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REVIEW - Rigol DS2072 - First Impressions of the DS2000 series from Rigol
AndyC_772:
--- Quote from: marmad on May 01, 2013, 05:30:43 pm ---Two quick questions: is the delay you measured from triggering on a channel input or external trigger in?
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See above; channel trigger looks to be a fraction faster. (Interestingly, I've just measured it again and it's come out at 30.2ns - maybe I have a little channel-to-channel skew to calibrate out, or I'm just tired at the end of a busy day and my experimental technique isn't at its sharpest. Apologies).
--- Quote ---Also, I've been reading a lot about the X- Series recently - trying to figure out Agilent's specifications for the memory usage (which ain't easy). From what I understand from their specs (assuming you don't have the 2MB Mem upgrade), if you're running all 4-channels simultaneously in Auto/Normal mode - you have 250kB per channel. Is that correct? Or does the halving of memory during Normal mode affect just a channel 'pair' (i.e. 500kB)?
Have you verified actual memory amounts when stopped (since Agilent is obviously fairly cagey in this regard; i.e. no tables anywhere in all of their literature)?
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I have the 4M memory upgrade. With just ch1 enabled, I can capture 500us worth of data @ 4Gsa/s before the sample rate starts dropping (2M points), and with ch1 and 3 enabled I can capture the same (ie. total of 4M points split across the two channels).
If I enable 1 & 2 (only), then I get 500us @ 2Gsa/s for a total of 1M points per channel (total 2M points). It can't sample any faster, and the other bank of RAM cannot be used.
So, it looks as though ch1 & 2 share a digitiser which is capable of 4Gsa/s, and they share a common block of 2M points of sample memory. Ch 3 & 4 appear to be separate, and share their own digitiser and RAM.
EV:
--- Quote from: marmad on May 01, 2013, 06:03:31 pm ---
--- Quote from: EV on May 01, 2013, 05:46:41 pm ---It was about 1.2 ns when trigged to CH1.
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Isn't that when you had it triggering itself?
I see the same 8ns when triggered from Ch2 with 1MHz sine.
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Yes, it was triggered to itself, but it is also same, if it is auto triggred and the trigger level is outside the trace. I get 8 ns only with external trigger.
marmad:
--- Quote from: EV on May 01, 2013, 07:31:09 pm ---Yes, it was triggered to itself, but it is also same, if it is auto triggred and the trigger level is outside the trace. I get 8 ns only with external trigger.
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I get 8ns in Normal mode with either channel or external trigger - which is the way I generally use the DSO.
marmad:
--- Quote from: AndyC_772 on May 01, 2013, 07:22:51 pm ---I have the 4M memory upgrade. With just ch1 enabled, I can capture 500us worth of data @ 4Gsa/s before the sample rate starts dropping (2M points), and with ch1 and 3 enabled I can capture the same (ie. total of 4M points split across the two channels).
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Hmm... but this doesn't match with Agilent's documents. If you can access a maximum of 2MB per channel-pair, that means when you are running in Normal mode with a single-channel enabled, according to Agilent, you would have a 1MB record length:
"When running (versus taking a single acquisition), the memory is divided in half. This lets the acquisition system acquire one record while processing the previous acquisition, dramatically improving the number of waveforms per second processed by the oscilloscope."
EDIT: Ahh, I just remembered our discussion over in the "Waveform Update Rate" thread! Perhaps the 3000 X is using 1MB until the final acquire = swapping 1MB banks for speed until you press STOP, and then fills the entire 2MB.
EV:
--- Quote from: marmad on May 01, 2013, 07:55:40 pm ---I get 8ns in Normal mode with either channel or external trigger - which is the way I generally use the DSO.
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I use usually auto mode and I think these jitter values are almost all trigged with auto mode. I try tomorrow normal mode and check if the results change.
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