[sdiy] A diode-ring SVF

[Aaron Lanterman]

A couple of students, one of whom just posted, are trying to get a 
one-pole lowpass diode-ring based filter working so they can do a 
four-pole cascade.

Another student, Chris Olinde, is trying to get a state-variable running 
using diode-rings in the variable integrators. I've posted his draft 
schematic here:

users.ece.gatech.edu/~lanterma/ece4803/drafts/diodering_svf.pdf

Alas, he can't seem to get anything going... If you tap into the BPout and 
LPout, you just hear noise (and see it on the scope) its seems.

The control circuit is based off the MOTM-485, since I figured you 
probably can't get a better control front end than whatever Paul did. I 
didn't have any of the op amps that Paul used, so I gave Chris some 
LM358s, which we later swapped out for some TL072s just to have something 
to try.

- Aaron

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Dr. Aaron Lanterman, Asst. Prof.
and Demetrius T. Paris Junior Prof.    Voice:  404-385-2548
School of Electrical and Comp. Eng.    Fax:    404-894-8363
Georgia Institute of Technology        E-mail: lanterma at ece.gatech.edu
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