Title:
ECHO REDUCTION METHOD AND TELEPHONE DEVICE
Document Type and Number:
Japanese Patent JP3553008
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To provide a method for reducing problems regarding the echoes of one's own transmission, by using a simple configuration.
SOLUTION: A reception attenuation circuit 21, where amount of attenuation is changed, is inserted into the transmission line of reception at the four-line side of a hybrid circuit 3 on one's side. The release time of the response speed of a transmission level detection circuit 22 is set to a value, in which the delay time where one's own transmission is bounced by a partner's hybrid circuit 5 and is returned as reception is taken into consideration, thus detecting the transmission level of the transmission line of the transmission at the four-line side of the hybrid circuit 3 on one's side. By the detection output of the transmission level detection circuit 22, the amount of attenuation of the reception attenuation circuit 21 is increased, when the detected transmission level is near a standard level, while, when the detected transmission level is smaller than the standard level, the amount of attenuation is decreased, thus reducing the level of the echo returning to the reception.
Inventors:
Yoshimasa Kamoto
Application Number:
JP2000291441A
Publication Date:
August 11, 2004
Filing Date:
September 26, 2000
Export Citation:
Assignee:
Iwasaki Tsushinki Co., Ltd.
International Classes:
H04M1/58; H04B3/20; (IPC1-7): H04B3/20; H04M1/58
Domestic Patent References:
| JP7250010A | ||||
| JP63128823A | ||||
| JP63046015A | ||||
| JP6232957A | ||||
| JP8204619A | ||||
| JP8335976A | ||||
| JP9233002A | ||||
| JP11205199A | ||||
| JP2002501336A | ||||
| JP49033709U | ||||
| JP58080937A | ||||
| JP8186525A |
Attorney, Agent or Firm:
Masami Sato
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