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CMOS MS20 Filter  A version of René Schmitz' late MS20 Filter using 4069U inverters. 
AR/AD Transient Generator  A variation of Ray Wilson's Retriggerable AR Envelope Generator. Several changes were made to the design. 
VCEcho  PT2395 based delay. 
Linearized LM13700 VCA (untested)  This uses a dual OTA with one in an opamp's feedback path. It seems to simulate ok, but there may be stability problems. 
Potentiometer Linearity  Just some description/plots of loading effects on potentiometers when used as an attenuator. It may be obvious, but it can be helpful to see a plot. note: I saw something like this a while back but could not find it so I made my own. 
SSM2040 Analysis Part 1  A basic analysis of a single filter stage and current sink for an SSM2040 filter clone. The design being analyzed is René Schmitz' version of Jürgen Haible's SSM2040 clone. Check those two sites for the complete schematics. note: I have done this while constructing my own slightly modified version of the filter, which will be published here soon. A Part 2 of this analysis will follow. 
Triangle to Sine Conversion with OTAs  A demonstration of tri>sine conversion by overdriving an OTA. Two designs, with and without feedback are considered. 
Tempco Calculations, Part 1  A design example of a temperature compensated expo converter using a PT146 resistor. If part 2 ever comes, it will be an active compensation but that will only happen if/when I finish and test the design. 
Operational Transconductance Amplifiers  Achim Gratz' notes on OTAs. These notes describe the derivation of OTA equations for several different ICs. Methods to reduce distortion are also discussed. The analysis will certainly help in understaning voltage controlled amplifiers and many voltage controlled filters. 
Whats that exp and tempco stuff?  René Schmitz' tutorial on exponential current sources. These circuits are common in synthesizers. The basic expo current source/sink is explained as well as a few methods of passive temperature compensation using "tempco" resistors. 
NonLinear Digital Implementation of the Moog Ladder Filter  Antti Huovilainen. This is a wonderful paper on digital implementations of analog filters. Euler's Method is used to solve the nonlinear differential equations in real time. This paper was published in the DAFx'04 Proceedings. 
Derivation of the Transfer Function of the Moog Ladder Filter  Timothy E. Stinchcombe. 