Over on his blog, Ray Ring has posted about his neat little “Mini SDRadio” made from an Si5351 clock generator and a FV-1 reverb audio processor chip.
The Spin Semiconductor FV-1 is a digital reverb chip designed for creating custom audio effects in products. As it is a digital chip it makes use of an ADC and DAC, with the audio effects DSP placed in the middle of the chain. However, by using custom code Ray was able to convert the ADC into an SDR by creating custom AM/FM and LSB demodulators on the programmable DSP instead of the audio effects.
His post contains the full schematics, code and PCB files required to recreate his work if desired.