说明：  这是一本信号处理的英文经典教程。相对国内的信号处理教程来说，讲的更为具体易于理解，如果你学习信号处理时感到很抽象的话，这本书对你很有帮助
(This is an English classic signal processing tutorial. Are very abstract when compared to the signal processing tutorial, talking about the more specific is easy to understand, if you learn to signal processing, this book is helpful to you)