Patent ID: 6266422
Filing Date: 2001-07-24
Classification: G10L

Abstract:
A noise canceling method including the steps of inputting a reference noise signal received via a reference input terminal to a first adaptive filter to thereby generate a first pseudo noise signal in accordance with a filter coefficient assigned to said first adaptive filter, causing a first subtracter to subtract the pseudo noise signal from a received signal input via a speech input terminal and consisting of a speech signal and a background noise signal to thereby generate a first error signal, and sequentially correcting the filter coefficient of the first adaptive filter on the basis of the first error signal, the first subtracter outputting a received signal free from noise, said noise canceling method comprising the steps of:(a) inputting the reference noise signal to a second adaptive filter to thereby generate a second pseudo noise signal in accordance with a preselected filter coefficient;(b) causing a second subtracter to subtract said second pseudo noise signal from the received signal to thereby output a second error signal;(c) detecting mean power of said second error signal and mean power of said second pseudo error signal to thereby calculate a signal-to-noise power ratio;(d) extending a period of time of said signal-to-noise power ratio to output as an extended signal-to-noise power ratio; and(e) varying the filter coefficient of the first adaptive filter adaptively in accordance with a value of said extended signal-to-noise power ratio and a mean power of the reference noise signal.