Several years ago, one of the AQRP members developed a standalone transceiver for PSK-31 and later added SSB. It utilized the HobbyPCB Transceiver as the RF frontend and a STM32F746G for the microcontroller and color display. The interface between the two is I/Q signals and it's all DSP . It works pretty well according to Charley, W5BAA. I think that one is also a pretty darn good design point.
He made a Power Point presentation at Austin Summerfest one year.
73 Kees K5BCQ
