Lattice Structure for Regular Linear Phase Paraunitary Filter Bank With Odd Decimation Factor

Linear phase paraunitary filter bank (LPPUFB) with regular property, i.e. regular LPPUFB (RLPPUFB), can be efficiently designed via lattice structure. The key to the design of such filter bank is to formulate an easy-to-handle regular condition in terms of the lattice structure of LPPUFB, and the solution for the case with even decimation factor has been published. In this letter, a method is proposed to design RLPPUFB with odd decimation factor. First, small part of the free parameters in the lattice structure of LPPUFB is discarded. Then, the lattice structure is equivalently converted to a new one for which the easy-to-handle regular condition can be easily obtained. In contrast to a simple method that discards about a half of the free parameters, the proposed method only discards small part of the free parameters and it therefore can produce better RLPPUFBs.