Method of and apparatus for reducing acoustic nois

专利名称：Method of and apparatus for reducing

acoustic noise in wireless and landline basedtelephony

发明人：Elias J. Nemer申请号：US11447365申请日：20060605

公开号：US20060229869A1公开日：20061012

专利附图：

摘要：Acoustic noise for wireless or landline telephony is reduced using frequencydomain of optimal filtering in which each frequency band of every time frame is filtered as

a function of the estimated signal-two-noise ratio and the estimated total noise energyfor the frame. Non-speech, non-speech frames and other special frames are furtherattenuated by one or more predetermined multiplier values. Noise in a transmittedsignal comprised of frames each comprised of frequency bands is reduced. A respectivetotal signal energy and a respective current estimate of the noise energy for at least oneof the frequency bands is determined. A respective local signal-to-noise ratio-for at leastone of the frequency bands is determined as a function of the respective signal energyand the respective current estimate of the noise energy. A respective smoothed signal-to-noise ratio is determined from the respective local signal-to-noise ratio and anotherrespective signal-to-noise ratio estimated for a previous frame. A respective filter gainvalue is calculated for the frequency band from the respective smoothed signal-to-noiseratio. Also, it is determined whether at least a respective one as a plurality of frames is anon-speech frame. When the frame is a non-speech frame, a noise energy level of at leastone of the frequency bands of the frame is estimated. The band is filtered as a functionof the estimated noise energy level.

申请人：Elias J. Nemer

地址：Montreal CA

国籍：CA

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