cic_8.m

设计一个梳妆滤波器

function cic_seq=CIC_8(reg);
%三级CIC内插8倍滤波
reg=[0 0 0 0 0 0 0 0 0 0 0 0 0 0 1];
x=half_band_2(reg);
w1=x(1,1:65536);
w2=x(2,1:65536);
%------------------------------------------
%三级梳状
for j=1:3
    x1=w1;
    w1(1)=x1(1);
    for i=2:length(x1)
        w1(i)=x1(i)-x1(i-1);
    end
end
for j=1:3
    x2=w2;
    w2(1)=x2(1);
    for i=2:length(x2)
        w2(i)=x2(i)-x2(i-1);
    end
end
%----------------------------------------------
%8倍内插
ww1=upsample(w1,8);
y1=ww1;

ww2=upsample(w2,8);
y2=ww2;
%----------------------------------------------
%三级积分器
for j=1:3;
    ww1=y1;
    y1(1)=ww1(1);
    for i=2:length(ww1)
        y1(i)=ww1(i)+y1(i-1);
    end
end
for j=1:3;
    ww2=y2;
    y2(1)=ww2(1);
    for i=2:length(ww2)
        y2(i)=ww2(i)+y2(i-1);
    end
end
%----------------------------------------------
% cic_8=[y1:y2];
I_CIC_8=fft(y1);
Q_CIC_8=fft(y2);

figure(5);
subplot(2,2,1);
stem([1:524288],y1);axis([0 3000 -40 40]);
xlabel('n');ylabel('I_CIC_8');title('I路信号CIC滤波8倍内插');grid;

subplot(2,2,2);
stem([1:524288],y2);axis([0 3000 -40 40]);
xlabel('n');ylabel('Q_CIC_8');title('Q路信号CIC滤波8倍内插');grid;

subplot(2,2,3);
n=1:524288;
plot(2*n/524288,abs(I_CIC_8));axis([0 2 -50 400]);grid;
xlabel('frequence(*pi)');ylabel('I_CIC_8_fft');title('I路信号CIC滤波8倍内插后频谱');grid;

subplot(2,2,4);
n=1:524288;
plot(2*n/524288,abs(Q_CIC_8));axis([0 2 -50 400]);grid;
xlabel('frequence(*pi)');ylabel('Q_CIC_8_fft');title('Q路信号CIC滤波8倍内插后频谱');grid;