Quadrature VCO

[Chris MacDonald]

Thanks Jim!  I will see if I can find those sources.  The book sounds
especially interesting.  I think PAIA has reprints of Polyphony issues
as well.

-Chris M.

patchell wrote:
> 
>     Yes it is.  In the Nov/.Dec 1980 issue of Polyphony there is a circuit
> that uses a single CA3280, but an LM13700 could be used instead.  Another
> reference, if you don't have that one is page 80 in the Analog Devices
> Non-linear circuits handbook (which is where the first circuit I mentioned
> was derived).  If you don't have either, I can xerox off a copy and send
> them to you.
> 
> Chris MacDonald wrote:
> 
> > Is it possible to build a QVCO around a single LM13700?  I have tried to
> > make one by starting with a 2nd order state variable filter but was
> > unable to achieve strong, stable oscillation without clipping on at
> > least one of the waveforms.  Did I miss something here?  Is there an
> > otherwise "standard" or "classic" circuit for a QVCO?  I don't need
> > through-zero or anything, just nice sine waves up to 25kHz or so.
> >
> > Thanks,
> >
> > Chris MacDonald
> 
> --
>  -Jim
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