METHOD AND APPARATUS FOR DETECTING AN INPUT SIGNAL LEVEL

摘要

A level detector detects an input signal lever (205). A rectifier (210) receives the input signal and provides a rectified signal (215). A prefilter (220) receives the rectified signal and attenuates high frequency components at frequencies near multiples of a decimation sample rate. The prefilter signal (225) is decimitated by a decimator (230) and low pass filtered by a low pass filter (240) having a passband below the input frequency of the input signal. The level detector can be provided to control a variable gain stage circuit which applies a gain to the input signal based on the level to form a dynamic range compressor or expander.