| 摘要 |
PROBLEM TO BE SOLVED: To enhance a filter convergence speed of a pseudo echo path. SOLUTION: A received signal x(k) is divided every short times each being 1/M division of an impulse response time of an echo path, FFT is applied to each block signal to obtain a signal X<SB>1</SB>(k), signals X<SB>2</SB>(k) to X<SB>M</SB>(k) resulting from delaying the signal X<SB>1</SB>(k) longer by each short time are obtained, the X<SB>m</SB>(m = 1,...,M) is multiplied with a partial predictive impulse response W<SB>m</SB>(k) of each frequency region corresponding to each of the M divisions of the impulse response by each corresponding component, M-sets of W<SB>m</SB>(k)X<SB>m</SB>(k) are summed, inverse FFT is applied to the sum to obtain a predictive echo y^(k) of a time region, an error signal between the y^(k) and an echo path acquired signal y(k) is converted into a signal E(k) of the frequency region by each short time, a correction vector dW<SB>m</SB>(k)=X<SB>m</SB>*(k)E(k) is produced, dW<SB>m</SB>(k) is weighted by a step sizeμ<SB>m</SB>that is attenuated at a prescribed ratio in response to the envelope of the impulse response, and the result is added to the W<SB>m</SB>(k) to update it. COPYRIGHT: (C)2005,JPO&NCIPI |
