FIRdesign

说明：  FIR数字滤波器的设计方法主要是建立在对理想滤波器频率特性作某种近似的基础上的。这些近似方法有窗函数法、频率抽样法、最佳一致逼近法。在这里只讨论窗函数法。程序中也是采用了这种方法。(FIR digital filter design method is mainly based on the frequency characteristics of the ideal filter for some kind of approximation on the basis of. These approximate methods are a window function method, frequency sampling method, the best uniform approximation method. Here only to discuss the window function method. Procedure is also adopted this approach.)