[sdiy] Bergfotron success!!!

[Aaron Lanterman]

Manu and I are hacking in lab right now.

We figured out that at some point the the SSM2210 we were using in the 
diff pair of the OTA got screwed up... I didn't have another 2210 handy 
but I had a 2SC1583 we swapped it out for, and it's working fine.

One clue was that measuring the current through the resistor at the 
emitters of the expo converter was giving good numbers... and also it 
seemed to track at 1 volt per octive - just with an additional 6 kilohertz 
offset!

It's purringly along happily now, and we got it trimmed by ear to 1 
V/octave.

Manu went through a bunch of 5.1K and hand matched them for the current 
mirror, so the triangle looks pretty symmetric now.

Happy happy!

- Aaron

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Dr. Aaron Lanterman, Asst. Prof.
and Demetrius T. Paris Junior Prof.  Voice:  404-385-2548
College of Electri. and Comp. Eng.   Fax:    404-894-8363
Georgia Institute of Technology      E-mail: lanterma at ece.gatech.edu
Mail Code 0250                       Web:    users.ece.gatech.edu/~lanterma
Atlanta, GA 30332                    Office: Centergy 5212