[sdiy] Tracking Generators?

[Grant Richter]

Hello All,

Has anybody taken a shot at implementing a "Tracking generator" like in the
Oberheim Xpander?

I'm still pursuing the idea of deliberate non-linearity as a control voltage
(and maybe audio processor). This is what I have managed to dig out so far.

1. Buchla Music Easel / 259 appears to be some kind of non-linear waveshaper

2. Most famous is Serge wave multipliers

3. There was a Moog 900 series module that had independent control of
positive and negative base clipping and peak clipping

4. Diode break point generators in the analog computers.

5. Then there is the Tracking generator in the Oberheim Xpander. I am sure
this is software though.

1-3 are audio processors and 4-5 are for control voltages. I am looking for
a simple design for versatile non-linear processor.

OK Why? We were talking about harmonic generators, Steve Curtin pointed out
that a harmonic generator by itself is practically useless since static
harmonics are boring. So each harmonic needs a VCA and envelope, which is a
lot of circuitry. However, if there was a simple enough non-linear function
generator, then a single envelope could be twisted into many envelopes and
used to control the harmonic VCAs, giving animation to the sound with about
half the parts hopefully.