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

--- Quote from: Wim13 on June 23, 2013, 06:05:22 pm ---Turning on anti aliasing does not change anything, only the brightness.

--- End quote ---
As part of How Thick is Your Baselne on Your Digital Oscilloscope?, I learned more about what anti-alias is doing.  We already knew it was a sample->display thing, but here's an example where it actually fixes up waveform aliasing.  These are all the same part of the same capture. 500uV/div, displaying dots, peak acquire (though it happens with Normal as well).  You can see the first makes it look like the noise is restricted to two horizontal bands, but switching to a shorter time base makes that effect disapper--it was an aliasing artifact! The third returns to the original timebase but enables Anti-Alias.
Galaxyrise:

--- Quote from: van-c on June 25, 2013, 02:34:15 am ---The anti-aliasing bug-- okay, you consider it an annoyance but others might consider it a serious bug.
--- End quote ---
It's almost certainly working as intended.  I wouldn't call it a bug, but it is deceptive.

I found Hi Res to be even worse: Putting "High Resolution" in the sample section of the datasheet (and the acquire menu of the scope) is pretty much a lie, especially if other scopes actually implement it at signal->sample time.  The thing is, I would have been fine if Hi Res and Anti-Alias were billed as display filters.  But instead I feel misled.
marmad:

--- Quote from: Galaxyrise on June 26, 2013, 05:39:04 am ---We already knew it was a sample->display thing, but here's an example where it actually fixes up waveform aliasing.

--- End quote ---

This is not fixing WAVEFORM aliasing - it's doing something with IMAGE aliasing. The anti-aliasing is a non-functioning/wrongly-implemented feature on the DS2000. There have already been many posts about this.


--- Quote from: Galaxyrise on June 26, 2013, 05:53:39 am ---I found Hi Res to be even worse: Putting "High Resolution" in the sample section of the datasheet (and the acquire menu of the scope) is pretty much a lie, especially if other scopes actually implement it at signal->sample time.

--- End quote ---

ALL DSOs with High-Res implement it the same way, and I suspect that if you look at Agilent documents, you'd see it listed in the same way (although I haven't checked).

rf-loop:

--- Quote from: Galaxyrise on June 26, 2013, 05:53:39 am ---I found Hi Res to be even worse: Putting "High Resolution" in the sample section of the datasheet (and the acquire menu of the scope) is pretty much a lie, especially if other scopes actually implement it at signal->sample time.

--- End quote ---



Tektronix acquisition modes  in acq menu.


--- Quote ---The digitizing oscilloscope supports five acquisition modes.

 Sample
 Peak Detect
 Hi Res
 Envelope
 Average
--- End quote ---

HighRes is acquisition mode - exactly.

Tell to Tektronix they have done it wrong. It is more like they have defined world of oscilloscpes (in history) and others have then followed....

Btw, it is also good to understand what is High Res mode, how it works.
marmad:

--- Quote from: rf-loop on June 26, 2013, 09:56:47 am ---HighRes is acquisition mode - exactly.

Tell to Tektronix they have done it wrong. It is more like they have defined world of oscilloscpes (in history) and others have then followed....

Btw, it is also good to understand what is High Res mode, how it works.

--- End quote ---

Galaxyrise was referring to the way it's listed in Rigol's specifications, but you're absolutely right. If you look at the DS2000 specs, it lists High-Resolution with the other Acquire modes (Peak Detect, Averaging, etc) and of course, they assume you understand how it works (just as Agilent assumes it in their X-Series datasheets - just checked them). The true Vertical Resolution (8-bit) is listed in the Vertical section. So I don't think Rigol can be accused of any kind of lying or misleading.
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