Query on crackpot scheme for recording audio with extended bandwidth

[Electronic M]

Originally Posted by KiM3Ce

Thanks! I'm thinking a modern data acquisition system might not be prohibitively expensive.

https://www.ni.com/en/shop/data-acquisition.html

Ideally I would like to do the digital signal processing like the Accuphase tuners do, without buying a $9,500 tuner :-).

https://www.accuphase.com/tuner.html

I don't have time to verify specs (got a swapmeet tomorrow), but you have to be careful with laboratory data loggers. Most do NOT record the actual signal but simply create an Excel or .CSV file containing the input voltage every so many seconds or mS...My last job was as a test engineer and I regularly used Agilent and DataQ data loggers that worked as described above and were not capable of recording a continuous audio waveform.

If you aren't married to using any specific tuner to capture your FM station SDRs can receive the raw RF from the air and digitally demodulate the FM stereo signal to audio on your PC....They can also decode the RDS data and HD radio signals hidden in the FM carrier.
Odds are that obscenely expensive tuner is basically a small embedded Linux computer running an SDR, high quality DAC and a fancy user interface.