New results on subband adaptive filters with nonuniform filter banks

In this paper nonuniform filter banks based on cosine and complex modulation are proposed for use in subband acoustic echo cancelers (AECs). These filter banks are derived from their uniform counterparts by combining adjacent filters. Both proposed analysis/synthesis filter banks require only one prototype filter respectively and both also result in improved computational complexity for the filtering algorithm. The improvement in computational complexity is compared against AECs using oversampled DFT filter banks based on low-delay eigenfilters. Design examples for each of the proposed filter banks are also presented and tested with real signals for implementation of an acoustic echo canceler.