Simulation of line coding scheme in Matlab

Manchester Coding Scheme:
Program :
data=[ 1 0 1 0 1 0  ];

i=1:length(data);
j=1.49:length(data)+0.49;
I=1.50:length(data)+0.50;
J=1.99:length(data)+0.99;
N=length(data);
time=[];
for k=1:length(data);
time=[time i(k),j(k),I(k),J(k)];
end

signal=[];
a=1;
prebit=1;

for t=1:length(data);
  
if(data(t)==0)
    signal(a:a+1)=1;
    signal(a+2:a+3)=-1;
      
elseif(data(t)==1)
    signal(a:a+1)=-1;
    signal(a+2:a+3)=1;
    
   
end
   
a=a+4;

end

plot(time,signal,'linewidth',4);
xlabel('time')
ylabel('signal')





Simulation Results

Differential Manchester Coding Scheme :
Program :
data=[ 1 0 1 0 1 0  ];

i=1:length(data);
j=1.49:length(data)+0.49;
I=1.50:length(data)+0.50;
J=1.99:length(data)+0.99;
N=length(data);
time=[];
for k=1:length(data);
time=[time i(k),j(k),I(k),J(k)]; %Time vector
end

signal=[];
a=1;
prebit=1;

%Signal Generation
for t=1:length(data);
    if(data(t)==0 && prebit==1)
        signal(a:a+1)=-1;
        signal(a+2:a+3)=1;
        prebit=1;
    elseif(data(t)==0 && prebit==-1)
        signal(a:a+1)=1;
        signal(a+2:a+3)=-1;
        prebit=-1;
    elseif(data(t)==1 && prebit==-1)
        signal(a:a+1)=-1;
        signal(a+2:a+3)=1;
        prebit=1;
    elseif(data(t)==1 && prebit==1) 
        signal(a:a+1)=1;
        signal(a+2:a+3)=-1;
        prebit=-1;

end
           a=a+4;
end
plot(time,signal,'linewidth',4); %Plot signal
title('Differential Manchester');
xlabel('Time');
ylabel('Differential Manchester');

%constellation diagram
   M = 4;
x = [0:M-1];
scatterplot(modulate(modem.pskmod(M),x));

Simulation Results :

  

Implementing  BPSK , QPSK and MFSK in Matlab

Program Code For BPSK 
clc;
clear all;
message=[1 1 0 0 1 0];
f_one=1.5;
fs=1000;% frequency
t=[0:1/fs:1];
A=5;
x=A*cos(2*pi*f_one*t+pi); %binary 0
y=A*cos(2*pi*f_one*t); %binary 1
time=t;
for i=1:length(message)-1;
    time=[time i+t];
end
%ask signal logic
ask_signal=[];
for i=1:length(message);
   if(message(i)==0)
       ask_signal=[ask_signal x];
   else
       ask_signal=[ask_signal y];
   end
end
   
plot(time,ask_signal,'linewidth',2);
xlabel('no of bits per second')
ylabel('signal value')

%constellation diagram BPSK
M = 2;
x = [0:M-1];
scatterplot(modulate(modem.pskmod(M),x));

Simulation :

  


Programme Code For MFSK :
clc; %clears the command window
clear all; %clears the workspace
message=[1 1 0 0 1 0 1 0 0]; %binary input is
                                                 
if (rem(length(message),3)~=0)     %for don’t care bits
    display('Error in Message'); 
end
f_one=1;
fs=1000; %frequency
t=[0:2/fs:1];
A=5;
w=A*cos(2*pi*f_one*t); %binary 000   (1 Hz)
x=A*cos(4*pi*f_one*t); %binary 001   (2 Hz)
y=A*cos(6*pi*f_one*t); %binary 010   (3 Hz)
z=A*cos(8*pi*f_one*t); %binary 011   (4 hz)
W=A*cos(10*pi*f_one*t);%binary 100   (5 Hz)
X=A*cos(12*pi*f_one*t);%binary 101   (6 Hz)
Y=A*cos(14*pi*f_one*t);%binary 110   (7 Hz)
Z=A*cos(16*pi*f_one*t);%binary 111   (8 Hz)
time=t;
for i=1:(length(message)/3)-1;
    time=[time i+t];
end
%ask signal logic
ask_signal=[];
for i=1:3:length(message);
   if(message(i)==0 && message(i+1)==0 && message(i+2)==0)
       ask_signal=[ask_signal y];
   elseif(message(i)==0 && message(i+1)==0 && message(i+2)==1)
       ask_signal=[ask_signal z];
   elseif(message(i)==0 && message(i+1)==1 && message(i+2)==0)
       ask_signal=[ask_signal x];
   elseif(message(i)==0 && message(i+1)==1 && message(i+2)==1)
       ask_signal=[ask_signal w];
   elseif(message(i)==1 && message(i+1)==0 && message(i+2)==0)
       ask_signal=[ask_signal W];
   elseif(message(i)==1 && message(i+1)==0 && message(i+2)==1)
       ask_signal=[ask_signal X];
   elseif(message(i)==1 && message(i+1)==1 && message(i+2)==0)
       ask_signal=[ask_signal Y];
   elseif(message(i)==1 && message(i+1)==1 && message(i+2)==1)
       ask_signal=[ask_signal Z];
   end
end
   %figure
   plot(time,ask_signal,'linewidth',2);
   xlabel('no of bits per second');
   ylabel('signal value');
    
% constellation diagram
inphase = [1 1 1 1 1 1 1 1];
quadr = [0 0 0 0 0 0 0 0];
 const = inphase + j*quadr;
scatterplot(const,1,0,'*');
axis([-3 3 -3 3]); 

Simulation :
  

Programme Code For QPSK :

clc; %clears the command window
clear all; %clears the workspace
message=[1 1 0 0 1 0]; %binary input is
                                                 
if (rem(length(message),2)~=0)     %for don’t care bits
    message(1,length(message)+1)=1; 
end
f_one=1.5;
fs=1000; %frequency
t=[0:2/fs:1];
A=5;
w=A*cos(2*pi*f_one*t+pi/4);%binary 11
x=A*cos(2*pi*f_one*t+3*pi/4); %binary 01
y=A*cos(2*pi*f_one*t-3*pi/4); %binary 00
z=A*cos(2*pi*f_one*t-pi/4); %binary 10
time=t;
for i=1:(length(message)/2)-1;
    time=[time i+t];
end
%ask signal logic
ask_signal=[];
for i=1:2:length(message);
   if(message(i)==0 && message(i+1)==0)
       ask_signal=[ask_signal y];
   elseif(message(i)==1 && message(i+1)==0)
       ask_signal=[ask_signal z];
   elseif(message(i)==0 && message(i+1)==1)
       ask_signal=[ask_signal x];
   elseif(message(i)==1 && message(i+1)==1)
       ask_signal=[ask_signal w];

end
end

%figure
plot(time,ask_signal,'linewidth',2);
xlabel('no of bits per second');
ylabel('signal value');
    
% constellation diagram
inphase = [1 -1 1 -1];
quadr = [1 1 -1 -1];
inphase = [inphase; inphase]; inphase = inphase(:);
quadr = [quadr; quadr]; quadr = quadr(:);
const = inphase + j*quadr;
scatterplot(const,1,0,'*');
     
axis([-3 3 -3 3]);


Simulation :