f_plotfir.m

digital signal processing常用工具箱

function f_plotfir (pv,han,fs,hc_dB,a,b,xm,method,win,F_0,F_1,B,delta_p,delta_s,user,fsize)

%F_PLOTFIR: Plot selected view for GUI module G_FIR
%
% Usage: f_plotfir (pv,han,fs,dB,a,b,xm,method,win,F_0,F_1,B,delta_p,delta_s,user,fsize)
%
% Inputs: 
%         pv      = view selector
%         han     = array of axes handles
%         fs      = sampling frequency
%         hc_dB   = handle to dB checkbox 
%         a       = coefficients of denominator polynomial
%         b       = coefficients of numerator polynomial
%         xm      = filter type
%         method  = filter design method (1 to 3)  
%         win     = window type (0 to 3)
%         F_0     = low frequency cutoff
%         F_1     = high frequency cutoff
%         B       = transition bandwidth
%         delta_p = passband ripple factor
%         delta_s = stopband attenuation factor
%         user    = string containing name of user-supplied amplitude
%                   response M-file function
%         fsize   = font size 

% Initialize

dB = get (hc_dB,'Value');
colors = get(gca,'ColorOrder');
p = 512;
m = length(b)-1;
A_p = -20*log10(1-delta_p);
A_s = -20*log10(delta_s);
f_type = xm - 1;
f_ploterase (han)

switch f_type
    case 0, caption = 'Lowpass';
    case 1, caption = 'Highpass';
    case 2, caption = 'Bandpass';
    case 3, caption = 'Bandstop';
    case 4, 
        user1 = f_cleanstring (user);
        caption = sprintf ('User-defined filter from file %s, ',user1);
end

switch method
   
   case 0, caption = [caption ' windowed filter, rectangular window'];
   case 1, caption = [caption ' windowed filter, Hanning window'];
   case 2, caption = [caption ' windowed filter, Hamming window'];
   case 3, caption = [caption ' windowed filter, Blackman window'];
   case 4, caption = [caption ' frequency-sampled filter'];
   case 5, caption = [caption ' least-squares filter'];
   case 6, caption = [caption ' equiripple filter'];
      
end

caption = [caption sprintf(': m = %d',m)];

% Plot results

switch pv

case 1,                                               % magnitude response 

   axes (han(6))
   axis on
   [H,f] = f_freqz (b,a,p,fs);
   A = abs(H);
   if dB
      A = 20*log10(max(A,eps));
      f_labels (caption,'f (Hz)','A(f) (dB)','',fsize)
      A_min = 3*A_s;
      hp(1) = plot (f,A,'Color',colors(2,:),'LineWidth',1.5);
      if xm < 4
         axis ([0 fs/2 -A_min 5])
      end
   else
      f_labels (caption,'f (Hz)','A(f)','',fsize)
      hp(1) = plot (f,A,'Color',colors(2,:),'LineWidth',1.5);
      if xm < 4
         axis ([0 fs/2 0 1.2])
     end
   end
   if (dB == 1)
      f_labels (caption,'f (Hz)','A(f) (dB)','',fsize)
   else   
      f_labels (caption,'f (Hz)','A(f)','',fsize)
   end
 
   hold on
   switch f_type
   case {0,1,2,3},
      
      if f_type == 0
         if dB
            fill ([0 F_0 F_0 0],[-A_p -A_p A_p A_p],'c')
            fill ([F_0+B fs/2 fs/2 F_0+B],[-A_min -A_min -A_s -A_s],'c')
         else
            fill ([0 F_0 F_0 0],[1-delta_p 1-delta_p 1+delta_p 1+delta_p],'c')
            fill ([F_0+B fs/2 fs/2 F_0+B],[0 0 delta_s delta_s],'c')
         end
      end
     
      if f_type == 1
         if dB
            fill ([F_1 fs/2 fs/2 F_1],[-A_p -A_p A_p A_p],'c')
            fill ([0 F_1-B F_1-B 0],[-A_min -A_min -A_s -A_s],'c')
         else
            fill ([F_1 fs/2 fs/2 F_1],[1-delta_p 1-delta_p 1+delta_p 1+delta_p],'c')
            fill ([0 F_1-B F_1-B 0],[0 0 delta_s delta_s],'c')
         end
      end
      
      if f_type == 2
         if dB
            fill ([0 F_0-B F_0-B 0],[-A_min -A_min -A_s -A_s],'c')
            fill ([F_0 F_1 F_1 F_0],[-A_p -A_p A_p A_p],'c')
            fill ([F_1+B fs/2 fs/2 F_1+B],[-A_min -A_min -A_s -A_s],'c')
         else
            fill ([0 F_0-B F_0-B 0],[0 0 delta_s delta_s],'c')
            fill ([F_0 F_1 F_1 F_0],[1-delta_p 1-delta_p 1+delta_p 1+delta_p],'c')
            fill ([F_1+B fs/2 fs/2 F_1+B],[0 0 delta_s delta_s],'c')
         end
      end
      
      if f_type == 3
         if dB
            fill ([0 F_0-B F_0-B 0],[-A_p -A_p A_p A_p],'c')
            fill ([F_0 F_1 F_1 F_0],[-A_min -A_min -A_s -A_s],'c')
            fill ([F_1+B fs/2 fs/2 F_1+B],[-A_p -A_p A_p A_p],'c')
         else
            fill ([0 F_0-B F_0-B 0],[1-delta_p 1-delta_p 1+delta_p 1+delta_p],'c')
            fill ([F_0 F_1 F_1 F_0],[0 0 delta_s delta_s],'c')
            fill ([F_1+B fs/2 fs/2 F_1+B],[1-delta_p 1-delta_p 1+delta_p 1+delta_p],'c')
         end
      end
      
   end
   plot (f,A,'Color',colors(2,:),'LineWidth',1.5)
   
% Add ideal magnitude response

   p = [f_type F_0 F_1 B];
   switch f_type
   case {0,1,2,3},
      A0 = f_firamp (f,fs,p);
      if dB
         A0 = 20*log10(max(abs(A0),1.e-4));
      else
         A0 = abs(A0);
      end
      hp(2) = plot (f,A0,'k');
   case 4,
      A0 = feval (user,f,fs);
      if dB
         A0 = 20*log10(max(abs(A0),1.e-4));
      else
         A0 = abs(A0);
      end
      hp(2) = plot (f,A0,'k');
   end

% Add legend

   legpos = [1 2 1 4 1];
   hl = legend (hp,'FIR filter','Ideal',legpos(f_type+1));
   set (hl,'FontName','FixedWidthFontName','FontSize',fsize)
   hold off
   
case 2,                                               % phase response  
   
   axes (han(6))
   axis on
   [H,f] = f_freqz (b,a,p,fs);
   phi = angle(H);
   plot (f,phi,'Color',colors(2,:))
   f_labels (caption,'f (Hz)','\phi','',fsize)
   
case 3,                                               % impulse response
   
   axes (han(7))
   axis on
   hold off 
   box off
   f_impulse (b,a,p,64,0,1,'Impulse response',fsize);
   axes (han(8))
   axis on
   f_pzplot (b,a,caption,fsize);
   
case 4,                                               % pole-zero plot
   
   axes (han(7))
   f_pzplot (b,a,caption,fsize);
   axes (han(8))
   axis on
   hold off 
   box off
   f_impulse (b,a,p,64,0,1,'Impulse response',fsize);
   
case 5,                                                 % window
   
   axes (han(6))
   axis on
   w = f_window(win,m);
   i = 0 : m;
   switch f_clip(win,0,3)
      case 0, title = sprintf('Rectangular window');
      case 1, title = sprintf('Hanning window');
      case 2, title = sprintf('Hamming window');
      case 3, title = sprintf('Blackman window');
   end
   if (dB == 1)
      w1 = real(20*log10(max(w,sqrt(eps))));
      plot (i,w1,'Color',colors(2,:))
      f_labels (title,'i','w(k) (dB)','',fsize)
   else
      plot (i,w,'Color',colors(2,:))
      f_labels (title,'i','w(k)','',fsize)
   end

end