V_DITHERQ add dither and quantize [Y,ZF]=(X,M,ZI) Inputs: x is the input signal m specifies the mode: 'w' white dither (default) 'h' high-pass dither (filtered by 1 - z^-1) 'l' low pass filter (filtered by 1 + z^-1) 'n' no dither
0001 function [y,zf]=v_ditherq(x,m,zi) 0002 %V_DITHERQ add dither and quantize [Y,ZF]=(X,M,ZI) 0003 % Inputs: 0004 % x is the input signal 0005 % m specifies the mode: 0006 % 'w' white dither (default) 0007 % 'h' high-pass dither (filtered by 1 - z^-1) 0008 % 'l' low pass filter (filtered by 1 + z^-1) 0009 % 'n' no dither 0010 0011 % Copyright (C) Mike Brookes 1997 0012 % Version: $Id: v_ditherq.m 10865 2018-09-21 17:22:45Z dmb $ 0013 % 0014 % VOICEBOX is a MATLAB toolbox for speech processing. 0015 % Home page: http://www.ee.ic.ac.uk/hp/staff/dmb/voicebox/voicebox.html 0016 % 0017 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 0018 % This program is free software; you can redistribute it and/or modify 0019 % it under the terms of the GNU General Public License as published by 0020 % the Free Software Foundation; either version 2 of the License, or 0021 % (at your option) any later version. 0022 % 0023 % This program is distributed in the hope that it will be useful, 0024 % but WITHOUT ANY WARRANTY; without even the implied warranty of 0025 % MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 0026 % GNU General Public License for more details. 0027 % 0028 % You can obtain a copy of the GNU General Public License from 0029 % http://www.gnu.org/copyleft/gpl.html or by writing to 0030 % Free Software Foundation, Inc.,675 Mass Ave, Cambridge, MA 02139, USA. 0031 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 0032 0033 s=size(x); 0034 n=length(x); 0035 if nargin<3 | ~length(zi) 0036 zi=rand(1); 0037 end 0038 if nargin<2 0039 m='w'; 0040 end 0041 if any(m=='n') 0042 y=round(x); 0043 elseif any(m=='h') | any(m=='l') 0044 v=rand(n+1,1); 0045 v(1)=zi; 0046 zf=v(end); 0047 if any(m=='h') 0048 y=round(x(:)+v(2:end)-v(1:end-1)); 0049 else 0050 y=round(x(:)+v(2:end)+v(1:end-1)-1); 0051 end 0052 else 0053 y=round(x(:)+rand(n,2)*[1;-1]); 0054 zf=rand(1); % output a random number anyway 0055 end 0056 if s(1)==1 0057 y=y.'; 0058 end