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Improved DC offset correction

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This commit is contained in:
f4exb 2018-02-01 02:45:55 +01:00
parent 373aa6960f
commit be049374ad
3 changed files with 45 additions and 11 deletions
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49
sdrbase/dsp/dspdevicesourceengine.cpp
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@ -173,25 +173,52 @@ QString DSPDeviceSourceEngine::sourceDeviceDescription()
return cmd.getDeviceDescription();
}
void DSPDeviceSourceEngine::iqCorrections(SampleVector::iterator begin, SampleVector::iterator end, bool imbalanceCorrection)
{
for(SampleVector::iterator it = begin; it < end; it++)
{
m_iBeta(it->real());
m_qBeta(it->imag());
if (imbalanceCorrection)
{
int32_t xi = it->m_real - (int32_t) m_iBeta;
int32_t xq = it->m_imag - (int32_t) m_qBeta;
m_avgII(xi*xi);
m_avgIQ(xi*xq);
// TODO
}
else
{
it->m_real -= (int32_t) m_iBeta;
it->m_imag -= (int32_t) m_qBeta;
}
}
}
void DSPDeviceSourceEngine::dcOffset(SampleVector::iterator begin, SampleVector::iterator end)
{
double count;
int io = 0;
int qo = 0;
Sample corr((FixReal)m_iOffset, (FixReal)m_qOffset);
// double count;
// int io = 0;
// int qo = 0;
// Sample corr((FixReal)m_iOffset, (FixReal)m_qOffset);
// sum and correct in one pass
for(SampleVector::iterator it = begin; it < end; it++)
{
io += it->real();
qo += it->imag();
*it -= corr;
m_iBeta(it->real());
m_qBeta(it->imag());
it->m_real -= (int32_t) m_iBeta;
it->m_imag -= (int32_t) m_qBeta;
// io += it->real();
// qo += it->imag();
// *it -= corr;
}
// moving average
count = end - begin;
m_iOffset = (15.0 * m_iOffset + (double)io / count) / 16.0;
m_qOffset = (15.0 * m_qOffset + (double)qo / count) / 16.0;
// // moving average
// count = end - begin;
// m_iOffset = (15.0 * m_iOffset + (double)io / count) / 16.0;
// m_qOffset = (15.0 * m_qOffset + (double)qo / count) / 16.0;
}
void DSPDeviceSourceEngine::imbalance(SampleVector::iterator begin, SampleVector::iterator end)

6
sdrbase/dsp/dspdevicesourceengine.h
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@ -27,6 +27,7 @@
#include "util/messagequeue.h"
#include "util/syncmessenger.h"
#include "util/export.h"
#include "util/movingaverage.h"
class DeviceSampleSource;
class BasebandSampleSink;
@ -101,12 +102,17 @@ private:
bool m_dcOffsetCorrection;
bool m_iqImbalanceCorrection;
double m_iOffset, m_qOffset;
MovingAverageUtil<int32_t, int64_t, 1024> m_iBeta;
MovingAverageUtil<int32_t, int64_t, 1024> m_qBeta;
MovingAverageUtil<int64_t, int64_t, 1024> m_avgII;
MovingAverageUtil<int64_t, int64_t, 1024> m_avgIQ;
qint32 m_iRange;
qint32 m_qRange;
qint32 m_imbalance;
void run();
void iqCorrections(SampleVector::iterator begin, SampleVector::iterator end, bool imbalanceCorrection);
void dcOffset(SampleVector::iterator begin, SampleVector::iterator end);
void imbalance(SampleVector::iterator begin, SampleVector::iterator end);
void work(); //!< transfer samples from source to sinks if in running state

1
sdrbase/util/movingaverage.h
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@ -49,6 +49,7 @@ class MovingAverageUtil
operator double() const { return m_num_samples > 0 ? m_total / std::min(m_num_samples, N) : 0.0d; }
operator float() const { return m_num_samples > 0 ? m_total / std::min(m_num_samples, N) : 0.0f; }
operator T() const { return m_total / N; }
private:
T m_samples[N];