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sdrangel/sdrbase/dsp/fftwindow.cpp
2020-02-26 12:57:47 +01:00

121 lines
3.2 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 //
// (at your option) any later version. //
// //
// 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/>. //
///////////////////////////////////////////////////////////////////////////////////
#include "dsp/fftwindow.h"
FFTWindow::FFTWindow() :
m_kaiserAlpha(M_PI) // first sidelobe at < -70dB
{
m_kaiserI0Alpha = zeroethOrderBessel(m_kaiserAlpha);
}
void FFTWindow::setKaiserAlpha(Real alpha)
{
m_kaiserAlpha = alpha;
m_kaiserI0Alpha = zeroethOrderBessel(m_kaiserAlpha);
}
void FFTWindow::setKaiserBeta(Real beta)
{
m_kaiserAlpha = beta / M_PI;
m_kaiserI0Alpha = zeroethOrderBessel(m_kaiserAlpha);
}
void FFTWindow::create(Function function, int n)
{
Real (*wFunc)(Real n, Real i);
m_window.clear();
if (function == Kaiser) // Kaiser special case
{
for(int i = 0; i < n; i++) {
m_window.push_back(kaiser(n, i));
}
return;
}
switch(function) {
case Flattop:
wFunc = flatTop;
break;
case Bartlett:
wFunc = bartlett;
break;
case BlackmanHarris:
wFunc = blackmanHarris;
break;
case Hamming:
wFunc = hamming;
break;
case Hanning:
wFunc = hanning;
break;
case Rectangle:
default:
wFunc = rectangle;
break;
}
for(int i = 0; i < n; i++) {
m_window.push_back(wFunc(n, i));
}
}
void FFTWindow::apply(const std::vector<Real>& in, std::vector<Real>* out)
{
for(size_t i = 0; i < m_window.size(); i++) {
(*out)[i] = in[i] * m_window[i];
}
}
void FFTWindow::apply(const std::vector<Complex>& in, std::vector<Complex>* out)
{
for(size_t i = 0; i < m_window.size(); i++) {
(*out)[i] = in[i] * m_window[i];
}
}
void FFTWindow::apply(std::vector<Complex>& in)
{
for(size_t i = 0; i < m_window.size(); i++) {
in[i] *= m_window[i];
}
}
void FFTWindow::apply(const Complex* in, Complex* out)
{
for(size_t i = 0; i < m_window.size(); i++) {
out[i] = in[i] * m_window[i];
}
}
void FFTWindow::apply(Complex* in)
{
for(size_t i = 0; i < m_window.size(); i++) {
in[i] *= m_window[i];
}
}