signt.m

信号实验常用的simulink模型和mfile,可直接在matlan下运行。

function signt(action,in1,in2);
%signt 交互式信号演示 - 1 : 信号的 DFT
%	Illustrating some basic signal processing concepts, such as 
%	sampling, aliasing, and windowing.

%	possible actions:
%	  'start'
%	  'down'
%	  'move'
%	  'up'
%	  'redraw'
%	  'done'
%         'setzq'
%	  'setfreq'
%	  'setwindow'
%	  'showwin'

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

global signt_DAT
global ADDIT_DAT	% this is for WINDOW pop-up button
global fun_str
global ws

if strcmp(action,'start'),

    %====================================
    % Graphics initialization
    oldFigNumber = watchon;
    figNumber = figure;
    set(gcf, ...
        'NumberTitle','off', ...
        'Name','离散周期信号傅立叶变换', ...
        'backingstore','off',...
        'Units','normalized');

    %====================================
    % Information for all buttons
    labelColor=192/255*[1 1 1];
    top=0.95;
    bottom=0.05;
    left=0.75;
    yInitLabelPos=0.90;
    left = 0.78;
    labelWid=0.18;
    labelHt=0.05;
    btnWid = 0.18;
    btnHt=0.07;
    % Spacing between the label and the button for the same command
    btnOffset=0.003;
    % Spacing between the button and the next command's label
    spacing=0.05;
 
    %====================================
    % The CONSOLE frame
    frmBorder=0.02;
    yPos=0.05-frmBorder;
    frmPos=[left-frmBorder yPos btnWid+2*frmBorder 0.9+2*frmBorder];
    h=uicontrol( ...
        'Style','frame', ...
        'Units','normalized', ...
        'Position',frmPos, ...
        'BackgroundColor',[0.5 0.5 0.5]);
    
    %====================================
    % The SIGNAL command popup button

    btnNumber=1;
    yLabelPos=top-(btnNumber-1)*(btnHt+labelHt+spacing);
    labelStr=' 信号';

    % Generic label information
    labelPos=[left yLabelPos-labelHt labelWid labelHt];
    uicontrol( ...
        'Style','text', ...
        'Units','normalized', ...
        'Position',labelPos, ...
        'BackgroundColor',labelColor, ...
        'HorizontalAlignment','left', ...
        'String',labelStr);

    btnPos=[left yLabelPos-labelHt-btnHt-btnOffset btnWid btnHt];
    popup=uicontrol('Style','Popup','String','方波序列',...
        'Position', btnPos, ...
        'BackgroundColor','w', ...
        'ForegroundColor','k', ...
        'Units','normalized',...
        'CallBack',[...
		'global signt_DAT;',...
		'popup=signt_DAT(11);',...
		'val = get(popup,''Value'');',...
		'if val<=3',...
		'	signt(''redraw'');',...
		'else',...
		'	getstr;',...
		'end']);

    %====================================
    % The zq command popup button
      btnNumber=2;
      yLabelPos=top-(btnNumber-1)*(btnHt+labelHt+spacing);
     labelPos=[left yLabelPos-labelHt labelWid+0.02 labelHt];
      zq_text= uicontrol( ...
          'Style','text', ...
        'Position',labelPos, ...
        'Units','normalized', ...
        'BackgroundColor',[0.5 0.5 0.5], ...
         'ForegroundColor','w',...
         'HorizontalAlignment','left', ...
          'String','离散周期(N):');

        btnPos=[left+0.02 yLabelPos-labelHt-btnHt-btnOffset...
                0.5*btnWid+frmBorder btnHt];
       zq_field = uicontrol( ...
        'Style','edit', ...
        'BackgroundColor','w', ...
        'ForegroundColor','k', ...
        'Position',btnPos, ...
         'Units','normalized', ...
         'HorizontalAlignment','left', ...
          'String','20', ...
	    'Callback','signt(''setzq'');signt(''redraw'')');

  %====================================
    % The FUNDAMENTAL editable text box
    btnNumber=3;
    yLabelPos=top-(btnNumber-1)*(btnHt+labelHt+spacing);
    labelPos=[left yLabelPos-labelHt labelWid+0.02 labelHt];
    freq_text = uicontrol( ...
        'Style','text', ...
        'Position', labelPos, ...
        'Units','normalized', ...
        'BackgroundColor',[0.5 0.5 0.5], ...
        'ForegroundColor','w', ...
        'HorizontalAlignment','left', ...
        'String','脉宽参数(N1):');

    btnPos=[left+0.02  yLabelPos-labelHt-btnHt-btnOffset ...
            0.5*btnWid+frmBorder  btnHt];
    freq_field = uicontrol( ...
        'Style','edit', ...
        'BackgroundColor','w', ...
        'ForegroundColor','k', ...
        'Position', btnPos, ...
        'Units','normalized', ...
        'HorizontalAlignment','left', ...
        'String','5',...
        'CallBack','signt(''setfreq''); signt(''redraw'')');


   %====================================
    % The INFO button
    uicontrol( ...
        'Style','push', ...
        'Units','normalized', ...
        'Position',[left bottom+(2*labelHt)+spacing btnWid 2*labelHt], ...
        'String','信息', ...
        'Callback','signt(''info'')');

   %========================================
   % The CLOSE button
    done_button=uicontrol('Style','Pushbutton', ...
        'Position',[left bottom btnWid 2*labelHt], ...
        'Units','normalized','Callback',...
        'signt(''done'')','String','关闭');
   %====================================

    % Create intial signal
    N=512;     % number of samples
     N1=30;
    zq=20;
    freq=5;    % hertz
    t0=-10;      % seconds
    t1=10;      % seconds
    t=-30:30;
    T=(t1-t0)/N;
    ws=t(2)-t(1);            % sampling rate in seconds
    M=512;     % length of fft
    window=ones(N,1);    % use window to lower side-lobes in the freq. domain
                             % (makes peaks wider)
    
    min_dB=0; % freq. domain lower axis limit
    %w=ws*(1:N/2)/N;
    %w2=ws*(-(0:N/2-1))/N;
    % create axes for time domain and frequency domain plot

     ax_freq=axes('Position',[.12 .14 .6 .3],'XLim',...
             [0,7],'YLim',[0 20]);

    % time domain
    val = get(popup,'Value');

    if (val == 1),   % square wave
          
        i=-30:30;
        
   for n=1:61
      j=fix(n/zq);
       if abs(n-j*zq-zq/2-1)<=freq
          f(n)=1;
    else
        f(n)=0;
    end
end 
        %tt=freq*t*2*pi;
        %tmp=rem(tt,2*pi);
        %f=amp*(2*rem((tt<0)+(tmp>pi | tmp<-pi)+1,2)-1);
    elseif (val == 2),   % sawtooth
        
           if t==N/2,f=1;
           else f=0;
           
           end   
     %tt=freq*t*2*pi;
       % f=amp*((tt < 0) + rem(tt,2*pi)/2/pi - .5)*2;
    elseif (val == 3),   % self-defined waveform
	f=eval(fun_str);
    end;

    % frequency domain
    F=fft(f,M);
       %F=F(1:M);
    w=2*pi/ws/M*(0:M-1);
    FF=sqrt(F.*conj(F));
    % ind=find(FF<min_dB);
    % FF(ind)=NaN*ones(size(ind)); % put NaN's in where
         % min_dB shows up - this is to work around no clipping in xor mode
       
      
     freq_line=plot(w,FF,'EraseMode','xor');
      axis([0 7 0 20]);
    grid;
    ylabel('幅频特性');
    xlabel('频率 (Hz)');

    ax_time=axes('Position',[.12 .58 .6 .3],'XLim',[-10 10],'YLim',[0 1]);
   
    time_line=plot(t,f,'EraseMode','xor');
    stem(t,f);
      axis([-30 30 0 1]);
    % (set to xor mode to prevent re-rendering, that is, for speed)
    grid;
    ylabel('波形');
    xlabel('时间（秒）');
    text(-20, 1.25,'点击并拖放信号波形以改变其基频与振幅。');
  
      %set(time_line,'ButtonDownFcn','signt(''down'')');

    signt_DAT = [freq; zq; N; M; zq_field; 0; 0; ...
		time_line; freq_line; freq_field; popup;-1; gcf; ...
		];
    %ADDIT_DAT = winHndl;

    watchoff(oldFigNumber);

elseif strcmp(action,'down'),

  popup=signt_DAT(11);
  val = get(popup,'value');
  if val<=3
    % assumes that a line was clicked
    time_line=signt_DAT(8);
    axes(get(time_line,'parent'));	% set the right axes

    % Obtain coordinates of mouse click location in axes units
    pt=get(gca,'currentpoint');
    x=pt(1,1);
    y=pt(1,2);


% find closest vertex of line to mouse click location (call it fixed_x, fixed_y)

    line_x=get(time_line,'XData');
    line_y=get(time_line,'YData');
    units_str = get(gca,'units');  % save normalized state
    set(gca,'units','pixels');     % distance must be in pixels
    p=get(gca,'pos');
    xa=get(gca,'xlim');
    ya=get(gca,'ylim');
    
    dist=((line_x-x)*p(3)/(xa(2)-xa(1))).^2 + ...
         ((line_y-y)*p(4)/(ya(2)-ya(1))).^2;
    [temp,i]=min(dist);
    fixed_x=line_x(i);
    fixed_y=line_y(i);
    set(time_line,'LineStyle',':');

    signt_DAT(6)=fixed_x;
    signt_DAT(7)=fixed_y;

    set(gca,'units',units_str );
    set(gcf,'WindowButtonMotionFcn', 'signt(''move'')');
    set(gcf,'WindowButtonUpFcn', 'signt(''up'')');
  %  set(gcf,'userdata',u);
end

elseif strcmp(action,'move'),
    % u = get(gcf,'userdata');
    freq=signt_DAT(1);
    zq=signt_DAT(2);
    N=signt_DAT(3);
    M=signt_DAT(4);
    zq_field=signt_DAT(5);
    fixed_x=signt_DAT(6);
    fixed_y=signt_DAT(7);
    time_line=signt_DAT(8);
    freq_line=signt_DAT(9);
    freq_field=signt_DAT(10);
    popup=signt_DAT(11);
    %zq_field=signt_DAT(12);
    %t=signt_DAT(14:14+N-1);
    %window=signt_DAT(14+N:14+N+N-1);

    pt=get(gca,'currentpoint');
    x=pt(1,1);
    y=pt(1,2);

   % amp1=y/fixed_y*amp;
    %if (abs(amp1)>1.0),
     %  amp1=1.0*sign(amp1);
    %end;
    %if (abs(amp1)<0.05),
     %  amp1=0.05*sign(amp1);
    %end;
    %if (amp1 == 0),
    %    amp1=0.05;
    %end;
    %freq1=fixed_x/x*freq;

    val = get(popup,'Value');
     %if(freq1<0.05)freq1=0.05;end
      %if(freq>0.95)freq1=0.95;end
     % if(amp1>1.0)amp1=1.0;end
    
%if (val == 1),
           %if t==0 f=1;
           %else 
 %         f=amp1*sin(freq1*t)./(t*pi);
         %  end;
    if (val == 1),   % square wave
           i=-30:30;
for n=1:61
    j=fix(n/T);
    if abs(n-j*T-N/2-1)<=N1/2
        x(n)=1;
    else
        x(n)=0;
    end
end