Title:
TWO-WIRE TYPE AUDIO CONFERENCE SYSTEM
Document Type and Number:
Japanese Patent JP2765494
Kind Code:
B2
Abstract:
PURPOSE: To effectively suppress echo in a speech state in the echo estimation process of an echo canceler for processing howling or echo or after estimation concerning the audio conference system of utilizing lines.
CONSTITUTION: Corresponding to the levels of a signal to a loudspeaker 001 after echo erasure by line echo erasing circuits (017 and 018) and a signal from a microphone 002 after echo erasure by acoustic echo erasing circuits (004 and 003), the residual echo of a microphone signal is suppressed by a suppressing circuit 005. Based on the amount of this residual echo suppression, the signal to the loudspeaker and the microphone signals before and after echo erasure, an echo estimating operation control part 009 detects a speaking direction and the suppressing amount and controls the ON/OFF of an estimating operation at an echo estimating circuit 004, so that echo can be exactly erased.
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Inventors:
HASEGAWA ATSUSHI
Application Number:
JP27412894A
Publication Date:
June 18, 1998
Filing Date:
November 09, 1994
Export Citation:
Assignee:
NIPPON DENKI KK
International Classes:
H03H21/00; H04B3/23; H04M1/60; H04M9/08; (IPC1-7): H04B3/23; H04M1/60
Domestic Patent References:
| JP575500A |
Attorney, Agent or Firm:
Yanagi Kawa Shin