kopia lustrzana https://github.com/f4exb/sdrangel
Added a FFT based correlation class
f4exb
rodzic
48cac5385b
commit
d673278f86
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@ -28,6 +28,7 @@ set(sdrbase_SOURCES
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dsp/dspengine.cpp
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dsp/dspdevicesourceengine.cpp
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dsp/dspdevicesinkengine.cpp
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dsp/fftcorr.cpp
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dsp/fftengine.cpp
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dsp/fftfilt.cxx
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dsp/fftwindow.cpp
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@ -118,6 +119,7 @@ set(sdrbase_HEADERS
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dsp/dspdevicesourceengine.h
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dsp/dspdevicesinkengine.h
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dsp/dsptypes.h
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dsp/fftcorr.h
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dsp/fftengine.h
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dsp/fftfilt.h
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dsp/fftwengine.h
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@ -0,0 +1,112 @@
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///////////////////////////////////////////////////////////////////////////////////
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// Copyright (C) 2018 F4EXB //
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// written by Edouard Griffiths //
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// //
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// FFT based cross correlation //
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// //
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// See: http://liquidsdr.org/blog/pll-howto/ //
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// Fixed filter registers saturation //
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// Added order for PSK locking. This brilliant idea actually comes from this //
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// post: https://www.dsprelated.com/showthread/comp.dsp/36356-1.php //
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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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// //
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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 "fftcorr.h"
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void fftcorr::init_fft()
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{
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flen2 = flen >> 1;
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fftA = new g_fft<float>(flen);
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fftB = new g_fft<float>(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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output = new cmplx[flen2];
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ovlbuf = new cmplx[flen2];
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std::fill(dataA, dataA+flen, 0);
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std::fill(dataB, dataB+flen, 0);
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std::fill(output, output+flen2, 0);
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std::fill(ovlbuf, ovlbuf+flen2, 0);
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inptrA = 0;
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inptrB = 0;
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}
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fftcorr::fftcorr(int len) : flen(len), flen2(len>>1)
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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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delete fftA;
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delete fftB;
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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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delete[] output;
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delete[] ovlbuf;
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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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fftA->ComplexFFT(dataA);
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if (inB) {
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fftB->ComplexFFT(dataB);
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}
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if (inB) {
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std::transform(dataB, dataB+flen, dataBj, [](const cmplx& c) -> cmplx { return std::conj(c); });
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} else {
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std::transform(dataA, dataA+flen, dataBj, [](const cmplx& c) -> cmplx { return std::conj(c); });
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}
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std::transform(dataA, dataA+flen, dataBj, dataP, [](const cmplx& a, const cmplx& b) -> cmplx { return a*b; });
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fftA->InverseComplexFFT(dataP);
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for (int i = 0; i < flen2; i++)
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{
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output[i] = ovlbuf[i] + dataP[i];
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ovlbuf[i] = dataP[flen2 + i];
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}
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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 = output;
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return flen2;
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}
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@ -0,0 +1,57 @@
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///////////////////////////////////////////////////////////////////////////////////
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// Copyright (C) 2018 F4EXB //
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// written by Edouard Griffiths //
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// //
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// FFT based cross correlation //
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// //
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// See: http://liquidsdr.org/blog/pll-howto/ //
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// Fixed filter registers saturation //
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// Added order for PSK locking. This brilliant idea actually comes from this //
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// post: https://www.dsprelated.com/showthread/comp.dsp/36356-1.php //
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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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// //
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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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#ifndef SDRBASE_DSP_FFTCORR_H_
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#define SDRBASE_DSP_FFTCORR_H_
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#include <complex>
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#include "gfft.h"
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#include "export.h"
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class SDRBASE_API fftcorr {
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public:
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typedef std::complex<float> cmplx;
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fftcorr(int len);
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~fftcorr();
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int run(const cmplx& inA, const cmplx* inB, cmplx **out); //!< if inB = 0 then run auto-correlation
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private:
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void init_fft();
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int flen; //!< FFT length
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int flen2; //!< half FFT length
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g_fft<float> *fftA;
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g_fft<float> *fftB;
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cmplx *dataA; // from A input
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cmplx *dataB; // from B input
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cmplx *dataBj; // conjugate of B
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cmplx *dataP; // product of A with conjugate of B
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cmplx *ovlbuf;
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cmplx *output;
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int inptrA;
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int inptrB;
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};
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#endif /* SDRBASE_DSP_FFTCORR_H_ */
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