Optimization of flexible filter banks based on fast-convolution

Multirate filter banks can be implemented very efficiently using fast-convolution (FC) processing. The main advantage of the FC filter banks compared with the conventional polyphase implementations is their increased flexibility, that is, the number of channels, their bandwidths, and the center frequencies can be independently selected. In this paper, an approach for optimizing the FC filter banks is proposed. First, a subband representation of the adjustable FC filter banks is derived. Then, the optimization problems are formulated with the aid of the subband model. Finally, these problems are conveniently solved with the aid of a nonlinear optimization algorithm. Two examples are included to illustrate the performance of the proposed overall scheme.