Hi, I'm struggling with some noise on the audio output from the RRC. I think it's originating from the RRC here at home, not the one connected to the radio, but not 100% sure about that.
According to Microbit Setup Manager I have:
Version: 004
Firmware: 2.95
HW: 005
At home I've tried adding optoisolators to all audio and it makes no difference. The noise is mostly only noticeably in two scenarios:
1. When the audio output level from the radio is low / or there is little audio / band noise.
2. With the radio audio level turned all the way down, there is still a slight background noise.
I've checked here locally whether or not disconnecting any of the IO makes a difference, and it does not.
In the attached recording I have added ~20dB of amplification (because the levels are quite low), the beginning of the clip is with the RRC on but with audio from the radio at 0, and then I turn off the RRC, noise level drops. There's still noise in the clip probably from the amplification.
My settings are as follows (at home):
Codec out gain: 240
Codec inp gain: 0
Codec inp HPF Hz: 163
Codec inp preamp: No (have also tried Yes, it makes no difference).
Radio side:
Codec out gain: 255
Codec inp gain: 0
Codec inp attenuation: No
P.s. I've also tested different codecs without any change (not that I was expecting any).
