Design of cosine-modulated filter banks with large number of channels based on FRM technique

Applications that using cosine-modulated filter banks (CMFB) with large number of channels may encounter the design of high order prototype filter (PF), which often makes the direct-form design method fail due to the impractical arithmetical complexity. An efficient indirect-form design approach of the PF is proposed based on frequency response masking (FRM) technique. First, the PF is substituted by various subfilters of the narrow band FRM. Then an iterative second-order cone-programming (SOCP) based scheme like [1] is used to solve the nonconvex optimization problem. An improved FRM based implementation structure is also presented for complex-exponential modulated filter banks (CEMFB). Numerical results indicate the efficiency of the proposed method.