关键词: DFT, 调制滤波器组, NPR, 原型滤波器

Abstract: A novel design method for the prototype filters of a Near Perfect Reconstruction（NPR） Discrete Fourier Transform（DFT）modulated filter bank is proposed.The objective is derived from the output distortion induced by the filter bank，the aliased components that appear in the output，and the stopband energy of the prototype filters.By means of the particular structure of DFT modulated filter bank，minimizing the aliased components that appear in the output is simplified to minimizing the intra-channel aliasing，and minimizing the output distortion induced by the filter bank is approximately substituted by minimizing the output distortion of the adjacent three channels.It is shown that the design of prototype filters can be transformed into a simple nonlinear optimization problem.Compared with the current methods of DFT modulated filter bank，the design method proposed in this paper can generate filter banks with equivalent，even better performances，at the same time，owns a simple optimization formulation and considerable design flexibility.The simulation results verify the effectiveness of the method.

Key words: DFT, modulated filter bank, NPR, prototype filter