Efficient Design of Cosine Modulated Filter Banks Based on Gradient Information

An efficient iterative algorithm is first proposed for the design of biorthogonal cosine modulated filter banks (CMFBs) with nearly perfect reconstruction. The design problem is formulated as a quadratic unconstrained least-squares minimization problem, in which the gradient vector of the objective function with respective to unknown parameters can be obtained analytically. The algorithm is then modified for the design of orthogonal CMFBs. Design examples and comparisons are included that show that the proposed design method leads to filter banks with improved performance.