Using a TV tuner as a high speed ADC

FWIW

Analog to Digital Converter with 16 bits and 448000 Samples
per second based in the Bt878A

—which takes you to

—Also see
btaudio.c module modification to get 896000 Samples
per second with the Bt878A ADC


My added comments:  The above is a cool hardware hack that claims to 
take care of the baseband problem only- but I find it intriguing to 
wonder if it would be possible also to do two more ambitious things-
1) Using its TV tuner module (under software control of course), 
down-convert a swath of its output spectrum (prior to any detection) 
into the band covered by the extended range of the ADC
2) All of the above is based on the audio ADC.  If some way could be 
found to hack into the video one also, MHz bandwidths could become 
theoretically possible...

Best Regards

Max