Patent ID: 6839426

Claim:
An echo canceller for suppressing an echo noise mixed in a sending signal, said echo noise caused by an echo produced by passage of a voice through an echo path used as a specified path for said voice, the echo canceller comprising: an adaptive digital filter that captures a tap coefficient used to mimic a transmission characteristic responsive to said echo path, establishes a pseudo transmission characteristic based on the captured tap coefficient, outputs a pseudo echo for canceling said echo noise, and calculates and outputs a new tap coefficient based on a residual amount of said echo noise existing after canceling; a main tap coefficient holding section that replaces a currently held tap coefficient with said new tap coefficient, for subsequent capture by said adaptive digital filter; a sub tap coefficient holding section that copies and holds a tap coefficient from said main tap coefficient holding section when echo suppression increases; an ambient noise detector that detects ambient noises mixed in said sending signal and outputs a detection signal indicative thereof; and a controller that controls said adaptive digital filter to capture the tap coefficient held by said sub tap coefficient holding section responsive to said detection signal.