[sdiy] State Variable Filter self oscillation

[Neil Johnson]

> Has anyone built a classic state variable that can oscillate?

Well, my own variation (using three integrators) also oscillates nicely
(thanks to Roman for the fix :-) as you increase the Q.

Also, the 4-pole filter in the Jen SX1000 oscillates as the resonance is
turned up (had to tweak the trimmer to get it into oscillation).

I'm not sure what you mean by "classic", but the design was worked out on
paper using state variable theory (then simulated in Octave, then
prototyped, modified, sworn-at, modified again, and then got working).

Neil

--
Neil Johnson :: Computer Laboratory :: University of Cambridge ::
http://www.njohnson.co.uk          http://www.cl.cam.ac.uk/~nej22
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