Design of IIR cosine modulated filter banks with approximate cosine-rolloff transition band
Yin Shishu · 2011
An efficient method was proposed for designing nearly perfect reconstruction(NPR) cosine modulated filter banks(CMFBs) with IIR prototype filters having an approximate cosine-rolloff(CR) transition band.The polyphase components of the prototype filters of these IIR CMFBs had the same denominator so as to simplify the PR condition.By using a prototype filter with a CR transition band,the flatness condition required for an NPR CMFB was automatically satisfied.Based on some given poles values,the design problem was formulated as a convex minimax optimization problem and solved by second order cone programming(SOCP).The NPR IIR CMFB so obtained had a reasonably low reconstruction error and it was employed as the initial guess to constrained nonlinear optimization software for designing the PR IIR CMFB.Design results show that both NPR and PR IIR CMFBs with good frequency characteristics can be obtained by the proposed method.