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https://github.com/f4exb/sdrangel.git
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BFM demod: working RDS demod
This commit is contained in:
f4exb
parent
8fa44a4ddb
commit
1a9dca1632
@ -92,7 +92,7 @@ void BFMDemod::configure(MessageQueue* messageQueue,
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void BFMDemod::feed(const SampleVector::const_iterator& begin, const SampleVector::const_iterator& end, bool firstOfBurst)
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{
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Complex ci, cs;
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Complex ci, cs, cr;
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fftfilt::cmplx *rf;
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int rf_out;
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Real msq, demod;
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@ -136,8 +136,15 @@ void BFMDemod::feed(const SampleVector::const_iterator& begin, const SampleVecto
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if (m_running.m_rdsActive)
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{
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m_rdsDemod.process(demod * 2.0 * cos(3.0 * m_pilotPLLSamples[2]), m_pilotPLLSamples[2]);
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//m_rdsDemod.process(demod, m_pilotPLLSamples[2]);
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//Complex r(demod * 2.0 * std::cos(3.0 * m_pilotPLLSamples[2]), 0.0);
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Complex r(demod * 2.0 * std::cos(3.0 * m_pilotPLLSamples[2]), m_pilotPLLSamples[2]);
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if (m_interpolatorRDS.interpolate(&m_interpolatorRDSDistanceRemain, r, &cr))
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{
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m_rdsDemod.process(cr.real(), cr.imag());
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m_interpolatorRDSDistanceRemain += m_interpolatorRDSDistance;
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}
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}
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Real sampleStereo;
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@ -158,6 +165,7 @@ void BFMDemod::feed(const SampleVector::const_iterator& begin, const SampleVecto
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if (m_interpolatorStereo.interpolate(&m_interpolatorStereoDistanceRemain, s, &cs))
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{
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sampleStereo = cs.real();
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m_interpolatorStereoDistanceRemain += m_interpolatorStereoDistance;
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}
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}
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@ -291,11 +299,6 @@ bool BFMDemod::handleMessage(const Message& cmd)
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void BFMDemod::apply()
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{
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if (m_config.m_inputSampleRate != m_running.m_inputSampleRate)
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{
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m_rdsDemod.setSampleRate(m_config.m_inputSampleRate);
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}
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if ((m_config.m_inputSampleRate != m_running.m_inputSampleRate)
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|| (m_config.m_audioStereo && (m_config.m_audioStereo != m_running.m_audioStereo)))
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{
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@ -314,12 +317,19 @@ void BFMDemod::apply()
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{
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m_settingsMutex.lock();
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qDebug() << "BFMDemod::handleMessage: m_interpolator.create";
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m_interpolator.create(16, m_config.m_inputSampleRate, m_config.m_afBandwidth);
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m_interpolatorDistanceRemain = (Real) m_config.m_inputSampleRate / m_config.m_audioSampleRate;
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m_interpolatorDistance = (Real) m_config.m_inputSampleRate / (Real) m_config.m_audioSampleRate;
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m_interpolatorStereo.create(16, m_config.m_inputSampleRate, m_config.m_afBandwidth);
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m_interpolatorStereoDistanceRemain = (Real) m_config.m_inputSampleRate / m_config.m_audioSampleRate;
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m_interpolatorStereoDistance = (Real) m_config.m_inputSampleRate / (Real) m_config.m_audioSampleRate;
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m_interpolatorRDS.create(4, m_config.m_inputSampleRate, 600.0);
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m_interpolatorRDSDistanceRemain = (Real) m_config.m_inputSampleRate / 250000.0;
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m_interpolatorRDSDistance = (Real) m_config.m_inputSampleRate / 250000.0;
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m_settingsMutex.unlock();
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}
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@ -159,9 +159,15 @@ private:
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Interpolator m_interpolator; //!< Interpolator between fixed demod bandwidth and audio bandwidth (rational)
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Real m_interpolatorDistance;
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Real m_interpolatorDistanceRemain;
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Interpolator m_interpolatorStereo; //!< Twin Interpolator for stereo subcarrier
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Real m_interpolatorStereoDistance;
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Real m_interpolatorStereoDistanceRemain;
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Interpolator m_interpolatorRDS; //!< Twin Interpolator for stereo subcarrier
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Real m_interpolatorRDSDistance;
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Real m_interpolatorRDSDistanceRemain;
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Lowpass<Real> m_lowpass;
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fftfilt* m_rfFilter;
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@ -23,77 +23,164 @@
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#include "rdsdemod.h"
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const Real RDSDemod::m_pllBeta = 50;
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const int RDSDemod::m_udpSize = 1472;
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RDSDemod::RDSDemod()
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{
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m_srate = 250000;
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m_fsc = 57000.0;
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m_subcarrPhi_1 = 0;
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m_dPhiSc = 0;
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m_subcarrBB_1 = 0.0;
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m_rdsClockPhase = 0.0;
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m_rdsClockPhase_1 = 0.0;
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m_rdsClockOffset = 0.0;
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m_rdsClockLO = 0.0;
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m_rdsClockLO_1 = 0.0;
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m_numSamples = 0;
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m_acc = 0.0;
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m_acc_1 = 0.0;
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m_counter = 0;
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m_readingFrame = 0;
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m_totErrors[0] = 0;
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m_totErrors[1] = 0;
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m_dbit = 0;
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m_parms.subcarr_phi = 0;
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m_parms.clock_offset = 0;
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m_parms.clock_phi = 0;
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m_parms.prev_clock_phi = 0;
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m_parms.lo_clock = 0;
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m_parms.prevclock = 0;
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m_parms.prev_bb = 0;
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m_parms.d_phi_sc = 0;
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m_parms.d_cphi = 0;
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m_parms.acc = 0;
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m_parms.subcarr_sample = 0;
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m_parms.c = 0;
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m_parms.fmfreq = 0;
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m_parms.bytesread;
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m_parms.numsamples = 0;
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m_parms.loop_out = 0;
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m_parms.prev_loop = 0;
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m_parms.prev_acc = 0;
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m_parms.counter = 0;
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m_parms.reading_frame = 0;
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m_socket = new QUdpSocket(this);
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m_sampleBufferIndex = 0;
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}
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RDSDemod::~RDSDemod()
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{
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delete m_socket;
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}
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void RDSDemod::setSampleRate(int srate)
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{
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m_srate = srate;
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m_fsc = 57000.0;
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}
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void RDSDemod::process(Real demod, Real pilotPhaseSample)
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void RDSDemod::process(Real demod, Real pilot)
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{
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pilotPhaseSample = fmod(pilotPhaseSample, M_PI);
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m_dPhiSc = pilotPhaseSample - m_subcarrPhi_1;
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double fsc = 57000;
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if (m_dPhiSc < 0)
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Real dPilot = pilot - m_pilotPrev;
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if (dPilot < 0)
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{
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m_dPhiSc += M_PI;
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dPilot += 2 * M_PI;
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}
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m_subcarrBB[0] = filter_lp_2400_iq(demod, 0); // working on real part only
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if (m_sampleBufferIndex < m_udpSize)
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{
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m_sampleBufferIndex++;
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}
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else
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{
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m_socket->writeDatagram((const char*)&m_sampleBuffer[0], (qint64 ) (m_udpSize * sizeof(Real)), QHostAddress::LocalHost, 9995);
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m_sampleBufferIndex = 0;
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}
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// 1187.5 Hz clock from 19 kHz pilot
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// Subcarrier downmix & phase recovery
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m_rdsClockPhase += (m_dPhiSc / 16.0) + m_rdsClockOffset;
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m_rdsClockPhase = fmod(m_rdsClockPhase, M_PI);
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m_rdsClockLO = (m_rdsClockPhase < 0.0 ? -1.0 : 1.0);
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m_parms.subcarr_phi += 2 * M_PI * fsc * (1.0 / m_srate);
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/*
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if (m_parms.subcarr_phi > 48 * 2 * M_PI)
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{
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m_parms.subcarr_phi -= 48 * 2 * M_PI;
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}*/
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m_parms.subcarr_bb[0] = filter_lp_2400_iq(demod, 0);
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//m_parms.subcarr_bb[1] = filter_lp_2400_iq(demod * std::sin(m_parms.subcarr_phi), 1);
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m_parms.clock_phi += dPilot / 16.0;
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m_parms.clock_phi = std::fmod(m_parms.clock_phi, 2 * M_PI);
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m_parms.lo_clock = (m_parms.clock_phi < M_PI ? 1 : -1);
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m_sampleBuffer[m_sampleBufferIndex] = m_parms.lo_clock * m_parms.subcarr_bb[0]; // UDP debug
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// 1187.5 Hz clock
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m_parms.clock_phi = (m_parms.subcarr_phi / 48.0) + m_parms.clock_offset;
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// Clock phase recovery
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if (sign(m_subcarrBB_1) != sign(m_subcarrBB[0]))
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if (sign(m_parms.prev_bb) != sign(m_parms.subcarr_bb[0]))
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{
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Real d_cphi = m_rdsClockPhase;
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m_parms.d_cphi = std::fmod(m_parms.clock_phi, M_PI);
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if (d_cphi >= M_PI_2)
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if (m_parms.d_cphi >= M_PI_2)
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{
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d_cphi -= M_PI;
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m_parms.d_cphi -= M_PI;
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}
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m_rdsClockOffset -= 0.005 * d_cphi;
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m_parms.clock_offset -= 0.005 * m_parms.d_cphi;
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}
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biphase(m_acc, m_rdsClockPhase - m_rdsClockPhase_1);
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/* Decimate band-limited signal */
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if (m_parms.numsamples % 8 == 0)
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{
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/* biphase symbol integrate & dump */
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m_parms.acc += m_parms.subcarr_bb[0] * m_parms.lo_clock;
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m_numSamples++;
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m_subcarrPhi_1 = pilotPhaseSample;
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m_rdsClockPhase_1 = m_rdsClockPhase;
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if (sign(m_parms.lo_clock) != sign(m_parms.prevclock))
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{
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biphase(m_parms.acc, m_parms.clock_phi - m_parms.prev_clock_phi);
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m_parms.acc = 0;
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}
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m_parms.prevclock = m_parms.lo_clock;
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}
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m_parms.numsamples++;
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m_parms.prev_bb = m_parms.subcarr_bb[0];
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m_parms.prev_clock_phi = m_parms.clock_phi;
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m_prev = demod;
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m_pilotPrev - pilot;
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}
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void RDSDemod::biphase(Real acc, Real d_cphi)
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{
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if (sign(acc) != sign(m_parms.prev_acc)) // two successive of different sign: error detected
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{
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m_parms.tot_errs[m_parms.counter % 2]++;
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}
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if (m_parms.counter % 2 == m_parms.reading_frame) // two successive of the same sing: OK
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{
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// TODO: take action print_delta(sign(acc + prev_acc));
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}
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if (m_parms.counter == 0)
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{
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if (m_parms.tot_errs[1 - m_parms.reading_frame] < m_parms.tot_errs[m_parms.reading_frame])
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{
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m_parms.reading_frame = 1 - m_parms.reading_frame;
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}
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Real qua = (1.0 * abs(m_parms.tot_errs[0] - m_parms.tot_errs[1]) / (m_parms.tot_errs[0] + m_parms.tot_errs[1])) * 100;
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qDebug("RDSDemod::biphase: frame: %d acc: %+6.3f errs: %3d %3d qual: %3.0f%% clk: %7.2f\n",
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m_parms.reading_frame,
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acc,
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m_parms.tot_errs[0],
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m_parms.tot_errs[1],
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qua,
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(d_cphi / (2 * M_PI)) * m_srate);
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m_parms.tot_errs[0] = 0;
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m_parms.tot_errs[1] = 0;
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}
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m_parms.prev_acc = acc; // memorize (z^-1)
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m_parms.counter = (m_parms.counter + 1) % 800;
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}
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Real RDSDemod::filter_lp_2400_iq(Real input, int iqIndex)
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@ -125,38 +212,3 @@ int RDSDemod::sign(Real a)
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{
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return (a >= 0 ? 1 : 0);
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}
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void RDSDemod::biphase(Real acc, Real clockDPhi)
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{
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if (clockDPhi < 0)
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{
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clockDPhi += M_PI;
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}
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double fsc = (m_dPhiSc / (2.0 * M_PI)) * m_srate;
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double fclk = (clockDPhi / (2.0 * M_PI)) * m_srate;
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if (m_counter == 0)
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{
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qDebug("RDSDemod::biphase: frame: %d pll: %.3f (ppm: %+8.3f) clk: %8.1f",
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m_readingFrame,
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fsc,
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((fsc - 19000.0) / 19000.0) * 1000000,
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fclk);
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}
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m_counter = (m_counter + 1) % 800;
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}
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void RDSDemod::print_delta(char b)
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{
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output_bit(b ^ m_dbit);
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m_dbit = b;
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}
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void RDSDemod::output_bit(char b)
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{
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// TODO: return value instead of spitting out
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//printf("%d", b);
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}
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@ -19,49 +19,70 @@
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#ifndef PLUGINS_CHANNEL_BFM_RDSDEMOD_H_
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#define PLUGINS_CHANNEL_BFM_RDSDEMOD_H_
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#include <QObject>
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#include <QHostAddress>
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#include <QUdpSocket>
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#include "dsp/dsptypes.h"
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class RDSDemod
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class RDSDemod : public QObject
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{
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Q_OBJECT
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public:
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RDSDemod();
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~RDSDemod();
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void setSampleRate(int srate);
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void process(Real rdsSample, Real pilotPhaseSample);
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void process(Real rdsSample, Real pilotSample);
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protected:
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void biphase(Real acc, Real d_cphi);
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Real filter_lp_2400_iq(Real in, int iqIndex);
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Real filter_lp_pll(Real input);
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int sign(Real a);
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void biphase(Real acc, Real dPhiClock);
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void print_delta(char b);
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void output_bit(char b);
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private:
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int m_srate;
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Real m_fsc;
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struct
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{
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double subcarr_phi;
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double subcarr_bb[2];
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double clock_offset;
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double clock_phi;
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double prev_clock_phi;
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double lo_clock;
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double prevclock;
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double prev_bb;
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double d_phi_sc;
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double d_cphi;
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double acc;
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double subcarr_sample;
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int c;
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int fmfreq;
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int bytesread;
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int numsamples;
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double loop_out;
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double prev_loop;
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double prev_acc;
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int counter;
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int reading_frame;
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int tot_errs[2];
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} m_parms;
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Real m_xv[2][2+1];
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Real m_yv[2][2+1];
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Real m_xw[2];
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Real m_yw[2];
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Real m_subcarrPhi_1;
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Real m_subcarrBB[2];
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Real m_dPhiSc;
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Real m_subcarrBB_1;
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Real m_rdsClockPhase;
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Real m_rdsClockPhase_1;
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Real m_rdsClockOffset;
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Real m_rdsClockLO;
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Real m_rdsClockLO_1;
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int m_numSamples;
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Real m_acc;
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Real m_acc_1;
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int m_counter;
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int m_readingFrame;
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int m_totErrors[2];
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int m_dbit;
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Real m_xw[1+1];
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Real m_yw[1+1];
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Real m_prev;
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Real m_pilotPrev;
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int m_srate;
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QUdpSocket *m_socket;
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Real m_sampleBuffer[1<<12];
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int m_sampleBufferIndex;
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static const int m_udpSize;
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static const Real m_pllBeta;
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};
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