3. Solve the problem of failure to save waveform in wfm format
4. Add education model equivalent settings
5. Solve the problem of unresponsive touch on startup screen

v00.01.01.00.02 2023/09/12

1. Self calibration optimization update
2. Update Help Documents

v00.01.01.00.01  2023/08/10

1. Remove all time-related displays on the instrument
2. To modify the vertical interface, click the wiring diagram to modify the AC coupling function
3. Modify the delayed scan Chinese display as Zoom
4. Modify the order of the menu in the upper right corner, put the measurement in the front and Default in the back
5. The probe ratio interface is removed, and the probe ratio option is added to the vertical first-level menu


v00.01.00.00.19  2023/07/24

1. The first version is released

What's the meaning of v00.01.02.00.00  2023/11/2 date "Nov 2 2023"? Is that when the release note was made, or something other. My 804 shows one week later.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on December 07, 2023, 10:23:58 pm
What's the meaning of v00.01.02.00.00  2023/11/2 date "Nov 2 2023"? Is that when the release note was made, or something other. My 804 shows one week later.

Never mind, a one week difference is spot-on for Rigol. They are not good with dates. Some of the release dates you find on their international sites are off by months, in either direction. ::)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on December 07, 2023, 10:28:19 pm
I think that's how it will be, first the notes, then the "release".
However, I also think that this version, which has since been withdrawn, only applies to certain hardware configurations* - they probably had to make improvements and this does not apply to all variants.
This also explains why my DHO couldn't cope with the firmware and I "deleted" it again.
*) Due to component shortages, alternative elements were presumably used that required correction.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: rpro on December 10, 2023, 09:07:48 pm
Note that you can set the channel labels to show the FFT window function in screenshots....

Also, while we wait for Rigol to add basic averaging features to their FFT, one can use pyvisa to acquire traces from the scope and display the avg result with a few lines of python code. Here is a minimalist working example:

import pyvisa as visa 
import matplotlib.pyplot as plt
import numpy as np

scopedev = 'TCPIP0::192.168.0.10::5555::SOCKET'  #four 5's
nSamples = 100

scope = visa.ResourceManager().open_resource(scopedev)
scope.read_termination = scope.write_termination = '\n'
print("Scope: ", scope.query("*IDN?"))

scope.write(":WAV:SOURCE MATH1;:WAV:FORM ASCii;:WAV:MODE NORMAL")
fstart = float(scope.query(":MATH1:FFT:FREQuency:START?"))
fend = float(scope.query(":MATH1:FFT:FREQuency:END?"))

X = np.linspace(fstart, fend, 1000, endpoint=True)/1e6
fftData =[]
for i in range(0,nSamples):
    fftData += [np.array(scope.query(":WAV:DATA?").split(","),dtype=float)]

avgFFTdata = np.mean(np.array(fftData),axis=0)
plt.plot(X,avgFFTdata)
plt.grid(True, which="both")
plt.show()
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on December 13, 2023, 02:15:02 pm
Hi,

Just for fun, the boot times of the three little pi...no, scopes. ;)
I was comparing something else and thought to myself, oh, just make a clip.
I personally don't care about the boot time, I hate it with multimeters and recently also with power supplies.

https://www.youtube.com/watch?v=Tr85IUfQSaQ (https://www.youtube.com/watch?v=Tr85IUfQSaQ)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on December 13, 2023, 03:02:57 pm
A short clip about using the UI, vertical adjustments, with a clear "winner".

https://www.youtube.com/watch?v=OThWm4VVzRI (https://www.youtube.com/watch?v=OThWm4VVzRI)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: sorenkir on December 14, 2023, 04:31:47 pm
Is it possible that this messed-up Flat Top window has been a Rigol tradition forever? My old DS1054Z shows very similar "leaky" spectral lines when using the Flat Top window. No easy way to swap out the window function on that scope, I'm afraid...

It seems that the MSO5074 has the same "traditional" Flat Top window:
(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1953219;image)


Michel.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Randy222 on December 15, 2023, 03:19:22 pm
Hi,

Just for fun, the boot times of the three little pi...no, scopes. ;)
I was comparing something else and thought to myself, oh, just make a clip.
I personally don't care about the boot time, I hate it with multimeters and recently also with power supplies.
The 804 I got with 01.02 firmware takes 54sec to get to the ready-for-use state.
I find it odd it boots up to an active CH1. IMHO it should boot to no active channels.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on December 16, 2023, 11:21:35 am
I wanted to measure the noise level, today I prepared something, but I have to realise that it's too loud in my study during the day.
So I'll do it all again(with different settings like more resolution) in the later evening or night, but I'll show the first results here anyway.
As I said before, the DHO804 is not the loudest scope I have here... 8)
It's actually the quietest of the three. ;)
(Software: REW, Microphone: UMIK-2, calibrated, 96khz samplerate)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: core on December 16, 2023, 07:05:06 pm
I wanted to measure the noise level, today I prepared something, but I have to realise that it's too loud in my study during the day.
So I'll do it all again(with different settings like more resolution) in the later evening or night, but I'll show the first results here anyway.
As I said before, the DHO804 is not the loudest scope I have here... 8)
It's actually the quietest of the three. ;)
(Software: REW, Microphone: UMIK-2, calibrated, 96khz samplerate)

A very good initiative. Thanks for sharing!
The more devices you can measure, the better chance we have of comparing to something we already have.
If you could find an MSO5000, SDS2000X Plus and a DHO1000, it would really fill in a picture of the noise of the devices we currently use. I suspect you will also measure for the SDS2000X HD  ;D
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on December 16, 2023, 07:10:58 pm
Hi,

At the moment I have SDS1104X-E, DS1054Z, DHO804, SDS2504X HD and SDS2104Xplus here... ;)
Maybe tonight or tomorrow in the early morning I´ll make some measurings.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on December 16, 2023, 09:49:25 pm
Not tonight, half an hour ago...
It's hardly going to be any quieter in the room, I might look for a quieter place - but that wouldn't be practical and that's really the point.
In addition to the actual measurement distance (0.5m away, 1.2m high (ear height when sitting)), I also made recordings in the immediate vicinity of the fan.
This not only blocks out the ambient noise, but also allows you to see the character of the fan in question.
I also took measurements on the SDS2504X HD - somewhat unfair, because unlike the other four scopes, my HD no longer has the original fan - but it wasn't any louder.
An integrated fan controller is quite nice.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Performa01 on December 17, 2023, 09:22:54 am
I also took measurements on the SDS2504X HD - somewhat unfair, because unlike the other four scopes, my HD no longer has the original fan - but it wasn't any louder.
These measurements also show how meaningless the dB figures of the "far-field" measurements are, as they indicate only 2.21 dB difference between the SDS2504X HD and the DHO804. Since I know from experience that the SDS2504X HD is barely audible even with the original fan, while on the other hand some people have complained about the fan noise of the DHO804, it's quite obvious that the actual difference must be much more than that.

Looking at the spectra confirms this very clearly: two dominant tones, ~35 dB @ 64 Hz + 34 dB @ 590 Hz for the DHO804 and only one dominant tone 32 dB @ 49 Hz for the SDS2504X HD. Since the human ear is much more sensisitive at medium frequencies like 590 Hz than at low frequencies like 49 Hz, it is clear that there must be a difference like day and night.

And the near-field measurement confirms this very nicely: 20 dB quieter and no dominant frequency for the SDS2504X HD is exactly as expected.

Even the comparison of the "veterans" is quite interesting - I never would have guessed that the DS1054Z is such a hell-machine and manages to be another 6.73 dB louder than the already loud SDS1104X-E...

Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on December 17, 2023, 09:38:56 am
I think that the noise spectra are hard to interpret and compare in general. Predicting from the spectra how annoying a particular fan sound will be perceived will only be possible with a lot of experience, at best.

My preference would be short audio recordings, to allow for a comparison of the "subjective" effect of each scope's fan noise. If a set of recordings can be made with the same microphone gain setting for a range of instruments, any user who has one of those instruments as their local reference could easily compare and get a good impression what noise to expect from the other devices.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on December 17, 2023, 09:47:34 am
Quote
These measurements also show how meaningless the dB figures of the "far-field" measurements are, as they incicate only 2.21 dB difference between the SDS2504X HD and the DHO804

That's why I recorded the spectrum and not just the numerical SPL value.
Whereby +3dB more already means a doubling of the volume and in some frequency ranges of the spectrum this is easily exceeded.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Performa01 on December 17, 2023, 10:16:00 am
I think that the noise spectra are hard to interpret and compare in general. Predicting from the spectra how annoying a particular fan sound will be perceived will only be possible with a lot of experience, at best.
Why do you think so? I happen to have some experience in the audio field, but even without that the fundamentals of human hearing together with a look at the Fletcher-Munson curves would be enough to interpret an audio spectrum correctly:

https://en.wikipedia.org/wiki/Equal-loudness_contour

We are talking about SPL (sound pressure levels) between 30 and 40 dB here. The threshold of human hearing at 50 Hz is at about 42 dB.

So why should I not be able to safely state that 32 dB @ 49 Hz is inaudible for the mere mortal?

34 dB @ 590 Hz on the other hand is equivalent to at least 30 phon – quite audible, independent from the age of a person.

Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on December 17, 2023, 12:03:20 pm
I think that the noise spectra are hard to interpret and compare in general. Predicting from the spectra how annoying a particular fan sound will be perceived will only be possible with a lot of experience, at best.
Why do you think so? I happen to have some experience in the audio field, but even without that the fundamentals of human hearing together with a look at the Fletcher-Munson curves would be enough to interpret an audio spectrum correctly:

https://en.wikipedia.org/wiki/Equal-loudness_contour

We are talking about SPL (sound pressure levels) between 30 and 40 dB here. The threshold of human hearing at 50 Hz is at about 42 dB.
So why should I not be able to safely state that 32 dB @ 49 Hz is inaudible for the mere mortal?
34 dB @ 590 Hz on the other hand is equivalent to at least 30 phon – quite audible, independent from the age of a person.

"Inaudible" is fine, of course, and knowing or looking up a threshold for that is no problem. Having a good feel for how much more noticeable +3dB are (at various absolute levels) may already be less clear.

But what I was mainly thinking about are deviations from white or pink noise. We frequently read descriptions of (and complaints about) noise that is perceived as "whiny", "high pitched", "with a clicking noise" etc. To recognize the signatures of such noise components in the spectra is where I think a lot of experience is needed. And to assess from looking at the spectrum how obnoxious the noise will sound is probably impossible, since it is a rather subjective perception anyway.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Performa01 on December 17, 2023, 01:54:49 pm
"Inaudible" is fine, of course, and knowing or looking up a threshold for that is no problem. Having a good feel for how much more noticeable +3dB are (at various absolute levels) may already be less clear.
Quite clear if one sticks to the fundamentals: an increase in 10 phone (above some 40 phone) is equivalent to a perceived doubling of the sound volume. Once again, the Fletcher-Munson curves help us to find the correlation of SPL and the loudness measured in phon. There’s usually no scaling, i.e. a 10 dB increase in the phon measure will correspond to 10 dB more SPL, but there is a frequency dependent shift in sensitivity.


But what I was mainly thinking about are deviations from white or pink noise. We frequently read descriptions of (and complaints about) noise that is perceived as "whiny", "high pitched", "with a clicking noise" etc. To recognize the signatures of such noise components in the spectra is where I think a lot of experience is needed. And to assess from looking at the spectrum how obnoxious the noise will sound is probably impossible, since it is a rather subjective perception anyway.
I don’t even believe that it’s that subjective. Yes, white (and even more so pink) noise should be quite unobtrusive – and it shows, since it’s used for medical purposes in noise masker systems for tinnitus treatment.

What is more annoying are dominant frequencies, and these in turn all the more so as closer they are to the maximum sensitivity of the human ear, i.e. 3 kHz.

Even more annoying are low frequencies (which would be inaudible themselves) with very high harmonic content that is audible (“ticking sounds”).
Or any form of frequency modulated dominant tones (“whining noise”). Here it might be a little subjective indeed, which one are perceived as more annoying.

And for all types of unwanted sounds and noises it is clear that they are all the more annoying the louder they are.

Title: Re: Rigol DHO804 Test and Compare Thread
Post by: core on December 17, 2023, 07:58:10 pm
The noise spectrum plots are very interesting. Since local conditions cannot be easily compared, measurements taken very close to the fan may be most useful.

Personally, I would not change a fan without knowing that the new one does not have at least the same airflow or without comparing the measured temperature with a thermal imaging camera.

Also, the average temperature measured by a speed controller added later to a default installed fan doesn't tell much about certain hot spots like local power supplies, which can get too hot without a minimal airflow.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on December 17, 2023, 09:07:18 pm
Personally, I would not change a fan without knowing that the new one does not have at least the same airflow or without comparing the measured temperature with a thermal imaging camera.

These have a single heatsink and can show their internal system temperature on screen. Thermal camera isn't really needed.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on December 17, 2023, 09:24:25 pm
If you take this a bit more seriously, I would want to capture the hotspots with a thermal camera - before replacing the fan.
Most people want to install a fan externally, so it would be a good idea to monitor the temperatures with the camera.
Unless there are enough internal sensors available that can be displayed.
Is this the case and how do you do it?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on December 17, 2023, 10:23:32 pm
Unless there are enough internal sensors available that can be displayed.
Is this the case and how do you do it?

You mean the Utility > Self Check > Board Test display? (If the manual is correct and it's in the same place as with the DHO1000.)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on December 17, 2023, 10:30:26 pm
Aha, will check this...Now.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on December 17, 2023, 10:38:24 pm
That's a bit meagre, actually too little.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on December 17, 2023, 10:52:09 pm
That was a good one. ;) edit post was removed from user
Here is an example of how to do it right, if you are already doing it.


Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on December 17, 2023, 11:16:03 pm
Aha, will check this...Now.

You didn't know??

That's a bit meagre, actually too little.

There were some thermal images posted earlier showing the CPU is the hotspot so that should be enough info with this big uni-heatsink.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on December 17, 2023, 11:17:58 pm
That was a good one. ;) edit post was removed from user

I was just rewording it carefully because my loyal fan club is out in force today.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on December 17, 2023, 11:35:12 pm
Let's stay reasonably objective here, that helps everyone much more than anything else.

Quote
There were some thermal images posted earlier showing the CPU is the hotspot so that should be enough info with this big uni-heatsink.

Let's see if I feel like voiding the warranty and getting an impression with my Flir.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on December 18, 2023, 12:07:18 am
Let's see if I feel like voiding the warranty and getting an impression with my Flir.

You really need to do it without the fan to find the true hotspots...  :)

Somebody did a simulation, you could verify it:

https://www.eevblog.com/forum/testgear/hacking-the-rigol-dho800900-scope/msg5189571/#msg5189571 (https://www.eevblog.com/forum/testgear/hacking-the-rigol-dho800900-scope/msg5189571/#msg5189571)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on December 18, 2023, 06:47:39 am
That's a bit meagre, actually too little.

Indeed, that's less than I expected. The DHO1000 dialog shows much more info.

Title: Re: Rigol DHO804 Test and Compare Thread
Post by: core on December 18, 2023, 08:03:57 am
Personally, I would not change a fan without knowing that the new one does not have at least the same airflow or without comparing the measured temperature with a thermal imaging camera.

These have a single heatsink and can show their internal system temperature on screen. Thermal camera isn't really needed.

Depends. If there is a buck power supply outside the single heatsink and the airflow in the case is too low, an overheat and a fault in this regulator will cause a major malfunction. The voltage at the input can reach the output. I have seen laptops in this situation.

This may not be noticeable in the temperatures monitoring menu.

That's why I wouldn't change the cooling conditions without making sure I'm not missing something.
A functional noisy device is better than a silent "dead" one  ;)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on December 18, 2023, 08:10:42 am
Then it's really silent. ;)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on December 18, 2023, 12:31:44 pm
That's a bit meagre, actually too little.

Indeed, that's less than I expected. The DHO1000 dialog shows much more info.

Not really. All it says is that "ambient temp" is a degree or two less than chip temp.

What's "ambient temp" anyway? was that screenshot taken in a room at 45 Celsius?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on December 18, 2023, 12:36:03 pm
Depends. If there is a buck power supply outside the single heatsink and the airflow in the case is too low, an overheat and a fault in this regulator will cause a major malfunction. The voltage at the input can reach the output. I have seen laptops in this situation.

A 100mm fan stuck to the back is going to have far more overall airflow than that little fan stuck to the heatsink.

(which isn't directly moving any air in/out of the case at all, it just moves it across the heatsink and convection does the rest)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on December 18, 2023, 12:57:07 pm
Indeed, that's less than I expected. The DHO1000 dialog shows much more info.

Not really. All it says is that "ambient temp" is a degree or two less than chip temp.

What's "ambient temp" anyway? was that screenshot taken in a room at 45 Celsius?

Umm -- when I look at the dialog, I also see temperature measurements for the ADC and (presumably) the leftmost and rightmost front-end amplifier?

The "ambient temperature" readings are obviously not room temperature, but apparently the immediate environment of the respective chips. I have wondered about those too: Did Rigol actually populate NTCs next to each of these four chips? It's the first model using the new chipset, so maybe they wanted to play it safe?

Not my own screenshot, btw. I took it from another thread (https://www.eevblog.com/forum/testgear/hacking-the-hdo1khdo4k-rigol-12-bit-scope/msg4619431/#msg4619431) which discusses tweaking the DHO1000 fan via its PWM control.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on December 18, 2023, 01:09:04 pm
Indeed, that's less than I expected. The DHO1000 dialog shows much more info.

Not really. All it says is that "ambient temp" is a degree or two less than chip temp.

What's "ambient temp" anyway? was that screenshot taken in a room at 45 Celsius?

Umm -- when I look at the dialog, I also see temperature measurements for the ADC and (presumably) the leftmost and rightmost front-end amplifier?

The "ambient temperature" readings are obviously not room temperature, but apparently the immediate environment of the respective chips. I have wondered about those too: Did Rigol actually populate NTCs next to each of these four chips? It's the first model using the new chipset, so maybe they wanted to play it safe?

Not my own screenshot, btw. I took it from another thread (https://www.eevblog.com/forum/testgear/hacking-the-hdo1khdo4k-rigol-12-bit-scope/msg4619431/#msg4619431) which discusses tweaking the DHO1000 fan via its PWM control.

Most chips with any complexity have built in temp measurements. Otherwise, mostly diodes are used as measurement sensors on PCBs.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on December 18, 2023, 01:28:56 pm
Most chips with any complexity have built in temp measurements. Otherwise, mostly diodes are used as measurement sensors on PCBs.

Did you look at the screenshot? For each chip there's an internal temperature readout (obvioulsy from a built-in sensor) plus an "ambient" temperature. It's the latter which we were discussing.

Whether it's a diode or a temperature-dependent resistor, it looks like Rigol went to the effort of populating four of them (plus providing some readout), so they can monitor all chips attached to the central heat spreader. Looks like they planned for a nice, temperature-controlled cooling solution for the DHO1000 and 4000, since PWM control for the fans has also been prepared. Unfortunately it is not enabled in software so far; the fans run at a constant and relatively high speed.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Randy222 on December 18, 2023, 02:02:35 pm
Depends. If there is a buck power supply outside the single heatsink and the airflow in the case is too low, an overheat and a fault in this regulator will cause a major malfunction. The voltage at the input can reach the output. I have seen laptops in this situation.

A 100mm fan stuck to the back is going to have far more overall airflow than that little fan stuck to the heatsink.

(which isn't directly moving any air in/out of the case at all, it just moves it across the heatsink and convection does the rest)
It does push air out the top and bottom vents on my 804, can noticebly feel air being forced out.
Since it's a 2-wire fan I don't see how the rpm's are monitored, so my goal is to slow the internal fan and use an external 90x15mm to push air in.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on December 18, 2023, 02:22:51 pm
It does push air out the top and bottom vents on my 804, can noticebly feel air being forced out.

Yeah, you're right. There's air coming out under the handle where the heatsink fins are very close to the vent.

There's nothing on the vents at the top though, which is where the "power" components mentioned are.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on December 18, 2023, 08:26:45 pm
Most chips with any complexity have built in temp measurements. Otherwise, mostly diodes are used as measurement sensors on PCBs.

Did you look at the screenshot? For each chip there's an internal temperature readout (obvioulsy from a built-in sensor) plus an "ambient" temperature. It's the latter which we were discussing.

Whether it's a diode or a temperature-dependent resistor, it looks like Rigol went to the effort of populating four of them (plus providing some readout), so they can monitor all chips attached to the central heat spreader. Looks like they planned for a nice, temperature-controlled cooling solution for the DHO1000 and 4000, since PWM control for the fans has also been prepared. Unfortunately it is not enabled in software so far; the fans run at a constant and relatively high speed.

Sorry, didn't look at screenshot 5 posts above..
What you are saying does not contradict with what I said. There are bunch of chips that have on chip and aux external temp sensors. RK3399 has built in 2 ADC channels for temp sensors (all you need is few analog multiplexers and you can have 16ch of temp no problem). Sensors are cheap and it is good that they populated them all. That is always better then too little. I don't know what is your room temp, but temps shown are not very high. Let's hope they provide temp regulation in code, it certainly looks like there is headroom for it on DHO1000...
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on December 18, 2023, 09:10:19 pm
I'm a little surprised that the DHO800 only evaluates the CPU temperatures, up to now the software was basically the same, so I would have expected at least the ADC temperatures to be included.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Randy222 on December 19, 2023, 09:17:16 pm
I may have missed it, what was the end-user fix to get FFT flattop working correctly?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on December 19, 2023, 09:23:01 pm
Apart from what the user Turbotom himself changed, there is still no firmware update that has fixed this bug.
Perhaps rigol doesn't know either, because an MSO5000 user has already reported that it is the same with this model.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on December 19, 2023, 09:35:27 pm
I may have missed it, what was the end-user fix to get FFT flattop working correctly?

TurboTom's fix is to replace the file which contains the window function's weight coefficients. Described here (https://www.eevblog.com/forum/testgear/hacking-the-hdo1khdo4k-rigol-12-bit-scope/msg5202903/#msg5202903) with step-by-step instructions.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Noy on December 20, 2023, 08:25:01 am
I'm in trouble..
Should i get a DH804 (hacked) or a DHO1074 mated to my MSO5354?
I know there is the discount for the DHO1074 currently, but still then it is nearly 1/3 more on top..

And my desk is space limited.. The size of the DHO804 is really nice / fitable ..
And i think it is enough for a MSO5k addition..? I only need / would like to have it for power supply checking / using with my current clamps..
The stuff where 12bit are nice (but do i really need it ?? )... For my main work (mostly digital stuff) i like the >350MHz BW / 8GS.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on December 20, 2023, 09:16:33 am
I'm in trouble..
Should i get a DH804 (hacked) or a DHO1074 mated to my MSO5354?
I know there is the discount for the DHO1074 currently, but still then it is nearly 1/3 more on top..

And my desk is space limited.. The size of the DHO804 is really nice / fitable ..
And i think it is enough for a MSO5k addition..? I only need / would like to have it for power supply checking / using with my current clamps..
The stuff where 12bit are nice (but do i really need it ?? )... For my main work (mostly digital stuff) i like the >350MHz BW / 8GS.

DHO1074 .

7" screen is really tiny...
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Noy on December 20, 2023, 09:25:13 am
Sure but i can use my PC Monitor / i'm using a HDMI Grabber on my 5k for documentation purpose..
And i can use the webserver.

The 8" from MSO5k are enough.. My Hameg HMO3524 which maybe has to leave (shelf space for DHO804) has less than 7".
So Display size is not a concern for me i think..
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on December 20, 2023, 09:45:51 am
Sure but i can use my PC Monitor / i'm using a HDMI Grabber on my 5k for documentation purpose..
And i can use the webserver.

The 8" from MSO5k are enough.. My Hameg HMO3524 which maybe has to leave (shelf space for DHO804) has less than 7".
So Display size is not a concern for me i think..

So you already know what you want but want us to confirm it?

DHO1000 is class above DHO800 in every respect. If you really want a scope from DHO series (and no other type/brand) DHO1000 is much more for your money, at the price it is now..
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: TurboTom on December 20, 2023, 10:00:10 am
+1 And since the Black Friday offers resulted in many new owners of this scope, a new "hacking wave" is underway which may present us with quite some new, cool features soon that so far were only available to the DHO4000 owners (fingers crossed...  ;) ).
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Noy on December 20, 2023, 10:42:25 am
Not really a "confirm"...
The question is, is it worth to spend 1/3 more money on top to get the DHO1000 if i already have a MSO5k as main scope..
The DHO800/DHO1000 would only be used for switching regulator / in combination with a CP2100A..
My question is, are 12bit are worth enough to get a 2. scope...?

I think 12bit are the main advantage.. anything else should better on MSO5k ? For HF / FFT / Bodeplot i have a Siglent SVA..


And regarding DHO1k hacking.. I think unless you get a spare ADC everything is squeezed out of the DHO1k until now..
And it looks like DHO1k is phasing out? So maybe it will be dropped from rigol? DHO800 will be a better "cash cow"?


Two points pro DHO1K are the 14/16bit mode which the DHO800 not has?
And the 10MHz ref in is nice to be used with my GPSDO but would this be a big advantage?? I don't know.. on the MSO5k it would probably more helpfull..?

Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on December 20, 2023, 11:51:51 am
I only need / would like to have it for power supply checking / using with my current clamps.

If you want to potentially do more in-depth work there: Neither the DHO800/900 nor the DHO1000 series offer Rigol's Power Analysis option. For the DHO1000, its big brother (the 4000 model) does support Power Analysis, and the "advanced hacking" approaches TurboTom mentioned should be able to unlock that option on the DHO1000 too. This is however work in progress, and there is no guarantee that it will be made available as a ready-to-use hack.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on December 20, 2023, 12:51:11 pm
And regarding DHO1k hacking.. I think unless you get a spare ADC everything is squeezed out of the DHO1k until now..
And it looks like DHO1k is phasing out? So maybe it will be dropped from rigol? DHO800 will be a better "cash cow"?

The recent hacking approach (patching some "which functions are supported here?" calls in the Auklet Android app) has been able to unlock the 50 Ohm inputs and other features normally reserved for the DHO4000, without the unwanted side effects of assuming the dual-ADC configuration of the 4000.

There is some speculation that the original DHO1000 series might be phased out, based on the large discounts currently offered. But reassuringly, the DHO4000 as well as the DHO120xU (recently introduced in China) share the same firmware. So I would hope that future maintenance/upgrade releases will be made available for the DHO1000 tooo, even if it should be discontinued.

Quote
Two points pro DHO1K are the 14/16bit mode which the DHO800 not has?
And the 10MHz ref in is nice to be used with my GPSDO but would this be a big advantage?? I don't know.. on the MSO5k it would probably more helpfull..?

If you want to use the DHO as your "precision scope", the 10 MHz reference might make sense. The 14/16 bit modes (with significantly reduced bandwidth) certainly do.

There are various additional aspects where the 1000 series is ahead of the 800/900; whether they are important to you, only you can decide: Separate EXT trigger input, 200 MHz usable in 4-channel mode (at 500 MSa/s per channel), higher waveform update rate, faster boot time, automated measurements in cursor-defined regions...

For me personally, the larger form factor is an important argument in favor of the 1000. It is not just the absolute screen size, but also its higher resolution which leaves more spave for "net content". For my taste, the relatively large control elements and window frames leave too little room for trace display on the DHO800. Also, I prefer the built-in power supply, but realize that others might see the external USB-C power as an advantage.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Noy on December 20, 2023, 01:12:44 pm

The recent hacking approach (patching some "which functions are supported here?" calls in the Auklet Android app) has been able to unlock the 50 Ohm inputs and other features normally reserved for the DHO4000, without the unwanted side effects of assuming the dual-ADC configuration of the 4000.


OK that was new to me. I thought 50Ohm input wasn't working on DHO1k even with hacking..
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on December 23, 2023, 06:44:25 pm
I have started to "play through" the Batronix demo board again with the rigol.
I will probably upload the results to googledrive.
I already have a few pictures in the box today.
Note to self: In the pass/fail menu do not activate the screenshot at fail, but save it yourself - otherwise the save message will be included in the picture.
DS17: Demo Acquisitionmode Normal/Average (16x)
DS18/19: Demo Acquisitionmode Normal/Peak
DS20: Demo cursors
DS21-DS24: Demo measurements, several modes
DS25: Demo persistence 1sec
DS26/DS27: Demo Pass/Fail

Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on December 26, 2023, 03:40:17 pm
I had to wait for dinner a while ago, so I did a little noise measurement on a channel when there was nothing on it.
Once with 50ohm termination, once blank 1Mohm, full bandwidth (200Mhz), 20Mhz limited.
Then once at 1µs/div, 1ms/div.
It really is a Rigol scope, it's hard to believe given the values if you had an MSO5354 like I did back then... ;)
(open a pic in a new tab, then zoom in for better viewing the values)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: gf on December 26, 2023, 06:35:29 pm
Once with 50ohm termination, once blank 1Mohm, full bandwidth (200Mhz), 20Mhz limited.
Then once at 1µs/div, 1ms/div.

Hmmm... Why is there so much difference between 1.25GSa/s and 625MSa/s?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Randy222 on December 26, 2023, 06:53:28 pm
On the DHO804, why does the scope lose signal sync if the vertical scale is increased?
Example;
Ch1 on the internal 1kHz 3v peak signal, set trigger to 1v, but then dial up the scale to 10v/div. The trigger does not change, so why the scope lose sync on the square wave (dancing signal)?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on December 26, 2023, 07:45:46 pm
Once with 50ohm termination, once blank 1Mohm, full bandwidth (200Mhz), 20Mhz limited.
Then once at 1µs/div, 1ms/div.

Hmmm... Why is there so much difference between 1.25GSa/s and 625MSa/s?
1µs/div as opposed to 1ms/div i would presume, not the sampling rate itself?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on December 26, 2023, 07:46:53 pm
Hmmm... Why is there so much difference between 1.25GSa/s and 625MSa/s?
If I reduce it from 1.25GSa/s  to 312MSa/s(by adding channels) at 1µs/div, nothing happens.
As the memory depth increases, so does the noise, see pictures (Auto, 10M, 50Mpts, 1Mohm termination, full bandwidth).
I'll take a closer look tomorrow or later.

Title: Re: Rigol DHO804 Test and Compare Thread
Post by: gf on December 26, 2023, 08:05:42 pm
As the memory depth increases, so does the noise, see pictures

Very strange. The standard deviation of noise samples should not depend significantly on the memory depth (except when the number of samples is very small).

Could this be related to the mapping of the samples to the screen?
Are the measurements taken directly from the captured samples or from the screen data?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on December 26, 2023, 08:13:31 pm
I can't tell you how Rigol handles it.
I can test tomorrow whether the measured values are only taken from the screen.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on December 26, 2023, 08:15:27 pm
On the DHO804, why does the scope lose signal sync if the vertical scale is increased?
Example;
Ch1 on the internal 1kHz 3v peak signal, set trigger to 1v, but then dial up the scale to 10v/div. The trigger does not change, so why the scope lose sync on the square wave (dancing signal)?

Have a look at the data sheet under "Trigger Sensivity".
It says 0.5div, at 10V/div and a 3V signal it is no wonder why it no longer triggers.

Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on December 26, 2023, 08:18:23 pm
Quote
The standard deviation of noise samples should not depend significantly on the memory depth (except when the number of samples is very small).

Here is another picture at 10ms/div, automemory (50Ohm).
(https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/?action=dlattach;attach=1963200;image)

I'll get back to it tomorrow and "drive through" everything.

Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Performa01 on December 26, 2023, 08:48:00 pm
As the memory depth increases, so does the noise, see pictures

Very strange. The standard deviation of noise samples should not depend significantly on the memory depth (except when the number of samples is very small).

Could this be related to the mapping of the samples to the screen?
Are the measurements taken directly from the captured samples or from the screen data?
The differences come from the very pronounced 1/f noise characteristic of scope frontends. Faster time base setting rises the lower bandwidth limit, thus cutting off a significant portion of the LF noise.

For example, a DSO with 1 GSa/s and 10 horizontal divisions (and automatic memory management) will have a record length of just 10 kpts and a lower bandwidth limit of 100 kHz at a time base setting of 1 µs/div.
The same DSO will have a record length of 10 Mpts and a lower bandwidth limit of 100 Hz at a timebase of 1 ms/div.


Title: Re: Rigol DHO804 Test and Compare Thread
Post by: gf on December 26, 2023, 09:42:49 pm
The differences come from the very pronounced 1/f noise characteristic of scope frontends.

Oh sh*t, I didn't expect it to be that much :phew:
Your explanation makes sense, of course.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on December 26, 2023, 10:01:12 pm
That sounds sensible, the longer the time base, the lower the lower cut-off frequency, the higher the noise.
You know what, I'm trying it out now, from the living room (scope is on the router in the study). ;)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: mawyatt on December 26, 2023, 10:22:55 pm
The differences come from the very pronounced 1/f noise characteristic of scope frontends.

Oh sh*t, I didn't expect it to be that much :phew:
Your explanation makes sense, of course.

If the Rigol front end chip is implemented in pure CMOS then likely a relatively high 1/f corner. Scope front ends don't/can't take advantage of signal processing like CAZ and Chopping which help reduce 1/f noise as well as offsets.

Some utilize bipolar front ends, often SiGe or SiGe BiCMOS, which have good BW and low 1/f corners, but tend to be more expensive, with fewer chip foundry sources available.

Best,
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on December 26, 2023, 10:38:15 pm
So...
The scope is now the only thing that was on in the room, even the light was off, so the noise values are correspondingly lower compared to before.
Input open, 1Mohm, full bandwidth, auto-memory.
Starting at 1µs/div.
The values increase up to 1ms/div, after that no more.

Title: Re: Rigol DHO804 Test and Compare Thread
Post by: pakakezu on December 27, 2023, 08:31:47 am
Maybe a bit unrelated. But i could not find the file format for the ARB waveform for the DHO924S. Looked in the programming and user manual. Can select csv from the menu but shows load fail if i load a saved trace.

I expected the arb file to be selectable and even uploadable from SCPI but only the arb mode can be seleceted without specifics.

If someone managed to output an arb trace can please post how the csv should look like?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Performa01 on December 27, 2023, 08:45:31 am
If the Rigol front end chip is implemented in pure CMOS then likely a relatively high 1/f corner. Scope front ends don't/can't take advantage of signal processing like CAZ and Chopping which help reduce 1/f noise as well as offsets.
This is only the harmless part of the story.

The major contribution to the extremely pronounced 1/f noise is the LF path of the split path input buffer.

The HF path is not bad at all and its noise can be well below 3 nV/sqrt(Hz) at e.g. 10 MHz.

The LF path on the other hand has a noise figure of up to 20 dB by design - in addition to the 1/f noise of the FET amplifier utilized here. Bipolar wouldn't be an option since high input impedance is required, and it is almost irrelevant because of the high NF by design mentioned before.

The crossover frequency between LF and HF path is usually only a few kHz, yet the LF path affects the noise of the HF path up to at least 100 kHz.

In practice we get the expected 1/f noise characteristics down to about 100 kHz and  see an excessive increase in noise below 10 kHz. The reason why even lower bandwidth limits than 100 Hz would not make much of a difference anymore might be the small portion of the total bandwidth.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: core on December 27, 2023, 12:39:05 pm
I have started to "play through" the Batronix demo board again with the rigol.
I will probably upload the results to googledrive.
I already have a few pictures in the box today.
Note to self: In the pass/fail menu do not activate the screenshot at fail, but save it yourself - otherwise the save message will be included in the picture.
DS17: Demo Acquisitionmode Normal/Average (16x)
DS18/19: Demo Acquisitionmode Normal/Peak
DS20: Demo cursors
DS21-DS24: Demo measurements, several modes
DS25: Demo persistence 1sec
DS26/DS27: Demo Pass/Fail

Please go through all the tests on this demo board, as much as you have time to do so. Very interesting.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on December 27, 2023, 01:36:51 pm
Promised. ;)

I still have some time, all scopes except the 1104X-E are back to work.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Randy222 on December 27, 2023, 03:06:45 pm
On the DHO804, why does the scope lose signal sync if the vertical scale is increased?
Example;
Ch1 on the internal 1kHz 3v peak signal, set trigger to 1v, but then dial up the scale to 10v/div. The trigger does not change, so why the scope lose sync on the square wave (dancing signal)?

Have a look at the data sheet under "Trigger Sensivity".
It says 0.5div, at 10V/div and a 3V signal it is no wonder why it no longer triggers.
Trigger is based on the display? If the signal is 3v and the trigger is 1v, why should it matter what the V/div is set to?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on December 27, 2023, 03:53:48 pm
Trigger is based on the display? If the signal is 3v and the trigger is 1v, why should it matter what the V/div is set to?

Trigger hysteresis is based on the vertical sensitivity, it seems. You set the trigger threshold to 1V, and that's where it will remain. But there is no independent control over what is considered a significant signal excursion across the threshold (which leads to a trigger event), rather than noise. That is derived from your vertical sensitivity setting (V/div).

Not sure whether that's how other scopes commonly do it? Are there scopes which give you a separate hysteresis control?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on December 27, 2023, 05:12:08 pm
I have just tried this on the 1104X-E and it is exactly the same.
But it makes no sense, you can hardly see anything of the 3V signal at 10V/div.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: 2N3055 on December 27, 2023, 06:03:35 pm
On the DHO804, why does the scope lose signal sync if the vertical scale is increased?
Example;
Ch1 on the internal 1kHz 3v peak signal, set trigger to 1v, but then dial up the scale to 10v/div. The trigger does not change, so why the scope lose sync on the square wave (dancing signal)?

Have a look at the data sheet under "Trigger Sensivity".
It says 0.5div, at 10V/div and a 3V signal it is no wonder why it no longer triggers.
Trigger is based on the display? If the signal is 3v and the trigger is 1v, why should it matter what the V/div is set to?

Trigger is not based on display.

Even on analog scope minimum signal amplitude for reliable triggering will be based on certain percentage of dynamic range, i.e. input sensitivity.

Ths scope has digital trigger. It works on signal after ADC has sampled it... So if you have signal that is less than step of ADC you cannot trigger on it, right?  And of course you don't need only few steps of ADC, because you need hysteresis, and enough sample points to interpolate curve through trigger point with enough accuracy...
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Randy222 on December 27, 2023, 06:21:42 pm
I have just tried this on the 1104X-E and it is exactly the same.
But it makes no sense, you can hardly see anything of the 3V signal at 10V/div.
Try 5V/div 1V trigger, which fails to sync on the Rigol.
The signal is the signal in the front-end, trigger setting is relative to signal, so why can't it display it, even if squashed in the display, a 10V/div makes a 3v signal look almost flat on a small 7" screen. What if the actual screen size was 14" with same number of div boxes making a div box physically bigger on the screen, that squashed line on 7" screen suddenly is not so squashed on a 14" screen.

Is it just that it did actually trigger but the device can't paint it to the screen?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: ebastler on December 27, 2023, 07:53:20 pm
The signal is the signal in the front-end, trigger setting is relative to signal, so why can't it display it, even if squashed in the display, a 10V/div makes a 3v signal look almost flat on a small 7" screen. What if the actual screen size was 14" with same number of div boxes making a div box physically bigger on the screen, that squashed line on 7" screen suddenly is not so squashed on a 14" screen.

Is it just that it did actually trigger but the device can't paint it to the screen?

I'm afraid you are on the wrong track there. Yes, "the signal is in the front-end". But it is then amplified or attenuated according to your V/div setting, A/D-converted, and the trigger engine works based on those digital data.

If you change the V/div setting, your "trigger setting" does indeed not change: As mentioned before, the trigger threshold you have set will remain unchanged. (I.e. the scope will adjust its ADC count value for the trigger threshold, such that the trigger threshold's voltage remains unchanged.) But the trigger hysteresis, i.e, the signal swing required to detect a "significant" crossing of the trigger threshold, will change.

The hysteresis gets larger as you go to higher V/div settings. That makes sense from a technical perspective: The scope cannot determine an accurate trigger time from just a few ADC counts of signal swing.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on January 10, 2024, 09:59:04 pm
Finally...
After excactly 3 month of testing my conclusion, only from my point of view, of course.
Summarized in pros and cons:

+Very compact housing with external power supply unit.
+Sharp 7" display with high resolution
+Very low noise, native 12 bit vertical resolution
+Very clear, easy-to-use user interface.
+Unique window function in this price range and far beyond.
+Easy to hack
+Inexpensive

-Touch function in the screen size can no longer be used only with fingers
-No hires mode (14, 16 bit)
-Sample rate drops to 312.5 MSa/s from 3 active channels, must be kept in mind when displaying high-frequency signals
-No bodeplot
-Memory drops to a meager 1Mpt when all channels are active(original state)
-Few decoding functions
-No upgradeable options(original state)
-Relatively useless "ultra acquisition" mode
-Poorly equipped FFT function, also error-prone
-Various inconsistencies in the software in general
-Only one usb port
-Somewhat high-frequency sounding fan
-Limited window functions

As I said, just my impressions, I won't compare it with other scopes.
Some, if not many negative points could easily be corrected by rigol via the software, but unfortunately we all know that probably won't happen.
Instead, the users (Turbotom, FFT) have to fix their bugs - very embarrassing.
But that doesn't mean that you can't work with these scopes, of course you can.
After the first firmware update, I didn't experience any more crashes.
And if you don't need a bodeplot and only rarely use FFT, then it's a good scope with some innovative new features compared to older models in this price range.
But if rigol does nothing more to the scope and if the SDS800X HD becomes available on the world market, at a similar price, then it will be very, very difficult to find reasons to buy it, except perhaps that you wouldn't buy anything from the competition.
But it's not currently available, so the DHO800 is the choice if you don't want an older entry-level scope.

That´s all folks, thanks for reading.

Martin
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Randy222 on January 11, 2024, 12:34:53 am
The FFT cal file is fixed using the info from the DHO1000 thread.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: rpro on January 11, 2024, 02:53:00 am
-Touch function in the screen size can no longer be used only with fingers
-No hires mode (14, 16 bit)
-Sample rate drops to 312.5 MSa/s from 3 active channels, must be kept in mind when displaying high-frequency signals
-No bodeplot
-Memory drops to a meager 1Mpt when all channels are active(original state)
-Few decoding functions
-No upgradeable options(original state)
-Relatively useless "ultra acquisition" mode
-Poorly equipped FFT function, also error-prone
-Various inconsistencies in the software in general
-Only one usb port
-Somewhat high-frequency sounding fan
-Limited window functions

Thank you for your summary.  While I generally agree with your list of pros and cons, and observations, I would like to add a few observations of my own that may help others:

1. I found the x-y functionality more responsive and featured than in other low-priced scopes.
2. The scope hdmi output makes it very convenient to add a HD monitor, that I use with a wireless mouse all the time. With this setup (using an USB hub), on the scope I mostly tend to use the flex knobs, (for which I find their "continuous" feel convenient.)   
3. While the scope has no upgradeable options for sale, it can be easily hacked to higher frequencies, which for $400 makes it a bargain if you are looking for a 12-bit 200/300 MHz scope (measured @ 1.25Gsa/s with 1-ch.), with more memory, additional decoders, 200uV/div and 2ns/div scales, and with very low noise (to complement an 8-bit scope like the MSO5000).  The hacks can be literally changed in seconds, via well developed adb methods that can be found in this forum.
4. While the FFT can be (and should be) vastly improved, its particularly fast refresh rate makes it amenable to be used with (python/pyvisa) scripts to quickly acquire FFT traces, that can be further processed for averaging, peak/max holding, etc. (For example, I have scripts with aliases defined on my Mac to perform these tasks (and the hacks) with a couple of keystrokes on-demand. You can find an example script on this thread.) 
5. My hearing may not be very good, but this scope is literally significantly quieter than any other scope with an OEM fan that I have heard. (I have returned a very popular scope because of its fan noise, and hence I consider myself relatively sensitive in this regard, yet I have really no issues with the fan noise of this scope.) 
6. While the windowing system could have more features, I have found its flexibility almost sufficient when used with a 22 inch monitor, as I normally do. Also, the Android os (the scope runs on) offers additional useful screen features. For example, I like being able to adjust the overall scope screen brightness as needed, a feature unfortunately not present in some other popular scopes. 
7. To remain competitive, I expect and hope Rigol will significantly improve this scope software (and release process) in the future. This thread and others have a wealth of bug finds and suggestions to help that end.
 
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on January 11, 2024, 08:21:55 pm
Hi,
Good and important additions, I would like to comment on them from my point of view.
To:
1) I agree, I hadn't mentioned it.
2) Same
3) See my list (original state)
4) I was interested in what the scope itself can do, what you can use directly - if it has an FFT function, I want to be able to use it immediately as I am used to from other scopes and not just indirectly.
5) The sound is high frequency, but certainly not the loudest in my lab.
The DS1054Z is incomparably louder, even an SDS1104 is louder.
However, the high frequency becomes annoying over time, but that might be different for everyone, hence the emphasis on personal opinion.
7) I really hope so for all Rigol owners and those interested in the future.
Only I don't believe in it, I'm a bit branded, owned the DS1054Z, DS2072, MSO5074, DHO804 and had the DHO4204 on loan.
And had active contact with rigol support between 2018 and 2020.
I know Rigol a little, you could say.


Title: Re: Rigol DHO804 Test and Compare Thread
Post by: tiagoalecio on June 30, 2024, 01:33:08 pm
Thank you very much, you saved my life. :-+ :-+
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: KedasProbe on September 28, 2024, 07:40:14 am
Some info on the function generator warm up time and accuracy of the DHO914S
t0 = is power button on
It was measured with the FA-5, accuracy less than 10mHz

second picture is stability after about 1 hour.

(This is with the first Firmware, may be different with the latest one)

Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on September 28, 2024, 04:12:21 pm
Nice information but maybe in the "wrong" thread... :-+
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: TurboTom on October 19, 2024, 02:36:00 pm
I'm not sure if this has been reported here before, but since I couldn't resist to get one of the DHO804 at the current bargain price (~370€, VAT included) as my new carry-around scope, I found Rigol includes a different PSU now! This time, it's a Delta Electronics thingy with USB-C connector plus a proprietary, latching shell that mates with the DHO800/900 orifices around the power socket. This way, at least pulling the cable won't put all the stress on the scope's power connector / PCB. On the other hand, removing the power connector is a fiddly thing with rather big hands. Anyway, I prefer this over the standard USB C connector since it protects the scope significantly better.

This "bargain" unit apparently is an instrument meant for the Chinese domestic market, so I don't know if the recently shipped "standard" export versions include this Delta PSU as well.

Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Fungus on October 19, 2024, 03:36:13 pm
Removed.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: RogerG on October 19, 2024, 04:11:23 pm
Please have a look at the data label. It delivers all the USB PD voltages between 5 and 20 Volts. This type of power supply is also delivered with the new Rigol function generators and multimeters with DHO form factor.

I was always wondering why the scopes dont't come with it. Now Rigol has changed that.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: RoGeorge on October 19, 2024, 04:17:05 pm
I couldn't resist to get one of the DHO804 at the current bargain price (~370€, VAT included)

Is 370 with or without VAT?
Where did you found DHO804 at 300€ + VAT, please?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: iMo on October 19, 2024, 04:31:14 pm
https://www.tequipment.net/Rigol/DHO804/Digital-Oscilloscopes/ (https://www.tequipment.net/Rigol/DHO804/Digital-Oscilloscopes/)

439->373 special offer

Not sure it is VAT inclusive, however..
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: TurboTom on October 19, 2024, 06:32:39 pm
Is 370 with or without VAT?
Where did you found DHO804 at 300€ + VAT, please?

On Banggood, two weeks ago the "DHO804" was offered for 367.99€, shipping and 19% German VAT included. I opted for the shipping insurance and put in a small coupon, so I ended up just below 370€. Peculiarly, the advertisement nowhere mentioned the brand "Rigol", and even in the photos of the scope, the phrase was removed. Obviously, I received the scope in its original Rigol box, yet with chinese language preset (no-brainer) and a "mickey mouse" mains cable with a chinese plug at the other end. Also no big deal.

Unfortunately, now you will only find the DHO802 at that price there. I don't know if it was an error and the "early birds" got lucky or if they simply ran out of stock...

Sorry for this unfortunate news.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: iMo on October 19, 2024, 06:42:48 pm
"Spurlos" in the invoice, like "Spurlos verschwunden".. Luckily you got it..  :D
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: TurboTom on October 19, 2024, 06:48:12 pm
"Spurlos" in the invoice, like "Spurlos verschwunden".. Luckily you got it..  :D

Yes, that's quite funny. But they e-mailed me a working tracking link right after they shipped the parcel. Maybe they were just too lazy to copy the tracking info to the invoice...
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: magic_smoke on October 21, 2024, 07:37:08 am
It went as low as 358,05€ weeks ago, and 350,57€ last May from Banggood. Is there a downside though? How can Banggod offer such a discount? Does Rigol know or support this?
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 21, 2024, 10:39:56 am
You will notice this when you register the product online and/or check the warranty.
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: TurboTom on October 21, 2024, 01:33:56 pm
You will notice this when you register the product online and/or check the warranty.

Not that I really worry about any warranty -- when I'm done with the scope, I'll have voided it many times anyway  8)

But just out of curiosity, I entered the S/N of mine on eu.rigol.com to check the warranty status, and here's what it tells:
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: iMo on October 21, 2024, 02:03:31 pm
It went as low as 358,05€ weeks ago, and 350,57€ last May from Banggood. Is there a downside though? How can Banggod offer such a discount? Does Rigol know or support this?

Greed is one of the seven deadly sins.. :)
Title: Re: Rigol DHO804 Test and Compare Thread
Post by: Martin72 on October 21, 2024, 02:51:38 pm
Plus.....See my signature. ;)