Patent ID: 8538034
Filing Date: 2013-09-17
Classification: H04B,H04M

Abstract:
1. A method for canceling echoes in a communication terminal during a voice call with an opposite party, the terminal comprising a loudspeaker and a microphone, the method comprising the following steps being executed by an echo canceling unit in the terminal: a) receiving speech signals from the microphone on a first input of the echo canceling unit, said speech signals from the microphone referred to as microphone signals; b) feeding the received microphone signals into a first branch and a second branch; c) receiving speech signals from the opposite party on a second input of the echo canceling unit; d) producing, in the first branch, a first estimate of an echo information in the microphone signals, based on the received microphone signals and the received speech signals from the opposite party; e) performing a subtraction wherein the produced first estimate is subtracted from the signals fed into the second branch; and f) outputting the result from the subtraction from the echo canceling unit; and wherein the step of producing a first estimate further comprises the following sub-steps: down-sampling the received microphone signals in the first branch with a down-sampling factor i; down-sampling the received speech signals from the opposite party with the down-sampling factor i; producing a down-sampled second estimate of the echo information in the microphone signals, by filtering the down-sampled speech signals from the opposite party in a digital filter; and producing the first estimate by up-sampling the second estimate with an up-sampling factor i, equal to the down-sampling factor i.