mirror of https://github.com/f4exb/sdrangel.git
129 lines
3.9 KiB
C++
129 lines
3.9 KiB
C++
///////////////////////////////////////////////////////////////////////////////////
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// Copyright (C) 2018-2020 Edouard Griffiths, F4EXB <f4exb06@gmail.com> //
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// //
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// FFT based cross correlation. Uses FFTW/Kiss engine. //
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// //
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// This program is free software; you can redistribute it and/or modify //
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// it under the terms of the GNU General Public License as published by //
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// the Free Software Foundation as version 3 of the License, or //
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// (at your option) any later version. //
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// //
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// This program is distributed in the hope that it will be useful, //
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// but WITHOUT ANY WARRANTY; without even the implied warranty of //
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the //
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// GNU General Public License V3 for more details. //
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// //
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// You should have received a copy of the GNU General Public License //
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// along with this program. If not, see <http://www.gnu.org/licenses/>. //
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///////////////////////////////////////////////////////////////////////////////////
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#include <algorithm>
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#include "dsp/dspengine.h"
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#include "dsp/fftfactory.h"
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#include "dsp/fftengine.h"
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#include "fftcorr.h"
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void fftcorr::init_fft()
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{
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FFTFactory *fftFactory = DSPEngine::instance()->getFFTFactory();
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fftASequence = fftFactory->getEngine(flen, false, &fftA);
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fftBSequence = fftFactory->getEngine(flen, false, &fftB);
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fftInvASequence = fftFactory->getEngine(flen, true, &fftInvA);
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m_window.create(FFTWindow::Hanning, flen);
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dataA = new cmplx[flen];
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dataB = new cmplx[flen];
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dataBj = new cmplx[flen];
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dataP = new cmplx[flen];
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std::fill(dataA, dataA+flen, 0);
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std::fill(dataB, dataB+flen, 0);
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inptrA = 0;
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inptrB = 0;
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outptr = 0;
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}
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fftcorr::fftcorr(int len) :
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flen(len),
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flen2(len>>1),
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fftA(nullptr),
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fftB(nullptr),
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fftInvA(nullptr),
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fftASequence(0),
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fftBSequence(0),
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fftInvASequence(0)
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{
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init_fft();
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}
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fftcorr::~fftcorr()
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{
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FFTFactory *fftFactory = DSPEngine::instance()->getFFTFactory();
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fftFactory->releaseEngine(flen, false, fftASequence);
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fftFactory->releaseEngine(flen, false, fftBSequence);
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fftFactory->releaseEngine(flen, true, fftInvASequence);
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delete[] dataA;
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delete[] dataB;
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delete[] dataBj;
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delete[] dataP;
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}
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int fftcorr::run(const cmplx& inA, const cmplx* inB, cmplx **out)
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{
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dataA[inptrA++] = inA;
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if (inB) {
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dataB[inptrB++] = *inB;
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}
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if (inptrA < flen2) {
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return 0;
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}
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m_window.apply(dataA, fftA->in());
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fftA->transform();
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if (inB)
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{
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m_window.apply(dataB, fftB->in());
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fftB->transform();
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}
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if (inB) {
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std::transform(fftB->out(), fftB->out()+flen, dataBj, [](const cmplx& c) -> cmplx { return std::conj(c); });
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} else {
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std::transform(fftA->out(), fftA->out()+flen, dataBj, [](const cmplx& c) -> cmplx { return std::conj(c); });
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}
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std::transform(fftA->out(), fftA->out()+flen, dataBj, fftInvA->in(), [](const cmplx& a, const cmplx& b) -> cmplx { return a*b; });
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fftInvA->transform();
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std::copy(fftInvA->out(), fftInvA->out()+flen, dataP);
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std::fill(dataA, dataA+flen, 0);
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inptrA = 0;
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if (inB)
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{
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std::fill(dataB, dataB+flen, 0);
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inptrB = 0;
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}
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*out = dataP;
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return flen2;
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}
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const fftcorr::cmplx& fftcorr::run(const cmplx& inA, const cmplx* inB)
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{
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cmplx *dummy;
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if (run(inA, inB, &dummy)) {
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outptr = 0;
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}
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return dataP[outptr++];
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}
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