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kaiser_flatness

PURPOSE ^

KAISER_FLATNESS returns the flatness in dB of the central bin of a kaiser

SYNOPSIS ^

function flatness = kaiser_flatness(alpha)

DESCRIPTION ^

 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 1.1 2007/05/19 09:04:59 hewitson Exp $

CROSS-REFERENCE INFORMATION ^

This function calls: This function is called by:

SOURCE CODE ^

0001 function flatness = kaiser_flatness(alpha)
0002 
0003 % KAISER_FLATNESS returns the flatness in dB of the central bin of a kaiser
0004 % window with parameter alpha.
0005 %
0006 % Taken from C code of Gerhard Heinzel:
0007 %
0008 %    Compute the flatness in the central bin [dB]
0009 %    of Kaiser windows from the parameter alpha.
0010 %    Best-fit polynomial was obtained from 180 data
0011 %    points between alpha=1 and alpha=9.95.
0012 %    Maximum error is 0.013 dB.
0013 %
0014 % M Hewitson 19-05-07
0015 %
0016 % $Id: kaiser_flatness.m,v 1.1 2007/05/19 09:04:59 hewitson Exp $
0017 %
0018 
0019 a0       = 0.141273;
0020 a1       = 0.262425;
0021 a2       = 0.00642551;
0022 a3       = -0.000405621;
0023 x        = alpha;
0024 flatness =  -1. / (((((a3 * x) + a2) * x) + a1) * x + a0);
0025 
0026 % END

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