[Octave-cvsupdate] SF.net SVN: octave:[10205] trunk/octave-forge/main/comm

[<car...@us...>]

Revision: 10205
          http://octave.svn.sourceforge.net/octave/?rev=10205&view=rev
Author:   carandraug
Date:     2012-04-13 09:08:01 +0000 (Fri, 13 Apr 2012)
Log Message:
-----------
convenc: new function for comm package by Anthony Richardson <ar...@ev...> on octave-forge mailing list

Modified Paths:
--------------
    trunk/octave-forge/main/comm/NEWS

Added Paths:
-----------
    trunk/octave-forge/main/comm/inst/convenc.m

Modified: trunk/octave-forge/main/comm/NEWS
===================================================================
--- trunk/octave-forge/main/comm/NEWS	2012-04-12 21:22:47 UTC (rev 10204)
+++ trunk/octave-forge/main/comm/NEWS	2012-04-13 09:08:01 UTC (rev 10205)
@@ -1,6 +1,10 @@
 Summary of important user-visible changes for communications 1.1.1:
 -------------------------------------------------------------------
 
+ ** The following functions are new:
+
+      convenc
+
  ** The function `reedmullerdec' had a bug fix introduced on the
     previous release
 
@@ -10,4 +14,3 @@
  ** Use of deprecated functions has been removed
 
  ** Package is no longer automatically loaded.
-

Added: trunk/octave-forge/main/comm/inst/convenc.m
===================================================================
--- trunk/octave-forge/main/comm/inst/convenc.m	                        (rev 0)
+++ trunk/octave-forge/main/comm/inst/convenc.m	2012-04-13 09:08:01 UTC (rev 10205)
@@ -0,0 +1,50 @@
+## Copyright (C) 2012 Tony Richardson <richardson.tony@gmailcom>
+##
+## 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/>.
+
+% -- Function File: convenv(m, G, k)
+%    Compute the output of an (n, k, L) convolutional encoder with vector input
+%    m and matrix of generator polynomials G.
+%
+%   The input vector m can be of arbitrary length.   G is a matrix with n rows
+%   and k*(L+1) columns.  The rows of G are the generator polynomials for each
+%   of the n output bits (per k input bits).
+%
+%   The output is a vector whose length is n*floor([length(m)+k*(L+1)-1]/k).
+%   With two inputs, k is assumed to be equal to 1.
+%
+%   Example 1: Compute the output from a (2, 1, 2)  convolutional encoder
+%   with generator polynomials g1 = [ 1 1 1 ] and g2 = [ 1 0 1 ]
+%   when the input message is m = [ 1 1 0 1 1 1 0 0 1 0 0 0 ]
+%
+%   x = convenc(m, [g1; g2])
+%   x = 1101010001100111111011000000
+%
+%   Example 2: Compute the output from a (3, 2, 1) conv encoder with
+%   generator polynomials g1 = [ 1 0 1 1 ], g2 = [ 1 1 0 1 ] and
+%   g3 = [ 1 0 1 0 ] when the input is m = [ 0   1   1   0   0   0   1   1 ]
+%
+%   x = convenc(m, [g1; g2; g3], 2)
+%   x = 111 111 110 101
+%
+%   Note: This function is not compatible with Matlab's convenc()
+
+function x = convenc(m, G, k=1)
+	% Use conv2 to do repeated 1d convolutions of m with each row of G. 
+	% rem is used to transform the standard convolution result to one
+	% which uses modulo-2 addition.  Only cols with index a mult. of k 
+	% are in the actual enc. output
+
+	x = rem(conv2(1, m(:)', G),2)(:,!rem(1:numel(m),k))(:)';
+end

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