examp_speech.m

Matlab时频分析工具箱,希望能对大家有所帮助啊

%EXAMP_SPEECH  Spectrogram of speech signal.
%
%   This example show how to work with almost real world data.
%
%   FIGURE 1 Linus
%
%    This show a spectrogram of Linus Thorvalds saying "My name is
%    Linus Thorvalds, and I pronounce Linux as Linux"
%
%    The 90% lowest values have been filtered away, to produce a
%    cleaner plot.
%

% This program is free software: you can redistribute it and/or modify
% it under the terms of the GNU General Public License as published by
% the Free Software Foundation, either version 3 of the License, or
% (at your option) any later version.
% 
% This program is distributed in the hope that it will be useful,
% but WITHOUT ANY WARRANTY; without even the implied warranty of
% MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
% GNU General Public License for more details.
% 
% You should have received a copy of the GNU General Public License
% along with this program.  If not, see <http://www.gnu.org/licenses/>.

disp('Type "help examp_speech" to see a description of how this example works.');

% Load the signal
f=linus;

% The parameters below are choosen such that the last part of the signal is
% cut of; this does not matter, it is zero anyway. 
L=40320;
a=224;
M=280;

b=L/M;

% Optimally centered window.
g=pgauss(L,a/b);

% Get some coefficients.
c=dgt(f,g,a,M,L);

% Since the signal is real, then the absolute value of the
% upper half of crect is a mirror image of the lower half. Therefore, we skip
% it. 
cplot=abs(c(1:floor(M/2)+1,:)).^2;

% Plot.
figure(1);

% Plotting is diffent in Matlab and Octave.
if isoctave
  title('Linus speaking.');
  imagesc(flipud(largestr(cplot,.1)));
else
  contour(log(largestr(cplot,.1)+realmin));
  title('Linus speaking.');
end;
% XXL: Wouldn't it be better to have 'real' time and frequency scales?
% use sgram here????

% We need to figure out what this example should do.
% XXL: For speech I was expecting sound output
%if ~isoctave % maybe only working for matlab?
%    if ispc
%        wavplay(f,8000) % SR= 8000 estimated
%    else % unix : does it work?
%       % there should not be other systems, no?
%        auwrite(f,8000,16,'/tmp/tmpsnd.au');
%        unix('cat /tmp/tmpsnd.au >/dev/audio'); 
%        % % also possible:
%        % wavwrite(SIG.sig/m,SIG.fs,'/tmp/tmp.wav');
%        % unix('play /tmp/tmp.wav');
%        % unix('rm -f /tmp/tmp.wav');   
%    end
%end