%call_caiyang2  在頻域繪制周期延拓波形
function []=call_caiyang2(h)
fs=get(gcbo,'string');
fs=str2num(fs);
axes(h);hold off;
fs=fs/1000;
n=floor(1/fs);
x=[0:0.1:1,0.9:-0.1:0];
k=-10:10;
df=0.01;
fc=0.1;
w=df*k;
for i=0:n
    f1=w+i*fs;
    f2=w-i*fs;
    plot(f1,x);hold on
    plot(f2,x);hold on
    if fs<2*fc
        n1=fs/df;
        x1=(n1-10)*df+i*fs; x3=(n1-10)*df-i*fs;
        x2=10*df+i*fs;  x4=10*df-i*fs; 
        y1=(20-n1)*0.1; y3=(20-n1)*0.1;
        plot([x1,x2],[y1,y1],'color','r','linestyle','-.');
        plot([x3,x4],[y3,y3],'color','r','linestyle','-.');
        hold on
    end
    axis([-1,1,0,1.5]);pause(0.1);hold on
end