Direct design of linear-phase nonuniform filter banks with arbitrary integer decimation factors

In this paper, we study the direct design of M-channel nonuniform filter banks (NUFBs) and propose a novel method for the NUFBs with linear-phase (LP) property. The filter banks we are concerned with have integer decimation factors and satisfy the maximal decimation condition. We derive a design criterion for the LP NUFBs. In addition, we propose certain modification on the direct structure, achieving LP NUFBs with arbitrary integer decimation factors. A detailed analysis on the new structure is presented to show that the significant aliasing can also be cancelled. Design examples are given to show that the proposed method is capable of achieving near-perfect-reconstruction NUFBs with LP property.