Circuit detector and compression-expansion networks utilizing same

This invention discloses new and unique detectors suitable for controlling any device needing precise conversion of AC voltage to an equivalent DC voltage. The detector may also be used as an excellent non-linear low pass filter. More particularly, the detector is suitable for controlling meter movements and the variable gain amplifiers which are used in compressors, expanders, compandors, limiters and other noise reduction systems, The detectors control gain such that unnecessary gain changes are eliminated, overshoot transient distortion is minimized, distortion due to ripple is minimized, and pumping is eliminated. As described herein, the detector uses two interacting memories to provide a output signal from the detector which can be used to drive a variable gain amplifier for achieving optimum characteristics of a compressor, expandor or compandor. This is achieved by using inter-connecting circuitry between the two memories and between the inputs and outputs of the detector such that one of the memories dominates and controls the output signal for most input voltage situations, but in the event of drastic input signal changes the second memory interreacts with the first memory.