http://www.freescale.com/files/app_s...C44BS373CA.pdf
I think this is what Darryl is searching for.
Having a look at the pdf I noticed the IC makes not 100% video modulation.
So maybe there is a intercarier option for the sound.
But it seems so easy to use this IC so your idea David to use one
with the video input for audio is not a complicated way.
The audio carrier must be 7dBs under peak white.
I did not find anything about this in the pdf.
But it doesn't matter if you use a seperate IC for audio.
Hope the audio carrier can be switched off.
Kind regards
Darius