Digital signal sub-band separating / combining apparatus achieving band-separation and band-combining filtering processing with reduced amount of group delay

摘要

An apparatus having a band-separating filter bank (1) for separating a digital signal into a plurality of sub-band signals, to be processed or transmitted, and a band-combining filter bank (2) for subsequently combining the resultant sub-band signals into a single digital signal, wherein each of the band-separating filter bank (1) and band-combining filter bank (2) incorporates a FIR low pass filter having an asymmetric impulse response, as the prototype filter of the filter bank. A significant reduction can thereby be achieved in the amount of overall group delay that results from the processing performed by these filter banks.