VE7UWU/sdrangel
1
0
Fork 0
mirror of https://github.com/f4exb/sdrangel.git synced 2025-11-17 13:43:17 -05:00
Code Issues Projects Releases Wiki Activity

Interferometer: fixes and optimization of Inverse FFT star

Browse Source
This commit is contained in:
f4exb 2019-10-11 00:32:32 +02:00
parent 6b8fa93425
commit 1cc38c74ad
2 changed files with 49 additions and 14 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

62
plugins/channelmimo/interferometer/interferometercorr.cpp
View File

@ -126,8 +126,6 @@ InterferometerCorrelator::InterferometerCorrelator(int fftSize) :
m_tcorr.resize(fftSize);
m_scorrSize = fftSize;
m_tcorrSize = fftSize;
m_fftProdScale = SDR_RX_SCALEF / (8*m_fftSize);
}
InterferometerCorrelator::~InterferometerCorrelator()
@ -186,6 +184,25 @@ bool InterferometerCorrelator::performCorr(
}
else if ((m_phase == -180) || (m_phase == 180))
{
if ((m_corrType == InterferometerSettings::CorrelationIFFT)
|| (m_corrType == InterferometerSettings::CorrelationIFFT2)
|| (m_corrType == InterferometerSettings::CorrelationIFFTStar)
|| (m_corrType == InterferometerSettings::CorrelationFFT))
{
if (size1 > m_data1p.size()) {
m_data1p.resize(size1);
}
std::transform(
data1.begin(),
data1.begin() + size1,
m_data1p.begin(),
[](const Sample& s) -> Sample {
return Sample{-s.real(), -s.imag()};
}
);
}
switch (m_corrType)
{
case InterferometerSettings::Correlation0:
@ -379,14 +396,22 @@ bool InterferometerCorrelator::performFFTCorr(
if (star)
{
// sum first half with the reversed second half as one is the conjugate of the other this should yield constant phase
*m_tcorr.begin() = invfft2star(m_invFFT->out()[0]); // t = 0
SampleVector::iterator it = m_tcorr.begin() + 1;
for (int i = 1; i < m_fftSize; i++)
{
*it = invfft2star(m_invFFT->out()[i] + m_invFFT->out()[2*m_fftSize-i]);
++it;
}
std::reverse(m_invFFT->out() + m_fftSize, m_invFFT->out() + 2*m_fftSize);
std::transform(
m_invFFT->out() + 1,
m_invFFT->out() + m_fftSize,
m_invFFT->out() + m_fftSize,
m_tcorr.begin() + nfft*m_fftSize,
[](const std::complex<float>& a, const std::complex<float>& b) -> Sample {
Sample s;
std::complex<float> sum = a + b;
s.setReal(sum.real()/2.82842712475f); // 2*sqrt(2)
s.setImag(sum.imag()/2.82842712475f);
return s;
}
);
}
else
{
@ -576,15 +601,26 @@ bool InterferometerCorrelator::performFFTProd(
}
);
// copy product to time domain - convert and scale to FFT size
// copy product to time domain - re-order, convert and scale to FFT size
std::transform(
m_invFFT2->in(),
m_invFFT2->in() + m_fftSize/2,
m_tcorr.begin() + nfft*m_fftSize + m_fftSize/2,
[](const std::complex<float>& a) -> Sample {
Sample s;
s.setReal(a.real()*16.0f);
s.setImag(a.imag()*16.0f);
return s;
}
);
std::transform(
m_invFFT2->in() + m_fftSize/2,
m_invFFT2->in() + m_fftSize,
m_tcorr.begin() + nfft*m_fftSize,
[this](const std::complex<float>& a) -> Sample {
[](const std::complex<float>& a) -> Sample {
Sample s;
s.setReal(a.real()*m_fftProdScale);
s.setImag(a.imag()*m_fftProdScale);
s.setReal(a.real()*16.0f);
s.setImag(a.imag()*16.0f);
return s;
}
);

1
plugins/channelmimo/interferometer/interferometercorr.h
View File

@ -95,7 +95,6 @@ private:
SampleVector m_data0w; //!< windowed data 0
SampleVector m_data1w; //!< windowed data 1
SampleVector m_data1p; //!< data1 with phase correction
float m_fftProdScale; //!< scaling factor for FFT products
int m_scorrSize; //!< spectrum correlations vector size
int m_tcorrSize; //!< time correlations vector size
int m_phase; //!< phase correction