Rf (Ch3 TV) to audio/video RCA conversion

does anyone know or has the schematic of an rf demodulator? (Rf (CH3 TV to audio/video converter)

i will use it between a cable tuner and a tv, which only has audio/video rca input. the tv channels are already scrambled and untuned, and the remote is the only way to tune it but it was lost.

hope someone may help.