[sdiy] Hopf bifurcation VCOs

[Jonathan Lutz]

As a musician -

How does it sound? What type of waveforms are generated? I am always looking
for unique sound sources...

JON

On 11/11/05, JH. <jhaible at debitel.net> wrote:
>
> > The oscillator runs easily to beyond 30kHz. At that frequency there is
> > some increase in amplitude, probably due to opamp phase shifts.
>
> As long as both outputs increase in the same way, it's ok for a
> frequency shifter.
>
> >
> > At the low end, I checked operation at 0.5Hz. Here there is an
> interesting
> > issue. On power-up it takes the system about 2 minutes to build up to
> full
> > amplitude with both nonlinear circuits in place, and about twice that
> with
> > just one, as in the posted schematic. However, once the system is
> running
> > it changes frequency rapidly when the control current is changed,
> probably
> > because the quadrature phase relation is already established. So I think
> > it can be swept OK.
>
> This is good news!
>
> > It should be fairly simple to make a kickstart
> > circuit to ensure things get running at power up.
>
> Yes, either force a high frequency on power-on, or a stronger
> nonlinearity,
> or maybe even both.
>
> JH.
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://synth-diy.org/pipermail/synth-diy/attachments/20051112/749a751b/attachment.htm>