1 ## Copyright (C) 2006 Charalampos C. Tsimenidis
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} {@var{y} = } pskmod (@var{x}, @var{m})
18 ## @deftypefnx {Function File} {@var{y} = } pskmod (@var{x}, @var{m}, @var{phi})
19 ## @deftypefnx {Function File} {@var{y} = } pskmod (@var{x}, @var{m}, @var{phi}, @var{type})
21 ## Modulates an information sequence of integers @var{x} in the range
22 ## @code{[0 @dots{} M-1]} onto a complex baseband phase shift keying
23 ## modulated signal @var{y}. @var{phi} controls the initial phase and
24 ## @var{type} controls the constellation mapping. If @var{type} is set
25 ## to 'Bin' will result in binary encoding, in contrast, if set to 'Gray'
26 ## will give Gray encoding. An example of Gray-encoded QPSK is
30 ## d = randint(1,5e3,4);
31 ## y = pskmod(d,4,0,'Gray');
40 function y=pskmod(x,M,phi,type)
44 if ~isempty(find(ismember(x,m)==0))
45 error("x elements should be integers in the set [0, M-1].");
56 constellation=exp(1j*2*pi*m/M+1j*phi);
58 if (strcmp(type,"Bin")||strcmp(type,"bin"))
60 elseif (strcmp(type,"Gray")||strcmp(type,"gray"))
61 [a,b]=sort(bitxor(m,bitshift(m,-1)));
62 y=constellation(b(x+1));
64 usage("y = pskmod (x, M, [phi, [type]])");
68 %!assert (round(pskmod([0:3],4,0,'Bin')),[1 j -1 -j])
69 %!assert (round(pskmod([0:3],4,0,'Gray')),[1 j -j -1])