Designing the fast filter bank with a minimum complexity criterion

The fast filter bank (FFB) is an extremely efficient single-rate filter bank due to the sparse population of non-zero coefficients in the subfilters. Its subfilters are designed and operated based on the frequency response masking (FRM) technique. The node-modulated fast filter bank (nm-FFB) was proposed as a modification to the fast filter bank to further reduce its complexity when processing real-input, real output signals. An optimal implementation of the nm-FFB can be achieved by shifting the terminal stage at which node-modulation is performed. Such an implementation is extended to the complex signal case and found to provide a lower complexity when compared to the original FFB implementation.