what is the Matlab code for Duobinary Encoding and Decoding?

 function [c,b_r]=Duobinary_EncDec(b)
% Precoded Duobinary coder and decoder
% b = input binary sequence:precoder input
% c = duobinary coder output
 %b_r = duobinary decoder output
a(1) = xor(1,b(1));
if(a(1)==1)
  a_volts(1) = 1;
end
for k =2:length(b)
  a(k) = xor(a(k-1),b(k));
  if(a(k)==1)
    a_volts(k)=1;
  else
    a_volts(k)=-1;
  end
end
a = a';
a_volts = a_volts';
disp(a,'Precoder output in binary form:')
disp(a_volts,'Precoder output in volts:')
% Duobinary coder output in volts
c(1) = 1+ a_volts(1);
for k =2:length(a)
  c(k) =  a_volts(k-1)+a_volts(k);
end
c = c';
disp(c,'Duobinary coder output in volts:')
% Duobinary decoder output  by applying decision rule
for k =1:length(c)
  if(abs(c(k))>1)
    b_r(k) =  0;
  else
    b_r(k) = 1;
  end
end
b_r = b_r';
disp(b_r,'Recovered original sequence at detector oupupt:')
endfunction

[Geoff Hayes]

What exactly is your question, as you have seemed to have answered it by posting some MATLAB code to do the encoding and decoding....?

Answer 1

[Krishna Lankipalli]

function [c,b_r]=Duobinary_EncDec(b)

% Precoded Duobinary coder and decoder

% b = input binary sequence:precoder input

% c = duobinary coder output

%b_r = duobinary decoder output

a(1) = xor(1,b(1));

if(a(1)==1)

a_volts(1) = 1;

end

for k =2:length(b)

a(k) = xor(a(k-1),b(k));

if(a(k)==1)

a_volts(k)=1;

else

a_volts(k)=-1;

end

end

a = a';

a_volts = a_volts';

disp(a,'Precoder output in binary form:')

disp(a_volts,'Precoder output in volts:')

% Duobinary coder output in volts

c(1) = 1+ a_volts(1);

for k =2:length(a)

c(k) = a_volts(k-1)+a_volts(k);

end

c = c';

disp(c,'Duobinary coder output in volts:')

% Duobinary decoder output by applying decision rule

for k =1:length(c)

if(abs(c(k))>1)

b_r(k) = 0;

else

b_r(k) = 1;

end

end

b_r = b_r';

disp(b_r,'Recovered original sequence at detector oupupt:')

endfunction