I decided to take the discrete VCO design I'd been leaving on the
project back-burner for a year or more and finish building the
prototype. It works, but it needs a little debugging, mostly in
stabilizing the frequency vs. power supply tolerances. When I get a
chance, I'll record the raw output of the VCO sawtooth waveform both
with and without the curious little one-shot pulse that is mixed into
the leading edge of each cycle. It is only 30 microseconds wide, but
it definitely makes an audible difference, and gives that signature
CS 'rasp' to the tone.
Here are some scope shots of the actual IG00153 VCO output to see
what I'm talking about. I'll add scope shots of my discrete VCO
later.
Crow
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