[sdiy] Simple voltage controlled clock/counter

[Matthias Herrmann-DEU]

> -----Original Message-----
> From: synth-diy-bounces at dropmix.xs4all.nl [mailto:synth-diy-
> bounces at dropmix.xs4all.nl] On Behalf Of Paul Perry
> Sent: Friday, November 11, 2011 11:35 AM
> To: synthdiy diy
> Subject: Re: [sdiy] Simple voltage controlled clock/counter
> 
> The voltage controlled triangle oscillator from the LM13700 data sheet
> application notes works well over a wide range, and it is easy to use a
> comparator to turn the output into a voltage controlled PWM.

In the VC Clock Module I built recently I used a saw core (falling ramp) VCO and a subsequent comparator for PWM. Using a falling ramp the clock pulse keeps the timing, even when you change the duty cycle with the comparators threshold going up/down. A triangle would not provide this:
http://www.modular.fonik.de/pdf/VCClockSCH.pdf

I cannot remember when I posted here last time. I simply had not the feeling I could contribute anything valuable...

Cheers,
Matthias
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