the only problem with that design is that it only works well with pure
waveforms one note at a time. sounds rich in harmonics like guitar or
other natural instruments confuse counters and give very unpredictable
results. try playing a guitar chord through a MOTM-700 and listen to
what comes out. the pitch to cv from tomg has this problem, it's only
accurate over a small frequency range, plus it only responds well to
clean waveforms (i believe it was based on dr. bob's theremin to cv
circuit) -Nate
Dave Bradley wrote:
> Seems simple enough conceptually. Square up the input signal with a
> comparator, feed it to a counter and timer that determine the time
> between 2 cycles, use that number to index into a memory lookup table
> representing the output voltage transfer function that you want, use
> a DAC to bring it back into the analog realm. Add an envelope
> follower cause you'll need a gate extracter, a latch to hold the
> lookup table address at the last valid value whenever the input
> signal disappears, and bingo!
>
> The fun would be in designing some data compression tricks so that
> you would have good resolution, but could avoid a giant table.
>
> It would still have the limitation that all P-V converters have, in
> that you have to wait a full cycle before you know what the pitch is -
>
> the source of notorious lag problems on bass frequencies.
>
> Moe
>
> --- In motm@egroups.com, "Tkacs, Ken" <ken.tkacs@j...> wrote:
> > I don't know if a pitch-cv converter is the kind of thing you want
> to return
> > to a 25-year-old schematic for, though, is it? It's not like a
> filter that
> > might have a vintage sound; in this case you have a very specific
> result in
> > mind, and accuracy is everything. I would think (could be wrong)
> that after
> > a quarter century of electronic advances, we (not meaning 'me')
> should be
> > able to come up with a better design, no?
>
>
>
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