Rigol's New DHO800 Oscilloscope unbox & teardown

[Kleinstein]

Dunno about you but I trust Dot mode and when I see a waveform from a Bodnar pulser without over/undershoots I am very suspicious of inaccurate waveform reconstruction.

Even the bottom of the heap 50 MHz SDS1052DL+ and right to current flagship model SDS6204A, both in Dot mode show us what should not be hidden as they also do in Vector mode.

The high end scope showed some ringing at the edges, but only very fast one and the rinding is also before the transistion, which is a bit suspecious. So even that ringing may be an artifact of the scope. The main point is showing no slow ringing. 

How much ringing one gets in the reconstructed waveform one than gets depends on the filter that is used to do the BW limiting - the slower overshoot is not really there but only an articat of the slower scopes and maybe a point depending on the actual input impedance of the different scopes. Near there BW limit the input impedance may be different from the simple 1 M + some 20 pF  as the nominal value and this can effect the pulser.  The reconstruction of the rigol scope with no overshoot could be just a result of the filter with a slower roll off - the front end and ADC that are in theory capable of much higher speed could alow for a rather good reconstruction, e.g. with the ADC interally using oversampling and averaging to get away with a less steep filter. The custom ADC chip may be more than just 1 simple 12 bit ADC.

Alternatively they could have also just choosen a different balance between ringing and aliasing - so avoid ringing and accept more aliasing.

[tautech]

tautech looks for his risetime waveform capture from Leo Bodnar......

[ebastler]

tautech looks for his risetime waveform capture from Leo Bodnar......

I gave a link to Leo's site in the post above.

[tautech]

tautech looks for his risetime waveform capture from Leo Bodnar......

Yeah well tell me there's no ringing in this:



Still there's a significant error in the stated RT by an order of magnitude.
1 GHz SDS5104X displays ringing too.

[dreamcat4]

ok so call be dumb or whatever. But: for an input filter (that creates a ringing)... it cannot be in the scope design as an adjustable parameter (at least: for some scopes)?

i.e. to calibrate or perhaps to adjust for improving on a specific task?

[tautech]

tautech looks for his risetime waveform capture from Leo Bodnar......

I gave a link to Leo's site in the post above.

You did and I'll give you another to the development of Leo's pulser where many screenshots show ringing.
https://www.eevblog.com/forum/projects/yet-another-fast-edge-pulse-generator/

[ebastler]

Yeah well tell me there's no ringing in this:

As I said above: There is no ringing on that scale, i.e. the timescale on which the Siglent scopes show ringing. In fact, every Siglent screenshot you shared seems to show ringing at a frequency in the range of the respective scope's bandwidth limit. It seems quite clear that the ringing is caused by the scopes' bandwidth limiting filters.

I don't mean to criticize the Siglent scopes here; as mentioned above, one can argue that it is a matter of philosophy or personal preference how the bandpass should be designed. Although I personally do prefer the smoother roll-off which is apparently used by R&S and Rigol -- lest I chase overshoots which aren't really in the signal.

[iMo]

tautech looks for his risetime waveform capture from Leo Bodnar......

Yeah well tell me there's no ringing in this:

Definitely not the 0.24/0.29ps..

[mawyatt]

I also wonder why some of you are so obsessed with FFT. What is it good for (in this category)? Many old scopes have it too. Practically useless. At least to what I've seen. You need it often? Get a spectrum analyzer! You need it once a year? Dump the data and use Octave.

As nctnico and iMo mentioned, the recent implementations of the DSO FFT can be quite useful indeed. If you search for the recent R&S FFT implementation videos this performance is impressive. Siglent does a good job, but is slow and lacks some features which would augment its' use (log frequency scale for example). We don't have a Rigol, so can't comment on their implementation other than what we've seen reviewed, which seems to indicate some areas lacking.

Long ago back in the old analog Tek scope days, we would take the vertical channel output from the lab Tek scopes and feed this into an HP SA so we could get the benefit of the scope channel inputs & probes (WB Hi Z and such), and see the Time Domain and Frequency Domain results, now the modern DSO does this for us!! Sure the DSO FFT has nowhere near the Dynamic Range of a proper SA, nor the upper frequency range, but has the benefit of the lower frequency range (SA usually don't drop below ~9KHz), and Time and Frequency Domain viewing.

There are speciality instruments like Signal Analyzers that cover the lower frequency ranges and have good DR, but they are dedicated expensive and bulky instruments. Here, when one employs a modern quality DSO FFT implementation, one appreciates the value and convenience of the DSO implemented FFT.

Sure there's lots of room for improvement, but please don't discount the value of a quality implemented FFT on a modern DSO, similar to discounting/utilizing the Bode function...but that's another discussion.

Wrt to the FFT parameters, this can be confusing when jumping between Time and Frequency Domains since the FFT bridges both, whereas the SA just deals in the Frequency Domain and simpler to visualize. Something that can help folks jumping between these domains is to realize they are "orthogonal or inverse" type domains, meaning that something Narrow in one domain is Wide in the other. For example; a narrow voltage pulse in the TD appears as a wide frequency response in the FD, and a narrow frequency response (sine) in the FD appears as a wide response in the TD (long cycles of sine)*.

So when one thinks of FFT resolution (narrow FD) this implies TD length (long), and the Sample Rate (high for narrow pulses) determines the frequency span (wide).

An interesting function is the Gaussian, which has the same general characteristics in both Time and Frequency Domains meaning the Time and frequency responses have the same shape. This was a reason for using Gaussian Shaped Pulses way back in the early days.

Anyway, these are just some concepts that might help get ones arms around the FFT.

* Here the assumption is the signal is continuous before and after the FFT capture window and leads into Windowing Functions which is another separate complex FFT topic.

Best,

[exe]

My friends, I think I'm on the market of buying a new scope. I've got my old and trusty micsig TO1004 which I love. The only thing that's a bit annoying is the UI is a bit slow (though still much faster than RTB2004). Also the screen is a bit too low in resolution (800x600). So I'm thinking of an upgrade.

TBH, I don't find a small form factor appealing as that means a tiny screen. So, I'd prefer a micsig with the screen taking most of the space, if only they had 12bit model. I'm also looking at vertical space. On my micsig I have 10 divisions, but on rigol it's only 8. Is there a way to get more? That would be useful for me, as even on my old micsig with averaging and DC offset I can make use of the whole screen.

BTW, I can scroll the waveform "outside" of the screen, like on the screenshot included. The signal is ~5.5V p-p, but I only display a top portion of it. No magnification or anything, I just put part of the trace below the screen (DC offset?). While it can't properly show value of low voltage (it's about 0.1V instead of displayed "2.12V?"), the top portion is correct, and doesn't contain any traces of frontend overload or something. It also can capture data at least one vertical division above what's on display. So, how's rigol in this regard?

Question 2: is there a "response" from Siglent? I mean, do they have any plans to release something new in 12bit world?

[Njk]

The HW in the new Rigol series is more advanced, but the FFT feature seems ported from the 8-bit series. With the new HW, the efforts to make it more convenient seems justifiable but it will likely take years for Rigol to do something. BTW, it's no problem to use it as is. Some preparation work is required from user, but it's a one-time effort, to calculate all the related settings in the table. Some time ago I did that for DS1000Z and similar table can be calculated for the new series.

It can be found on the internet that according to 2019 "Global and Chinese Electronic Measuring Instrument Industry Independent Market Report" by Frost & Sullivan, Rigol is one of the five leading manufacturers on the global oscilloscope market and is the only rated Chinese manufacturer. For a leading companies, it's natural to be on the conservative side and do not present the product such that it appears to perform better than it actually can. A position that the competitors usually just can't afford. Too much activity in the SW area can backfire, especially on not so experienced users, as it's demonstrated by the competitors. So it's not so bad, actually.

Edit: added the frequency span column in the table.

[Fungus]

TBH, I don't find a small form factor appealing as that means a tiny screen.

It's You can use any HDMI touch screen, as big as you want.

Question 2: is there a "response" from Siglent? I mean, do they have any plans to release something new in 12bit world?

Not at this price point.

The only hint at new devices is this: https://www.eevblog.com/forum/testgear/siglent-sds1000x-hd-coming/

[tautech]

My friends, I think I'm on the market of buying a new scope. I've got my old and trusty micsig TO1004 which I love. The only thing that's a bit annoying is the UI is a bit slow (though still much faster than RTB2004). Also the screen is a bit too low in resolution (800x600). So I'm thinking of an upgrade.

TBH, I don't find a small form factor appealing as that means a tiny screen. So, I'd prefer a micsig with the screen taking most of the space, if only they had 12bit model. I'm also looking at vertical space. On my micsig I have 10 divisions, but on rigol it's only 8. Is there a way to get more? That would be useful for me, as even on my old micsig with averaging and DC offset I can make use of the whole screen.

BTW, I can scroll the waveform "outside" of the screen, like on the screenshot included. The signal is ~5.5V p-p, but I only display a top portion of it. No magnification or anything, I just put part of the trace below the screen (DC offset?). While it can't properly show value of low voltage (it's about 0.1V instead of displayed "2.12V?"), the top portion is correct, and doesn't contain any traces of frontend overload or something. It also can capture data at least one vertical division above what's on display. So, how's rigol in this regard?

Question 2: is there a "response" from Siglent? I mean, do they have any plans to release something new in 12bit world?

All recent Siglent models offer Ref Position settings, for Horizontal when set to Fixed the H Pos marker remains fixed regardless of timebase settings when not in the 0s position.
For Vertical, a similar feature is available to much further extend channel vertical offset limits and allow vertical zoom in on the limits/peaks of the waveform. 

[exe]

BTW, nobody was surprised that it runs on android 7? It's a 7 years old OS, long-time discontinued. I guess, that was one of the ways to cut costs. The RK3399 is also from the same era. So, compatibility with newer android application will be limited (if it matters, not sure what I'd install on this scope).

[Veteran68]

I'm not an Android SME, but generally speaking it's not unusual for embedded systems to run on "mature" and even EOS versions of operating systems. They tend to be more stable and rock solid. I still see commercial kiosks, self-checkout systems, etc. running embedded versions of Windows XP and even 2000.

[TomKatt]

I don't think Android was selected as the OS for the ability to install apps.  It just needs to do it's job running the scope.  The only 'concern' I'd have is that of network security, but that is never really achievable and at least you can mitigate security issues with an appropriate firewall or similar.

[2N3055]

I don't think Android was selected as the OS for the ability to install apps.  It just needs to do it's job running the scope.  The only 'concern' I'd have is that of network security, but that is never really achievable and at least you can mitigate security issues with an appropriate firewall or similar.

Android was probably not even "chosen" but simply it pretty much came with the chip, ready to use...
That and the fact that once you start development you don't want any changes while in active development cycle is probably reason for the version.

[Fungus]

I'm not an Android SME, but generally speaking it's not unusual for embedded systems to run on "mature" and even EOS versions of operating systems. They tend to be more stable and rock solid. I still see commercial kiosks, self-checkout systems, etc. running embedded versions of Windows XP and even 2000.

Yep. The last thing you want when developing something like this is a daily popup saying "An update is available!!!"

People aren't supposed to be installing apps on these.

[hbozyq]

Are there any applications that you must install on a oscilloscope? Genshin?

[RAPo]

I really like the application that Micsig has added to their scopes.
A second one would be a good calculator.
An application for ftp-transfer would also be handy.

Are there any applications that you must install on a oscilloscope? Genshin?

[DaneLaw]

The age of these older legacy Android ROMs can also cause problems for third-party apks.
 Even at something as diversed as fx browser...when recording videos on the Micsig, I tend to just use the browser to upload the video to fx Youtube but it doesn't seem to play along anymore.
You can obviously browse EEVblog, or watch YouTube videos or dump all your scopedata directly into office programs on the scope .

What 7" display technology are Rigols DHO800 & 900 series using.. LCD "TFT or IPS".?

[Fungus]

An application for ftp-transfer would also be handy.

I use my micsig's Wifi FTP server all the time for copying screenshots to my PC. I hope there's a neat/simple way to make WiFi work on these new Rigols.

[ptluis]

An application for ftp-transfer would also be handy.

I use my micsig's Wifi FTP server all the time for copying screenshots to my PC. I hope there's a neat/simple way to make WiFi work on these new Rigols.

what's the micsig model you own? I haven't decided yet between this Rigol dho800 or the micsig sto1004c i need portability mostly.  i don't think the price difference between sato vs sto justifies the first vs features

[DaneLaw]

An application for ftp-transfer would also be handy.

I use my micsig's Wifi FTP server all the time for copying screenshots to my PC. I hope there's a neat/simple way to make WiFi work on these new Rigols.

what's the micsig model you own? I haven't decided yet between this Rigol dho800 or the micsig sto1004c i need portability mostly.  i don't think the price difference between sato vs sto justifies the first vs features

There isn't a STO1004C model as per se.
-there is STO1004 (4x 4way joystick + 19 buttons) current entryline, likely that model, you'r wondering about.
-there is STO1104C (7x rotary knobs + 23 buttons) previous line. (STO1000 & 2000 C/E line)
There are also differences in mem-depth and waveform update rate fx between STO1004 & STO1104C.. STO1104C seems to peak at 100.000 in practice, while STO1004 is 130.000 on paper.
STO1104C https://tinyurl.com/48ahf9y5

The DHO800/900 would also work great as a mobile scope, as you can suit it up with more or less any power bank delivering its protocol and piggyback ride that  on the back..
I guess the Rigol DHO800 & 900 series is using 15v PD charge protocol?
Just as I do with the Micsig, just with 12v power delivery tr-cable. (PD) even though it obviously got built-in battery
If you wanna use the scope outside screen brightness is also a factor to include.
Micsig 8" screen seems to top at a tad over 410nits with just a small blank white slide to check peak. (its screen is TFT LCD) I am not sure how bright the DHO 7" series are or what LCD panel tech its using..(TFT or IPS?)

 

[hbozyq]

A second one would be a good calculator.
An application for ftp-transfer would also be handy.

Are there any applications that you must install on a oscilloscope? Genshin?

I always got a casio calculator near my bench. Calculator with touch screen isn't a good idea.
It's do be shameful for lacking WIFI supporting. But I got some thumb drive for waveform storage or screenshots. So it's not a big deal to me.