x=0:351
for i=1:352
 if x(i)<=31
                y(i)=1-x(i)/31;
 elseif (x(i)<=126)&(x(i)>=32)
                y(i)=0;
 elseif (x(i)<=159)&(x(i)>=127)
                y(i)=(x(i)-127)/32;
 elseif (x(i)<=191)&(x(i)>=160)
                y(i)=1-(x(i)-160)/32;
 elseif (x(i)<=287)&(x(i)>=192)
                y(i)=0;
 elseif (x(i)<=319)&(x(i)>=288)
                y(i)=(x(i)-287)/32;
 elseif (x(i)<=351)&(x(i)>=320)
                y(i)=1-(x(i)-320)/32;
         else 
               y(i)=0;
 end
end
subplot(3,1,1)
plot(x,y)
axis([0 351 -0.5  1.2]);
%xlabel('采樣點');
%ylabel('循環前綴的相關值')
%title('理想情況下的循環前綴互相關值')

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%55


x=0:351
for i=1:352
 if x(i)<=31
                y(i)=1-x(i)/31;
 elseif (x(i)<=126)&(x(i)>=32)
                y(i)=[rand(1)-0.5]*0.1;
 elseif (x(i)<=159)&(x(i)>=127)
                y(i)=(x(i)-127)/32;
 elseif (x(i)<=191)&(x(i)>=160)
                y(i)=1-(x(i)-160)/32;
 elseif (x(i)<=287)&(x(i)>=192)
                y(i)=[rand(1)-0.5]*0.1;
 elseif (x(i)<=319)&(x(i)>=288)
                y(i)=(x(i)-287)/32;
 elseif (x(i)<=351)&(x(i)>=320)
                y(i)=1-(x(i)-320)/32;
         else 
               y(i)=[rand(1)-0.5]*0.1;
 end
end
for i=154:164
    y(i)=0.98
end
for i=314:324
    y(i)=1
end


y=y*0.9+[rand(1,352)-0.5]*0.11;
subplot(3,1,2)
plot(x,y)
axis([0 351 -0.5  1.2]);
%xlabel('采樣點數/時間(τ)');
ylabel('循環前綴的互相關值Rxy(τ)')
%title('高斯白噪聲信道下的循環前綴相關特性')

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%55

x=0:351
for i=1:352
 if x(i)<=31
                y(i)=1-x(i)/31;
 elseif (x(i)<=126)&(x(i)>=32)
                y(i)=[rand(1)-0.5]*0.2;
 elseif (x(i)<=159)&(x(i)>=127)
                y(i)=(x(i)-127)/32;
 elseif (x(i)<=191)&(x(i)>=160)
                y(i)=1-(x(i)-160)/32;
 elseif (x(i)<=287)&(x(i)>=192)
                y(i)=[rand(1)-0.5]*0.2;
 elseif (x(i)<=319)&(x(i)>=288)
                y(i)=(x(i)-287)/32;
 elseif (x(i)<=351)&(x(i)>=320)
                y(i)=1-(x(i)-320)/32;
         else 
               y(i)=[rand(1)-0.5]*0.2;
 end
end
for i=149:170
    y(i)=0.98
end
for i=309:329
    y(i)=1
end
y=y*0.75+[rand(1,352)-0.5]*0.2;
subplot(3,1,3)
plot(x,y)
axis([0 351 -0.5  1.2]);
xlabel('采樣點數/時間(τ)');
%ylabel('循環前綴的相關值')
%title('多徑信道下的循環前綴相關特性')