Simple Tone Detector?
3flp wrote:
The PLL will keep the shift constant.
You'll also have to detect when the PLL is not locked and remove the
counter-tone on this condition.
Use a CMOS switch (4016 or 4066) to mute the tone.
No idea how well this would work... but
I'd cost only a few $, for the 4046, an opamp or two and some Rs&Cs.
It works really well - I used to use this method to remove the 96 kHz
(approx) interference in "scrambled" cable TV signals.
Bob
--
Everything gets easier with practice, except getting up in the morning!
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