Abstract: A system and method for reducing noise in an audio signal. The system includes an encoder, a decoder and a single feedforward sidechain for generating a control signal that is used as input to a variable gain element in the encoder and in the decoder. The system is substantially audibly transparent, minimizes audible noise modulation, minimizes dynamic distortion of low frequency signals due to a level detector tracking these waveforms, minimizes distortion of signals due to phase shift in a transmission channel, minimizes distortion of fast, high-level transients due to the attack time of the level detector, and has virtually no effect on the audio signal if the level of the signal stays within a reasonable range around the nominal signal level.

Abstract: A method and apparatus for combining analog and digital processing techniques to thereby capture a much wider dynamic range of an original input signal than an A/D converter can by itself, to thereby preserve a maximum amount of information from the original input signal, wherein a processing amplifier combines a level-dependent, soft logarithmic limiting function with a high-frequency pre-emphasis filter, such that the pre-emphasis helps to compensate for a disproportionate reduction of high frequency information when portions of the signal are in an overload region, and wherein digital de-emphasis of the digitized signal enables recovery of the dynamic range that was sacrificed to create the overload region.