[sdiy] Synthex Oscillator

[Tom Wiltshire]

I'd be interested to see the LTSpice sim too, if you don't mind sharing, Neil.

What did you learn about it? What's the advantage over a simple voltage-output DAC? What did you do with the transistor/cap reset? What signals did you use to reset the cap?
Also what assumptions did you make about the pulse train driving the counter? It struck me that looking at the counter alone ignores the fact that the pulses going to it aren't nice and constant. Instead, the upper divider section provides the right *average* number of pulses to get the correct output frequency, but they're not evenly distributed. Instead, you get a variable-length "dead patch", followed by 128 clocks.

Thanks,
Tom

==================
       Electric Druid
Synth & Stompbox DIY
==================




On 12 Jul 2017, at 04:40, Neil Johnson <neil.johnson71 at gmail.com> wrote:

> Deary me, what a thread!
> 
> I've just simulated the counter/DAC part in LTSpice, and I must say it
> is rather a neat solution!  Not perfect - as Brian alluded to the DAC
> is not perfect - but the result is a very usable sawtooth.
> 
> Neil
> -- 
> http://www.njohnson.co.uk
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