[d6dad2]: inst / qamdemod.m Maximize Restore History

Download this file

qamdemod.m    43 lines (36 with data), 1.4 kB

 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
## Copyright (C) 2007 Sylvain Pelissier <sylvain.pelissier@gmail.com>
## Copyright (C) 2009 Christian Neumair <cneumair@gnome.org>
##
## 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} {} qamdemod (@var{x}, @var{m})
## Create the QAM demodulation of x with a size of alphabet m.
## @seealso{qammod, pskmod, pskdemod}
## @end deftypefn
function z = qamdemod (y, m)
if (nargin < 2)
print_usage ();
endif
c = sqrt (m);
if (c ~= fix (c) || log2 (c) ~= fix (log2 (c)))
error ("m must be a square of a power of 2");
endif
x = qammod (0:(m-1), m);
x = reshape (x, 1, m);
z = zeros (size (y));
for k = 1:numel (y)
[n z(k)] = min (abs (y(k) - x));
endfor
z = z - 1;
endfunction