[sdiy] High frequency VCO designs

[The Old Crow]

   I actually tinkered with sort of thing oh, 17-18 years ago.  I was 
using an NCO chip to drive the clock of a PIC in an attempt to create a 
tunable top-octave reference tone.  I'll have to dig around and see if 
anything from that is on an old disk somewhere.  --Crow

On 9/22/2014 4:01 PM, Tom Wiltshire wrote:
> Hi All,
>
> What contemporary VCO designs are there that can cope with frequencies between 20-40MHz?
>
> There were several synth designs based on top-octave-dividers that used a high frequency VCO to clock the divider (PolyMoog, for one example). It occurred to me (and I'm not the first) that whilst you can't copy aTOG chip in a PIC, you can adequately copy a single output of a clock chip and it's associated divider. This is closer to the older 12-separate-oscillators-plus-dividers scheme. But that's fine, better even. The important thing is to get some voltage control in there by using a VCO for the uP clock.
>
> So, VC-clocks for a PIC? Any ideas?
>
> Thanks,
> Tom
>
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