(1) I am working on integrating the Re-Speaker 2-MIC board on a Xavier NX Board. The basic driver now works ok, but we have annoying white noise on the mic captures. The driver we use is available here
(2) We have done some hardware probing to isolate the source of Noise. One of the strange thing is that 3.3 AVDD from Xavier-NX board is not clean. We use Pin-17 of 40-Pin header for 3.3V and as per the jetson-io.py, this pin is configured for 3.3 AVDD. This is the DTS file we use.
(3) There is strong noise on the 3.3V. Even if I remove the ReSpeaker board from the 40-pin header, this noise can be seen. So the source of this noise seems something internal on the Xavier board. I am attaching screenshots of the AVDD measurements done using oscilloscope in DC and AC mode.
Can some one suggest why this noise can be seen. Also, any inputs on how I can get rid of this noise. Again, note that this is the Pin-17 of 10-pin header.