| 摘要 |
PROBLEM TO BE SOLVED: To provide a hands-free speech device for canceling acoustic echoes by a stable operation without readjusting a filter coefficient of an echo canceler (22) even if a characteristic that is hard to predict intervenes in a path for generating the acoustic echoes. SOLUTION: A reference signal line (2) that connects the start point of an echo path to the echo canceler (22) is wired via a receiving side buffer (15) in the echo path and a transmitting side buffer (20). Even if unpredictable phases occur in these circuit elements, the filter coefficient does not have to be reset and the echo canceler (22) can be made to operate stably because the same phase as that by the echo path appears in a reference signal inputted to the echo canceler (22). COPYRIGHT: (C)2004,JPO
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