clc; 
clear all; 
close all; 
 
 
 
% Generate carrier signal 
Tb=1; 
t=0:Tb/100:Tb; 
fc=2; 
c=sqrt(2/Tb)*sin(2*pi*fc*t); 
% Generate message signal 
N=8; 
m=rand(1,N); 
t1=0;t2=Tb 
for i=1:N 
 t=[t1:.01:t2] 
 if m(i)>0.5 
 m(i)=1; 
 m_s=ones(1,length(t)); 
 else 
 m(i)=0; 
 m_s=-1*ones(1,length(t)); 
 end 
 message(i,:)=m_s; 
 %Product of carrier and message signal 
 bpsk_sig(i,:)=c.*m_s; 
 %Plot the message and BPSK modulated signal 
 subplot(5,1,2);axis([0 N -2 2]);plot(t,message(i,:),'r'); 
 title('message signal(POLAR form)');xlabel('t--->');ylabel('m(t)'); 
 grid on; hold on; 
 subplot(5,1,4);plot(t,bpsk_sig(i,:)); 
 title('BPSK signal');xlabel('t--->');ylabel('s(t)'); 
 grid on; hold on; 
 t1=t1+1.01; t2=t2+1.01; 
end 
 
 
 
hold off 
%Plot the input binary data and carrier signal 
subplot(5,1,1);stem(m); 
title('binary data bits');xlabel('n--->');ylabel('b(n)'); 
grid on; 
subplot(5,1,3);plot(t,c); 
title('carrier signal');xlabel('t--->');ylabel('c(t)'); 
grid on; 
% PSK Demodulation 
t1=0;t2=Tb 
 for i=1:N 
 t=[t1:.01:t2] 
 %Correlator 
 x= sum(c.*bpsk_sig(i,:)); 
 %Decision device 
 if x>0 
 demod(i)=1; 
 else 
 demod(i)=0; 
 end 
 t1=t1+1.01; 
 t2=t2+1.01; 
 end 
 %Plot the demodulated data bits 
 subplot(5,1,5);stem(demod); 
 title('demodulated data');xlabel('n--->');ylabel('b(n)'); 
 grid on