1 ## Copyright (C) 2007 Sylvain Pelissier <sylvain.pelissier@gmail.com>
3 ## This program is free software; you can redistribute it and/or modify it under
4 ## the terms of the GNU General Public License as published by the Free Software
5 ## Foundation; either version 3 of the License, or (at your option) any later
8 ## This program is distributed in the hope that it will be useful, but WITHOUT
9 ## ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
10 ## FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
13 ## You should have received a copy of the GNU General Public License along with
14 ## this program; if not, see <http://www.gnu.org/licenses/>.
17 ## @deftypefn {Function File} qammod (@var{x},@var{m})
18 ## Create the QAM modulation of x with a size of alphabet m.
19 ## @seealso{qamdemod,pskmod,pskdemod}
22 function y = qammod(x,m)
24 usage('y = qammod(x,m)');
28 error('values of x must be in range [0,M-1]');
33 error('values of x must be integer');
37 if(c ~= fix(c) || log2(c) ~= fix(log2(c)))
38 error('m must be a square of a power of 2');
41 b = -2.*mod(x,(c))+c-1;
42 a = 2.*floor(x./(c))-c+1;