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DATV demod: implement interpolator (decimator) so that DVB engine input rate is always twice the symbol rate

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This commit is contained in:
f4exb 2023-03-31 00:28:12 +02:00
parent 9f75b0647f
commit afd8d492c5
2 changed files with 66 additions and 70 deletions
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126
plugins/channelrx/demoddatv/datvdemodsink.cpp
View File

@ -51,7 +51,6 @@ DATVDemodSink::DATVDemodSink() :
//*************** DATV PARAMETERS ***************
m_blnInitialized=false;
ResetDATVFrameworkPointers();
m_objRFFilter = new fftfilt(-256000.0 / 1024000.0, 256000.0 / 1024000.0, m_rfFilterFftLength);
}
DATVDemodSink::~DATVDemodSink()
@ -68,8 +67,6 @@ DATVDemodSink::~DATVDemodSink()
if (m_videoThread) {
delete m_videoThread;
}
delete m_objRFFilter;
}
void DATVDemodSink::stopVideo()
@ -539,12 +536,13 @@ void DATVDemodSink::InitDATVFramework()
<< " RollOff: " << m_settings.m_rollOff
<< " Viterbi: " << m_settings.m_viterbi
<< " Excursion: " << m_settings.m_excursion
<< " Sample rate: " << m_channelSampleRate;
<< " channel Sample rate: " << m_channelSampleRate
<< " Input sample rate: " << 2 * m_settings.m_symbolRate;
m_objCfg.standard = m_settings.m_standard;
m_objCfg.fec = (leansdr::code_rate) getLeanDVBCodeRateFromDATV(m_settings.m_fec);
m_objCfg.Fs = (float) m_channelSampleRate;
m_objCfg.Fs = (float) 2 * m_settings.m_symbolRate; // maintained at twice the symbol rate
m_objCfg.Fm = (float) m_settings.m_symbolRate;
m_objCfg.fastlock = m_settings.m_fastLock;
@ -875,14 +873,15 @@ void DATVDemodSink::InitDATVS2Framework()
<< " RollOff: " << m_settings.m_rollOff
<< " Viterbi: " << m_settings.m_viterbi
<< " Excursion: " << m_settings.m_excursion
<< " Sample rate: " << m_channelSampleRate
<< " Channel sample rate: " << m_channelSampleRate
<< " Input sample rate: " << 2 * m_settings.m_symbolRate
<< " m_softLDPCMaxTrials: " << m_settings.m_softLDPCMaxTrials
<< " m_softLDPCToolPath: " << m_settings.m_softLDPCToolPath;
m_objCfg.standard = m_settings.m_standard;
m_objCfg.fec = (leansdr::code_rate) getLeanDVBCodeRateFromDATV(m_settings.m_fec);
m_objCfg.Fs = (float) m_channelSampleRate;
m_objCfg.Fs = (float) 2 * m_settings.m_symbolRate; // maintained at twice the symbol rate
m_objCfg.Fm = (float) m_settings.m_symbolRate;
m_objCfg.fastlock = m_settings.m_fastLock;
@ -1271,67 +1270,61 @@ void DATVDemodSink::feed(const SampleVector::const_iterator& begin, const Sample
}
//********** Bis repetita : Let's rock and roll buddy ! **********
#ifdef EXTENDED_DIRECT_SAMPLE
qint16 * ptrBuffer;
qint32 intLen;
//********** Reading direct samples **********
SampleVector::const_iterator it = begin;
intLen = it->intLen;
ptrBuffer = it->ptrBuffer;
ptrBufferToRelease = ptrBuffer;
++it;
for(qint32 intInd=0; intInd<intLen-1; intInd +=2)
{
fltI= ((qint32) (*ptrBuffer)) << 4;
ptrBuffer ++;
fltQ= ((qint32) (*ptrBuffer)) << 4;
ptrBuffer ++;
#else
for (SampleVector::const_iterator it = begin; it != end; ++it /* ++it **/)
{
fltI = it->real();
fltQ = it->imag();
#endif
//********** iq stream ****************
Complex objC(fltI,fltQ);
objC *= m_objNCO.nextIQ();
intRFOut = m_objRFFilter->runFilt(objC, &objRF); // filter RF before demod
Complex c(it->real(), it->imag());
for (int intI = 0 ; intI < intRFOut; intI++, objRF++)
if (m_interpolatorDistance < 1.0f) // interpolate - should never get there...
{
m_objMagSqAverage(norm(*objRF));
Complex ci;
c *= m_nco.nextIQ();
if (m_blnDVBInitialized
&& (p_rawiq_writer != nullptr)
&& (m_objScheduler != nullptr))
while (!m_interpolator.interpolate(&m_interpolatorDistanceRemain, c, &ci))
{
processOneSample(ci);
m_interpolatorDistanceRemain += m_interpolatorDistance;
}
}
else // decimate
{
Complex ci;
c *= m_nco.nextIQ();
p_rawiq_writer->write(*objRF);
m_lngReadIQ++;
lngWritable = p_rawiq_writer->writable();
//Leave +1 by safety
//if(((m_lngReadIQ+1)>=lngWritable) || (m_lngReadIQ>=768))
if ((m_lngReadIQ + 1) >= lngWritable)
{
m_objScheduler->step();
m_lngReadIQ = 0;
p_rawiq_writer->reset(m_RawIQMinWrite);
}
if (m_interpolator.decimate(&m_interpolatorDistanceRemain, c, &ci))
{
processOneSample(ci);
m_interpolatorDistanceRemain += m_interpolatorDistance;
}
}
} // Samples for loop
}
void DATVDemodSink::processOneSample(Complex &ci)
{
m_objMagSqAverage(norm(ci));
if (m_blnDVBInitialized
&& (p_rawiq_writer != nullptr)
&& (m_objScheduler != nullptr))
{
p_rawiq_writer->write(ci);
m_lngReadIQ++;
int writable = p_rawiq_writer->writable();
//Leave +1 by safety
//if(((m_lngReadIQ+1)>=lngWritable) || (m_lngReadIQ>=768))
if ((m_lngReadIQ + 1) >= writable)
{
m_objScheduler->step();
m_lngReadIQ = 0;
p_rawiq_writer->reset(m_RawIQMinWrite);
}
}
}
void DATVDemodSink::applyChannelSettings(int channelSampleRate, int channelFrequencyOffset, bool force)
{
qDebug() << "DATVDemodSink::applyChannelSettings:"
@ -1343,7 +1336,7 @@ void DATVDemodSink::applyChannelSettings(int channelSampleRate, int channelFrequ
if ((m_settings.m_centerFrequency != channelFrequencyOffset) ||
(m_channelSampleRate != channelSampleRate) || force)
{
m_objNCO.setFreq(-(float) channelFrequencyOffset, (float) channelSampleRate);
m_nco.setFreq(-(float) channelFrequencyOffset, (float) channelSampleRate);
qDebug("DATVDemodSink::applyChannelSettings: NCO: IF: %d <> TF: %d ISR: %d",
channelFrequencyOffset, m_settings.m_centerFrequency, channelSampleRate);
callApplySettings = true;
@ -1351,10 +1344,10 @@ void DATVDemodSink::applyChannelSettings(int channelSampleRate, int channelFrequ
if ((m_channelSampleRate != channelSampleRate) || force)
{
//Bandpass filter shaping
Real fltLowCut = -((float) m_settings.m_rfBandwidth / 2.0) / (float) channelSampleRate;
Real fltHiCut = ((float) m_settings.m_rfBandwidth / 2.0) / (float) channelSampleRate;
m_objRFFilter->create_filter(fltLowCut, fltHiCut);
m_interpolator.create(m_interpolatorPhaseSteps, channelSampleRate, m_settings.m_rfBandwidth / 2.2, m_interpolatorTapsPerPhase);
m_interpolatorDistanceRemain = 0;
m_interpolatorDistance = (Real) channelSampleRate / (Real) (2 * m_settings.m_symbolRate);
qDebug("DATVDemodSink::applyChannelSettings: m_interpolatorDistance: %f", m_interpolatorDistance);
}
m_channelSampleRate = channelSampleRate;
@ -1400,17 +1393,15 @@ void DATVDemodSink::applySettings(const DATVDemodSettings& settings, bool force)
if ((m_settings.m_rfBandwidth != settings.m_rfBandwidth)
|| force)
{
//Bandpass filter shaping
Real fltLowCut = -((float) settings.m_rfBandwidth / 2.0) / (float) m_channelSampleRate;
Real fltHiCut = ((float) settings.m_rfBandwidth / 2.0) / (float) m_channelSampleRate;
m_objRFFilter->create_filter(fltLowCut, fltHiCut);
m_interpolator.create(m_interpolatorPhaseSteps, m_channelSampleRate, m_settings.m_rfBandwidth / 2.2, m_interpolatorTapsPerPhase);
m_interpolatorDistanceRemain = 0;
m_interpolatorDistance = (Real) m_channelSampleRate / (Real) (2 * m_settings.m_symbolRate);
}
if ((m_settings.m_centerFrequency != settings.m_centerFrequency)
|| force)
{
m_objNCO.setFreq(-(float) settings.m_centerFrequency, (float) m_channelSampleRate);
m_nco.setFreq(-(float) settings.m_centerFrequency, (float) m_channelSampleRate);
}
if ((m_settings.m_udpTS != settings.m_udpTS) || force) {
@ -1489,4 +1480,3 @@ int DATVDemodSink::getLeanDVBModulationFromDATV(DATVDemodSettings::DATVModulatio
return -1;
}
}

10
plugins/channelrx/demoddatv/datvdemodsink.h
View File

@ -44,6 +44,7 @@
#include "dsp/interpolator.h"
#include "dsp/movingaverage.h"
#include "dsp/agc.h"
#include "dsp/interpolator.h"
#include "audio/audiofifo.h"
#include "util/messagequeue.h"
#include "util/movingaverage.h"
@ -175,6 +176,7 @@ private:
};
inline int decimation(float Fin, float Fout) { int d = Fin / Fout; return std::max(d, 1); }
void processOneSample(Complex &ci);
void CleanUpDATVFramework();
void ResetDATVFrameworkPointers();
@ -328,8 +330,12 @@ private:
// Audio
AudioFifo m_audioFifo;
fftfilt * m_objRFFilter;
NCO m_objNCO;
NCO m_nco;
Interpolator m_interpolator;
Real m_interpolatorDistance;
Real m_interpolatorDistanceRemain;
static const int m_interpolatorPhaseSteps = 4; // Higher than these two values will struggle to run in real-time
static const int m_interpolatorTapsPerPhase = 3.5f; // without gaining much improvement in PER
bool m_blnInitialized;
bool m_blnRenderingVideo;