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IQ correction with phase imbalance: floating point implementation

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This commit is contained in:
f4exb
2018-02-04 10:49:13 +01:00
parent 58f0145705
commit b9b2c41ba2
5 changed files with 220 additions and 39 deletions
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sdrbase/dsp/dspdevicesourceengine.cpp
+59 -34
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@@ -23,6 +23,7 @@
#include <stdio.h>
#include <QDebug>
#include "dsp/dspcommands.h"
#include "util/fixed.h"
#include "samplesinkfifo.h"
#include "threadedbasebandsamplesink.h"
@@ -182,14 +183,41 @@ void DSPDeviceSourceEngine::iqCorrections(SampleVector::iterator begin, SampleVe
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
// DC correction and conversion
float xi = (it->m_real - (int32_t) m_iBeta) / SDR_RX_SCALEF;
float xq = (it->m_imag - (int32_t) m_qBeta) / SDR_RX_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
it->m_real = zi * SDR_RX_SCALEF;
it->m_imag = zq * SDR_RX_SCALEF;
}
else
{
// DC correction only
it->m_real -= (int32_t) m_iBeta;
it->m_imag -= (int32_t) m_qBeta;
}
@@ -198,11 +226,6 @@ void DSPDeviceSourceEngine::iqCorrections(SampleVector::iterator begin, SampleVe
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);
// sum and correct in one pass
for(SampleVector::iterator it = begin; it < end; it++)
{
@@ -210,15 +233,7 @@ void DSPDeviceSourceEngine::dcOffset(SampleVector::iterator begin, SampleVector:
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;
}
void DSPDeviceSourceEngine::imbalance(SampleVector::iterator begin, SampleVector::iterator end)
@@ -289,15 +304,20 @@ void DSPDeviceSourceEngine::work()
if (part1begin != part1end)
{
// correct stuff
if (m_dcOffsetCorrection)
{
dcOffset(part1begin, part1end);
}
if (m_dcOffsetCorrection)
{
iqCorrections(part1begin, part1end, m_iqImbalanceCorrection);
}
if (m_iqImbalanceCorrection)
{
imbalance(part1begin, part1end);
}
// if (m_dcOffsetCorrection)
// {
// dcOffset(part1begin, part1end);
// }
//
// if (m_iqImbalanceCorrection)
// {
// imbalance(part1begin, part1end);
// }
// feed data to direct sinks
for (BasebandSampleSinks::const_iterator it = m_basebandSampleSinks.begin(); it != m_basebandSampleSinks.end(); ++it)
@@ -316,15 +336,20 @@ void DSPDeviceSourceEngine::work()
if(part2begin != part2end)
{
// correct stuff
if (m_dcOffsetCorrection)
{
dcOffset(part2begin, part2end);
}
if (m_dcOffsetCorrection)
{
iqCorrections(part2begin, part2end, m_iqImbalanceCorrection);
}
if (m_iqImbalanceCorrection)
{
imbalance(part2begin, part2end);
}
// if (m_dcOffsetCorrection)
// {
// dcOffset(part2begin, part2end);
// }
//
// if (m_iqImbalanceCorrection)
// {
// imbalance(part2begin, part2end);
// }
// feed data to direct sinks
for (BasebandSampleSinks::const_iterator it = m_basebandSampleSinks.begin(); it != m_basebandSampleSinks.end(); it++)