| 摘要 |
PROBLEM TO BE SOLVED: To sufficiently suppress an echo even when the reverberation time is long. SOLUTION: The echo suppression apparatus is provided with: a first frequency analysis means 401 for converting a reproduction signal x(k) into a frequency band reproduction signal X(m,f); a second frequency analysis means 402 for converting a superimposing signal y(k) into a frequency band superimposing signal Y(m,f); an initial echo strength calculation means 506 for calculating an initial echo strength PB0(m,f) from the frequency band reproduction signal and an echo path coupling amount C(m,f); a total echo strength calculation means 507 for calculating a present total echo strength PB(m,f) from the initial echo strength, a past total echo strength PB(m-1,f), and an echo time Tr(f); an echo suppression gain calculation means 508 for calculating an echo suppression gain G(m,f) from the frequency band superimposing signal, the present total echo strength, and a past frequency band suppression signal S'(m-1,f); an echo suppression gain superimposing means 509 for multiplying the echo suppression gain with the frequency band superimposing signal to calculate the present frequency band suppression signal S'(m,f); and a frequency composition means 403 for converting the present frequency band suppression signal into a time region suppression signal s'(k). COPYRIGHT: (C)2004,JPO
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