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| Using (and living with) Siglent SDS1000X-E Series Oscilloscopes |
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| bdunham7:
Read my post #16 and his reply #17. If he did what he said he did--both probes to one channel, switching the connections at the scope and observing no change or reversal of the phase shift--that scope is borked. I have no idea what could possibly be going on with that scope, but something isn't right. 29ns is huge for any physical delay and the only thing I can think of is that there is a factory-only calibration constant (or at least not done during self-cal) that has a range greater than necessary and that value has accidentally been set to the min or max somehow. |
| tautech:
--- Quote from: bdunham7 on July 06, 2021, 03:14:18 am ---Read my post #16 and his reply #17. If he did what he said he did--both probes to one channel, switching the connections at the scope and observing no change or reversal of the phase shift--that scope is borked. I have no idea what could possibly be going on with that scope, but something isn't right. 29ns is huge for any physical delay and the only thing I can think of is that there is a factory-only calibration constant (or at least not done during self-cal) that has a range greater than necessary and that value has accidentally been set to the min or max somehow. --- End quote --- You may be correct but I'm not convinced as yet. SimonM needs to do a factory reset on his AWG so to eliminate any possibility the SDG1032X is not the source of phase difference. His last screenshots show ~180o phase difference @ 15 MHz and there's no way it should be that far out. I believe something has been overlooked. |
| StillTrying:
--- Quote from: tautech on July 06, 2021, 02:16:04 am ---Yeah I know......been busy.... --- End quote --- I/we mean SimonM's dealer in the UK. Definitely the scope, first 2 images in Reply#13 https://www.eevblog.com/forum/testgear/using-(and-living-with)-siglent-sds1000x-e-series-oscilloscopes/msg3597615/#msg3597615 CH2 overwrites CH1, but CH3 doesn't overwrite CH1 "His last screenshots show ~180o phase difference @ 15 MHz and there's no way it should be that far out" 1/15M = 66.6ns, half a cycle is 33ns which is the 29ns error, getting close to 180 deg for 15MHz. |
| bdunham7:
--- Quote from: tautech on July 06, 2021, 03:26:29 am ---SimonM needs to do a factory reset on his AWG so to eliminate any possibility the SDG1032X is not the source of phase difference. His last screenshots show ~180o phase difference @ 15 MHz and there's no way it should be that far out. --- End quote --- How could the SDG be the issue if he only used one channel?? The phase difference just seems to be about the same 29ns lag in the 3/4 ADC, although it seems to reduce a bit at 500MSa/s. --- Quote ---I believe something has been overlooked. --- End quote --- It certainly seems like something that you eventually figure out and slap yourself in the head, "DOH!" and wonder what you were thinking. I just can't think of any user setting that would cause this. |
| StillTrying:
--- Quote from: bdunham7 on July 06, 2021, 03:39:10 am ---It certainly seems like something that you eventually figure out and slap yourself in the head, "DOH!" and wonder what you were thinking. I just can't think of any user setting that would cause this. --- End quote --- I had to read Reply#13 3 times the first time, and now again so 4 times. "29ns is huge for any physical delay" I could imagine the PCB needs a fixed 29ps delay somewhere and the firmware is using ns instead. :) |
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