DSP lab10

%decode sound to morse

    %your code goes here!!!
    % sound to morse


inputPath = 'morseCode4.wav';
[Y, FS] = audioread(inputPath);
info = audioinfo(inputPath);


t = 0:seconds(1/FS):seconds(info.Duration);
t = t(1:end-1);

plot(t,Y)
xlabel('Time')
ylabel('Audio Signal')

max = 0;

% for it = 1 :length(Y)
%    if(Y(it) == 0)
%       max = max + 1;
%    else
%        if (max ~= 0) fprintf('space of %d units\n', max); end
%        max = 0;
%    end
% end

% for it = 1 :length(Y)
%    if(Y(it) ~= 0)
%       max = max + 1;
%    else
%        if (max ~= 0) fprintf('part length of %d units\n', max); end
%        max = 0;
%    end
% end

spaceParts = 2000;
spaceLetters = 6000;
spaceWords = 12000;

lenDot = 699;
lenDash = 1999;

zeroes = -1;
mcode = [];

for it = 1 :length(Y)
    if (zeroes == 1)
       if(Y(it) == 0)
           max = max + 1;
       else
           if (max == spaceLetters)
              mcode = [mcode ' '];
           end
           if (max == spaceWords)
              mcode = [mcode '/'];
           end
           max = 0;
           zeroes = zeroes * -1;
       end
    end
    if (zeroes == -1)
        if(Y(it) ~= 0)
          max = max + 1;
        else
           if (max == lenDot)
               mcode = [mcode '.'];
           end
           if (max == lenDash)
               mcode = [mcode '-'];
           end
           max = 0;
           zeroes = zeroes * -1;
        end
    end
end

disp(mcode);

%decode morse to text
%for simplicity, the space character is encoded to '/' in Morse Code
code = '-.. ... .--./.-.. .- -... ...';   %dsp labs
deco = [];
code = mcode;
code = [code ' '];
lcode = [];

for j=1:length(code)
    if(strcmp(code(j),' ') || strcmp(code(j),'/'))
        for i=double('a'):double('z')
            letter = getfield(morse,char(i));
            if strcmp(lcode, letter)
                deco = [deco char(i)];
            end
        end
        for i=0:9
            numb = getfield(morse,['n',num2str(i)]);
            if strcmp(lcode, numb)
                deco = [deco, num2str(i)];
            end
        end
        lcode = [];
    else
        lcode = [lcode code(j)];
    end
    if strcmp(code(j),'/')
        deco = [deco ' '];
    end
end

fprintf('Decode : %s \n', deco);