METHOD FOR DETECTING WHETHER INCOMING COMMUNICATION SIGNAL IS VOICE SIGNAL OR PERIODIC SIGNAL, METHOD FOR CONTROLLING ADAPTATION OF FILTER COEFFICIENT OF ECHO CANCELLER, AND ECHO CANCELLER USED FOR CANCELLING ECHO IN COMMUNICATION SYSTEM

摘要

PROBLEM TO BE SOLVED: To obtain an echo canceller and a method, capable of speedily detecting the existence of a periodic signal and optimized for fast convergence of a filter coefficient by sampling a communication signal incoming during an evaluating time, deciding the counting value of the number of samples having a value within a counting interval and detecting whether the incoming communication signal is a voice signal or the periodic signal.;SOLUTION: The maximum amplitude restricting value which can be constituted is set and the amplitude restricting lower value is set so that a counting interval is decided between the lower value and the maximum amplitude restricted value. Then, a communication signal incoming during an evaluating time is sampled, the counting value of the number of samples having a value within the counting interval is decided and whether the incoming communication signal is a voice signal or a periodic signal is detected. For example, in a telephone system 29, an echo canceller 30a operates so as to filter-remove the voice of a far-end speaking person 22 reflected from a hybrid 28a and an echo chanceller 30b operates, so as to filter- remove the voice of a near end speaking person 20 reflected from a hybrid 28b.;COPYRIGHT: (C)2001,JPO