Chelys Lyra

UBZR1 Noise Generator


Functional Description

The noise module uses a transistor operated in reverse mode above breakdown voltage with current limited.

The following opamp circuits filter for white noise (cutting non-audible high frequency), pink noise with a spectrum d p / d ln f = constant and "red" noise with still more emphasis on low frequencies.

Final amplification is done with an LM 13700 transconductance amplifier, which serves as a built-in VCA and provides for two separate current outputs, one for white/pink noise and one for pink/red noise. The former can be used in the audio path, the latter is available in the modulation matrix.

Performance Specs

Schematics as PDF or JPG



Last change: 2019-09-19
© 2002-2020 Dr. Thomas Redelberger