| 摘要 |
<p>On identifying an unknown system (2) by the use of adaptive filters (601 to 60K) by supplying the unknown system with an input signal, subjecting the input signal to subband analysis (3) to produce subband signals, supplying the subband signals to the adaptive filters as input filter signals, respectively, subjecting an output signal of the unknown system to subband analysis (4) to produce a predetermined number K of subband reference signals, producing a predetermined number K of subband error signals representative of differences between the subband reference signals and output signals of the adaptive filters, respectively, and renewing tap coefficients in connection with the taps of each of the adaptive filters on the basis of each of the subband error signals, a first circuit (10 + 12) varies the number of the taps of each of the adaptive filters in response to a coefficient value signal representative of values of the tap coefficients in connection with the taps of each of the adaptive filters and to an input information signal relating to each of the filter input signals. A second circuit (13) adaptively controls the number of the taps varied in a single tap-redistribution among subbands either with reference to continuous variations of the number of the taps varied among the subbands or with reference to a relative relationship of the number of the taps varied among the subbands. <MATH></p> |
