说明：  P. P. Vaidyanathan关于Multirate filter banks的一篇论文，是multirate systems and filter banks这本DSP圣经的一个缩影，感兴趣可以看一下！
(The practical side is not the focus. The large number of examples and figures make it easy to follow (reading it from cover to cover is not that difficult). The intuition beyond the theory is well developed, at the expense of a light mathematical treatment. )