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

--- Quote from: Galaxyrise on November 18, 2013, 04:34:40 pm ---As far as I know, the only time Rigol doesn't let you change the High Res setting on existing data is in record mode.  It absolutely does let you change the setting when stopped normally.
--- End quote ---

This makes perfect sense since the stored frames are the waveforms constructed from the already-averaged samples (with the original samples no longer available). OTOH, when the DSO is stopped (when not in Record), the last group of captured samples still sits in sample memory - so the DSO can apply (or not apply) the averaging to the display memory by turning High Res on or off.

It seems to me there is some strange idea about "oversampling". Oversampling, in this context, just means using the samples which would be otherwise ignored or discarded when using a time base that normally requires a slower sampling rate than the maximum 2GSa/s rate.

For example, running the Agilent @ 500us/div gives you a nominal sample rate of 50MSa/s (with it discarding 39 out of every 40 samples). Turning on High Res mode just makes the DSO start averaging together the samples it would normally have discarded (thus the "oversampling"). Running the Rigol @ 500us/div and a 14MB memory depth gives you a 2GSa/s rate, with all of the samples ready to be averaged saved into sample memory.


--- Quote ---There's a practical difference between the two approaches and it affects record mode: You get to store fewer waveforms if you want the high res averaging.
--- End quote ---

I'm not sure I understand you: on my DSO I haven't noticed any difference in the maximum frames I can record when using High Res mode.
Galaxyrise:

--- Quote from: marmad on November 18, 2013, 05:44:44 pm ---I'm not sure I understand you: on my DSO I haven't noticed any difference in the maximum frames I can record when using High Res mode.

--- End quote ---
I admit I'm operating on some assumptions there; I'll do some experiments in the next day or two and get back to you.
marmad:

--- Quote from: Galaxyrise on November 18, 2013, 06:37:51 pm ---I admit I'm operating on some assumptions there; I'll do some experiments in the next day or two and get back to you.

--- End quote ---

I'd be curious to know what the bandwidth of the High Res mode is at each time base setting between 50us/div - 10ms/div in the Agilent 2000 X-Series.

Some of it you can calculate based on their published specs, such as 20us/div = 12 bits = 3.4MHz BW - but I'm curious if that bandwidth remains the same until 5ms/div - when it clearly must be lower due to the fact that the DSO must discard more samples than the 256 needed for 12-bit averaging.

I wish there were owners of that DSO who did as much testing and publishing about it as we have done for the Rigol DS2000. Although Agilent is, of course, much better than Rigol at providing information, even they tend to be rather tight-lipped about any drawbacks/weaknesses of certain features. ;)
Teneyes:

--- Quote from: marmad link=topic=11695.msg333256#msg333256 ---I wish there were owners of that Agilent DSO who did testing

--- End quote ---

A short report:  I was down south, in Silicon Valley, and checked a large electronics store (Frys), and I saw a:  AGILENT DSO1052B 50MHz Oscilloscope, 2-channels for sale at $790

I laughed,  and informed the sale person, they better check on the Rigol DSO's
The sale person asked me to write the info down for them.
I foresee Agilent dropping out of the lower end market.
marmad:

--- Quote from: Teneyes on November 19, 2013, 08:14:36 am ---I foresee Agilent dropping out of the lower end market.

--- End quote ---

I don't know... Agilent has a good product in the X-Series and they've already done all of the development. It may be that they will just lower their prices on that line.
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