I am working with the AX5043 in GMSK and I am unable to make the AFC work properly.
I am working at a bitrate of 2400 bps, to be sure to lock on the carrier I have set a BW to the range of 3.6 kHz. Given the documentation, I have set the AFC to 1/4 of the BW in AX RadioLab, so it is set to +/- 0.9 kHz
From what I understand AX Radio Lab has set the outer AFC loop.
Now the thing is, it seems that the AFC is unable to lock to 0 Hz of offset. In order for me to lock on the incoming signal, I have to emit this signal at:
f_carrier + (around) max_AFC_offset Hz
If and only if this condition is valid, then the AX5043 fully receives the packet. But when I remove that offset in the incoming signal, the AFC loose tracks.
I tried that with several values of AFC ranges: +/- 1.8 kHz, +/- 0.9 kHz, +/- 0.5kHz.
Nothing changed, I always had to add the maximum AFC range as an offset to the carrier. TRKRFFREQ always display respectively, around +1800, around + 900 and around +500 when it is working.
The interesting part is that it is not working with a negative AFC position, like -1800 Hz, -900 Hz and -500 Hz, never.
I have seen another post in the forum that was in the same situation, but I was unable to make the AFC work properly even with the answers.
Thank in advance for your help