| 摘要 |
An arrangement for cancelling the composite echo signal formed by, for example, a linear component and a variable-phase component, comprises a linear echo canceller and a variable phase echo canceller, the difference circuits of these echo cancellers being arranged in cascade. The adjustable signal processing arrangements of each echo canceller are controlled for minimizing a predetermined function (mean square value or time average of this means square value), either of a residual echo signal appearing at the output of the difference circuit of this echo canceller itself or of a residual echo signal appearing at the output of the cascade arrangement of the difference circuits. In all cases the signal at the output of the linear echo canceller contains only a residual variable-phase signal which can be compensated for by the variable-phase echo canceller.
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