[sdiy] Buchla 295 10-band comb filter topology

[David G Dixon]

I've struggled with this idea of "phase modulation" -- I don't really get
it.

It seems to me that all you are doing is moving the waveform left and right
in time, within the span of one or two wavelengths.  I don't know how to do
that, but I suspect that it wouldn't sound like much unless it was done
"against" another waveform which isn't being phase-modulated.

Also, since one has to slightly speed up or slow down a waveform in order to
move it left or right, even if just a little, it seems to me that phase
modulation would always involve a very slight change in pitch.

Hence, phase modulation is really just frequency modulation with a very
constrained range of motion.

Is any of that correct?  If not, then I'd very much appreciate an
explanation of phase modulation -- specifically, what the hell is it?

Thanks