Patent ID: 8229107
Filing Date: 2012-07-24
Classification: H04B

Abstract:
1. An echo canceler comprising: an adaptive filter for carrying out echo elimination by generating a dummy echo signal from a received signal and by subtracting the dummy echo signal from a transmission signal; a state deciding unit for detecting a double talk state when the received signal and the transmission signal are in a speech burst, when an amount of reduction in an echo removal level per prescribed time period exceeds a predetermined threshold, the echo removal level being represented as a level difference between the transmission signal and a residual signal passing through the echo elimination by said adaptive filter, and when an amount of changes of a signal level of the received signal per prescribed time period is less than a prescribed reference value; a variable attenuator for adding a loss to the residual signal; and an attenuator controller for controlling an amount of loss of said variable attenuator in accordance with a decision result of said state deciding unit.