Add a useful package (from Source forge) for octave

[CreaPhase.git] / octave_packages / signal-1.1.3 / sampled2continuous.m

diff --git a/octave_packages/signal-1.1.3/sampled2continuous.m b/octave_packages/signal-1.1.3/sampled2continuous.m
new file mode 100644 (file)
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+++ b/octave_packages/signal-1.1.3/sampled2continuous.m
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+## Copyright (C) 2009 Muthiah Annamalai <muthiah.annamalai@uta.edu>
+##
+## 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/>.
+
+## Usage:
+## 
+## xt = sampled2continuous( xn , T, t )
+## 
+## Calculate the x(t) reconstructed
+## from samples x[n] sampled at a rate 1/T samples
+## per unit time.
+## 
+## t is all the instants of time when you need x(t) 
+## from x[n]; this time is relative to x[0] and not
+## an absolute time.
+## 
+## This function can be used to calculate sampling rate
+## effects on aliasing, actual signal reconstruction
+## from discrete samples.
+
+function xt = sampled2continuous( xn , T, t )
+  if ( nargin < 3 )
+    print_usage()
+  endif
+  
+  N = length( xn );
+  xn = reshape( xn, N, 1 );
+  [TT,tt]= meshgrid(T*(0:N-1)',t);
+  S = sinc((tt -TT)./T);
+  xt = S*xn;
+  return
+end