说明：  本文档介绍窗函数法设计FIR滤波器的概念和方法，观察用几种常用窗函数设计的FIR数字滤波器技术指标。并给出相应的matlab代码和结果分析。
(This document describes the window function design FIR filter concepts and methods of observation window function with several common FIR digital filter design specifications. And the corresponding matlab code and results analysis.)