mirror of
https://github.com/f4exb/sdrangel.git
synced 2024-11-24 00:48:41 -05:00
83 lines
2.9 KiB
C
83 lines
2.9 KiB
C
|
///////////////////////////////////////////////////////////////////////////////////
|
||
|
|
// Copyright (C) 2012 maintech GmbH, Otto-Hahn-Str. 15, 97204 Hoechberg, Germany //
|
||
|
|
// written by Christian Daniel //
|
||
|
|
// //
|
||
|
|
// 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 as version 3 of the License, or //
|
||
|
|
// //
|
||
|
|
// This program 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 V3 for more details. //
|
||
|
|
// //
|
||
|
|
// You should have received a copy of the GNU General Public License //
|
||
|
|
// along with this program. If not, see <http://www.gnu.org/licenses/>. //
|
||
|
|
///////////////////////////////////////////////////////////////////////////////////
|
||
|
|
|
||
|
|
#ifndef INCLUDE_FFTWINDOW_H
|
||
|
|
#define INCLUDE_FFTWINDOW_H
|
||
|
|
|
||
|
|
#include <vector>
|
||
|
|
#define _USE_MATH_DEFINES
|
||
|
|
#include <math.h>
|
||
|
|
#include "dsp/dsptypes.h"
|
||
|
|
#include "util/export.h"
|
||
|
|
|
||
|
|
class SDRANGELOVE_API FFTWindow {
|
||
|
|
public:
|
||
|
|
enum Function {
|
||
|
|
Bartlett,
|
||
|
|
BlackmanHarris,
|
||
|
|
Flattop,
|
||
|
|
Hamming,
|
||
|
|
Hanning,
|
||
|
|
Rectangle
|
||
|
|
};
|
||
|
|
|
||
|
|
void create(Function function, int n);
|
||
|
|
void apply(const std::vector<Real>& in, std::vector<Real>* out);
|
||
|
|
void apply(const std::vector<Complex>& in, std::vector<Complex>* out);
|
||
|
|
void apply(const Complex* in, Complex* out);
|
||
|
|
|
||
|
|
private:
|
||
|
|
std::vector<float> m_window;
|
||
|
|
|
||
|
|
static inline Real flatTop(Real n, Real i)
|
||
|
|
{
|
||
|
|
// correction ?
|
||
|
|
return 1.0 - 1.93 * cos((2.0 * M_PI * i) / n) + 1.29 * cos((4.0 * M_PI * i) / n) - 0.388 * cos((6.0 * M_PI * i) / n) + 0.03222 * cos((8.0 * M_PI * i) / n);
|
||
|
|
}
|
||
|
|
|
||
|
|
static inline Real bartlett(Real n, Real i)
|
||
|
|
{
|
||
|
|
// amplitude correction = 2.0
|
||
|
|
return (2.0 / (n - 1.0)) * ( (n - 1.0) / 2.0 - fabs(i - (n - 1.0) / 2.0)) * 2.0;
|
||
|
|
}
|
||
|
|
|
||
|
|
static inline Real blackmanHarris(Real n, Real i)
|
||
|
|
{
|
||
|
|
// amplitude correction = 2.79
|
||
|
|
return (0.35875 - 0.48829 * cos((2.0 * M_PI * i) / n) + 0.14128 * cos((4.0 * M_PI * i) / n) - 0.01168 * cos((6.0 * M_PI * i) / n)) * 2.79;
|
||
|
|
}
|
||
|
|
|
||
|
|
static inline Real hamming(Real n, Real i)
|
||
|
|
{
|
||
|
|
// amplitude correction = 1.855, energy correction = 1.586
|
||
|
|
return (0.54 - 0.46 * cos((2.0 * M_PI * i) / n)) * 1.855;
|
||
|
|
}
|
||
|
|
|
||
|
|
static inline Real hanning(Real n, Real i)
|
||
|
|
{
|
||
|
|
// amplitude correction = 2.0, energy correction = 1.633
|
||
|
|
return (0.5 - 0.5 * cos((2.0 * M_PI * i) / n)) * 2.0;
|
||
|
|
}
|
||
|
|
|
||
|
|
static inline Real rectangle(Real, Real)
|
||
|
|
{
|
||
|
|
return 1.0;
|
||
|
|
}
|
||
|
|
};
|
||
|
|
|
||
|
|
#endif // INCLUDE_FFTWINDOWS_H
|