V_PCMU2LIN Convert Mu-law PCM to linear X=(P,S)
lin = v_pcmu2lin(pcmu) where pcmu contains a vector
of mu-law values in the range 0 to 255.
No checking is performed to see that numbers are in this range.
Output values are divided by the scale factor s:
s Output Range
1 +-8031 (integer values)
4004.2 +-2.005649 (default)
8031 +-1
8159 +-0.9843118 (+-1 nominal full scale)
The default scaling factor 4004.189931 is equal to
sqrt((2207^2 + 5215^2)/2) this follows ITU standard G.711.
The sine wave with PCM-Mu values [158 139 139 158 30 11 11 30]
has a mean square value of unity corresponding to 0 dBm0.0001 function x=v_pcmu2lin(p,s) 0002 %V_PCMU2LIN Convert Mu-law PCM to linear X=(P,S) 0003 % lin = v_pcmu2lin(pcmu) where pcmu contains a vector 0004 % of mu-law values in the range 0 to 255. 0005 % No checking is performed to see that numbers are in this range. 0006 % 0007 % Output values are divided by the scale factor s: 0008 % 0009 % s Output Range 0010 % 0011 % 1 +-8031 (integer values) 0012 % 4004.2 +-2.005649 (default) 0013 % 8031 +-1 0014 % 8159 +-0.9843118 (+-1 nominal full scale) 0015 % 0016 % The default scaling factor 4004.189931 is equal to 0017 % sqrt((2207^2 + 5215^2)/2) this follows ITU standard G.711. 0018 % The sine wave with PCM-Mu values [158 139 139 158 30 11 11 30] 0019 % has a mean square value of unity corresponding to 0 dBm0. 0020 0021 0022 0023 % Copyright (C) Mike Brookes 1998 0024 % Version: $Id: v_pcmu2lin.m 10865 2018-09-21 17:22:45Z dmb $ 0025 % 0026 % VOICEBOX is a MATLAB toolbox for speech processing. 0027 % Home page: http://www.ee.ic.ac.uk/hp/staff/dmb/voicebox/voicebox.html 0028 % 0029 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 0030 % This program is free software; you can redistribute it and/or modify 0031 % it under the terms of the GNU General Public License as published by 0032 % the Free Software Foundation; either version 2 of the License, or 0033 % (at your option) any later version. 0034 % 0035 % This program is distributed in the hope that it will be useful, 0036 % but WITHOUT ANY WARRANTY; without even the implied warranty of 0037 % MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 0038 % GNU General Public License for more details. 0039 % 0040 % You can obtain a copy of the GNU General Public License from 0041 % http://www.gnu.org/copyleft/gpl.html or by writing to 0042 % Free Software Foundation, Inc.,675 Mass Ave, Cambridge, MA 02139, USA. 0043 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 0044 0045 if nargin<2 0046 t=9.98953613E-4; 0047 else 0048 t=4/s; 0049 end 0050 0051 m=15-rem(p,16); 0052 q=floor(p/128); 0053 e=(127-p-m+128*q)/16; 0054 x=(q-0.5).*(pow2(m+16.5,e)-16.5)*t;