| 摘要 |
<p>An echo canceller circuit (25) for use in an echo canceller system is set forth that provides sensitive non-linear echo path response detection (300). The echo canceller circuit (25) comprises a first digital filter (35) having non-adaptive tap coefficients to simulate an echo response occurring during a call. A second digital filter (30) having adaptive tap coefficients to simulate an echo response occurring during a call. The adaptive tap coefficients of the second digital filter are updated over the duration of the call. A coefficient transfer controller is disposed in the echo canceller circuit (25) to a transfer the adaptive tap coefficients of the second digital filter to replace the tap coefficients of the first digital filter when a set of one or more transfer conditions is met. A non-linear echo path response detector (300) is provided. The non-linear echo path detector is responsive to one or more parameters of the first and second digital filters to detect a non-linear path condition. In accordance with one embodiment of the present invention, the non-linear echo path detector (300) is responsive to a transfer density value corresponding to a number of transfers executed by the coefficient transfer controller (65). In accordance with a further embodiment of the present invention, the non-linear echo path detector (300) is responsive to a coefficient time dispersion characteristic of the second digital filter for detecting a non-linear path condition.</p> |
