REVIEW - Rigol DS2072 - First Impressions of the DS2000 series from Rigol

[marmad]

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*****************************Special XMAS Post! (Now Redacted!)*****************************
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This hasn't been discussed very much in the forum, perhaps because we don't want to give away too much
info to Rigol, but and I have to assume that
Rigol MUST be aware of this 'problem'. And I want to encourage people to buy one of these DS2000s NOW,
because the bigger the user base - the more knowledge (and utility) all of us will have. So... for those of you
on the fence about buying one of these scopes, let me just confirm that there is a bug in the current firmware
version(s) which allows you to . Think of it as a
Xmas present to early adopters - those of us who normally suffer through the early hardware and/of firmware
revisions with little to no appreciation    So go buy the damn scope 

I'm not going to write publicly about methods for invoking this bug (and I hope others won't either) - since I
don't want to give Rigol any extra help in squashing it - and since it seems fairly easy to figure it out. But if
you're an owner - and you've been unable to suss it out - I'm happy to pass on my info to you if/once you've
been posting here for a short while - just PM me.

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EDIT: Xmas is over.

[EV]

For comparison here is rise time with Tektronix TDS3032. It has 50 ohm input. So no terminator is needed. Rise time is 1.137 ns and it gives bandwidth 308 MHz (in specs it is 300 MHz). Overshoot is only 2.6% (Rigol had 5.0 %).

[zibadun]

...and between the 2202 is the 2 nsec timebase.

And the 100MHz BW limit setting - which you would think would be set "ON" all the time on the 2072/2102.

don't give rigol any ideas

I do know FFT function on 2072 works way way beyond 70 Mhz (posted a picture somewhere above)

[Wim13]

...and between the 2202 is the 2 nsec timebase.

And the 100MHz BW limit setting - which you would think would be set "ON" all the time on the 2072/2102.

don't give rigol any ideas

I do know FFT function on 2072 works way way beyond 70 Mhz (posted a picture somewhere above)

The FFT is just calculated from the samples, and goes uo to 3.5 Ghz. Depends on the selected timebase.

And Rigol knows what  it is shipping, if you are selling test equipment, you can count on it that they will
check the specs..search for the limits.

[marmad]

I do know FFT function on 2072 works way way beyond 70 Mhz (posted a picture somewhere above)

The FFT is just calculated from the samples, and goes uo to 3.5 Ghz. Depends on the selected timebase.

And Rigol knows what  it is shipping, if you are selling test equipment, you can count on it that they will
check the specs..search for the limits.

I do think that the FFT is perhaps the one area that's a little feeble on the DS2000 series. It doesn't matter to me all that much - since it's relatively feeble on most low cost DSOs - and there are so many other great features (50k wfrm/s capture, segmented memory with histogram analysis, 500uV scale, hi-res mode, measurement history graphs, 2GSa/s sampling, etc) to offset that

[larsie]

These hacks or rumours of such on Rigol must have a fantastic marketing effect. Surely they sell more scopes this way, and get a lot of PR. I bought a DS2022, because so many people in this forum said the brand was good. I would guess it would have been less well known without the earlier 50 to 100 mhz hacks on the older scope.

[marmad]

These hacks or rumours of such on Rigol must have a fantastic marketing effect. Surely they sell more scopes this way, and get a lot of PR. I bought a DS2022, because so many people in this forum said the brand was good. I would guess it would have been less well known without the earlier 50 to 100 mhz hacks on the older scope.

It's not just because people say so - look at Dave's video tearing down one of the DS2000s. Beautifully made inside - and it's the same with their latest series of AWGs and SAs.

And you're right -  it's quite possible that Rigol wouldn't have had the money to put into the R&D for these new series without the sales generated by the public posting of the DS1052E hack 

Edit: The place they lag behind the serious companies is in software and after-sales support. But I guess there has to be some trade-off for the low prices.

[EV]

It's not just because people say so - look at Dave's video tearing down one of the DS2000s. Beautifully made inside - and it's the same with their latest series of AWGs and SAs.

Yes, likely this video is the main reason why I bought my DS2202. I have been satisfied far now.

[Wim13]

I do know FFT function on 2072 works way way beyond 70 Mhz (posted a picture somewhere above)

The FFT is just calculated from the samples, and goes uo to 3.5 Ghz. Depends on the selected timebase.

And Rigol knows what  it is shipping, if you are selling test equipment, you can count on it that they will
check the specs..search for the limits.

I do think that the FFT is perhaps the one area that's a little feeble on the DS2000 series. It doesn't matter to me all that much - since it's relatively feeble on most low cost DSOs - and there are so many other great features (50k wfrm/s capture, segmented memory with histogram analysis, 500uV scale, hi-res mode, measurement history graphs, 2GSa/s sampling, etc) to offset that

FFT on all these devices with 8 bit samplers are useless anyway...
With 8 bit samplers you have only 48 dB range which is not serious.
You need at least 14 or more for 84 dB or more to see any detail.

[larsie]

I have a question about 8 vs 12 bit. I bought ds2022 thinking it was 12 bit, because many sites say this. Now, I am confused. Is it only 8 bit, but has some sort of averaging that supposedly makes it more accurate by considering many 8 bit samples?

[marmad]

I have a question about 8 vs 12 bit. I bought ds2022 thinking it was 12 bit, because many sites say this. Now, I am confused. Is it only 8 bit, but has some sort of averaging that supposedly makes it more accurate by considering many 8 bit samples?

Yes, it's 8-bit - and HiRes mode is averaging - but a different kind than the standard type used on all DSOs as an Acquire type. There's a good explanation of it in this post (and throughout that thread).

[marmad]

I've been working on a new version of my Rigol software for the last couple of days, and I seem to have found the first bug in the DS2000 that is, IMO, rather a serious one:

I don't seem to be able to read the contents of the DSO memory reliably when the scope is in the STOP state - in other words, I can't get the full sample depth out of the scope (getting just the displayed data is not a problem) - which is a big deal if anyone is planning to do any post-processing with 3rd party software, including MATLAB or LabVIEW (one of the big selling points of the Rigol scope over it's competitors).

Here is the procedure to use copied from the Rigol DS2000 programming guide:

Procedures of the internal memory waveform data reading:
S1. :STOP
The internal memory waveform data can only be read in STOP state
S2. :WAV:SOURce CHAN1
Set the channel source to be read
S3. :WAV:MODE RAW
Set the waveform mode to RAW
S4. :WAV:RESet
Reset the waveform reading
S5. :WAV:BEGin
Start the waveform reading
S6. :WAV:STATus?
1) IDLE
:WAV:DATA?
:WAV: END
2) READ
:WAV:DATA?
Repeat S6

This order of commands does NOT work correctly with the DS2000 - it doesn't return or read the correct number of samples when run as a loop if the memory depth is set to anything higher than 14k.  In fact, you can test that it doesn't work correctly by just using Rigol's own software Ultra Sigma:
Just set the memory depth to >= 140k; STOP the scope; start Ultra Sigma; type in the listed SCPI commands one by one; and you will see it fail.

Perhaps the correct method has changed since the programming guide was published by Rigol - I've passed this info along to my dealer to pass to Rigol. We'll see what they have to say about it.

[marmad]

While thinking about this apparent bug, it dawned on me that perhaps this is why Rigol has not released either an IVI driver - or any application software - for the DS2000 series yet. I'd love to know if this is something the DS4000 series has a problem with - or if it's confined to the 2000s. Any owners of a 4000 want to test it (or already know)?

[zibadun]

I have a question about 8 vs 12 bit. I bought ds2022 thinking it was 12 bit, because many sites say this. Now, I am confused. Is it only 8 bit, but has some sort of averaging that supposedly makes it more accurate by considering many 8 bit samples?

I think there are some DSP tricks (i.e. I don't understand the math ) during down sampling that can increase the effective bit depth of the ADC.  the sampling rate has to be set to lower than 2 GSa/s in order to get the extra bits of resolution.

[marmad]

I've just posted the latest version of RUU, the software I'm working on for UltraVision DSOs which allows fast grabbing, viewing, and saving of captured frames, waveform memory, or the DSO display - as either WFM, CSV, BMP, PNG, JPG, TIF, GIF, or animated GIF files.

As of this version, you can:

1) Fully manipulate Recording and Playing back of frames on the DSO.
2) Save frames as numbered image files, numbered CSV files, or animated GIF.
3) Save CH1/CH2 waveform data as CSV file (suspected firmware bug currently limits memory size to display memory = 1400 points).
4) Save DSO display as any of the supported bitmap image formats.

There are still two features not fully implemented, so they're currently disabled when running:

1) The saving of waveform data/frames as WFM files. As mentioned above, there seems to be a bug in the firmware preventing the reading of the entire sample memory. I'm waiting to hear what Rigol has to say about it - in the meantime, I will implement writing WFM files from just display memory (1400 points) in the next day or two.

2) The real-time PC display of the DSO display - an 'SVGA' mode. Once 'SVGA' is operational, the software can be run on an LCD monitor at 800x600 and maximized - for a psuedo-VGA output.

A nice engine for writing the 2D oscilloscope display data needs to be written. Does anyone either have some code already written (preferably using DirectX 2D or OpenGL under .NET) or want to contribute? I can do it but I'd rather not reinvent a wheel.

[marmad]

BTW, Rigol has radically changed their WFM format on the DS2000 series (and I assume the whole UltraVision line) which means older WFM viewers such as this nice one (and routines written in MATLAB or LabVIEW) won't work with the new files. And as of now, there is ZERO documentation around for the new format.  So I've decided to write my software to use the older format - as opposed to the new one which the scope will output.

[Wim13]

I have a question about 8 vs 12 bit. I bought ds2022 thinking it was 12 bit, because many sites say this. Now, I am confused. Is it only 8 bit, but has some sort of averaging that supposedly makes it more accurate by considering many 8 bit samples?

I think there are some DSP tricks (i.e. I don't understand the math ) during down sampling that can increase the effective bit depth of the ADC.  the sampling rate has to be set to lower than 2 GSa/s in order to get the extra bits of resolution.

Yes , its all about statistics, here is a example how you can get more digits,
if a measure 6 times with 1 digit, 5 , 5, 6, 5, 6, 5, then the average is 5.33
so sudenly i have three digits...!, with a kind of uncertainy.

There are a lot of statistics ways you can use to get more resolution, you just need
the right number of samples, and the uncertainy you will accept.

[marmad]

note, The probes which come with the scoop are useless above 30 Mhz.

BTW, Wim, did you check the bandwidth of the probes (which Rigol rates at 350MHz) at 10x? I'm curious if they're rated 1x/35MHz - 10x/350MHz (or something like that) and I don't have any information about them anymore (if info even came with them - I don't remember) - and I don't have adequate gear here to do any serious testing .

[marmad]

Someone (a ZeroPoster) sent me a PM about my Special XMAS Post (Now Redacted) - asking for a method to invoke the Special Xmas bug. Please understand - under normal circumstances it's completely accepted and encouraged to ask for help from other members here without ever having contributed yourself. Unfortunately, this is not a normal circumstance.

Rigol is currently working on (and now at least 1 and 1/2 months behind schedule on) the latest firmware for the DS2000 series. One would assume that they would like to plug any exploits which give 'free stuff' to people before they release the next version. As you might understand, now is NOT a good time to be a Guest/ZeroPoster/Newbie member asking regular members for this kind of info. As I mentioned in the XMAS post, it's not rocket science, but if you can't figure it out yourself then get on the thread and start contributing. Either you'll start to be known here and someone will share - or Rigol will finally release the next damn version and render it moot.

[EV]

I'm curious if they're rated 1x/35MHz - 10x/350MHz (or something like that)

Bandwidths are 1X/8MHz and 10X/350MHz. Rise times are 1X/40ns and 10X/900ps.

[marmad]

Bandwidths are 1X/8MHz and 10X/350MHz. Rise times are 1X/40ns and 10X/900ps.

@EV: are these the written specifications - or tested by you?

[EV]

Bandwidths are 1X/8MHz and 10X/350MHz. Rise times are 1X/40ns and 10X/900ps.

@EV: are these the written specifications - or tested by you?

They are from specs. I made some tests with Rigol DG4162 generator:
Sweep is from 1Hz to 160 MHz (there is no bigger value)  with sweep time 1.4 sec.

Picture 1: 50 ohm output from generator connected with BNC cable and 50 ohm terminator to DS2202.

Picture 2: BNC cable with 50 ohm terminator connected to 10X probe

Picture 3: High resistance output from generator connected to 10X probe

[marmad]

They are from specs. I made some tests with Rigol DG4162 generator:
Sweep is from 1Hz to 160 MHz (there is no bigger value)  with sweep time 1.4 sec.

Very nice... and interesting! Thanks for doing that.

[marmad]

Strange... I was just playing around with Recording frames of an AM waveform while in Delayed Sweep mode (Zoom) - and I got this for the first ~120 frames before it changed to the correct data. The animated GIF is +/- 10 frames from the changeover.

EDIT: Of course, I'm unable to replicate the glitch 

[larsie]

Got my ds2202 just now. Looks great. I can't get marmad's way of getting system info with f7 keys etc, but in system details it says:

Serial: ds2a143401531
Sw ver: 00.00.01.00.02
Hw ver: 1.1.0.0
Spu: 03.01.02
Wpu:00.06.00
Ccu: 12.29.00
Mcu: 00.05

Bought in Europe from tekequip.com. Just in case this is useful to anybody...