An efficient design method of cosine-modulated QMF banks satisfying PR property

This paper deals with the design of cosine-modulated QMF banks satisfying the perfect-reconstruction property (PR). This problem has been formulated as a novel quadratic-constrained least-squares (QCLS) minimization problem in which all constrained matrices of the QCLS optimization problem are symmetric and positive definite. In order to efficiently solve this kind of QCLS optimization problems, we construct a cost function that is a convex function of our desired prototype filter coefficients. Therefore, a global minimizer of this problem can be easily obtained. Moreover, this design approach has the ability to obtain solutions that are a compromise between PR conditions and stopband performance. The results of two design examples are presented to support our derivations and analyses. (C) 1998 John Wiley & Sons, Ltd.