| 摘要 |
<p>PURPOSE:To shorten the time required for coefficient renewal by obtaining a mutual correlation between error and reference signal in a convergence evaluation part and stopping the coefficient renewal by that a mean value becomes a minimum value. CONSTITUTION:A white noise is sent from a white noise generator 10 to a cross talk prevention filter 2 and an acoustic feedback transmission system (b), and the coefficient renewal of the cross talk prevention filter 2 is performed. At this time, the mutual correlation between an error signal obtained by an subtracter 21 and the white noise from the white noise generator 10 is calculated by a mutual correlation calculation part in the convergence evaluation part 9, and when the mutual correlation exists, the moving average value of the error signal is obtained by a moving calculation part. The moving average value is compared with the moving average value obtained beforehand, and whether or not the further lower minimum value is obtained, is investigated. As the result, when the minimum value which can not be lowered more is decided finally, a renewal stop instruction part is instructed to send a renewal stop instruction signal to the white noise generator 10 and a coefficient renewal part 11. Thus, the white noise generator 10 stops the sending of the white noise.</p> |
