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/*****************************************************************************
* ITU-R P.525 Free Space Path Loss model for Signal Server by Alex Farrant *
* 15 January 2014 *
* optimised G6DTX April 2017 *
* This program is free software; you can redistribute it and/or modify it *
* under the terms of the GNU General Public License as published by the *
* Free Software Foundation; either version 2 of the License or any later *
* version. *
* *
* This program is distributed in the hope that it will useful, but WITHOUT *
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or *
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License *
* for more details. *
*
* https://www.itu.int/rec/R-REC-P.525/en
* Free Space Path Loss model
* Frequency: Any
* Distance: Any
*/
#include <math.h>
// use call with log/ln as this may be faster
// use constant of value 20.0/log(10.0)
static __inline float _20log10f(float x)
{
return(8.685889f*logf(x));
}
double FSPLpathLoss(float f, float d)
{
return(32.44 + _20log10f(f) + _20log10f(d));
}