| 摘要 |
PROBLEM TO BE SOLVED: To absorb learning fluctuations due to noise by calculating a filter coefficient for a back up by using a prescribed learning process. SOLUTION: When a changeover switch 23 is connected to a contact 'a', a signal in which a 1st dummy echo signal that is produced by a first echo canceler part 21 is eliminated from an input signal is outputted. The production of the first dummy echo signal uses a filter coefficient that is stored in a coefficient memory 32. Next, when count value reaches a prescribed count in one time learning which is performed by a filter coefficient learning part 31 in the part 21, a backup coefficient is calculated and backup to back up memory 41 in a second echo canceler part is performed. Next, when the switch 23 is connected to a contact 'b', a signal in which a second dummy echo signal produced by the part 22 is eliminated from an input signal is outputted. At this time, the backup coefficient in the memory 41 is used.
|
