function ammod(action,s,ss,sss,ssss);
% AMMOD Demonstrates modulation and demodulation.
%
% 03/26/2003  Polytechnic University

if nargin<1,
    action='initialize';
end;

if strcmp(action,'initialize'),
    shh = get(0,'ShowHiddenHandles');
    set(0,'ShowHiddenHandles','on');


    figNumber=figure( ...
        'Name','Modulation/Demodulation Demo', ...
        'handlevisibility','callback',...
        'IntegerHandle','off',...
        'NumberTitle','off');

    %to accomodate labels in the figure
    figpos = get(figNumber,'Position');
    set(figNumber,'Position',[figpos(1) figpos(2)-160 figpos(3)+150 figpos(4)+180]);
    
    
    %=================================
    % Set up the axes
    mhndl = axes( ...
        'Units','normalized', ...
        'Position',[0.05 0.79 0.35 0.17], ...
        'XTick',[],'YTick',[], ...
        'Box','on');
    mfhndl =  axes( ...
        'Units','normalized', ...
        'Position',[0.45 0.79 0.35 0.17], ...
        'XTick',[],'YTick',[], ...
        'Box','on');
    chndl = axes( ...
        'Units','normalized', ...
        'Position',[0.05 0.60 0.35 0.16], ...
        'XTick',[],'YTick',[], ...
        'Box','on');
    cfhndl = axes( ...
        'Units','normalized', ...
        'Position',[0.45 0.60 0.35 0.16], ...
        'XTick',[],'YTick',[], ...
        'Box','on');
    shndl = axes( ...
        'Units','normalized', ...
        'Position',[0.05 0.41 0.35 0.16], ...
        'XTick',[],'YTick',[], ...
        'Box','on'); 
    sfhndl = axes( ...
        'Units','normalized', ...
        'Position',[0.45 0.41 0.35 0.16], ...
        'XTick',[],'YTick',[], ...
        'Box','on');
    rhndl = axes( ...
        'Units','normalized', ...
        'Position',[0.05 0.22 0.35 0.16], ...
        'XTick',[],'YTick',[], ...
        'Box','on');
    fhndl = axes( ...
        'Units','normalized', ...
        'Position',[0.45 0.22 0.35 0.16], ...
        'XTick',[],'YTick',[], ...
        'Box','on');
    fohndl = axes( ...
        'Units','normalized', ...
        'Position',[0.05 0.03 0.35 0.16], ...
        'XTick',[],'YTick',[], ...
        'Box','on');
    thndl = axes( ...
        'Units','normalized', ...
        'Position',[0.45 0.03 0.35 0.16], ...
        'XTick',[],'YTick',[], ...
        'Box','on');

    %====================================
    % Information for all buttons (and menus)
    labelColor=[0.3 0.8 0.5];
    yInitPos=0.90;
    menutop=0.95;
    btnTop = 0.6;
    top=0.75;
    left=0.83;
    btnWid=0.14;
    btnHt=0.06;
    textHeight = 0.05;
    textWidth = 0.10;
    spacing=0.012;
    
    %====================================
    % The CONSOLE frame
    frmBorder=0.019; frmBottom=0.05; 
    frmHeight = 0.895; frmWidth = btnWid;
    yPos=frmBottom-frmBorder;
    frmPos=[left-frmBorder yPos frmWidth+2*frmBorder frmHeight+2*frmBorder];
    h=uicontrol( ...
        'Style','frame', ...
        'Units','normalized', ...
        'Position',frmPos, ...
	    'BackgroundColor',[0.1 0.15 0.25]);

    yPos=menutop;
    
    %===================================
    % Carrier frequency label and text field
    top = yPos - btnHt - spacing;
    labelWidth = frmWidth-textWidth-.01;
    labelBottom = top-textHeight;
    labelLeft = left;
    labelPos = [labelLeft labelBottom labelWidth textHeight];
    h = uicontrol( ...
        'Style','text', ...
        'Units','normalized', ...
        'Position',labelPos, ...
        'HorizontalAlignment','left', ...
        'String','Fc', ...
        'Interruptible','off', ...
        'BackgroundColor',[0.15 0.75 0.5], ...
        'ForegroundColor','white');
	% Text field
    textPos = [labelLeft+labelWidth labelBottom textWidth textHeight];
    callbackStr = 'ammod(''setFc'')';
    FcHndl = uicontrol( ...
        'Style','edit', ...
        'Units','normalized', ...
        'Position',textPos, ...
        'HorizontalAlignment','center', ...
        'Background','white', ...
        'Foreground','black', ...
        'String','400','Userdata',400, ...
        'callback',callbackStr);

    %===================================
    % Sampling frequency label and text field
    labelBottom=top-2*textHeight-spacing;
	labelLeft = left;
    labelPos = [labelLeft labelBottom labelWidth textHeight];
    h = uicontrol( ...
        'Style','text', ...
        'Units','normalized', ...
        'Position',labelPos, ...
        'String','Fs', ...
        'HorizontalAlignment','left', ...
        'Interruptible','off', ...
        'Background',[0.15 0.75 0.5], ...
        'Foreground','white');
	% Text field
    textPos = [labelLeft+labelWidth labelBottom textWidth textHeight];
    callbackStr = 'ammod(''setFs'')';
    FsHndl = uicontrol( ...
        'Style','edit', ...
        'Units','normalized', ...
        'Position',textPos, ...
        'HorizontalAlignment','center', ...
        'Background','white', ...
        'Foreground','black', ...
        'String','1000','Userdata',1000, ...
        'Callback',callbackStr);

    %===================================
    % Phase difference label and text field
    labelBottom=top-3*textHeight-2*spacing;
	labelLeft = left;
    labelPos = [labelLeft labelBottom labelWidth textHeight];
    h = uicontrol( ...
        'Style','text', ...
        'Units','normalized', ...
        'Position',labelPos, ...
        'String','Ph', ...
        'HorizontalAlignment','left', ...
        'Interruptible','off', ...
        'Background',[0.15 0.75 0.5], ...
        'Foreground','white');
	% Text field
    textPos = [labelLeft+labelWidth labelBottom textWidth textHeight];
    callbackStr = 'ammod(''setPh'')';
    Phndl = uicontrol( ...
        'Style','edit', ...
        'Units','normalized', ...
        'Position',textPos, ...
        'HorizontalAlignment','center', ...
        'Background','white', ...
        'Foreground','black', ...
        'String','0','Userdata',0, ...
        'Callback',callbackStr);


    
    %===================================
    % Cut_off frequency label and text field
    labelBottom=top-4*textHeight-3*spacing;
	labelLeft = left;
    labelPos = [labelLeft labelBottom labelWidth textHeight];
    h = uicontrol( ...
        'Style','text', ...
        'Units','normalized', ...
        'Position',labelPos, ...
        'String','Co', ...
        'HorizontalAlignment','left', ...
        'Interruptible','off', ...
        'Background',[0.15 0.75 0.5], ...
        'Foreground','white');
	% Text field
    textPos = [labelLeft+labelWidth labelBottom textWidth textHeight];
    callbackStr = 'ammod(''setCo'')';
    Cohndl = uicontrol( ...
        'Style','edit', ...
        'Units','normalized', ...
        'Position',textPos, ...
        'HorizontalAlignment','center', ...
        'Background','white', ...
        'Foreground','black', ...
        'String','20','Userdata',20, ...
        'Callback',callbackStr);

    %====================================
    % AM radio button
    btnTop = labelBottom-spacing;
    btnNumber=1;
    yPos=btnTop-(btnNumber-1)*(btnHt+spacing);
    labelStr='AM';
    callbackStr='ammod(''radio'',1,''am'');';

    % Generic button information
    btnPos=[left yPos-btnHt btnWid btnHt];
    btn1Hndl=uicontrol( ...
        'Style','radiobutton', ...
        'Units','normalized', ...
        'Position',btnPos, ...
        'String',labelStr, ...
        'value',1,'Userdata','am', ...
        'BackgroundColor',[0.15 0.75 0.5],...
        'Callback',callbackStr);

    %====================================
    % Conventional AM radio button
    btnTop = labelBottom-spacing;
    btnNumber=2;
    yPos=btnTop-(btnNumber-1)*(btnHt+spacing);
    labelStr='AMcon';
    callbackStr='ammod(''radio'',2,''amcon'');';

    % Generic button information
    btnPos=[left yPos-btnHt btnWid btnHt];
    btn2Hndl=uicontrol( ...
        'Style','radiobutton', ...
        'Units','normalized', ...
        'Position',btnPos, ...
        'String',labelStr, ...
        'value',0, ...
        'BackgroundColor',[0.15 0.75 0.5],...
        'Callback',callbackStr);

  
   %====================================
    % Message box in center of figure 
    messageHndl = uicontrol('style','edit',...
          'string','Resampling speech waveform ...',...
          'units','normalized',...
          'position',[.15 .45 .5 .15],...
          'max',2,...
          'visible','off');

    %====================================
    % The INFO button
    labelStr='Info';
    callbackStr='ammod(''info'')';
    helpHndl=uicontrol( ...
        'Style','pushbutton', ...
        'Units','normalized', ...
        'Position',[left frmBottom+btnHt+spacing btnWid btnHt], ...
        'String',labelStr, ...
        'BackgroundColor',[0.15 0.75 0.5],...
        'Callback',callbackStr);

    %====================================
    % The CLOSE button
    labelStr='Close';
    callbackStr='close(gcf)';
    closeHndl=uicontrol( ...
        'Style','pushbutton', ...
        'Units','normalized', ...
        'Position',[left frmBottom btnWid btnHt], ...
        'String',labelStr, ...
        'BackgroundColor',[0.15 0.75 0.5],...
        'Callback',callbackStr);

    hndlList=[mhndl mfhndl chndl cfhndl ...
              shndl sfhndl rhndl fhndl fohndl thndl ...
              FcHndl FsHndl  btn1Hndl btn2Hndl  ...
              messageHndl helpHndl closeHndl Phndl Cohndl];
    
     set(figNumber, ...
	'Visible','on', ...
	'UserData',hndlList);

    set(gcf,'Pointer','watch');
    drawnow
    ammod('changewave')
    set(gcf,'Pointer','arrow');
    set(0,'ShowHiddenHandles',shh)
    return

elseif strcmp(action,'setFc'),
    hndlList=get(gcf,'Userdata');
    %filtHndl = hndlList(12);
    FcHndl = hndlList(11);
    FsHndl = hndlList(12);
    Phndl = hndlList(18);
    Cohndl = hndlList(19);
    v = get(gco,'Userdata');
    s = get(gco,'String');
    vv = eval(s,num2str(v));
    Fs = get(FsHndl,'UserData');
    if vv<0, vv = v; end
    vv = round(vv);
    if vv>=Fs/2
        waitfor(msgbox({'Sorry, the carrier frequency Fc must be less than'...
                  'half the sampling frequency Fs.'},...
                 'ammod Error','error','modal'))
        vv = v;
    end
    set(gco,'Userdata',vv,'String',num2str(vv))
    if vv == v
        return
    end
    Fs = get(FsHndl,'UserData'); % Sampling frequency
    Fc = get(FcHndl,'UserData'); % Carrier frequency
    Ph = get(Phndl,'UserData');  % Phase difference
    Co = get(Cohndl,'UserData');  % Cut_off frequency
    ammod('changewave',Fc,Fs,Ph,Co)

elseif strcmp(action,'setFs'),
    fig = gcf;
    set(fig,'Pointer','watch');
    hndlList=get(fig,'Userdata');
    FcHndl = hndlList(11);
    FsHndl = hndlList(12);
    Phndl = hndlList(18);
    Cohndl = hndlList(19);
    messageHndl = hndlList(15);

    v = get(gco,'Userdata');
    s = get(gco,'String');
    vv = eval(s,num2str(v));
    if vv<=0, vv = v; end
    Fc = get(FcHndl,'UserData'); % Carrier frequency
    Co = get(Cohndl,'UserData'); % Cut_off frequency
    vv = round(vv*10)/10;
    if Fc>=vv/2
        waitfor(msgbox({'Sorry, the sampling frequency Fs must be more than'...
                  'twice the carrier frequency Fc.'},...
                 'ammod Error','error','modal'))
        vv = v;
    end
    if Co>=vv/2
        waitfor(msgbox({'Sorry, the sampling frequency Fs must be more than'...
                  'twice the cut_off frequency Co.'},...
                 'ammod Error','error','modal'))
        vv = v;
    end
    set(gco,'Userdata',vv,'String',num2str(vv))
    if vv == v
        set(fig,'Pointer','arrow');
        return
    end

    Fs = get(FsHndl,'UserData'); % Sampling frequency
    Fc = get(FcHndl,'UserData'); % Carrier frequency
    Ph = get(Phndl,'UserData');  % Phase difference
    Co = get(Cohndl,'UserData');  % Cut_off frequency
    ammod('changewave',Fc,Fs,Ph,Co)
    
    return
 
    
elseif strcmp(action,'setPh'),
    fig = gcf;
    set(fig,'Pointer','watch');
    hndlList=get(fig,'Userdata');
    FcHndl = hndlList(11);
    FsHndl = hndlList(12);
    Phndl = hndlList(18);
    Cohndl = hndlList(19);
    messageHndl = hndlList(15);

    v = get(gco,'Userdata');
    s = get(gco,'String');
    vv = eval(s,num2str(v));
    vv = round(vv*10)/10;
    set(gco,'Userdata',vv,'String',num2str(vv))
    if vv == v
        set(fig,'Pointer','arrow');
        return
    end

    Fs = get(FsHndl,'UserData'); % Sampling frequency
    Fc = get(FcHndl,'UserData'); % Carrier frequency
    Ph = get(Phndl,'UserData');  % Phase difference
    Co = get(Cohndl,'UserData');  % Cut_off frequency
    ammod('changewave',Fc,Fs,Ph,Co)
    
    return
    
elseif strcmp(action,'setCo'),
    fig = gcf;
    set(fig,'Pointer','watch');
    hndlList=get(fig,'Userdata');
    FcHndl = hndlList(11);
    FsHndl = hndlList(12);
    Phndl = hndlList(18);
    Cohndl = hndlList(19);
    
    messageHndl = hndlList(15);

    v = get(gco,'Userdata');
    s = get(gco,'String');
    vv = eval(s,num2str(v));
    Fs = get(FsHndl,'UserData'); % Carrier frequency
    vv = round(vv*10)/10;
    
    
    if Fs<=vv*2
        waitfor(msgbox({'Sorry, the cut_off frequency Co must be less than'...
                  'thalf of the sampling frequency Fs.'},...
                 'ammod Error','error','modal'))
        vv = v;
    end
       
    set(gco,'Userdata',vv,'String',num2str(vv))
    if vv == v
        set(fig,'Pointer','arrow');
        return
    end

    Fs = get(FsHndl,'UserData'); % Sampling frequency
    Fc = get(FcHndl,'UserData'); % Carrier frequency
    Ph = get(Phndl,'UserData');  % Phase difference
    Co = get(Cohndl,'UserData'); % Cut_off frequency
    ammod('changewave',Fc,Fs,Ph,Co)
    
    return

elseif strcmp(action,'changewave')

    set(gcf,'Pointer','watch');
    axHndl=gca;
    hndlList=get(gcf,'Userdata');
    FcHndl = hndlList(11);
    FsHndl = hndlList(12);
    Phndl = hndlList(18);
    Cohndl = hndlList(19);
    
      if nargin<2
          Fc = 400;
          Fs = 1000;
          Ph = 0;
          Co = 20;
      else
          Fc = s;
          Fs = ss;
          Ph = sss;
          Co = ssss;
      end

    set(FcHndl,'string',num2str(Fc),'userdata',Fc);
    set(FsHndl,'string',num2str(Fs),'userdata',Fs);
    set(Phndl,'string',num2str(Ph),'userdata',Ph);
    set(Cohndl,'string',num2str(Co),'userdata',Co);
    ammod('modulate')
     

elseif strcmp(action,'radio'),
    axHndl=gca;
    hndlList=get(gcf,'Userdata');
    for i=13:14,
      set(hndlList(i),'value',0) % Disable all the buttons
    end
    set(hndlList(s+12),'value',1) % Enable selected button
    set(hndlList(13),'Userdata',ss) % Remember selected button
    ammod('modulate')
    return

elseif strcmp(action,'modulate'), % modulate, demodulate, and update display
    set(gcf,'Pointer','watch');
    axHndl=gca;
    hndlList=get(gcf,'Userdata');
    mhndl = hndlList(1);
    mfhndl = hndlList(2);
    chndl = hndlList(3);
    cfhndl = hndlList(4);
    shndl = hndlList(5);
    sfhndl = hndlList(6);
    rhndl = hndlList(7);
    fhndl = hndlList(8);
    fohndl = hndlList(9);
    thndl = hndlList(10);
    FcHndl = hndlList(11);
    FsHndl = hndlList(12);
    btn1Hndl = hndlList(13);
    btn2Hndl = hndlList(14);
    Phndl = hndlList(18);
    Cohndl = hndlList(19);
    
    set(gcf,'nextplot','add')

    edgecolor = get(gca,'colororder'); edgecolor = edgecolor(1,:);
    
    Fs = get(FsHndl,'UserData'); % Sampling frequency
    Fc = get(FcHndl,'UserData'); % Carrier frequency
    Ph = get(Phndl,'UserData');  % Phase difference
    Co = get(Cohndl,'UserData'); % Cut_off frequency
    
    method = get(btn1Hndl,'Userdata');
    
    t= linspace(0,1,Fs) ;
    m= ones(1, Fs);
    m= [m(1:round(.4*Fs))*1 m(round(.4*Fs)+1:round(.7*Fs))*-2 m(round(.7*Fs)+1:Fs)*0]; %signal I
    %m= sinc (4*t);      %signal II
    %m= cos(2*pi*10*t);  %signal III
    c= cos(2*pi*Fc*t);   %carrier signal
    s= m .* c;           %modulated signal
    
    a= 0.50;                  %modulation index for conventional AM case
    if strcmp(method,'amcon')
        m_n = m /max(abs(m)); %normalized message signal for AMcon
        s = (1+a*m_n).*c ;    %modulated signal for AMcon
    end
            
    N= 512;
    m_f= fft(m, N); m_f= fftshift (m_f); %Fourier Trans. of the message signal
    c_f= fft(c, N); c_f= fftshift (c_f); %Fourier Trans. of the carrier signal
    s_f= fft(s, N); s_f= fftshift (s_f); %Fourier Trans. of the modulated signal
    
    dt_fft= 1/Fs; 
    df_fft= 1/(N*dt_fft);
    x_f1= ((N/2+1):N)-(N+1);
    x_f2= (1:(N/2))-1;
    x_f= [x_f1 x_f2]*df_fft;
     
    r= s.*(cos(2*pi*Fc*t+Ph)); %input to the filter
    r_f= fft(r,N); r_f= fftshift (r_f); %filter input in frequency domain    
    
    Nd=5;
    Wn=Co/(Fs/2);
    [B, A]= butter(Nd, Wn);
    [Fw, ww]= freqz(B,A,N,'whole');
    Fw= fftshift(Fw);                %filter frequency response
    to= 2*filter(B,A,r);             %output in time domain
    fo= fft(to,N); fo= fftshift(fo); %output in fequency domain
    
    %following portion is envelope detection for AMcon  
    if strcmp(method,'amcon')
        rs = abs(s);
        cm = rs(1);
        for i = 1:Fs
            if rs(i)<cm 
                cm = cm - (cm * .01);
            else 
                cm = rs(i);
            end
            to(i) = cm;
            mo(i) = (cm - 1)/a;
        end
    end
    %-----------------------------------
    
      axes(mhndl), plot(t,m), grid on
      ylabel('Message Signal')
      axes(mfhndl), plot(x_f,abs(m_f)), grid on
      ylabel('FT of Message Signal')
      
      axes(chndl), plot(t, c), grid on
      ylabel('Carrier Signal')
      axes(cfhndl), plot(x_f,abs(c_f)), grid on
      ylabel('FT of Carrier Signal')
      
      axes(shndl), plot(t,s), grid on
      ylabel('Modulated Signal')
      axes(sfhndl), plot(x_f,abs(s_f)), grid on
      ylabel('FT of Modulated Signal')
      
      axes(rhndl), plot(x_f, abs(r_f)), grid on
      ylabel('Input of Filter')
      axes(fhndl), plot(x_f, abs(Fw)), grid on
      ylabel('Butterworth Filter')

      axes(fohndl), plot(x_f, abs(fo)), grid on
      ylabel('Output of Filter')
      axes(thndl), plot(t, to), grid on
      ylabel('Demodulated')
      
      if strcmp(method,'amcon')
        axes(mhndl), plot(t,m_n), grid on
        ylabel('Norm. Msg. Signal')
        axes(rhndl), plot(t, to), grid on
        ylabel('Output of Env. Det.')
        axes(fhndl), plot(t, mo), grid on
        ylabel('Demodulated')

        axes(fohndl), plot(x_f, 0), grid on
        ylabel('')
        axes(thndl), plot(t, 0), grid on
        ylabel('')
    end
      
      xlabel('Time (Seconds)')
      set(gcf,'Pointer', 'arrow')
    return

elseif strcmp(action,'info'),
    set(gcf,'pointer','arrow')
	ttlStr = get(gcf,'Name');
	hlpStr= [...
             'This demo lets you experiment with AM modulation.                          '
             '                                                                           '
             '                                                                           '
             'The message signal and its Fourier Transform are displayed in the top.     '
             'In the second line of plots, the carrier and its Fourier Transform are     '
             'displayed. Then comes the modulated signal and its Fourier Transform.      '
             '                                                                           '
             'The following are the receiving and the demodulation of the modulated      '
             'signal. Input to the filter in frequency domain and the filter`s frequency '
             'response are displayed on the fourth line. The last two graphs are the     '
             'output signal in frequency and time domains, respectively.                 '
             '                                                                           '
             'Fc and Fs are the carrier and sampling frequencies, respectively, in Hertz.'
             'Ph is the phase difference between the carrier and the signal we multiply  '
             'the received signal before filtering it.                                   '
             'In the best case Ph=0, and in the worst case it is pi/2.                   '
             'Co stands for the cut_off frequency of the Butterworth filter used         '
             'for detection.                                                             '
             '                                                                           '
             'In each modulation scheme, a "carrier signal" (cosine) of frequency Fc is  '
             'altered in some way by the message signal:                                 '
             '    AM    - amplitude of carrier is message signal                         '
             '    AMcon - conventional AM                                                '
             '            very similar to DSB-AM. Message signal is substituted          '
             '            with [1+am_n(t)], where m_n is the normalized message signal.  '
         ];
    myFig = gcf;
    helpwin(hlpStr,ttlStr);

elseif strcmp(action,'closehelp'),
    % Restore close button help behind helpwin's back
    ch = get(gcf,'ch');
    for i=1:length(ch),
      if strcmp(get(ch(i),'type'),'uicontrol'),
        if strcmp(lower(get(ch(i),'String')),'close'),
          callbackStr = get(ch(i),'callback');
          k = findstr('; ammod(',callbackStr);
          callbackStr = callbackStr(1:k-1);
          set(ch(i),'callback',callbackStr)
          break;
        end
      end
    end
    ch = get(0,'ch');
    if ~isempty(find(ch==s)), figure(s), end 

end