Patent ID: 6243462
Filing Date: 2001-06-05
Classification: H04B

Abstract:
An echo canceller wherein a group of tap coefficients are successively updated on the basis of a residual echo signal and receive-in signals successively received, a pseudo echo signal is generated by a filter whose inputs are the receive-in signals and whose filter coefficients are the group of tap coefficients, the pseudo echo signal is subtracted from a send-in signal, thereby to execute an echo cancelling operation for the send-in signal, and a send-out signal is delivered on the basis of a result of the subtraction; comprising:an echo-cancelling-operation-state detecting unit which detects a state where a transmission delay time of an echo path exceeds an echo control time of said echo canceller, on the basis of the tap coefficients successively updated; andan echo-cancelling-operation stopping unit which stops the echo cancelling operation, including a process for subtracting said pseudo echo signal from said send-in signal, when the state has been detected.