/usr/share/octave/packages/communications-1.2.1/dpcmdeco.m is in octave-communications-common 1.2.1-2.
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 | ## Copyright (C) 2012 Leonardo Araujo <leolca@gmail.com>
##
## 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 3 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 should have received a copy of the GNU General Public License along with
## this program; if not, see <http://www.gnu.org/licenses/>.
## -*- texinfo -*-
## @deftypefn {Function File} {@var{sig} =} dpcmdeco (@var{indx}, @var{codebook}, @var{predictor})
## Decode using differential pulse code modulation (DPCM).
##
## @table @code
## @item sig = dpcmdeco (indx, codebook, predictor)
## Decode the signal coded by DPCM.
## Use the prediction model and the coded prediction error given by a codebook and
## the index of each sample in this codebook.
##
## @end table
## @seealso{dpcmenco, dpcmopt}
## @end deftypefn
function sig = dpcmdeco (indx, codebook, predictor)
if (nargin != 3)
print_usage ();
endif
quants = codebook(indx+1);
sig = zeros (size (quants));
for i = 1 : length (sig)
## signal prediction (convolution of signal and predictor coefficients) + quantization error
sig(i) = sig(max (i - length (predictor) + 1, 1):i) * predictor(end:-1:max (end-i+1, 1))' + quants(i);
endfor
endfunction
%% Test input validation
%!error dpcmdeco ()
%!error dpcmdeco (1)
%!error dpcmdeco (1, 2)
%!error dpcmdeco (1, 2, 3, 4)
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