| 摘要 |
PROBLEM TO BE SOLVED: To enable noise filtering processing in real time by reducing calculation quantity of the noise filtering processing by a MUSIC (multiple signal classification) method. SOLUTION: An observation signal y formed by superposing a noise signal with an original signal is segmented by every frame with prescribed length by a frame segmentation section 1, DFT (design for testability) processing is carried out for the observation signal y by every frame by a DFT section 2, amplitude spectrum and phase spectrum of the frame are extracted and variance of the noise signal from the observation signal y is presumed by a noise variance presumption section 6. A dimension resolution section 3 of a signal subspace resolves dimension of the signal subspace of the observation signal based on the variance of the presumed noise signal. A noise filtering section 4 extracts amplitude spectrum with the resolved dimension from the amplitude spectrum of the extracted frame, presumes amplitude spectrum of the original signal from the variance of the estimated noise signal, presumes spectrum of the original signal from a presumed value of the amplitude spectrum of the original signal and the phase spectrum of the frame and restores the original signal by filtering the noise. COPYRIGHT: (C)2004,JPO
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