Design of discrete Fourier transform modulated filter bank with sharp transition band

The authors consider a high-performance discrete Fourier transform (DFT)-modulated finite impulse response (FIR) filter bank with sharp transition width. The design of this filter bank is very expensive by the standard method, and hence the frequency response masking (FRM) technique is developed so as to reduce the complexity in the design process. The relationship between the interpolator in the FRM structure and the channel number of the filter bank is established. The authors formulate the optimum design of a DFT-modulated filter bank with sharp transition band as a non-linear optimisation problem with continuous inequality constraints. An effective approach is proposed to solve this optimisation problem. To illustrate the effectiveness of the proposed method, simulation examples are presented.