ODP: Frequency multiplication

Roman Sowa rsowa at WizjaTV.pl
Tue Sep 1 13:59:36 CEST 1998


I got an idea for you...

If you had a sine VCO, you could wave-shape it through squareing device
(like multiplying the signal by itself, maybe in a precise RM or some
function generator - AD633 if i recall)
You get sine squared which actually is a cosine with doubled frequency
and DC offset. Remowe DC offset and square it again. You get quadrupled
frequency sine wave, and so on, till 32 times normal F is acheived. 

Another way to do that:
Take triangle (bipolar) wave and rectify it. You'll get another triangle
wave
with doubled frequency, half the amplitude and DC offset. Adjust gain
and
offset, and rectify again. When you do it 5 times, the output wave would
be of frequency 32 times higher than the normal one.

there's a trick: rectified triangles must be linear all the time and
with not a bit of
DC offset. Otherwise the owerall wave won't be a "clean" triangle
i.e. pulses within 32-cycles period will spread sort of randomly.

I got totally different another idea for multiplying f. It's simpler as
a concept,
but can be very unreliable if done bad, and does not work with LF.
Let me know if you want me to use your bandwidth for it. 

Roman

> -----Oryginalna wiadomość-----
> Od:	Tony Allgood [SMTP:oakley at enterprise.net]
> Wysłano:	30 sierpnia 1998 22:33
> Do:	synth diy
> Temat:	Frequency multiplication
> 
> Hi all,
> 
> I want to make a high frequency VCO, 32 times the normal frequency, to
> use
> as a driver osc for a walsh bank. 
> 
> 
> 4. I'm open to any other ideas.
> 
> Regards,
> 
> Tony Allgood, Cumbria, UK
> 
> 
> 



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