FRQ2MIDI Convert frequencies to musical note numbers [N,T]=(F) notes are numbered in semitones with middle C being 60 Note 69 (the A above middle C) has a frequency of 440 Hz. These note numbers are used by MIDI. Note numbers are not necessarily integers. t is a text representation of the note in which C4# denotes C sharp in octave 4. Octave 4 goes from middle C up to the B above middle C. For the white notes on the piano, the third character is a space. Negative frequencies are equivalent to positive frequencies except that flats will be used instead of sharps. Thus C4# would become D4- see MIDI2FRQ for the inverse transform

0001 function [n,t]=frq2midi(f) 0002 %FRQ2MIDI Convert frequencies to musical note numbers [N,T]=(F) 0003 % notes are numbered in semitones with middle C being 60 0004 % Note 69 (the A above middle C) has a frequency of 440 Hz. 0005 % These note numbers are used by MIDI. Note numbers are not necessarily 0006 % integers. 0007 % 0008 % t is a text representation of the note in which 0009 % C4# denotes C sharp in octave 4. Octave 4 goes 0010 % from middle C up to the B above middle C. For the white 0011 % notes on the piano, the third character is a space. 0012 % 0013 % Negative frequencies are equivalent to positive frequencies 0014 % except that flats will be used instead of sharps. Thus 0015 % C4# would become D4- 0016 % 0017 % see MIDI2FRQ for the inverse transform 0018 0019 0020 0021 0022 % Copyright (C) Mike Brookes 1998 0023 % Version: $Id: frq2midi.m 713 2011-10-16 14:45:43Z dmb $ 0024 % 0025 % VOICEBOX is a MATLAB toolbox for speech processing. 0026 % Home page: http://www.ee.ic.ac.uk/hp/staff/dmb/voicebox/voicebox.html 0027 % 0028 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 0029 % This program is free software; you can redistribute it and/or modify 0030 % it under the terms of the GNU General Public License as published by 0031 % the Free Software Foundation; either version 2 of the License, or 0032 % (at your option) any later version. 0033 % 0034 % This program is distributed in the hope that it will be useful, 0035 % but WITHOUT ANY WARRANTY; without even the implied warranty of 0036 % MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 0037 % GNU General Public License for more details. 0038 % 0039 % You can obtain a copy of the GNU General Public License from 0040 % http://www.gnu.org/copyleft/gpl.html or by writing to 0041 % Free Software Foundation, Inc.,675 Mass Ave, Cambridge, MA 02139, USA. 0042 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 0043 0044 n=(69+12*log(abs(f)/440)/log(2)); 0045 if nargout > 1 0046 m=round(n(:)); 0047 o=floor(m/12)-1; 0048 m=m-12*o+6*sign(f(:))-5; 0049 a=('CDDEEFGGAABBCCDDEFFGGAAB')'; 0050 b=(' - - - - - # # # # # ')'; 0051 t=setstr([a(m) mod(o,10)+'0' b(m)]); 0052 end

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