Thanks for this! It's interesting that the article says doing it in software can be more power efficient than having a dedicated chip for the intermediate frequencies. Does that mean there exists "dumber" RF chips that do less, offloading the math to the main CPU for power savings? It seems like the kinda thing that would be commonplace if so...?

I guess my fundamental confusion is why "listening" to a broadcast signal takes so much power, vs say a FM receiver or passive wifi snooping.