--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/m-toolbox/classes/@specwin/kaiser_alpha.m	Wed Nov 23 19:22:13 2011 +0100
@@ -0,0 +1,29 @@
+function alpha = kaiser_alpha(req_psll)
+
+% KAISER_ALPHA returns the alpha parameter that gives the required input
+% PSLL.
+% 
+% Taken from C code of Gerhard Heinzel:
+% 
+%    Compute the parameter alpha of Kaiser windows
+%    from the required PSLL [dB]. Best-fit polynomial
+%    was obtained from 180 data points between alpha=1
+%    and alpha=9.95. Maximum error is 0.05 
+%    Maximum error for PSLL > 30 dB is 0.02
+% 
+% M Hewitson 19-05-07
+% 
+% $Id: kaiser_alpha.m,v 1.2 2011/04/08 08:56:36 hewitson Exp $
+% 
+
+
+a0 = -0.0821377;
+a1 = 4.71469;
+a2 = -0.493285;
+a3 = 0.0889732;
+
+x = req_psll / 100;
+alpha = (((((a3 * x) + a2) * x) + a1) * x + a0);
+
+
+% END