Program for QPSK
x= input('enter input sequence');
A=input('enter amplitude');
f1=input('enter carrier frequency');
fs=64*f1;
subplot(3,2,1:2);
stem(x,'LineWidth',2);
title('Input Sequence');
grid on;
l=length(x);
j=1;
p=1;
xi=[];
xq=[];
for i=1:l
if mod(i,2)~=0
xi(j)=x(i);
j=j+1;
else
xq(p)=x(i);
p=p+1;
end
end
a=length(xi);
n1=0:(fs*a)-1;
x1=[ ];
for k=1:a
if xi(k)==1
x11=ones(1,fs);
x1=[x1 x11];
else
x11=-ones(1,fs);
x1=[x1 x11];
end
end
subplot(3,2,3);
stem(n1,x1,'LineWidth',2);