| 摘要 |
PURPOSE:To save the quantity of operation and to attain easeof real time processing by calculating the correlation coefficient sequence of the output of the 1st and 2nd acoustic pickups and the autocorrelation coefficient string of the output of the 2nd acoustic pickup and providing a filter coefficient setting means for a transversal filter. CONSTITUTION:A correlation calculation device 6 calculates the correlation coefficient sequence between a detected waveform Su(t) outputted from the acoustic pickup 2 and a detected waveform Sn(t) outputted from the acoustic pickup 4, an autocorrelation calculator 7 calculates the autocorrelation coefficient sequence of the detected waveform Sn(t) outputted from the acoustic pickup 4 and they are fed to a coefficient deciding device 8 respectively. The detected waveform outputted from the acoustic pickup 4 is fed to an equivalent noise generation filter 9 constituted as a traversal filter. The weight coefficient of multipliers 92-1-92-P is estimated and supplied one after another one by one from the coefficient decision device 8 and finally, they are decided as the transversal filter where the power level of the noise residual waveform U(t) is a prescribed set value of below.
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