www.pudn.com > voicebox2.zip > FRQ2MEL.M

function mel = frq2mel(frq) 
%FRQ2ERB  Convert Hertz to Mel frequency scale MEL=(FRQ) 
%	mel = frq2mel(frq) converts a vector of frequencies (in Hz) 
%	to the corresponding values on the Mel scale which corresponds 
%	to the perceived pitch of a tone 
 
%	The relationship between mel and frq is given by: 
% 
%	m = ln(1 + f/700) * 1000 / ln(1+1000/700) 
% 
%  	This means that m(1000) = 1000 
% 
%	References: 
% 
%	  [1] S. S. Stevens & J. Volkman "The relation of pitch to 
%		frequency", American J of Psychology, V 53, p329 1940 
%	  [2] C. G. M. Fant, "Acoustic description & classification 
%		of phonetic units", Ericsson Tchnics, No 1 1959 
%		(reprinted in "Speech Sounds & Features", MIT Press 1973) 
%	  [3] S. B. Davis & P. Mermelstein, "Comparison of parametric 
%		representations for monosyllabic word recognition in 
%		continuously spoken sentences", IEEE ASSP, V 28, 
%		pp 357-366 Aug 1980 
%	  [4] J. R. Deller Jr, J. G. Proakis, J. H. L. Hansen, 
%		"Discrete-Time Processing of Speech Signals", p380, 
%		Macmillan 1993 
%	  [5] HTK Reference Manual p73 
%	 
 
 
 
%      Copyright (C) Mike Brookes 1998 
% 
%      Last modified Fri Apr  3 14:57:14 1998 
% 
%   VOICEBOX home page: 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. 
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 
 
mel = log(1+frq/700)*1127.01048;