dfdpzp4.m

很多matlab的源代码

function dfdpzp4(mode)
% DFDPZP4 Interactive digital filter design by pole-zero placement
%
%         DFDPZP4 invokes the digital filter design environment for Matlab
%         versions 4.x and 5.x.
%
%         Push Button Scheme:
%
%            Add Poles - sets the Add Poles mode for the mouse.  Adding poles
%                        is accomplished by selecting a point within the
%                        Pole-Zero Diagram [the z-plane and unit circle]
%
%            Add Zeros - sets the Add Zeros mode for the mouse.  Adding zeros
%                        is accomplished by selecting a point within the
%                        Pole-Zero Diagram
%
%            Del Poles - sets the Delete mode for the mouse.  Deleting poles
%                        is accomplished by selecting the desired pole to be 
%                        deleted
%
%            Del Zeros - sets the Delete mode for the mouse.  Deleting zeros
%                        is accomplished by selecting the desired zero to be 
%                        deleted
%         
%              Update -  updates all plots
%
%             To Work - To Workspace allows coefficients of H(z) to be  
%                       transferred to the workspace in descending powers 
%                       of z and numerator/denominator format
%
% Notes:  1) In the add modes, the pointer is a crosshair.
%         2) In the delete modes, the pointer is a bullseye (circle).
%         3) The xlabel of the Pole-Zero Diagram displays the current mode.


% ADSP Toolbox: Version 2.0 
% For use with "Analog and Digital Signal Processing", 2nd Ed.
% Published by PWS Publishing Co.
%
% Ashok Ambardar, EE Dept. MTU, Houghton, MI 49931, USA
% http://www.ee.mtu/faculty/akambard.html
% e-mail: [e-mail]
% Copyright (c) 1998


j=sqrt(-1);
if nargin==0, % setup environment

 if exist('version')~=5,
  disp('This routine is not for MATLAB v3')
  return
 end

 clf
 axs_han(1) = subplot(2,2,1);
 xn=exp(j*(pi/6:pi/6:2*pi));
 ellipse(1)
 axis('square')
 set(gca,'Xtick',[],'Ytick',[])
 hold on
 ellipse(0.25)
 ellipse(0.5)
 ellipse(0.75)
 zn=zeros(length(xn));
 plot([zn;real(xn)],[zn;imag(xn)])
 title('Pole-Zero Diagram');
%polar(2*pi,1),hold on,axis(axis),grid on,
 mode = 0;
 btn(1) = uicontrol('style','push','units','norm','pos',[0.0080,0.8907,0.1400,0.0533],...
                    'string','Add Poles','callback','dfdpzp4(1)');
 btn(2) = uicontrol('style','push','units','norm','pos',[0.0080,0.8240,0.1400,0.0533],...
                    'string','Add Zeros','callback','dfdpzp4(2)');
 btn(3) = uicontrol('style','push','units','norm','pos',[0.0080,0.7573,0.1400,0.0533],...
                    'string','Del Poles','callback','dfdpzp4(3)');
 btn(4) = uicontrol('style','push','units','norm','pos',[0.0080,0.6907,0.1400,0.0533],...
                    'string','Del Zeros','callback','dfdpzp4(4)');
 btn(5) = uicontrol('style','push','units','norm','pos',[0.0080,0.6240,0.1400,0.0533],...
                    'string','Plot','callback','dfdpzp4(9)'); 
 btn(6) = uicontrol('style','push','units','norm','pos',[0.0080,0.5573,0.1400,0.0533],...
                    'string','To Work','callback','pzpvar(0)');
 set(btn(3),'userdata',axs_han(1));

if matverch < 5,typ='yes';else,typ='on';end
 set(gcf,'userdata',btn,'interruptible',typ);
 dfdpzp4(1);
else
 f = gcf;
 btn = get(f,'userdata');
 axs_han = get(btn(3),'userdata');
 subplot(2,2,1);
 ax = gca;
 deleted = 0;
end

if any(mode == [1,5]), % add poles
 if mode == 1,
  xlabel('Mode:  Add Poles');
  set(f,'pointer','crosshair','windowbuttondownfcn','dfdpzp4(5)');
% refresh pole/zero axis
  set(axs_han,'color',get(axs_han,'color'));
 else
  pt = get(ax,'currentpoint');
  xx = pt(1,1); yy = pt(1,2);
  if abs(xx+j*yy) < 0.02, % snap to origin
   xx=0; yy=0;
  end
  if abs(yy) < 0.02, % snap to real axis
   yy=0;
  end
  if yy ~= 0, 
   xx=[xx,xx]; yy=[yy,-yy];
  end
if matverch < 5,typ1='none';else,typ1='xor';end
%typ1='xor';
  pole = plot(xx,yy,'rx','erase',typ1);
  all_poles = get(btn(1),'userdata');
  all_poles = [all_poles,pole];
  set(btn(1),'userdata',all_poles);
 end
 
elseif any(mode == [2,6]), % add zeros
 if mode == 2,
  xlabel('Mode:  Add Zeros');
  set(f,'pointer','crosshair','windowbuttondownfcn','dfdpzp4(6)');
% refresh pole/zero axis
  set(axs_han,'color',get(axs_han,'color'));
 else
  pt = get(ax,'currentpoint');
  xx = pt(1,1); yy = pt(1,2);
  if abs(xx+j*yy) < 0.02, % snap to origin
   xx=0; yy=0;
  end
  if abs(yy) < 0.02, % snap to real axis
   yy=0;
  end
  if yy ~= 0, 
   xx=[xx,xx]; yy=[yy,-yy];
  end
  zz=xx+j*yy;
  r=abs(zz);
  th=angle(zz);
  if abs(1-r(1)) < 0.02,
   xx=cos(th);
   yy=sin(th);
  end
if matverch < 5,typ1='none';else,typ1='xor';end
%typ1='xor';

  zero = plot(xx,yy,'go','erase',typ1);
  all_zeros = get(btn(2),'userdata');
  all_zeros = [all_zeros,zero];
  set(btn(2),'userdata',all_zeros);
 end
 
elseif any(mode == [3,7]), % delete pole
 if mode == 3,
  xlabel('Mode:  Delete Poles');
  set(f,'pointer','circle','windowbuttondownfcn','dfdpzp4(7)');
 else
  pt = get(ax,'currentpoint');
  sel_pt = pt(1,1)+j*pt(1,2);
% had to make a switch to using the currentpoint instead of the currentobject
% because matlab seems to scramble the stacking order or the x's and o's and
% the lines that make up the circular grid lines.  this caused the selection
% of a grid line instead of the desired x or o.
  all_poles = get(btn(1),'userdata');
  deleted = 0;
  for k = 1:length(all_poles),
   xdata = get(all_poles(k),'xdata');
   ydata = get(all_poles(k),'ydata');
   pol_pt = xdata+j*ydata;
   if any(abs(sel_pt - pol_pt)<0.05),
    deleted = 1;
    delete(all_poles(k));
    all_poles(k) = [];
    break;
   end
  end
    
  if deleted,
   set(btn(1),'userdata',all_poles);
  end
  
% refresh pole/zero axis
  set(axs_han,'color',get(axs_han,'color'));
 end
 
elseif any(mode == [4,8]), % delete zero
 if mode == 4,
  xlabel('Mode:  Delete Zeros');
  set(f,'pointer','circle','windowbuttondownfcn','dfdpzp4(8)');
 else
  pt = get(ax,'currentpoint');
  sel_pt = pt(1,1)+j*pt(1,2);
% had to make a switch to using the currentpoint instead of the currentobject
% because matlab seems to scramble the stacking order or the x's and o's and
% the lines that make up the circular grid lines.  this caused the selection
% of a grid line instead of the desired x or o.
  all_zeros = get(btn(2),'userdata');
  deleted = 0;
  for k = 1:length(all_zeros),
   xdata = get(all_zeros(k),'xdata');
   ydata = get(all_zeros(k),'ydata');
   zer_pt = xdata+j*ydata;
   if any(abs(sel_pt - zer_pt)<0.05),
    deleted = 1;
    delete(all_zeros(k));
    all_zeros(k) = [];
    break;
   end
  end

  if deleted,
   set(btn(2),'userdata',all_zeros);
  end
  
% refresh pole/zero axis
  set(axs_han,'color',get(axs_han,'color'));
 end
 
elseif mode==9,

 all_poles = get(btn(1),'userdata');
 all_zeros = get(btn(2),'userdata');
 
 if isempty(all_zeros),
  num=1;
 else
  zer=[];
  for k=1:length(all_zeros),
   xdata = get(all_zeros(k),'xdata');
   ydata = get(all_zeros(k),'ydata');
   zeros_loc = xdata + ydata*i;
   zer = [zeros_loc.';zer];
  end
  num=real(poly(zer.'));
 end
 
 if isempty(all_poles),
  den=1;
 else
  pol=[];
  for k=1:length(all_poles),
   xdata = get(all_poles(k),'xdata');
   ydata = get(all_poles(k),'ydata');
   poles_loc = xdata + ydata*i;
   pol = [poles_loc.';pol];
  end
  den=real(poly(pol.'));
 end

 n=0:100;
 n0=0*n';
 n0(1)=1;
 y1=filter(num,den,n0);
 y2=filter(num,den,0*n+1);
 n=n(1:2:101);
 y1=y1(1:2:101);
 y2=y2(1:2:101);
 w=0:pi/200:pi;
 zzz=exp(sqrt(-1)*w);
 h=polyval(num,zzz)./polyval(den,zzz);
%hold off,axis('normal');
%eval('figure(2)')

 subplot(2,2,2);
 cla
 plot(w/2/pi,abs(h))
 xlabel('Frequency Response vs F')
 subplot(2,2,3);
 cla
 dtplot(n,y1,'.');
 xlabel('Impulse response n=0:100')
 subplot(2,2,4);
 cla
 dtplot(n,y2,'.');
 xlabel('Step response n=0:100')
 
% refresh pole/zero axis
 set(axs_han,'color',get(axs_han,'color'));

end