gusucode.com > 语音信号处理工具箱 - Voicebox源码程序 > Voicebox\mel2frq.m
function frq = mel2frq(mel) %MEL2FRQ Convert Mel frequency scale to Hertz FRQ=(MEL) % frq = mel2frq(mel) converts a vector of Mel frequencies % to the corresponding real frequencies. % The Mel scale 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 14:57:18 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. %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% frq=700*(exp(mel/1127.01048)-1);