| 摘要 |
PROBLEM TO BE SOLVED: To provide a terminal for voice conference which realizes constitution of canceling sneak path signals from a speaker, improves sound collecting-characteristics and transmits natural voice signals. SOLUTION: The terminal decides that input signals from microphones 1-4 are sneak path signals from a speaker 5, if the levels of the input signals detected by a level detector 14 approximately equal, and inputs the input signals from the microphones 1-4 to phase inversion adders 10, 11 without attenuating them, thereby canceling them. If the input signals have different levels and the input signal to the microphone 1 has a maximum level, the terminal inputs the input signals from the microphones 1, 2 to the adders 10, 11 without attenuating them, and attenuates the remaining input signals from the microphones 3, 4 through attenuators 7, 9, to lower the levels of the input signals to the adders 10, 11, thereby avoiding canceling the input signals by the adders 10, 11 to improve the sound-collecting characteristics. COPYRIGHT: (C)2004,JPO
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