E4_2_Windows

代码说明：

  利用MATLAB软件分别设计截止频率为200Hz、采样频率为2000Hz的FIR低通滤波器，滤波器长度为81，并绘出各滤波器的幅度频率响应曲线。(FIR low-pass filters with cut-off frequency of 200 Hz and sampling frequency of 2000 Hz are designed by using MATLAB software. The length of the filters is 81, and the amplitude-frequency response curves of the filters are drawn.)