fs = 200;
n = 1:200;
nrx = -100:99;
w = 2*pi;
ran = 90*randn();
x = sin(w*n/fs + ran) ;
Rn = (1/2)*cos(w*nrx/fs);
nr = -199:199;
figure
   for k=1:2:10
    R = xcorr(x);
    subplot(5,2,k);
    plot(nr,R);
    axis([-100 100 -100 100]);
    title(['w =',num2str(w),' ran =',num2str(ran)]);
    w = w + (k-1.5)*pi;
    ran = ran + 90*randn();
   end
 w = 2*pi;
   for i=2:2:10
       subplot(5,2,i);
       plot(nrx,Rn);
       title(['w =',num2str(w)]);
       w = w + (i-2.5)*pi;
   end