Products > Test Equipment
Siglent SDS 1202X-E sampling anomaly?
MacMan72:
Can anyone tell me why, when I zoom in on a trace in the 1202, it has this “digital” appearance? I have the Aquisition set to Normal and the mem depth set to 1.4M. If I set the Aquisition type to Average, I get what I would expect to see when looking at the ripple in the test calibration signal. Is this expected behavior or is there a setting/filter I’m missing here?
tautech:
4 things scream at me why ?
Small mem depth.
Trigger off the display
20mV/div
Photo not the much smaller screenshoot ?
Press H Pos to zero the trigger position and get it back onto the display.
Check probe and input attenuation settings match and set appropriate vertical settings
Mem depth won't matter much for this but leave it at max 14Mpts and lt the scope manage memory depth.
In Utility, last page IIRC set Horizontal Ref Pos to Position, then the marker stays on screen regardless of timebase settings.
Use Print to USB to capture screenshots and there is no reason to need Stop the scope.
Martin72:
Another question is, what do you want to see from a 1khz signal at 10ns/div...
DavidAlfa:
You sampled the signal at 500mV/div, then zoomed in all the way to 20mV/div, what did you expect?
It's a 8bit ADC so this is completely normal, you have only 0-255, 256 different values.
500mv*8div = 4000mV -> 4000/256 = 15.6mV vertical resolution.
So of course it looks like that.
When you later sampled the signal at 20mV/div, the story changes, now it makes:
20mv*8div = 160mV -> 160/256 = 0.62mV vertical resolution.
But as you can see when zooming in, at 500mV the resolution is actually 20mV, so it's storing a bit more than 8 divisions:
20mv*256 = 5120mV -> 5120/500 = 10.24 vertical divisions.
bdunham7:
--- Quote from: MacMan72 on July 24, 2023, 08:54:41 pm ---Can anyone tell me why, when I zoom in on a trace in the 1202, it has this “digital” appearance?
--- End quote ---
You're zooming vertically with the scope stopped? So at 500mV/div, it has 8 bits of resolution, which is 256 levels from top to bottom, or 32 levels per division (at most). When you zoom in to 20mV/div--25X--on this already captured trace, those levels get expanded so that there are only about 10 levels from top to bottom, or a bit more than 1 per division at most. In practice, the capture window may extend off the top and bottom of the screen and it appears in this case that the result is that the trace is displayed at about 1 level per division.
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