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sdrangel/sdrbase/dsp/autocorrector.h

107 lines
3.6 KiB
C++

///////////////////////////////////////////////////////////////////////////////////
// Copyright (C) 2018 Edouard Griffiths, F4EXB //
// //
// This program is free software; you can redistribute it and/or modify //
// it under the terms of the GNU General Public License as published by //
// the Free Software Foundation as version 3 of the License, or //
// (at your option) any later version. //
// //
// This program is distributed in the hope that it will be useful, //
// but WITHOUT ANY WARRANTY; without even the implied warranty of //
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the //
// GNU General Public License V3 for more details. //
// //
// You should have received a copy of the GNU General Public License //
// along with this program. If not, see <http://www.gnu.org/licenses/>. //
///////////////////////////////////////////////////////////////////////////////////
#ifndef SDRBASE_DSP_AUTOCORRECTOR_H_
#define SDRBASE_DSP_AUTOCORRECTOR_H_
#include "util/movingaverage.h"
template<typename T>
class AutoCorrector
{
public:
AutoCorrector(qint32 intBits);
void process(const T& inreal, const T& inimag, qint32& outreal, qint32& outimag);
void process(qint32& xreal, qint32& ximag);
void setIQCorrection(bool iqCorrection) { m_iqCorrection = iqCorrection; }
private:
bool m_iqCorrection;
float m_scalef;
MovingAverageUtil<int32_t, int64_t, 1024> m_iBeta;
MovingAverageUtil<int32_t, int64_t, 1024> m_qBeta;
MovingAverageUtil<float, double, 128> m_avgII;
MovingAverageUtil<float, double, 128> m_avgIQ;
MovingAverageUtil<float, double, 128> m_avgII2;
MovingAverageUtil<float, double, 128> m_avgQQ2;
MovingAverageUtil<double, double, 128> m_avgPhi;
MovingAverageUtil<double, double, 128> m_avgAmp;
};
template<typename T>
AutoCorrector<T>::AutoCorrector(qint32 intBits) :
m_iqCorrection(false),
m_scalef((float) (1<<(intBits-1)))
{
}
template<typename T>
void AutoCorrector<T>::process(const T& inreal, const T& inimag, qint32& outreal, qint32& outimag)
{
outreal = inreal;
outimag = inimag;
process(outreal, outimag);
}
template<typename T>
void AutoCorrector<T>::process(qint32& xreal, qint32& ximag)
{
m_iBeta(xreal);
m_qBeta(ximag);
if (m_iqCorrection)
{
// DC correction and conversion
float xi = (xreal - (int32_t) m_iBeta) / m_scalef;
float xq = (ximag - (int32_t) m_qBeta) / m_scalef;
// phase imbalance
m_avgII(xi*xi); // <I", I">
m_avgIQ(xi*xq); // <I", Q">
if (m_avgII.asDouble() != 0) {
m_avgPhi(m_avgIQ.asDouble()/m_avgII.asDouble());
}
float yi = xi - m_avgPhi.asDouble()*xq;
float yq = xq;
// amplitude I/Q imbalance
m_avgII2(yi*yi); // <I, I>
m_avgQQ2(yq*yq); // <Q, Q>
if (m_avgQQ2.asDouble() != 0) {
m_avgAmp(sqrt(m_avgII2.asDouble() / m_avgQQ2.asDouble()));
}
// final correction
float zi = yi;
float zq = m_avgAmp.asDouble() * yq;
// convert and store
xreal = zi * m_scalef;
ximag = zq * m_scalef;
}
else
{
xreal -= (int32_t) m_iBeta;
ximag -= (int32_t) m_qBeta;
}
}
#endif /* SDRBASE_DSP_AUTOCORRECTOR_H_ */