01-07-2022, 04:52 AM
The microphone is definitely pickup noise when the modem is working -- like mobile data activity or in a call.
Easy to detect/record that by making sure you are using only 4G mobile data (i.e. disable Wifi). Then prepare the microphone for capture in alsamixer and increase the Mic1 Boost to maximum so to easier hear the modem noises.
Record the microphone using arecord (alsa-utils package):
arecord -f cd -V mono test.wav
(use Ctrl-C to terminate. Play back with: aplay test.wav for example)
During recording, whenever I use mobile data, the "RF noises" are recorded. Also when I do a voice call.
Can we (better) isolate/shield the microphone line/cable? Is there analog audio signal going on from the microphone (at the bottom of the phone) to the mainboard (at top)? I'm going to check these things out.
Easy to detect/record that by making sure you are using only 4G mobile data (i.e. disable Wifi). Then prepare the microphone for capture in alsamixer and increase the Mic1 Boost to maximum so to easier hear the modem noises.
Record the microphone using arecord (alsa-utils package):
arecord -f cd -V mono test.wav
(use Ctrl-C to terminate. Play back with: aplay test.wav for example)
During recording, whenever I use mobile data, the "RF noises" are recorded. Also when I do a voice call.
Can we (better) isolate/shield the microphone line/cable? Is there analog audio signal going on from the microphone (at the bottom of the phone) to the mainboard (at top)? I'm going to check these things out.
