| 摘要 |
PROBLEM TO BE SOLVED: To reduce acoustic echo without deteriorating a sound collection property such as directivity. SOLUTION: Sound collection signals from four microphones 12-15 disposed within an equal distance from a speaker 11 are paired two by two, adapters 41, 42 for correction a path difference from the speaker to the microphones are integrated into each pair, and phases are inverted and added in each of the pairs by adders 51, 52, thereby reducing acoustic echo between the speaker and the microphones. The adapter is mainly composed of an adaptive filter and performs learning operation with outputs of delayers 31, 32 as teaching materials. A phase shifter 60 applies phase shift to the output signals of adders, and the output signals are added by an adder 70. Thus, deterioration in the directional property of a sound collection signal is suppressed, and transmission sound can be recorded with high quality while reducing acoustic echo. COPYRIGHT: (C)2007,JPO&INPIT
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