On The Design Of A Class Of M-channel NPR And PR IIR Cosine Modulated Filter Banks Using Approximate Cosine Roll-off Prototype Filters And A Modified Model Reduction Technique

摘要

An efficient and flexible method for designing M-channel nearly perfect reconstruction (NPR) and perfect reconstruction (PR) causal stable IIR cosine modulated filter banks (CMFBs) is proposed. A PR FIR CMFB of similar specification is first designed by using a FIR prototype filter with an approximate cosine-rolloff transition band. The PR FIR prototype filter is then model reduced to an NPR IIR CMFB by modifying a model reduction technique proposed by Brandenstein and Unbehauen. The NPR IIR CMFB has a reasonably good reconstruction error and it is employed as the initial guess to constrained nonlinear optimisation software such as fmincon from MATLAB for designing the PR IIR CMFB. Design results show that both NPR and PR IIR CMFBs with good frequency characteristics and different system delays can be obtained readily by the proposed method.