> > Extracting frequency is more problematic, but can be done in e.g.
> > dsPIC, as others suggested.  If you need to detect a specific
> > frequency, LM565 phase-locked loop is good for audio frequencies.
> >
>=20
>=20
> I was thinking about the comparator, but since the amplitude of the
> signal gradually falls over a period of a few seconds, how would I
> constantly follow and update the cutoff?

This is where using a dsPic instead of a PIC32 would make sense. Microchip =
has an AGC library that would maintain the level AIUI in a similar manner t=
o some of the fuzz boxes.
--=20
Scanned by iCritical.

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