Patent ID: 7146316

Claim:
A system for reducing noise in an input speech signal, the input speech signal including intermittent speech in the presence of noise, the system comprising: an analysis filter bank accepting the input speech signal, the analysis filter bank comprising a plurality of filters, each filter in the analysis filter bank extracting a subband signal from the speech signal; a first plurality of variable gain multipliers, each first variable gain multiplier multiplying one subband signal by a first subband variable gain to produce a subband product signal; a synthesizer accepting the plurality of subband product signals and generating a reduced noise speech signal; a second plurality of variable gain multipliers, each second variable gain multiplier multiplying one subband signal by a second gain different than the corresponding first subband variable gain; a voice activity detector detecting the presence of speech in the reduced noise speech signal; and gain calculation logic for calculating the first subband variable gains, the gain calculation logic operative to: (a) determine a noise floor level based on the input speech signal if the presence of speech is not detected, (b) hold the noise floor level constant if the presence of speech is detected, and (c) determine the first subband variable gains based on the noise floor level.