dsss.m

direct sequence spread spectrum

clear all;
close all;
fc=5;
t=0:0.01:4.99;
data=[1 0 1 1 0];
pn=[-1     -1     -1     1     -1    -1     1     1    -1     1     -1     1     1     1     1];
f1=floor(t);
x=sin(2*pi*fc*t);
ask1=(1-x).*(data(1+f1));
ask=x.*(data(1+f1));
ask3=ask1+ask;
plot(t,ask3);
figure,plot(t,x);
psk=sin(2*pi*t*fc+(pi*data(1+f1)));
figure,plot(t,psk);
j=1;
for i=1:500
    if(j<16)
    dss(i)=psk(i).*pn(j);
    j=j+1;
    else
        j=1;
        i=i-1;
    end
end
figure,plot(t,dss);
j=1;
for i=1:500
    if(j<16)
        rdss(i)=dss(i).*pn(j);
        j=j+1;
    else
        j=1;
        i=i-1;
    end
end
figure,plot(t,rdss);
demodpsk=x-psk;
demodpsk1=2*ask1+demodpsk;
figure,plot(demodpsk1/2);