| 摘要 |
PROBLEM TO BE SOLVED: To provide an echo canceler circuit in which an echo can be canceled in a simple configuration even in a transmission line having delay without making a transmitted voice unclear in the echo canceler circuit applied to a telephone system equipped with a two-wire/four-wire converting circuit and having the delay on a four-wire transmission line. SOLUTION: On the hybrid circuit side of a counter station, a received signal level detecting circuit is provided, and an attenuation circuit is provided for applying attenuation corresponding to a level difference between the level of a received signal and a preset level to a transmitted signal outputted from a hybrid circuit to the four-wire transmission line when the detected level of the received signal is higher than the preset level. Thus, the echo can be canceled. COPYRIGHT: (C)2003,JPO
|
