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kaiser_alpha

PURPOSE ^

KAISER_ALPHA returns the alpha parameter that gives the required input

SYNOPSIS ^

function alpha = kaiser_alpha(req_psll)

DESCRIPTION ^

 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.html,v 1.14 2008/03/31 10:27:41 hewitson Exp $

CROSS-REFERENCE INFORMATION ^

This function calls: This function is called by:

SOURCE CODE ^

0001 function alpha = kaiser_alpha(req_psll)
0002 
0003 % KAISER_ALPHA returns the alpha parameter that gives the required input
0004 % PSLL.
0005 %
0006 % Taken from C code of Gerhard Heinzel:
0007 %
0008 %    Compute the parameter alpha of Kaiser windows
0009 %    from the required PSLL [dB]. Best-fit polynomial
0010 %    was obtained from 180 data points between alpha=1
0011 %    and alpha=9.95. Maximum error is 0.05
0012 %    Maximum error for PSLL > 30 dB is 0.02
0013 %
0014 % M Hewitson 19-05-07
0015 %
0016 % $Id: kaiser_alpha.html,v 1.14 2008/03/31 10:27:41 hewitson Exp $
0017 %
0018 
0019 
0020 a0 = -0.0821377;
0021 a1 = 4.71469;
0022 a2 = -0.493285;
0023 a3 = 0.0889732;
0024 
0025 x = req_psll / 100;
0026 alpha = (((((a3 * x) + a2) * x) + a1) * x + a0);
0027 
0028 
0029 % END

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