[sdiy] Vco for BBD clock generation

[Dave Garfield]

Hi!
If you need 1Volt/Octave accuracy, I'd suggest the SSM2031 High-Frequency VCO chip, usually found in Seil DK-600s and such-like.  This chip, when paired with a good exponential convertor (You know; the whole MAT 02 kinda' thing), will provide square wave clock and notclock (inverted waveform) signals at up to ?4? ?5? MHz.  Plus, the tracking means that phasing, flanging, or whatever will increase twofold for every octave increase.
If you don't need that kind of precision, though, I'd go with the 4046 PLL circuit below.  Mine dos centavos - GRIN!  :->
Your Hi-Freq. Pal,
Dave Garf, basking in Sunday afternoon frequency...


----- Original Message ----
From: Loscha <loscha at gmail.com>
To: matrix <matrixsynth at gmail.com>; synthdiy <synth-diy at dropmix.xs4all.nl>
Sent: Sunday, May 18, 2008 6:40:32 PM
Subject: [sdiy] Vco for BBD clock generation

http://www.flickr.com/photos/loscha/2503124435/

As the description in Flickr explains,
"Circuit for using a CD4046 PLL to generate a voltage controlled BBD
complimentary phase clock! I found this ripped out page on it's own in
a stack of magazines I purchased Yesterday; Sunday 18th of May, 2008.
The previous owner was interested in the other side (some notes on
there in pencil).
Thanks to Hugo Bramall of Canterbury, Victoria who came up with the
circuit and sent it ETI magazine in the first place!"

The circuit is pretty low parts count. An op-amp (they suggest LM301
in the circuit) and a CD4046 PLL. A few resistors, capacitors and a
trimmer pot fill out the plan.

I hope someone out there finds this useful, interesting or at least novel.
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