| 摘要 |
PROBLEM TO BE SOLVED: To provide an echo canceller circuit which simply and accurately adjusts the cancel signal level to realize an optimum echo cancel without manually adjusting the volume of cancel signals, while the conventional echo canceller circuit has the problem that the volume adjustment of the cancel signal is manually made and hence troublesome. SOLUTION: The echo canceller circuit makes an echo canceling adjusting operation using a reference signal for a transmission signal. A comparator 14 compares the reference signal with an echo signal generated from the reference signal to obtain a difference signal. An MPU 9 acquires the level of the echo signal from the difference signal. An electronic volume 42 is operated to adjust the level of the cancel signal, based on the echo signal level. COPYRIGHT: (C)2004,JPO
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