Patent ID: 6608897
Filing Date: 2003-08-19
Classification: H04M

Abstract:
A method of controlling an acoustical echo canceller in a telephone system to cancel echo signals from near end signals in a double talk condition wherein said echo signal comprises a reflected far end signal, the acoustical echo canceller implementing a double-talk normalized least mean square (DNLMS) algorithm and having means to converge said DNLMS algorithm, the method comprising generating a replica echo signal based on said far end signal and an estimated echo path length; subtracting said replica echo signal from said near end signal by adjusting convergence rate of said DNLMS algorithm; wherein the convergence rate is adaptively adjusted based on the relative strengths of said echo signals and said near end signals, and wherein the convergence rate is based on a variable step size in which the step size is reduced inversely proportional to the power level of the near end signal.