ECHO CANCELLER HAVING IMPROVED NON-LINEAR PROCESSOR

摘要

A non-linear processor (300) for use in an echo canceller (25) is set forth. The non-linear processor (300) includes a center clipping digital filter receiving an echo compensated signal. The non-linear processor provides a center clipped output signal having non-linear thresholds at values of + T(sub NLP) and -T(sub NLP).The value of T(sub NLP) is dynamically dependent, at least, in part on echo return loss measurements. To limit the processor's susceptibility to corruption from double-talk conditions, the non-linear processor (300) inhibits the dynamic setting of the T(sub NLP) value when a double talk condition is present. Additionally, or in the alternative, the non-linear processor (300) locks the value of the echo return loss measurement after a predetermined number of consecutive echo return loss measurements have values falling within a predetermined range of one another. Such locking further reduces the susceptibility of the non-linear processor to corruption from double-talk conditions.