Richard Fry wrote:
If you are still thinking of the broadcast television signal, the audio
portion is not a subcarrier -- it is a discrete carrier whose modulation
can be detected by any receiver capable of FM demodulation, and able to
tune to its r-f center frequency.

The confusing part, at least for me, was that the entire passband *can
be* downconverted and then demodulated assuming 4.5 MHz separation. That
doesn't imply a *necessary* condition for demodulation.
--
73, Cecil http://www.qsl.net/w5dxp