Rigol's New DHO800 Oscilloscope unbox & teardown

[Fungus]

Rigol must have had something in mind when they implemented this.

Maybe it simply didn't work out as well as they thought it would in the design phase... 

(and the managers had already announced it so it couldn't be removed)

[AndyBig]

As I've said before, I don't think it's there for capturing single glitches.

I think it's there so you can visualize a glitch in context with what went just before/after it.

You can also see evolving waveforms in 3D.

Edit: And it has a much faster waveform update rate than normal record mode...

But that's exactly the point, Fungus.
What else do you want with a very fast update rate if not to be able to capture very short events?
These various display options are simply a graphical gimmick with no real added value.
Rigol must have had something in mind when they implemented this.
I'm tempted to write to them, even if the prospect of a reply seems rather slim at the moment, because I've still been waiting for an answer to a question for weeks.

Does this video not give you an idea of the benefits of ultravision?

[S2084]

I just downloaded yours from Google Drive and installed it. Initially there was an offset, after calibration it became normal. But I didn't understand why I needed this firmware. What she gives me. Moreover, it is not officially available on the sites. And I installed firmware 01.01 again.

[2N3055]

As I've said before, I don't think it's there for capturing single glitches.

I think it's there so you can visualize a glitch in context with what went just before/after it.

You can also see evolving waveforms in 3D.

Edit: And it has a much faster waveform update rate than normal record mode...

But that's exactly the point, Fungus.
What else do you want with a very fast update rate if not to be able to capture very short events?
These various display options are simply a graphical gimmick with no real added value.
Rigol must have had something in mind when they implemented this.
I'm tempted to write to them, even if the prospect of a reply seems rather slim at the moment, because I've still been waiting for an answer to a question for weeks.

Does this video not give you an idea of the benefits of ultravision?

In that video there is cca 2 minutes of Ultra vision. 3  modes are shown and I personally don't understand what do you could use it for that is not already covered with persistence, analog intensity, color grading and segmented/history modes.
Not to mention that he demonstrated thing on the screen that is almost 2m diagonally. What do you see on a 7"?

They do look cool, but what is it used for? An example of work done with it? I'm not saying that there might not be some use (except for being cool for demonstrations and demos on exhibitions), but I don't see it and so far even Rigol failed to demonstrate actual use scenarios..

Not to mention that they decided to call PC software Ultra Acquire too.... Not confusing at all.. So trying to find some documentation on feature is really easy... not.

[enson72]

I just downloaded yours from Google Drive and installed it. Initially there was an offset, after calibration it became normal. But I didn't understand why I needed this firmware. What she gives me. Moreover, it is not officially available on the sites. And I installed firmware 01.01 again.

I experimented with calibrations on different firmware. (On the DHO802). I was guided by the DVM readings. The best results were obtained on firmware 01.02. with only the basic calibration options enabled. The rest of the ticks are removed (see screenshot).

[AndyBig]

I just downloaded yours from Google Drive and installed it. Initially there was an offset, after calibration it became normal. But I didn't understand why I needed this firmware. What she gives me. Moreover, it is not officially available on the sites. And I installed firmware 01.01 again.

I experimented with calibrations on different firmware. (On the DHO802). I was guided by the DVM readings. The best results were obtained on firmware 01.02. with only the basic calibration options enabled. The rest of the ticks are removed (see screenshot).

Do both channels have the same value?

[egonotto]

Concerns the Ultra Acquisition Mode:
Has anyone found a signal case where this mode is really useful for what?
It is only very sparsely described in all DHO manuals and there doesn't seem to be any kind of "white paper".
Well, you can create great graphics with it, but otherwise?
I had fed in various signals with random glitch pulses, but I was able to capture these glitches better in normal mode with the appropriate trigger than in Ultra mode, which with the (measured) high waveform update rate actually seems to be made for this.

Hello,

Other manufacturers have similar functions. With PicoScope it is "Rapid Trigger", with Rohde & Schwarz it is "Fast segmentation"

Best regards
egonotto

[enson72]

I just downloaded yours from Google Drive and installed it. Initially there was an offset, after calibration it became normal. But I didn't understand why I needed this firmware. What she gives me. Moreover, it is not officially available on the sites. And I installed firmware 01.01 again.

I experimented with calibrations on different firmware. (On the DHO802). I was guided by the DVM readings. The best results were obtained on firmware 01.02. with only the basic calibration options enabled. The rest of the ticks are removed (see screenshot).

Do both channels have the same value?

Yes. The same. The difference is quite small. When other SelfCal options are enabled, the accuracy deteriorates. As on other firmware versions. Well, if you look at the DVM readings.

[2N3055]

Concerns the Ultra Acquisition Mode:
Has anyone found a signal case where this mode is really useful for what?
It is only very sparsely described in all DHO manuals and there doesn't seem to be any kind of "white paper".
Well, you can create great graphics with it, but otherwise?
I had fed in various signals with random glitch pulses, but I was able to capture these glitches better in normal mode with the appropriate trigger than in Ultra mode, which with the (measured) high waveform update rate actually seems to be made for this.

Hello,

Other manufacturers have similar functions. With PicoScope it is "Rapid Trigger", with Rohde & Schwarz it is "Fast segmentation"

Best regards
egonotto

Egonotto,

respectfully it is not the same. There is much confusion about this UltrAcq.
Those two Pico and R&S modes are same as Siglent and Kesight segmented mode. Many scopes nowadays have it.
DHOXXXX also has it and call it Record mode. And it seems Record mode works similar to other scopes segmented mode. You can analyse data (search, view,  decode... from it etc.) acquired in Record mode. I haven't used it but from what I can see it seems to work in adequate manner.

But this UltraAcq  mode is separate from that and has these few visual representations and nothing else. You cannot measure, or do anything with data. It is similar to DPO mode in old Tektronix scopes (like old TDS754), where when you enable it all other functions are disabled. It triggers faster but you can only look at the waveform on the screen.

[ebastler]

DHOXXXX also has it and call it Record mode. And it seems Record mode works similar to other scopes segmented mode. You can analyse data (search, view,  decode... from it etc.) acquired in Record mode. I haven't used it but from what I can see it seems to work in adequate manner.

But this UltraAcq mode is separate from that and has these few visual representations and nothing else. You cannot measure, or do anything with data. It is similar to DPO mode in old Tektronix scopes (like old TDS754), where when you enable it all other functions are disabled. It triggers faster but you can only look at the waveform on the screen.

Do we know whether "UltraAcquire" actually triggers faster than regular "Record" mode in the DHO series? Not sure why it would be able to do that, from a technical perspective. But if that were indeed the case, the only reason for UltraAcquire's existence might be to have a faster waveform update rate in the spec sheet?

[2N3055]

DHOXXXX also has it and call it Record mode. And it seems Record mode works similar to other scopes segmented mode. You can analyse data (search, view,  decode... from it etc.) acquired in Record mode. I haven't used it but from what I can see it seems to work in adequate manner.

But this UltraAcq mode is separate from that and has these few visual representations and nothing else. You cannot measure, or do anything with data. It is similar to DPO mode in old Tektronix scopes (like old TDS754), where when you enable it all other functions are disabled. It triggers faster but you can only look at the waveform on the screen.

Do we know whether "UltraAcquire" actually triggers faster than regular "Record" mode in the DHO series? Not sure why it would be able to do that, from a technical perspective. But if that were indeed the case, the only reason for UltraAcquire's existence might be to have a faster waveform update rate in the spec sheet?

It does. Martin did some tests. Fact is Rigol does not usually lie with the facts. What they do is they twist what they mean and what is usability of it.

I personally think "bragging rights" to claim fast wfm/s is the only practical use of this mode at this moment.

In attachment a hard to find w.p. from Rigol that explains virtues of UltraAcq. It was written for big brothers 1000/4000.

It has 5 display modes:

1. Waterfall - Which is nothing like we call waterfall display on SA for instance. I fail to see how easy is to see some detail when everything is overlapping on same screen with same color.
2. Adjacent - Same as No.1 but horizontal shift instead of vertical. Even worse to grasp what is going on here.
3. Perspective - Ok, this looks similar to 3D surface plot, but badly looking. Gaps are too wide and no removal of hidden lines. No rotation?
4. Overlay - OK that one I get. And every scope with segments has this one. Useful.
5. Mosaic - I understand what is it. I have no use for it for practical work. Maybe some documentation? But has no connection to needing super fast  WFMS/s for this. This could have been added to normal segmented mode as display mode. All of these could have.

What is not there: any type of scales, time stamps, info. There are no measurements, cursors, search, math, nothing.
Even if you see some anomaly you won't know when it happened. OK, if it repeats on screen you could see how it repeats in relative terms, but without any data, you don't know frequency, timing. Nothing. If there is a voltage drop in there, you cannot measure it...
It is literally empty screen with bunch of wiggles on it.

In Overlay mode it is similar to DPO mode in old Tektronix scopes (for instance old TDS754). Minus intensity/color grading.
I guess in Overlay mode it could be used to catch some glitches faster than in normal mode.

It will give you information that something was there if you put it in Overlay mode and look for an anomaly, visually.
And then with that knowledge you design series of triggers to catch those in a way that will give you some actual information about it.

Which is something you can do on a many scopes out there in persistence mode... But those can do all the other things FastAcq cannot. And those  are very useful.

Getting wfm/s in this way is very limited in it's usefulness.

For instance, champion of wfm/s, Keysight Megazoom scopes, can reach 1M wfm/s in normal mode at certain time bases.  And do all the normal functions at the same time. So you do measurements and gather statistics at very fast rate.
With this FastAcq you cannot do ANY of that.
In normal mode you are actually slower than some competition that can do "only" 120k wfm/s. Because in normal mode DHO800 can do only 30k wfm/s.

[ebastler]

I still don't quite get it. How does the data acquisition phase of Ultraview mode differ from data acquisition in Record mode? (And related -- how does it provide a faster acquisition rate?)

And on the other hand: Why do the data need to be presented differently? Apparently the playback and search, as available in Record mode, can't be used on UltraAcquire data -- but why?

[2N3055]

I still don't quite get it. How does the data acquisition phase of Ultraview mode differ from data acquisition in Record mode? (And related -- how does it provide a faster acquisition rate?)

And on the other hand: Why do the data need to be presented differently? Apparently the playback and search, as available in Record mode, can't be used on UltraAcquire data -- but why?

I presume you cannot do anything with it because it gets hard decimated for the screen and hard processed totally in display processor block.
Looking at it, it might be repurposed digital phosphorus block, made to not calculate plot density but to simply render individual traces directly on canvas. App proc might not have access to actual sampled data at all...

[Martin72]

From the manual:

TIP
• The UltraAcquire mode is not available when any of the following functions is enabled:
cursors, decoding, Search, Zoom, Pass/Fail test, waveform recording, power analysis,
reference waveform, roll mode, slow sweep mode, and XY mode. To switch to the
UltraAcquire mode, please ensure that all of those functions are disabled.
• In UltraAcquire mode, the functions mentioned above (except for roll mode and slow
sweep mode) are disabled. When roll mode or slow sweep mode is enabled, the
acquisition mode is automatically switched to "Normal"

They were actually describing the fact that it is useless.

[ebastler]

So the only purpose of UltraAcquire mode really seems to be specsmanship. It allows Rigol to put those 1M waveforms/s into the datasheet, and that's about all it does. 

[Martin72]

In his review you realize that Dave can't really do anything with it either, but at least it's "cool".



(starting at 40min50sec)

[S2084]

Is it only 30,000? why can my 814 be 1000000. the second oscilloscope is connected to the external synchro nization output of rigol,....

[Martin72]

Hm ? You mean Wfms/s ?

Here is what I´ve measured on my DHO"814":

https://www.eevblog.com/forum/testgear/rigol-dho804-test-and-compare-thread/msg5171976/#msg5171976

[S2084]

yes I mean wfm/s.  You are based there on the readings of the internal counter, but I looked at the cursor measurements...

[Martin72]

I had connected a second scope to the trigger output, as is usually done.
1,000,000 Wfms/s can only be achieved in Ultra Acquire mode, otherwise not.

[S2084]

but I measured it in normal mode...

[S2084]

I suggest you repeat your measurements with cursors...

[Martin72]

I think there are two possibilities.
Either I have measured something wrong or you have.
Take another look at your setup.

[2N3055]

I suggest you repeat your measurements with cursors...

We spoke about this many times.
wfms/s second is exactly that. How many actual triggers can be in a second.

You are measuring fastest time between two triggers. Not the same.

If you make timebase on that second scope wider so you can see more data, you will see that Rigol is not triggering like that all the time. Data comes in bursts. Then nothing for some time. Then again a burst.  So to measure how many times it triggered in a second you need a counter, that will count how many pulses were in a second. Not what was fastest interval between two pulses.

[S2084]

Thank you!  but I know this very well, are you saying that the measurements taken above by Tektronix are reliable?  Does Tektronix have the necessary counter to count the number of synchronization pulses in one second?  or does he calculate some average value when indicating the signal frequency?.... please enlighten me.