Adventures with the Tilman modulator

[jhaible]

> AFAIK the Tilman proposal is a post processor, i.e.. rides on a
> saw given by an independend vco. Thus I can not understand why
> you hear a pitch change, ... ahh, say measure a frequency change.
> There should be no frequency change at all, until the circuit
> fails due to overload.

I'd expect a frequency change, when the "maximum" of each cycle
is modulated back and forth.

> Is it possible that the changing spectra lead to a changing pitch
> sensation? What do you mean by phase change?

Spectrum is a concept that might not exactly fit here. You can try to
develop a "spectrum" of a periodical signal from one cycle of your
momentary waveform. The fundamental of this spectrum might always
be at the same frequeny. (The phase of this fundamental would not
be the same for each "snapshot" of the modulated waveform, though.)

Now when you modulate the waveform, a similar thing will happen as
with more simple forms of modulation, like FM or PM:
The "momentary frequency" and the spectrum are something entirely
different.
When you just look at the fundamental of the triangle modulation,
and neglect the harmonics, it's obvious that there's some angle modulation
applied.

JH.