利用Matlab提供的firhalfband函数设计阶数为16、通阻带容限为0.0001的半带滤波器。 仿真测试滤波前后的信号时域图，绘制滤波器的频率响应特性图。- Matlab provides firhalfband function design of the order number is 16, stopband tolerance of 0.0001 half band filter. simulation test before and after filteri