A new procedure for the optimized design of CMFBs based on the frequency-response masking technique

FREQUENCY-RESPONSE MASKING TECHNIQUE Miguel B. Furtado Jr., Paulo S. R. Diniz, and Sergio L. Netto Programa de Engenharia Elétrica, COPPE/EPoli/UFRJ PO BOX 68504, Rio de Janeiro, RJ, 21945-970, BRAZIL furtado, diniz, sergioln @lps.ufrj.br ABSTRACT The frequency-response masking (FRM) method allows the design of selective prototype filters for cosine-modulated filter banks (CMFBs) with a reduced number of distinct coefficients. Such methodology may result in filter banks with large number of bands (e.g. 1024 or more) and a simplified optimization procedure, as there are less parameters to adjust. This work introduces a numerically efficient optimization procedure, based on a quasi-Newton algorithm, for designing selective FRM-based CMFBs. The proposed method uses a perfect-reconstruction FRM prototype filter as a starting point and updates the number of bands of the filter bank during the optimization procedure. Examples provided indicate that figures-of-merit, such as intersymbol and intercarrier interferences, for the optimized FRM-CMFB structure are significantly improved without increasing the complexity of the resulting structure.