[BC] Is overprocessing illegal?

[Jerry Mathis]

The short answer to your question is "Yes, but.....". For mono FM, your
"audio" can go as high frequency-wise as you want. Just remember the 75
microsecond pre-emphasis, though. All that high-frequency garbage will rob
you of modulation capability. And anyway, mono or stereo, any decent FM
audio processor will filter the audio at 15 kHz, unless you deliberately
defeat it.

With otherwise clean audio, a mono FM station can run subcarriers in the
space which would be occupied by the stereo subchannel.

JM




On 12/25/06, Kevin Tekel <amstereoexp at yahoo.com> wrote:
>
> Jerry Mathis wrote:
> > The FM stereo system now in use was not designed to pass audio above
> > about 15 kHz. So just filter it all out and be done with it.
>
> I do understand how putting unfiltered audio into an FM Stereo generator
> will produce aliasing problems.  However, in my question I was talking
> about a monaural FM station, at which no MPX generator is in use.  In that
> case, it seems that as long as the 19 kHz pilot tone region is protected
> (as the FCC rules require), then unfiltered audio above and below 19 kHz
> would be of no consequence to the receiver.
>
>