| 摘要 |
PROBLEM TO BE SOLVED: To stably cancel echoes regardless of distortion occurring in an echo path. SOLUTION: The echo canceler 10 includes an ERL measuring instrument 30 for measuring echo return loss ERL, a frequency analyzer 32 for analyzing the frequency components of reception output signals Rout, a frequency analyzer 34 for analyzing the frequency components of transmission input signals Sin, a distortion measuring instrument 36 for measuring whether the distortion occurs in the echo path EP, and a gain adjuster 38 for adjusting the gain of reception input signals Rin. The distortion measuring instrument 36 adds a power spectrum SinP_f(k) and an echo return loss ERL together and compares the addition results of adding a power spectrum RoutP_f(k) and an offset valueδf for decision together for each of the frequency components (k=0-127), and outputs control signals DIST. The gain adjuster 38 reduces the gain at a prescribed interval when the control signal DIST is "1" and increases the gain at a fine interval when it is "0". COPYRIGHT: (C)2009,JPO&INPIT
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