QMFDesign

代码说明：

  正交镜像滤波器的设计，从正交镜像滤波器的远离出发设计,而且从结果中观察其相位和幅度。( Design a two-channel QMF filter bank The four filters in the filter bank are based on a lowpass prototype H(z) which is designed by this procedure. The analysis filters are HL(z) and HH(z) and the synthesis filters are GL(z) and GH(z), HL(z) = H(z) HH(z) = H(-z) GL(z) = 2 H(z) GH(z) =-2 H(-z)