# v_ditherq

## PURPOSE

V_DITHERQ add dither and quantize [Y,ZF]=(X,M,ZI)

## SYNOPSIS

function [y,zf]=v_ditherq(x,m,zi)

## DESCRIPTION

    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

## CROSS-REFERENCE INFORMATION

This function calls:

This function is called by:

- v_writewav V_WRITEWAV Creates .WAV format sound files FIDX=(D,FS,FILENAME,MODE,NSKIP,MASK,MAD)

## SOURCE CODE

    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 Lesser General Public License as published by
    0020 %   the Free Software Foundation; either version 3 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 Lesser General Public License for more details.
    0027 %
    0028 %   You can obtain a copy of the GNU Lesser General Public License from
    0029 %   https://www.gnu.org/licenses/ .
    0030 %
    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