CIC滤波器matlab代码 D=5; r=D; fs=1e5; S3_cic=conv(conv(ones(1,D),ones(1,D)),ones(1,D)); %三个单级卷积 [h3,f3]=freqz(S3_cic,1,1000,fs); plot(f3/(fs/2),20*log10(abs(h3))-max(20*log10(abs(h3))),'r','LineWidth',1.4) ylabel('\fontsize{12}\bf幅度响应（dB）') xlabel('\fontsize{12}\bf归一化频率(\times\pi rad/sample)') grid; box on; axis([0 1 -80, 0])