NOISE REDUCTION AND COMFORT NOISE GAIN CONTROL USING BARK BAND WEINER FILTER AND LINEAR ATTENUATION

摘要

A combination of noise suppression using a Bark band modified Weiner filter (121) and linear noise reduction (122) improves elimination of noise in a telephone. A detector for detecting long, non-speech intervals is coupled to the output of the noise suppresser and controls selection of noise suppression or noise reduction. A gain smoothing filter has a long time constant when noise reduction is used and provides a gradual transition from one level of gain to another. Comfort noise is smoothly inserted by updating the data for generating comfort noise only during detected long, non-speech intervals.