--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/m-toolbox/classes/@specwin/kaiser_flatness.m	Wed Nov 23 19:22:13 2011 +0100
@@ -0,0 +1,26 @@
+function flatness = kaiser_flatness(alpha)
+
+% KAISER_FLATNESS returns the flatness in dB of the central bin of a kaiser 
+% window with parameter alpha.
+% 
+% Taken from C code of Gerhard Heinzel:
+% 
+%    Compute the flatness in the central bin [dB]
+%    of Kaiser windows from the parameter alpha.
+%    Best-fit polynomial was obtained from 180 data 
+%    points between alpha=1 and alpha=9.95.
+%    Maximum error is 0.013 dB.
+% 
+% M Hewitson 19-05-07
+% 
+% $Id: kaiser_flatness.m,v 1.2 2011/04/08 08:56:36 hewitson Exp $
+% 
+
+a0       = 0.141273;
+a1       = 0.262425;
+a2       = 0.00642551;
+a3       = -0.000405621;
+x        = alpha;
+flatness =  -1. / (((((a3 * x) + a2) * x) + a1) * x + a0);
+
+% END