Method of identifying an unknown system with a band-splitting adaptive filter and a device thereof

A method of identifying an unknown system with subband adaptive filters comprising:

• (a) generating a plurality of subband signals by subbanding an input signal to the unknown system;
• (b) generating a plurality of subband reference signals by subbanding an output signal from the unknown system;
• (c) generating a plurality of replica signals corresponding to the subband reference signals by filtering the subband signals with the subband adaptive filters;
• (d) generating a plurality of subband error signals based on differences between the subband reference signals and the replica signals;
• (e) updating coefficient values of the subband adaptive filters based on the subband error signals;
• and
• (f) controlling a number of taps of the subband adaptive filters based on the subband error signals.

A device for identifying an unknown system comprising:

• first analysis filter bank means for generating a plurality of subband signals by subbanding an input signal to the unknown system;
• second analysis filter bank means for generating a plurality of subband reference signals by subbanding an output signal from the unknown system;
• a plurality of adaptive filters, each of said adaptive filters generating a replica signal corresponding to the subband reference signals by filtering the subband signals, and outputting coefficient values for taps of said adaptive filters;
• a plurality of subtracters, each of said subtracters calculating a difference between the subband reference signals and the replica signal and outputting the difference as a subband error signal;
• a plurality of coefficient value adaptation means for updating coefficient values of the taps of said adaptive filters based on the subband error signal;
• analyzer means for analyzing the coefficient values and outputting results;
• and
• tap number control means for calculating the number of taps for each of said adaptive filters based on the results output by said analyzer means, and for controlling the number of taps of said adaptive filters based on the calculated number of taps for each of said adaptive filters.