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

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Wim13:

@Marmad, Waveform update rate..

When on 20 nSec timebase:
and input of a signal of 10 Mhz i get 41.000 WFM/sec
but when change input to 60 Mhz it drops to 22.000 WFM/sec

On 1uS timbase:
and input of 1 Mhz, i get 2.900 WFM/s
but with 10 Mhz it drops to 1.900 WFM/s

On 20 nSec timebase:
and 1 Mhz i get 46.000 WFM/s but change timebase to fine and 20.05 nSec it drops to 5.000 WFM/s

How does that fit in your explanation video about WFM/s, i dont get it.

marmad:

--- Quote from: Wim13 on June 09, 2013, 05:58:58 pm ---When on 20 nSec timebase:
and input of a signal of 10 Mhz i get 41.000 WFM/sec
but when change input to 60 Mhz it drops to 22.000 WFM/sec

On 1uS timbase:
and input of 1 Mhz, i get 2.900 WFM/s
but with 10 Mhz it drops to 1.900 WFM/s

On 20 nSec timebase:
and 1 Mhz i get 46.000 WFM/s but change timebase to fine and 20.05 nSec it drops to 5.000 WFM/s

How does that fit in your explanation video about WFM/s, i dont get it.

--- End quote ---

Well, since the waveform update rate is comprised of three distinct sections (i.e. acquisition time + fixed blind time + variable blind time), the rate could be affected by anything you do - depending on how the DSO manufacturer implements things - because they could affect the variable blind time. It's clear the DS2000 was finely tuned to be able to achieve ~50k wfrm/s in order to directly market it against the Agilent 2000X, but it only achieves that rate under very precise conditions.

I've noticed myself when testing that the wfrm/s rate can change depending on the input frequency - perhaps due to the way that the trigger circuitry is being processed (i.e. excess triggers cause a slight interruption in the process - even if they don't trigger another acquisition). But this might be common in DSOs - I've never tested it. Mostly when you see charts of wfrm/s speeds, they are specified against a particular input frequency.

Galaxyrise:

--- Quote from: marmad on June 07, 2013, 03:48:49 pm ---Or if someone could post just ONE 'before/after' example of it actually 'minimizing' aliasing, I would be happy  :)

--- End quote ---
This seemed like it might be interesting to play with, so I fed the DSO various frequencies and looked for an example where AA looked better.

The first thing I discovered is that Anti-Aliasing and High Res don't get along.  The difference is super obvious in dots.  In my tests, AA always made aliasing worse in High Res. I suspect Averaging, which was on in Xas' post is susceptible to the same problem.

I've only seen AA produce an improvement in cases where the scope was displaying low intensity.  So if you have dim traces, or a dim swath, turning on AA may add detail.  In the first normal acquisition images, you see that the vertical portions of the traces got more intense and easier to follow with the eye.  But this isn't a typical aliasing case of undersampling the waveform.  I don't know why the trace was so dim to start with.  Even at 185us with exactly 4 periods displayed, the wave (in dots) was still pretty dim and wide.  At 100us, it looks correct, and with AA turned on in 185us, it looks correct.  Is this another kind of aliasing?

The last two images were the only ones I came up with where it looked like AA actually reduced acquisition aliasing.  That's a 15.555555MHz signal.

marmad:

--- Quote from: Galaxyrise on June 09, 2013, 08:36:22 pm ---I've only seen AA produce an improvement in cases where the scope was displaying low intensity.  So if you have dim traces, or a dim swath, turning on AA may add detail.  In the first normal acquisition images, you see that the vertical portions of the traces got more intense and easier to follow with the eye.  But this isn't a typical aliasing case of undersampling the waveform.  I don't know why the trace was so dim to start with.  Even at 185us with exactly 4 periods displayed, the wave (in dots) was still pretty dim and wide.  At 100us, it looks correct, and with AA turned on in 185us, it looks correct.  Is this another kind of aliasing?

The last two images were the only ones I came up with where it looked like AA actually reduced acquisition aliasing.  That's a 15.555555MHz signal.

--- End quote ---

Thanks for your efforts, GR. With all I've seen, I'm almost of the belief that someone at Rigol told a programmer that they wanted a routine for anti-aliasing - and the coder thought they meant image anti-aliasing - not waveform anti-aliasing.  ;D

Seriously though, if you want to do any more playing around, I would strongly suggest that you don't use 14M or 56M sample lengths - since traditionally, one of the tools to battle against aliasing is to increase sample length (since that automatically increases sample rates and/or samples being decimated for the display). If anti-aliasing works at all on the Rigol, it should first and foremost be working when you have small sample lengths - so that switching it on might (in the background) automatically force the DSO to capture more samples for random decimation (or change sample speeds) in order to prevent the occurrence of the aliased waveform.

Electro Fan:

--- Quote from: grego on April 17, 2013, 02:51:51 am ---
--- Quote from: marmad on April 16, 2013, 09:12:49 pm ---I'm not sure if the DS6000 Demo Board has been mentioned before on EEVBlog or not (a quick search didn't turn up anything), but I found it at Batronix while searching for any possible new UltraVision products - and I hadn't seen it before and thought it was kind of interesting. It lists at €163 / $225 (excl.), and I've attached the user guide below.

"This Demo board is used to illustrate the basic functions of the oscilloscope. It is powered through USB port and can output 25 kinds of signals for the illustration of oscilloscope functions, i.e. sine, video (PAL/NTSC), AM Modulation, Sweeps, many digital signals and lots more. Delivery including Demo Board, USB Cable, CD with manual."



--- End quote ---

It's got the Instek one beat - Instek demo board only does 10 analog and 5 digital/LA functions for $205 list (so probably about $185 discounted).

I might have to get me one of these to play around with.

--- End quote ---

Hi Greg,

Just checking to see if you might have sprung for one of these demo boards (and where you think one could be purchased for $185?)

- anyone else have any demo boards you like better (new or used)?

Also, any updates on the GWI Logic Analyzer impressions? :)

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