mirror of
https://github.com/f4exb/sdrangel.git
synced 2024-11-13 20:01:46 -05:00
79 lines
2.2 KiB
C
79 lines
2.2 KiB
C
// ----------------------------------------------------------------------------
|
|
// misc.h -- Miscellaneous helper functions
|
|
//
|
|
// Copyright (C) 2006-2008
|
|
// Dave Freese, W1HKJ
|
|
//
|
|
// This file is part of fldigi. These filters were adapted from code contained
|
|
// in the gmfsk source code distribution.
|
|
//
|
|
// Fldigi 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 3 of the License, or
|
|
// (at your option) any later version.
|
|
//
|
|
// Fldigi is distributed in the hope that it will be 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.
|
|
//
|
|
// You should have received a copy of the GNU General Public License
|
|
// along with fldigi. If not, see <http://www.gnu.org/licenses/>.
|
|
// ----------------------------------------------------------------------------
|
|
|
|
#ifndef _MISC_H
|
|
#define _MISC_H
|
|
|
|
#include <math.h>
|
|
|
|
#undef M_PI
|
|
#define M_PI 3.14159265358979323846
|
|
|
|
inline float sinc(float x)
|
|
{
|
|
return (fabs(x) < 1e-10) ? 1.0 : (sin(M_PI * x) / (M_PI * x));
|
|
}
|
|
|
|
inline float cosc(float x)
|
|
{
|
|
return (fabs(x) < 1e-10) ? 0.0 : ((1.0 - cos(M_PI * x)) / (M_PI * x));
|
|
}
|
|
|
|
inline float clamp(float x, float min, float max)
|
|
{
|
|
return (x < min) ? min : ((x > max) ? max : x);
|
|
}
|
|
|
|
/// This is always called with an int weight
|
|
inline float decayavg(float average, float input, int weight)
|
|
{
|
|
if (weight <= 1) return input;
|
|
return ( ( input - average ) / (float)weight ) + average ;
|
|
}
|
|
|
|
// following are defined inline to provide best performance
|
|
inline float blackman(float x)
|
|
{
|
|
return (0.42 - 0.50 * cos(2 * M_PI * x) + 0.08 * cos(4 * M_PI * x));
|
|
}
|
|
|
|
inline float hamming(float x)
|
|
{
|
|
return 0.54 - 0.46 * cos(2 * M_PI * x);
|
|
}
|
|
|
|
inline float hanning(float x)
|
|
{
|
|
return 0.5 - 0.5 * cos(2 * M_PI * x);
|
|
}
|
|
|
|
inline float rcos( float t, float T, float alpha=1.0 )
|
|
{
|
|
if( t == 0 ) return 1.0;
|
|
float taT = T / (2.0 * alpha);
|
|
if( fabs(t) == taT ) return ((alpha/2.0) * sin(M_PI/(2.0*alpha)));
|
|
return (sin(M_PI*t/T)/(M_PI*t/T))*cos(alpha*M_PI*t/T)/(1.0-(t/taT)*(t/taT));
|
|
}
|
|
|
|
#endif
|