plot_formant.m

来自「这是一个用于语音信号处理的工具箱」· M 代码 · 共 89 行

% To plot the formants 
% Author: Albert Hsiao  2/97
%Changes by Karthik

% construct the formant polynomial
 
  rts=ff2root(Ff1(segment_no,:),Fb1(segment_no,:));
  pcofa=real( poly(rts) );

%     plot Z-plane zero-plot and digital filter frequency response.
%          zplane(B,A) is defined as the following filter
%                                      -1                -nb 
%             jw  B(z)   b(1) + b(2)z + .... + b(nb+1)z
%          H(e) = ---- = ----------------------------
%                                    -1                -na
%                 A(z)    1   + a(2)z + .... + a(na+1)z

A=pcofa;
B=1;

PV = [420 300 380 202];
s2 = 'Pole Zero Plot';
% Open analysis fig
while exist('formant_display_fig1')==1
   try1 = 'get(formant_display_fig1,''position'');';
   eval(try1,catch2);
   if check ==0
      clear formant_display_fig1;
      check = 1;
      break;
   else
      close(formant_display_fig1);
      clear formant_display_fig1;
   end
end

   
formant_display_fig1= figure('Position',PV,...
   'Resize','on',...
   'Numbertitle','off',...
   'Name',s2);

%figure(formant_display_fig1);
zplane([],A);
title(' ');
xlabel('Real');
ylabel('Imaginary');

% Z-transform digital filter frequency response
[h,f]=freqz(B,A,128);

PV = [420 51 377 203];
s22 = 'Frequency respose';
% Open analysis fig
while exist('formant_display_fig2')==1
   try1 = 'get(formant_display_fig2,''position'');';
   eval(try1,catch2);
   if check ==0
      clear formant_display_fig2;
      check = 1;
      break;
   end
   s12 = get(formant_display_fig2,'Name');
   if ~strcmp(s12,s22)
      clear formant_display_fig2;
      break;
   end
   figure(formant_display_fig2);
   break;
end;

if exist('formant_display_fig2')~=1;
   formant_display_fig2= figure('Position',PV,...
      'Resize','on',...
      'Numbertitle','off',...
      'Name',s22);
end
subplot(211);
plot(f/2/pi*Srate,20*log10(abs(h)),'color', LINE_COLOR);
grid on;
xlabel('Frequency');
ylabel('Magnitude(dB)')

subplot(212)
plot(f/2/pi*Srate,unwrap(angle(h))*180/pi,'color',LINE_COLOR);
grid on;
xlabel('Frequency')
ylabel('Phase')