该实例主要是对离散时间系统建模与仿真。例子是以设计一个数字低通滤波器F（z），从受噪声干扰的多频率混合信号x（t）中获取10hz的信号。希望对研究电磁兼容以及学习MATLAB的学者有所帮助。-The examples are mainly discrete-time systems modeling and simulation. Example is the design of a digital low-pass filter F (z), acquiring a signal 10hz noise interference　multi-frequency mixed signal x (t) in. I hope to study electromagnetic compatibility and scholars studying the MATLAB help.