11-09-2021 07:43 PM
Hello,
I'm using USB6210 to test a 8 channel signal with differential mode. The original signals are 8 channels photocurrent and then go to the same op-amps to be converted into voltages and then sent into the daq. I recorded the 8 DC signal for 10 seconds with sample rate of 30000. I found that the noise level of AI0 is alway higher than the other 7 channels. Is that normal? Is there any ways to reduce the AI0 noise?
Thanks,
Xiaotong
11-09-2021 09:09 PM
The best way to measure the noise of DAQ is to ground all the analog inputs and capture the signal.
Based on your description it is possible that your OPAMPs has a voltage offset.
If by grounding all the AI of DAQ results in almost comparable noise, then the issue is not in the DAQ but the external circuit, moreover the noise values are specified in the datasheet of DAQ but there is no guarantee that channel-channel matching is guaranteed.
11-10-2021 10:53 AM
Also try swapping inputs of AI0 with another AI channel and see if the noise floor still follows AI0.
-AK2DM