86 lines
2.2 KiB
C++
86 lines
2.2 KiB
C++
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#include "tdrbandpass.h"
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#include "Traces/fftcomplex.h"
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#include <QLabel>
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using namespace Math;
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using namespace std;
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TDRBandpass::TDRBandpass()
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{
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}
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TraceMath::DataType TDRBandpass::outputType(TraceMath::DataType inputType)
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{
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if(inputType == DataType::Frequency) {
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return DataType::Time;
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} else {
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return DataType::Invalid;
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}
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}
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QString TDRBandpass::description()
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{
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return "TDR (bandpass mode)";
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}
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void TDRBandpass::edit()
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{
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// nothing to do for now
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}
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QWidget *TDRBandpass::createExplanationWidget()
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{
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return new QLabel("Test");
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}
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void TDRBandpass::inputSamplesChanged(unsigned int begin, unsigned int end)
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{
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Q_UNUSED(begin);
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const double PI = 3.141592653589793238463;
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if(input->rData().size() >= 2) {
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// TDR is computationally expensive, only update at the end of sweep
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if(end != input->rData().size()) {
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// not the end, do nothing
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return;
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}
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// create vector for frequency data
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vector<complex<double>> dft(end);
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// window data and perform FFTshift ("zero"-bin expected at index 0 but is in the middle of input data)
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for(unsigned int i=0;i<end;i++) {
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// TODO implement other windows as well
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constexpr double alpha0 = 0.54;
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auto hamming = alpha0 - (1.0 - alpha0) * cos(2 * PI * i / end);
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auto windowed = input->rData()[i].y * hamming;
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// swap upper and lower half
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if(i < end/2) {
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dft[i + (end+1)/2] = windowed;
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} else {
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dft[i - end/2] = windowed;
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}
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}
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// perform IFT operation on data
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Fft::transform(dft, true);
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// calculate sample distance
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auto freqStep = input->rData()[1].x - input->rData()[0].x;
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auto timeStep = 1.0 / (freqStep * end);
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// copy DFT data to output data
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data.resize(dft.size());
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for(unsigned int i=0;i<dft.size();i++) {
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data[i].y = dft[i];
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data[i].x = i * timeStep;
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}
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emit outputSamplesChanged(0, data.size());
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success();
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} else {
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// not enough input data
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data.clear();
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emit outputSamplesChanged(0, 0);
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warning("Not enough input samples");
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}
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}
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