Lattice structure for arbitrary-length oversampled linear phase paraunitary filter bank with unequal numbers of symmetric and antisymmetric filters

Abstract

Oversampled linear phase paraunitary filter bank (OLPPUFB) can be efficiently designed via lattice structure. Xu et al. have studied the lattice structure for arbitrary-length OLPPUFB (ALOLPPUFB), i.e. OLPPUFB with filter length KM+β, where M is the integer decimation factor, K is an integer, and β is an integer between 0 and M. Such work was restricted to be used for the case with equal numbers of symmetric and antisymmetric filters, and cannot be easily generalized for other possible cases. To address this issue, we develop in this letter the lattice structure for ALOLPPUFB with unequal numbers of symmetric and antisymmetric filters. The proposed method is carried out by combining the polyphase matrices of OLPPUFB with filter length KN, where N is the integer decimation factor, K is an integer. The efficiency of the method is shown by design examples.