[Octave-cvsupdate] SF.net SVN: octave:[10889] trunk/octave-forge/main/signal/inst/firls.m

[<jo...@us...>]

Revision: 10889
          http://octave.svn.sourceforge.net/octave/?rev=10889&view=rev
Author:   jordigh
Date:     2012-08-20 17:10:59 +0000 (Mon, 20 Aug 2012)
Log Message:
-----------
firls.m: ensure N is even

Modified Paths:
--------------
    trunk/octave-forge/main/signal/inst/firls.m

Modified: trunk/octave-forge/main/signal/inst/firls.m
===================================================================
--- trunk/octave-forge/main/signal/inst/firls.m	2012-08-20 17:05:50 UTC (rev 10888)
+++ trunk/octave-forge/main/signal/inst/firls.m	2012-08-20 17:10:59 UTC (rev 10889)
@@ -13,12 +13,12 @@
 ## You should have received a copy of the GNU General Public License along with
 ## this program; if not, see <http://www.gnu.org/licenses/>.
 
-## b = firls(N, F, A);
-## b = firls(N, F, A, W);
+## b = firls(N, F, A); b = firls(N, F, A, W);
 ##
 ##  FIR filter design using least squares method. Returns a length N+1
 ##  linear phase filter such that the integral of the weighted mean
-##  squared error in the specified bands is minimized.
+##  squared error in the specified bands is minimized. N must be an even
+##  integer or
 ##
 ##  F specifies the frequencies of the band edges, normalized so that
 ##  half the sample frequency is equal to 1.  Each band is specified by
@@ -28,7 +28,8 @@
 ##
 ##  W is an optional weighting function that contains one value for each
 ##  band that weights the mean squared error in that band. A must be the
-##  same length as F, and W must be half the length of F.
+##  same length as F, and W must be half the length of F. N must be
+##  even. If you specify an odd value, firls increments it by 1.
 ##
 ## The least squares optimization algorithm for computing FIR filter
 ## coefficients is derived in detail in:
@@ -59,6 +60,8 @@
     error("This feature is implemented yet");
   else
 
+    N += mod (N, 2);
+
     M = N/2;
     w = kron (weight(:), [-1; 1]);
     omega = frequencies * pi;

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