I'm using the fast_attack agc with the AD9361 to adjust gain with BPSK signals. I have an FMCOMMS5 connected to a ZC702, and I'm using the standard linux image available from the analog wiki.
What I find is that the AGC target gain seems to be only about 1/4 scale (I get ADC readings of magnitude 500 out of 2047). I'd like to be around 1/2 to 3/4 scale.
I've been tweaking the agc settings described on this page:
To do that, I'm echoing new values to the debug registers in /sys/kernel/debug/iio/iio:device1
I started by trying to change the adi,agc-inner-thresh-high because Lock Level is set via slow AGC inner high threshold. I've also tried changing some of the other registers available there.
However, I find that none of the changes that I'm making to those registers cause any difference in my received signal strength.
What am I doing wrong?
How can I change the target lock level of the fast_attack agc?