With the new RadioInterface add-on board working it was time to revisit the digital modulation/demodulation to tune and integrate them with it. Both AFSK-1200 and FSK-9600 (G3RUH) have been tested again but this time the modulation, TX, was tested using the RTL.SDR + SDR# + SoundModem combo to test that it works with HAM Radios.

This test can be seen in the short screen recording bellow, for AFSK-1200:

On the receiving side, the received packets are transmitted over USB and UART using the KISS protocol. The software of the RadioInterface has received an update so that it can receive and decode these packets and display their content on the screens GUI, as can be seen in the Figure bellow:

I also got back to make BPSK work and finally figured out the problem: There is a dedicated register, MODCFGP (0xF5F), for PSK modulation settings that is not mentioned anywhere in the documentation. I only found out about it in a recent blog post from OnSemi... (AX-RadioLAB configures that register appropriately).

With this, BPSK-9600 modulation is now also working and the emitted spectrum can be seen in the Figure bellow. The reception side on the VUHFRadio is not as good and need further testing and tuning.

As always, the software can be found on GitHub and more in-depth information on the website.