Circuit for selectively obtaining automatic dynamic compression or expansion

摘要

A circuit for the selective automatic dynamic compression and expansion of a signal having frequency components within a given frequency spectrum. It comprises amplifier means having at least one input coupled to the input terminal of the circuit and a summing circuit having its output coupled to the output terminal of the circuit. A plurality of frequency selective channels, each capable of transmitting signals having frequencies within a predetermined portion of the frequency spectrum are coupled between the output of the amplifier means and the input of the summing circuit. One of the frequency selective channels is adapted for transmitting signals in the high frequency range of the frequency spectrum and consists of only a passive filter and an associated adjusting device. The remaining frequency selective channels each include a passive filter, an associated adjusting device and an impedance converter.