Patent ID: 6044108
Filing Date: 2000-03-28
Classification: H04B

Abstract:
A modem configured to perform echo suppression, comprising:a vocoder; anda controller configured to provide a first series of compressed speech frames to said vocoder, wherein each of said first series of compressed speech frames includes a volume parameter, wherein said controller is operable to maintain a history of said volume parameters of one or more of said first series of compressed speech frames;wherein said vocoder is configured to receive said first series of compressed speech frames from said controller and to decompress said first series of compressed speech frames to produce a first speech signal for transmission on a telephone line;wherein said vocoder is further configured to receive a second speech signal from said telephone line and to compress said second speech signal into a second series of compressed speech frames, wherein each of said second series of compressed speech frames includes a volume parameter, wherein said second speech signal may include an echo of said first speech signal;wherein said controller is operable to receive said second series of compressed speech frames from said vocoder and for at least a subset of said second series of compressed speech frames to compare said volume parameter of each of said subset of said second series of compressed speech frames to a volume parameter in said history to determine if said echo of said first speech signal is present in said each of said subset of said second series of compressed speech frames;wherein said controller is operable to substitute a quiet frame for said each of said subset of said second series of compressed speech frames in which said echo is determined to be present in order to suppress said echo.