The CGS75 VCS module is an extremely versatile control voltage generator and audio source. In the early 1970s, Serge Tcherepnin developed the Positive Slew and Negative Slew modules for the original Serge synthesizer. In time these merged into the classic Dual Universal Slope Generator. The CGS75 is an adaptation of Serge's original circuit with a few new features.
The VCS is a unity gain voltage follower. The rising and falling slopes are independently and jointly voltage controllable over a wide range.