由设计要求可知，wp<=0.2π，允许误差幅度小于1dB，ws>=0.3π内衰减应大于15dB。为了验证数字滤波器的实际滤波功能，设计程序时，把输入序列定为验证函数x（t）=4sin（100πt）以及x（t）=4sin（200πt）和x（t）=4sin（400πt）。又因为Ts=1.25ms，T=80ms，故采样点为64，即N=64，所以当M=6，可以同时调试并验证程序的滤波功能。-Seen by the design requirements, wp < = 0.2π, allow a margin of error of less than 1dB, ws>　= 0.3π within attenuation greater than 15dB. In order to verify the actual filtering function of the digital filter design program, the input sequence as validation function x (t) = 4sin (100πt) and x (t) = 4sin (200πt) and x (t) = 4sin (400πt) . And because Ts = 1.25ms, T = 80ms, so the sampling points is 64, that is N = 64, so when M = 6, can debug and validate filtering program.