[sdiy] Moog ladder & State-variable example lectures up

[Aaron Lanterman]

For your watching pleasure, two more mostly incoherent lectures:

users.ece.gatech.edu/~lanterma/ece4803

3/15 - state variable VCF examples, Oberheim SEM, EML 101 (uses 
differential integrators, strange circuits), my rant about Doepferization, 
and I also make an ass out of myself at the end of the lecture where I try 
to analyze one of Rene Schmitz's VCAs on the fly and get stuck...

Help! Here's where I got stuck - Check out Rene's VCA-2...

I see the diff pair ladder, which makes me want to make the collectors be 
at opposite voltages, which I then want to sum up with an op amp thingy - 
but looking at the op amp, I apply op amp rules, which makes the 
collectors be at the same voltage.

So I must be reasoning about that circuit terribly wrong...

3/27 - Moog ladder! Whoo hoo! Also some handwaving about diode ladders and 
diode rings (Yamaha GX-1, etc)

The other day I puzzled out the large-signal V/I relationship for a GX-1 
style ring, and came up with

I = [something with Ic I forget off the top of my head] *
     (sinh(v/vt) / [1 + cosh(v/vt)]

So it's almost tanh, but it has this extra "1" in the denominator...
I'll write up my derivation when I get time.

- 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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