close all;
clear all;
% MATLAB program to sort data captured using 
% the Com-8002 and the Com-3001 modules into 
% I and Q samples.The file must have been saved 
% in binary format (decimal files are
% NOT supported in this code).

n_b = 20;

% Replace 'file_name_including_full_path'
% with the full path and file name for the 
% file where the binary data is stored. 
% For example:
% fid = fopen('c:\My Documents\Captured_Data.txt','r');

fid = fopen('test2','r');  
 
% Read the content of the file into an array.
data = fread(fid,inf,'uchar') 
  
% Find out how many samples are in the array.
[dataHeight garbage] = size(data); 
  
% Find out how big the matrix holding the
% 20-bit wide data needs to be. 
binArrayHeight = ceil(dataHeight/2.5); 
 
% Pre-initialize the matrix holding 20-bit data 
% for faster program execution. 
binArray = zeros(binArrayHeight,20); 
  
% Initialize the index counter.
rowCounter = 1; 

% Start the conversion from 8 bits to 20 bits.
% Note: the de2bi function places the MSb 
% on the rightmost position. Therefore, 
% use it with fliplr to get the MSb in the
% leftmost position.
for i = 1:2:binArrayHeight 
    % Store I sample 
    binArray(i,1:8) = fliplr(de2bi(data(rowCounter),8));        % Store bits 19-12
    rowCounter = rowCounter + 1;

    binArray(i,9:16) = fliplr(de2bi(data(rowCounter),8));       % Store bits 11-4
    rowCounter = rowCounter + 1;

    binaryWord = fliplr(de2bi(data(rowCounter),8));             % A temporary array
    binArray(i,17:20) = binaryWord(1:4);                        % Store bits 3-0


    % Store Q sample
    binArray(i+1,1:4) = binaryWord(5:8);                        % Store bits 19-16
    rowCounter = rowCounter + 1;

    binArray(i+1,5:12) = fliplr(de2bi(data(rowCounter),8));     % Store bits 15-8
    rowCounter = rowCounter + 1;

    binArray(i+1,13:20) = fliplr(de2bi(data(rowCounter),8));    % Store bits 7-0
    rowCounter = rowCounter + 1;
end  

 
% Compensate for the fact that the pinouts are
% reversed (MSb on Com 8002 input connector 
% corresponds to LSb on Com 3001 output connector). 
binArray(:, 1:10) = binArray(:, 10:-1:1);     % Reverse I
binArray(:, 11:20) = binArray(:, 20:-1:11);   % Reverse Q


% Pre-initialize the arrays for faster program execution.
iSamples = zeros(binArrayHeight, 1); 
qSamples = zeros(binArrayHeight, 1); 


% Convert the 10-bit binary numbers into decimal numbers
% in the range 0-1023. 
for i = 1:binArrayHeight 
    iSamples(i,1) = bi2de(fliplr(binArray(i, 1:10)));
    qSamples(i,1) = bi2de(fliplr(binArray(i, 11:20)));
end 


%place time sync sequence from transmitter here
ts = [1 -1 -1 1   -1 1 1 -1   -1 1 1 1   1 1 -1 -1   -1 1 1 -1   1 1 1 -1   1 -1 1 -1   -1 -1 -1 1];

%cosinefilter pn
yf = rcosine(1,8,'fir');
tsf = rcosflt(ts, 1, 8, 'filter',yf);

newts = tsf(25:304-24);
%newts = tsf;

corr_peak=conv((iSamples+sqrt(-1)*qSamples),conj(newts(length(newts):-1:1)));
peak=find((abs(corr_peak)>max(abs(corr_peak))-10000));

peaknew = peak < 20992;
peak_new = peaknew.*peak;

start=peak_new+9;

newi = iSamples(start: start+10250-1);
newq = qSamples(start: start+10250-1);

%downsample to bring back to original length
dsiSamp = newi(1:8:length(newi));
dsqSamp = newq(1:8:length(newq));

%shift received signal down to x-axis
for i = 1:length(dsiSamp)
   downishift(i) = dsiSamp(i)-500;
   downqshift(i) = dsqSamp(i)-500;
end

%PN code
pn = [1 1 -1 1  -1 -1 1 1  1 -1 -1 1  -1 1 -1 -1  -1 1 -1 1  -1 -1 -1 -1  -1 -1 1 1  1 -1 1 -1];

k=1;
for i = 1:length(pn)
   pnf(k:k+1) = pn(i);
   k=k+2;
end
newpnf = .3*pnf;

%use PN code to get back to original signal 
o = 1;
for i = 1:20
   unpni(o:o+63) = downishift(o:o+63).*newpnf;
   unpnq(o:o+63) = downqshift(o:o+63).*newpnf;
   o = o+64;
end

%constellation code
%shift back up to original position
%shift received signal down to x-axis
for i = 1:(length(dsiSamp)-2)
   upishift(i) = unpni(i)+500;
   upqshift(i) = unpnq(i)+500;
end


%taking area under these 2 samples of the
%curve per bit when shifted and not shifted
k = 1;
for i = 1:20
        %totali(i) = sum(unpni(k+11:k+12));
        totali(i) = sum(unpnq(k+10:k+11));
        newtotali(i) = sum(dsiSamp(k:k+63)); 
        newtotalq(i) = sum(dsqSamp(k:k+63));        
        k=k+64;
end       

%average under the whole received signal
%avi = sum(totali)/20;
%avq = sum(totalq)/20;

%if the area of the first quarter of the bit 
%(when shifted) is less than 0 then it is a -1 else 1
for i = 1:20
     if totali(i) > 0
        consti(i) = -newtotali(i);
     	  constq(i) = -newtotalq(i);   
     else
        consti(i) = newtotali(i);
     	  constq(i) = newtotalq(i);   
     end
     
     %if totalq(i) > 0
      %  constq(i) = -newtotalq(i);
     %else 
      %  constq(i) = newtotalq(i);
     %end
end        

%extracting data sequence
g = 1;
for i = 1:20
   if consti(i) > 0
      extractedxt(g:g+63) = 1;
   else
      extractedxt(g:g+63) = -1;
   end
   g=g+64;   
end

figure(1)
subplot(2,1,1)
plot(iSamples); 
grid on;
xlabel('Time');
ylabel('Amplitude');
legend('Received I Samples');

subplot(2,1,2)
plot(qSamples,'r'); 
grid on;
xlabel('Time');
ylabel('Amplitude');
legend('Received Q Samples');

figure(2)
plot(abs(corr_peak));
grid on;
xlabel('Time');
ylabel('Amplitude');
legend('Time Synchronization');

%figure(3)
%subplot(2,1,1)
%plot(dsiSamp); 
%grid on;
%xlabel('Time');
%ylabel('Amplitude');
%legend('Downsampled I Samples After Synchronization');

%subplot(2,1,2)
%plot(dsqSamp,'r'); 
%grid on;
%xlabel('Time');
%ylabel('Amplitude');
%legend('Downsampled Q Samples After Synchronization');

%figure(4)
%subplot (2,1,1)
%plot(upishift);
%grid on;
%xlabel('Time');
%ylabel('Amplitude');
%legend('Extracted I Signal Using PN Code');

%subplot(2,1,2)
%plot(upqshift, 'r')
%grid on;
%xlabel('Time');
%ylabel('Amplitude');
%legend('Extracted Q Signal Using PN Code');

figure(5)
plot(consti,constq,'b.'); 
xlabel('Real - I');
ylabel('Imaginary - Q');
legend('Constellation Points');

%figure(6)
%plot(extractedxt);
%grid on;
%xlabel('Time');
%ylabel('Amplitude');
%legend('Extracted Data Stream');