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Interferometer: implemented direct FFT multiplication

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This commit is contained in:
f4exb
2019-10-09 07:37:28 +02:00
parent d925781d9a
commit 6b8fa93425
4 changed files with 143 additions and 22 deletions
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plugins/channelmimo/interferometer/interferometercorr.cpp
+117 -9
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@@ -126,6 +126,8 @@ InterferometerCorrelator::InterferometerCorrelator(int fftSize) :
m_tcorr.resize(fftSize);
m_scorrSize = fftSize;
m_tcorrSize = fftSize;
m_fftProdScale = SDR_RX_SCALEF / (8*m_fftSize);
}
InterferometerCorrelator::~InterferometerCorrelator()
@@ -166,15 +168,18 @@ bool InterferometerCorrelator::performCorr(
case InterferometerSettings::CorrelationMultiply:
results = performOpCorr(data0, size0, data1, size1, sMulConj);
break;
case InterferometerSettings::CorrelationFFT:
case InterferometerSettings::CorrelationIFFT:
results = performFFTCorr(data0, size0, data1, size1);
break;
case InterferometerSettings::CorrelationFFT2:
case InterferometerSettings::CorrelationIFFT2:
results = performFFT2Corr(data0, size0, data1, size1);
break;
case InterferometerSettings::CorrelationFFTStar:
case InterferometerSettings::CorrelationIFFTStar:
results = performFFTCorr(data0, size0, data1, size1, true);
break;
case InterferometerSettings::CorrelationFFT:
results = performFFTProd(data0, size0, data1, size1);
break;
default:
break;
}
@@ -195,15 +200,18 @@ bool InterferometerCorrelator::performCorr(
case InterferometerSettings::CorrelationMultiply:
results = performOpCorr(data0, size0, data1, size1, sMulConjInv);
break;
case InterferometerSettings::CorrelationFFT:
case InterferometerSettings::CorrelationIFFT:
results = performFFTCorr(data0, size0, m_data1p, size1);
break;
case InterferometerSettings::CorrelationFFT2:
case InterferometerSettings::CorrelationIFFT2:
results = performFFT2Corr(data0, size0, m_data1p, size1);
break;
case InterferometerSettings::CorrelationFFTStar:
case InterferometerSettings::CorrelationIFFTStar:
results = performFFTCorr(data0, size0, m_data1p, size1, true);
break;
case InterferometerSettings::CorrelationFFT:
results = performFFTProd(data0, size0, m_data1p, size1);
break;
default:
break;
}
@@ -244,15 +252,18 @@ bool InterferometerCorrelator::performCorr(
case InterferometerSettings::CorrelationMultiply:
results = performOpCorr(data0, size0, m_data1p, size1, sMulConj);
break;
case InterferometerSettings::CorrelationFFT:
case InterferometerSettings::CorrelationIFFT:
results = performFFTCorr(data0, size0, m_data1p, size1);
break;
case InterferometerSettings::CorrelationFFT2:
case InterferometerSettings::CorrelationIFFT2:
results = performFFT2Corr(data0, size0, m_data1p, size1);
break;
case InterferometerSettings::CorrelationFFTStar:
case InterferometerSettings::CorrelationIFFTStar:
results = performFFTCorr(data0, size0, m_data1p, size1, true);
break;
case InterferometerSettings::CorrelationFFT:
results = performFFTProd(data0, size0, m_data1p, size1);
break;
default:
break;
}
@@ -504,6 +515,103 @@ bool InterferometerCorrelator::performFFT2Corr(
return nfft > 0;
}
bool InterferometerCorrelator::performFFTProd(
const SampleVector& data0,
int size0,
const SampleVector& data1,
int size1
)
{
unsigned int size = std::min(size0, size1);
int nfft = 0;
SampleVector::const_iterator begin0 = data0.begin();
SampleVector::const_iterator begin1 = data1.begin();
adjustSCorrSize(size);
adjustTCorrSize(size);
while (size >= m_fftSize)
{
// FFT[0]
std::transform(
begin0,
begin0 + m_fftSize,
m_fft2[0]->in(),
[](const Sample& s) -> std::complex<float> {
return std::complex<float>{s.real() / SDR_RX_SCALEF, s.imag() / SDR_RX_SCALEF};
}
);
m_window.apply(m_fft2[0]->in());
m_fft2[0]->transform();
// FFT[1]
std::transform(
begin1,
begin1 + m_fftSize,
m_fft2[1]->in(),
[](const Sample& s) -> std::complex<float> {
return std::complex<float>{s.real() / SDR_RX_SCALEF, s.imag() / SDR_RX_SCALEF};
}
);
m_window.apply(m_fft2[1]->in());
m_fft2[1]->transform();
// conjugate FFT[1]
std::transform(
m_fft2[1]->out(),
m_fft2[1]->out() + m_fftSize,
m_dataj,
[](const std::complex<float>& c) -> std::complex<float> {
return std::conj(c);
}
);
// product of FFT[1]* with FFT[0] and store in both results
std::transform(
m_fft2[0]->out(),
m_fft2[0]->out() + m_fftSize,
m_dataj,
m_invFFT2->in(),
[this](std::complex<float>& a, const std::complex<float>& b) -> std::complex<float> {
return (a*b);
}
);
// copy product to time domain - convert and scale to FFT size
std::transform(
m_invFFT2->in(),
m_invFFT2->in() + m_fftSize,
m_tcorr.begin() + nfft*m_fftSize,
[this](const std::complex<float>& a) -> Sample {
Sample s;
s.setReal(a.real()*m_fftProdScale);
s.setImag(a.imag()*m_fftProdScale);
return s;
}
);
// feed spectrum with the direct conjugate product
std::transform(
begin0,
begin0 + m_fftSize,
begin1,
m_scorr.begin() + nfft*m_fftSize,
sMulConj
);
size -= m_fftSize;
begin0 += m_fftSize;
begin1 += m_fftSize;
nfft++;
}
// update the samples counters
m_processed = nfft*m_fftSize;
m_remaining[0] = size0 - nfft*m_fftSize;
m_remaining[1] = size1 - nfft*m_fftSize;
return nfft > 0;
}
void InterferometerCorrelator::adjustSCorrSize(int size)
{
int nFFTSize = (size/m_fftSize)*m_fftSize;