Hello Roman,

> Hi Dale, maybe a variation on the TV sync-separator
> circuit, using one transistor? This will detect only
> the very peak of each wave, and is self adjusting.

    do you have (or know where to find) an squematic of this? It seems very
interesting circuit.

> With the simple low pass RC filter this should give
> good triggering on your wave as the harmonics are
> much lower in amplitude. I don't think that zero-cross
> or any half voltage conversion to digital will work
> as well. :o)

    The waveform of an electric or acoustic guitar/bass is very complex. I'm
looking at a bass sample (low E, the thickest string) right now and the 2nd
harmonic (3x fundamental frequency) is about 10dB above the fundamental.
This is a very problem, because if the circuit locks to this frequency the
PIC will think you're playing a B. The funny side of this is that it will
show that the B is in tunning almost exactly when the E is in tune also. :)

    Best regards,

    Brusque

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Edson Brusque                 C.I.Tronics Lighting Designers Ltda
Research and Development               Blumenau  -  SC  -  Brazil
Say NO to HTML mail                          www.citronics.com.br
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