Design of Nearly Perfect Reconstruction Cosine Modulated Filter Banks Based on Eigenfilter

Traditional designs for M-channel cosine modulated filter banks usually involve optimization with many unknown parameters. As a result, it is difficult to design filter banks with high stopband attenuation. In contrast, a simple design approach that involves the optimization of only a single parameter is presented such that cosine modulated filter banks with high stopband attenuation can be easily obtained. In this method, the prototype filter of the M-channel cosine modulated filter banks is formulated as an eigenfilter. The cosine modulated filter banks can be efficiently designed by changing the passband edge frequency of the eigenfilter. Moreover, a simple time domain objective function based on the properties of Nyquist filter is used. Two design examples are presented to show that cosine modulated filter banks with high stopband attenuation can be obtained.