gusucode.com > 语音信号处理工具箱 - Voicebox源码程序 > Voicebox\spgrambw.m
function [tt,f,b]=spgrambw(data,fs,bw) %SPGRAMBW Draw grey-scale spectrogram [T,F,B]=(DATA,FS,BW) % Copyright (C) Mike Brookes 1997 % % Last modified Mon Dec 21 09:00:01 1998 % % VOICEBOX is a MATLAB toolbox for speech processing. Home page is at % http://www.ee.ic.ac.uk/hp/staff/dmb/voicebox/voicebox.html % %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% % 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 2 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 can obtain a copy of the GNU General Public License from % ftp://prep.ai.mit.edu/pub/gnu/COPYING-2.0 or by writing to % Free Software Foundation, Inc.,675 Mass Ave, Cambridge, MA 02139, USA. %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% if nargin<1 error('Usage: SPGRAMBW(data,fs,bw)'); end if nargin<2 fs=11025; end if nargin<3 bw=200; end fftmin = 256; winlen = fix(2*fs/bw); fftlen = max([winlen fftmin]); win = [hamming(winlen) ; zeros(fftlen-winlen,1)]; win = win/sum(win); windel = (0:(length(win)-1)) * win; ntime = 200; overlap = fix(max(fftlen/2, (ntime*fftlen-length(data))/(ntime-1))); ntime=fix((length(data)-overlap)/(fftlen-overlap)); c1=(1:fftlen)'; r1=(0:ntime-1)*(fftlen-overlap); b=rfft(data(c1(:,ones(1,ntime))+r1(ones(fftlen,1),:)).*win(:,ones(1,ntime))); f=(0:fftlen/2)*fs/fftlen; b = b.*conj(b); t = (r1+windel)/fs; lim = max(b(:))*0.0001; b=10*log10(max(b,lim)); imh = imagesc(t,f/1000,b); axis('xy'); xlabel('Time (s)'); ylabel('Frequency (kHz)'); map = (0:63)'/63; colormap([map map map]); colorbar; if(nargout>0) tt=t; end