| 摘要 |
The invention relates to an echo canceller (1, 2, 3, 6) including an adaptive filter (3) which can be inserted between a receive path (r) and a send path (s), and including a non-linear filter (2) which can be inserted in the send path (s). The echo canceller is to have an improved echo cancellation, especially when the state of doubletalk occurs, thus substantially avoiding an erroneous activation of the non-linear filter when the state of doubletalk is detected. For this purpose, it is proposed that the echo canceller (1, 2, 3, 6) comprises an up/down counter (11) provided for counting up with a first value (ZU) when the state of doubletalk (d) occurs and for counting down with a second value (ZD) smaller than the first value (ZU) when the states of non-doubletalk (a, b, c) occur, the non-linear filter (2) being provided to be inserted in the send path (s) only when the state of far-end speech (c) occurs and when the up/down counter (11) reaches a predeterminable small value (ZN), especially the zero value.
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