SOUND ECHO CANCELLER, HANDSFREE TELEPHONE USING SOUND ECHO CANCELLER, AND SOUND ECHO CANCELING METHOD

摘要

PROBLEM TO BE SOLVED: To solve a problem of instability caused by a difference of transfer characteristic from that of actual operation even if it is made nearer to the transfer characteristic based on the reference signal of the large delay in a studying process of multiple times from sampling to next sampling, in which the transfer characteristic of sound space changes if a reference signal of small delay and a reference signal of large delay are used in the same frequency.;SOLUTION: As to the small delay and the large delay in a reference signal accumulating unit 6, the reference signals of the delay are not used in the same frequency. In an update frequency control unit 10, the filter coefficient of the filter coefficient accumulating unit 6 is updated by a filter coefficient update unit according to the largeness of delay of the reference signal. Then, the transfer characteristic of newest sound space can be reflected, the transfer characteristic near to that of actual sound space can be acquired, and a stable sound echo canceler with large amount of echo canceling can be acquired.;COPYRIGHT: (C)2006,JPO&NCIPI