[sdiy] VCO HF compensation - Rossum vs. Franco

Justin Owen juzowen at gmail.com
Sat Jun 14 17:15:03 CEST 2014

Anyone got any insights/thoughts/comments on the pros & cons of these two different HF compensation methods when used with an NPN expo converter running a Tri core VCO?

Sims show pretty close frequency results - so far, maybe a little bit better with the Franco integrator R - but that's at the costs of some waveform deformation.

For the Rossum diode I'm running the output of the OA with the first transistor in it's feedback loop, into the Cathode of the diode into a voltage divider and then into the non-inverting input of the exponential CV summing amp. Seen a few different variations on this - but this is the one that seems to work best.

- J

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