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−function alpha = kaiser_alpha(req_psll)
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−
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−% KAISER_ALPHA returns the alpha parameter that gives the required input
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−% PSLL.
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−% 
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−% Taken from C code of Gerhard Heinzel:
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−% 
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−%    Compute the parameter alpha of Kaiser windows
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−%    from the required PSLL [dB]. Best-fit polynomial
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−%    was obtained from 180 data points between alpha=1
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−%    and alpha=9.95. Maximum error is 0.05 
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−%    Maximum error for PSLL > 30 dB is 0.02
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−% 
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−% M Hewitson 19-05-07
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−% 
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−% $Id: kaiser_alpha.m,v 1.2 2011/04/08 08:56:36 hewitson Exp $
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−% 
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−
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−
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−a0 = -0.0821377;
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−a1 = 4.71469;
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−a2 = -0.493285;
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−a3 = 0.0889732;
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−
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−x = req_psll / 100;
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−alpha = (((((a3 * x) + a2) * x) + a1) * x + a0);
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−
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−
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−% END