通过调用IIR5函数对所给的信号进行滤波，其中通过fdatool 设计的直接1型切比雪夫滤波器的参数保存在coefficients1.mat文件中。-by calling IIR5 function as a signal to the filter, which it adopted fdatool design a direct-Chebyshev filter parameters stored in coefficients1.mat document.