Rigol's New DHO800 Oscilloscope unbox & teardown

[switchabl]

I suppose it is technically possible that they are actually sampling at 2 or 4 GS/s and the ADC has the ability to filter and decimate digitally. Having a single ASIC across your product range can favour topologies that would normally be considered wasteful or unreasonably costly.

Then again, given some of the weird things they have done in the past, I wouldn't exactly be shocked if it turns out that the 250 MHz are just there to tick a box and lead to horrible aliasing.

We won't know until someone measures the frequency response with and without all channels enabled.

[Martin72]

If it were possible to hack the 804 not only to 100Mhz but even to 250Mhz, I could make the measurements when my 804 arrived.
I find that interesting anyway, this 250Mhz and 1.25GSa/s.
That doesn't fit from the logic if you add the DHO1000 and DHO4000 models.

[Fungus]

This is where a low cost logic analyzer can help as well.  Something like the DS Logic Plus can be a better investment than adding the LA option to many scopes, and even an $8 clone with Sigrock can sometimes provide more functionality than the LA add-on.

Yes, but none of those have a real-time view with triggering.

[Fungus]

Then again, given some of the weird things they have done in the past, I wouldn't exactly be shocked if it turns out that the 250 MHz are just there to tick a box and lead to horrible aliasing.

We won't know until someone measures the frequency response with and without all channels enabled.

Yep. I'm very interested to see what happens on the 250Mhz bandwidth models.

I'm sure the Siglent boys will have an extensive thread on the subject. 

[iMo]

..
It depends on type of antialiasing filter used . If filter is really sharp, 2,5X is starting point where it works. If you are using more traditional filter with Gausian response (slower roll off), then 4X or 5X might be needed.

Yep, would be great to see the real life measurements, as even the "Max" 100MHz BW with 312.5MS/s sampling rate would be something new, imho For 100Mhz BW I would expect at least 2GS/4=500MS per channel (even my vintage DS1062 I've been playing with is 2GS/s with 60MHz BW single channel, they write).

[thm_w]

This is where a low cost logic analyzer can help as well.  Something like the DS Logic Plus can be a better investment than adding the LA option to many scopes, and even an $8 clone with Sigrock can sometimes provide more functionality than the LA add-on.

Yes, but none of those have a real-time view with triggering.

You generally don't need real-time viewing on a logic analyzer, its just meaningless numbers streaming past. Triggering is available on a $80 DSLogic, which has far more protocols than any rigol. I have a diy PLA2216 and 99% of the time use a $8 sigrok clone or the dslogic.
Of course, personal preference may vary and has been discussed here 1000 times, some people don't like using the PC or need a portable LA. Just that dropping $400 on a LA probe and potentially an extra $200 for the DHO900 is hilariously poor value.

[nctnico]

..
It depends on type of antialiasing filter used . If filter is really sharp, 2,5X is starting point where it works. If you are using more traditional filter with Gausian response (slower roll off), then 4X or 5X might be needed.

Yep, would be great to see the real life measurements, as even the "Max" 100MHz BW with 312.5MS/s sampling rate would be something new, imho For 100Mhz BW I would expect at least 2GS/4=500MS per channel

Those days are long gone. A typical, well designed DSO has the maximum bandwidth right up to the samplerate divided by 2.5. That is a little below the frequency where sin x/x reconstruction stops working. This allows the user to choose between maximum bandwidth or a lower bandwidth with a Gaussian roll-off. A decent DSO typically has multiple bandwidth choices to give the user maximum flexibility.

[Fungus]

This thing is badly in need of a good and thorough review.

Yeah I'm also eagerly awaiting the first impressions, and especially how it stacks up against the SDS1104X-E.

Have you guys seen this video?


I haven't tried it yet (obviously) but all that UltraAcquire stuff is in the DHO800 manual with the exact same feature set.

Bottom line: These Rigol DHOs aren't just a "12-bit ADC", they're a game changer. A whole a new class of oscilloscope. Right now I wouldn't even be looking at the SDS1104X-E, I'd be either getting one of these or waiting to see how Siglent responds.

(PS: check out the way the UI works at 4:43  ... and I love the display at 6:00 )

[Fungus]

You generally don't need real-time viewing on a logic analyzer, its just meaningless numbers streaming past.

Yes, but that's the way usually I end up using it.

I've got one of those cheapo logic analyzers somewhere. It doesn't get used much. I'm typically looking at signal integrity or using it for software debugging so I need real time display with trigger.

I thought long and hard about getting a DHO900 instead of a DHO800 but the price of the logic probes put me off.

Rigol needs to fix that. You can charge those prices when the 'scope costs $2000 but not when it costs $400. They're just a bunch of wires with clips and a few comparators. They could probably sell them at cost price and make a ton of money from everybody buying the DHO900 instead of the DHO800 (everybody would pay $200 more for basically the same hardware).

I'll go with a 4-channel 'scope for now. It's worked for me so far.

[Martin72]

You'll get one soon, then you can work with it - that's something completely different than always "living" from reports, pictures and videos.
I, for example, have known since February what to expect.

or waiting to see how Siglent responds.

Possibly not at all.
Quality also has a price limit somewhere below which it is no longer possible to maintain the standards to which customers have become accustomed.

[Mortymore]

... but here given the price difference is only $100 MSRP between the 914S and the 924S, I think I'd probably just bite that bullet, ...

I'd say that $100 justifies the price difference with 4x 350MHz passive probes, instead of hacking a 912 from 125MHz to the 250MHz of the 924, and fell short with 4x 150MHz probes

[Fungus]

... but here given the price difference is only $100 MSRP between the 914S and the 924S, I think I'd probably just bite that bullet, ...

I'd say that $100 justifies the price difference with 4x 350MHz passive probes, instead of hacking a 912 from 125MHz to the 250MHz of the 924, and fell short with 4x 150MHz probes

I'd want to know what happens at 200MHz with 4 channels enabled before going for a 924.

[Nx-1997]

So, I replaced my scope's vendor.bin (DHO804) file with @hubertyoung's vendor file (DHO924). My scope became a DHO924 but there were vertical offset issues on every channel that couldn't be removed even with selfcal. At 250MHz, rise time with Leo Bodnar's pulse generator is 1.64ns.

Then I copied Dave's DHO814 SD card dump onto an SD card and inserted it into my scope. My scope is now a DHO814. I copied back my original cal data and performed a selfcal. The rise time is around 2.68ns.

Replacing the vendor file changes the scope's model. Cal data is stored in /rigol/data.

[Fungus]

So, I replaced my scope's vendor.bin (DHO804) file with @hubertyoung's vendor file (DHO924). My scope became a DHO924...
...rise time with Leo Bodnar's pulse generator is 1.64ns.

OK, so what happens if you enable 4 channels and feed it that pulse?

(or a 200MHz signal if you can do that?)

[Nx-1997]

The rise time increases as the sample rate (312MSa/s) goes down. This scope does not have equivalent-time sampling.

[ptluis]

No CAN decoding meh  

[souldevelop]

So, I replaced my scope's vendor.bin (DHO804) file with @hubertyoung's vendor file (DHO924). My scope became a DHO924 but there were vertical offset issues on every channel that couldn't be removed even with selfcal. At 250MHz, rise time with Leo Bodnar's pulse generator is 1.64ns.

Then I copied Dave's DHO814 SD card dump onto an SD card and inserted it into my scope. My scope is now a DHO814. I copied back my original cal data and performed a selfcal. The rise time is around 2.68ns.

Replacing the vendor file changes the scope's model. Cal data is stored in /rigol/data.

Have you tried the calibration of the built-in hidden debug mode? Crazy clicking on the menu <About Me > can enter debug mode and expect your results.

[EEVblog]

Delta replacement fan test.
TLDR, it's quieter if you run a thicker Delta it at 5V, about 2-3degC temp rise, but still not silent. The blades are just too close to the heatsink fins which generates extre noise.

[EEVblog]

Have you guys seen this video?

https://youtu.be/enBad0a1B2U

I've always wanted to do that talking head touch screen thing, I realised this after I got my non-touchscreen 70in TV for my talking head backdrops. It works really well.

[iMo]

..
It depends on type of antialiasing filter used . If filter is really sharp, 2,5X is starting point where it works. If you are using more traditional filter with Gausian response (slower roll off), then 4X or 5X might be needed.

Yep, would be great to see the real life measurements, as even the "Max" 100MHz BW with 312.5MS/s sampling rate would be something new, imho For 100Mhz BW I would expect at least 2GS/4=500MS per channel

Those days are long gone. A typical, well designed DSO has the maximum bandwidth right up to the samplerate divided by 2.5. That is a little below the frequency where sin x/x reconstruction stops working. This allows the user to choose between maximum bandwidth or a lower bandwidth with a Gaussian roll-off. A decent DSO typically has multiple bandwidth choices to give the user maximum flexibility.

Interesting.. How they do that with 250MHz BW and 312.5MS/s then?

The 250MHz DHO924 samples at 312.5 MSa/s for 3 or 4 channels enabled.

[mwb1100]

Interesting.. How they do that with 250MHz BW and 312.5MS/s then?

The 250MHz DHO924 samples at 312.5 MSa/s for 3 or 4 channels enabled.

They refer you to the section of the user guide that starts "A sample rate that is too low might have the following effects on the waveform:..."

[dreamcat4]

No CAN decoding meh  

yes but if a future contribution / pr ever updates the libsigrok (open source project) to support this family of scopes hardware... then you will be able to decode it over on a pc / laptop link connection. so that maybe? that then is not as convenient (especially for auto)... but then at least not any worse than having to resort to any other regular logic analyzer. since the scope itself just becomes like any another l.a.

we could also ask rigol as a firmware request: to add can bus decode

[iMo]

Interesting.. How they do that with 250MHz BW and 312.5MS/s then?

The 250MHz DHO924 samples at 312.5 MSa/s for 3 or 4 channels enabled.

They refer you to the section of the user guide that starts "A sample rate that is too low might have the following effects on the waveform:..."

Thanks, page 55 of the DHO900 user manual for reference (and yes, those are the issues you will encounter..). At least you got 625Msa/s with two channels enabled ("half channel mode"), they write..

This 800/900 series is indeed designed as, say, max 100MHz BW with max 2 channels, imho.

[Fungus]

Thanks, page 55 of the DHO900 user manual for reference (and yes, those are the issues you will encounter..).

Section 7.3... it's all laid out, at least they're open about it. They even detail all the problems, with pictures. 

It's a tough trade: Do you want full bandwidth with one or two channels? How often will a 200MHz signal make it all the way into the system in "All channels mode"? What effect will using the "150MHz" probes have?

Let the testing begin! 

[2N3055]

Have you guys seen this video?

Did you watch it?

That is cool looking display mode. But what it is used for?
If you have any kind of persistence, you can overlay millions of captures to look for existence of the glitch. It is an old technique.
There are no measurements while it is running or displaying it. No decoding..
What will you use it for? It looks cool on on a shelf in a store but what do you use it for?
It is just a marketing gimmick....

Many of those visualization modes are already there on other scopes. With segmented mode you can overlay segments on Keysight, even on older Rigols. With segmented and history mode you can overlay captures on Siglent too.  And they will measure and decode on that data...

What part of your process will it make so better that it will change your life?
That is definition of phrase "game changer".