A new structure and design method for low group delay maximally-decimated DFT filter banks

This paper presents a new formulation and design method for a maximally-decimated discrete-Fourier-transform (MDDFT) filter bank with an adjustable group delay. The objective is to show how far we can reduce the group delay in this proposed MDDFT filter bank by using a new design method for a maximum stop-band attenuation FIR low pass prototype filter. However, the design of this filter bank consists of two different series of equidistant frequency shifts from one single low-pass prototype filter. Simulation results show that the overall group delay of our new approach can be reduced to about 59% of the conventional MDDFT filter bank group delay. And most importantly, when we are dealing with mean-square-error-reconstruction (MSER), there is no degradation in performance with our proposed new design method (with the overall group delay reduced), when compared to the conventional MDDFT filter bank.