clc;
clear all;
close all;
d=round(rand(1,25));
signal=[];
carrier=[];
t=[0:2*pi/119:2*pi];
for k=1:25
if d(1,k)==0
sig=-ones(1,120);
else
sig=ones(1,120);
end
c=cos(t);
signal=[signal sig];
carrier=[carrier c];
end
subplot(5,1,1);
plot(signal);
axis([-100 3000 -1.5 1.5]);
title('original sequence');
bpsk_signal=signal.*carrier;
subplot(5,1,2);
plot(bpsk_signal);
%axis([
title('bpsk signal');
t1=0:2*pi/9:2*pi;
t2=0:2*pi/19:2*pi;
t3=0:2*pi/29:2*pi;
t4=0:2*pi/39:2*pi;
t5=0:2*pi/59:2*pi;
t6=0:2*pi/119:2*pi;
c1=cos(t1);
c1=[c1 c1 c1 c1 c1 c1 c1 c1 c1 c1 c1 c1];
c2=cos(t2);
c2=[c2 c2 c2 c2 c2 c2 ];
c3=cos(t3);
c3=[c3 c3 c3 c3];
c4=cos(t4);
c4=[c4 c4 c4];
c5=cos(t5);
c5=[c5 c5];
c6=cos(t6);
spread_signal=[];
for n=1:25
c=randint(1,1,[1 6]);
switch(c)
case(1)
spread_signal=[spread_signal c1];
case(2)
spread_signal=[spread_signal c2];
case(3)
spread_signal=[spread_signal c3];
case(4)
spread_signal=[spread_signal c4];
case(5)
spread_signal=[spread_signal c5];
case(6)
spread_signal=[spread_signal c6];
end
end
subplot(5,1,3);
plot(spread_signal);
axis([-100 3000 -1.5 1.5]);
title('spread signal');
hopped_signal= bpsk_signal.*spread_signal;
subplot(5,1,4);
plot([1:3000],hopped_signal);
axis([-100 3000 -1.5 1.5]);
title('hopped signal');
subplot(5,1,5);
plot([1:3000],abs(fft(hopped_signal)));
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