Research And Implementation Of Oversampled Linear-phase Perfect Reconstruction Filter Banks

The paper researched a lattice factorization of critically sampled BOLPFBs calledhigher-order feasible (HOF) building block. It realizes an order-N LPPRFB with one HOFbuilding block. Additionally, it is also regarded as an extended class of traditional (criticallysampled) order-1building blocks. Under the same filter length, LPPRFBs based on HOFbuilding blocks realize comparable performance to those based on cascaded order-1ones, inspite of having fewer number of building blocks and design parameters.The paper extended the HOF building block from critically sampled to oversampledLPPRFBs. It inherits all the merits from the critically sampled HOF structure. Furthermore, itprovides a new structure of a P×Mrectangular oversampling matrix different from the otherbuilding blocks. Our new structure has feasibility for any P and M, thus it is an extension oftraditional order-1building blocks of OLPPRFBs. This paper provides all possible solutions forP≥Mand both BO and PU paramaterizations, whereas the previously proposed HOF structureis focused on the conditions under BO and P=M. Thus, the proposed structure can be regardedas not only a generalization of the traditional OLPPRFBs but also a broadened class of criticallysampled HOF structure.The oversampled HOF building block could change the size of a polyphase matrix fromM×Mto P×Mas well as having the higher-order structure. The previous oversampledstructure cannot have such feature. In the design examples, our OLPPRFBs based on HOFbuilding blocks show comparable frequency characteristics to those based on the cascadedorder-1structure in spite of having fewer number of design parameters.