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FreeDV demod: implemented interpolator/decimator

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This commit is contained in:
f4exb 2019-06-09 19:04:32 +02:00
parent fb0ec4a680
commit 8d493a9d2d
2 changed files with 69 additions and 52 deletions
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120
plugins/channelrx/demodfreedv/freedvdemod.cpp
View File

@ -266,62 +266,22 @@ void FreeDVDemod::feed(const SampleVector::const_iterator& begin, const SampleVe
Complex c(it->real(), it->imag());
c *= m_nco.nextIQ();
if(m_interpolator.decimate(&m_interpolatorDistanceRemain, c, &ci))
{
n_out = SSBFilter->runSSB(ci, &sideband, true);
m_interpolatorDistanceRemain += m_interpolatorDistance;
}
else
{
n_out = 0;
}
for (int i = 0; i < n_out; i++)
{
// Downsample by 2^(m_scaleLog2 - 1) for SSB band spectrum display
// smart decimation with bit gain using float arithmetic (23 bits significand)
m_sum += sideband[i];
if (!(m_undersampleCount++ & decim_mask))
{
Real avgr = m_sum.real() / decim;
Real avgi = m_sum.imag() / decim;
m_magsq = (avgr * avgr + avgi * avgi) / (SDR_RX_SCALED*SDR_RX_SCALED);
m_magsqSum += m_magsq;
if (m_magsq > m_magsqPeak)
{
m_magsqPeak = m_magsq;
}
m_magsqCount++;
m_sampleBuffer.push_back(Sample(avgr, avgi));
m_sum.real(0.0);
m_sum.imag(0.0);
}
// fftfilt::cmplx z = sideband[i];
// Real demod = (z.real() + z.imag()) * 0.7;
Real demod = sideband[i].real(); // works as good
if (m_agcActive)
if (m_interpolatorDistance < 1.0f) // interpolate
{
while (!m_interpolator.interpolate(&m_interpolatorDistanceRemain, c, &ci))
{
m_simpleAGC.feed(demod);
demod *= (m_settings.m_volumeIn * 3276.8f) / m_simpleAGC.getValue(); // provision for peak to average ratio (here 10) compensated by m_volumeIn
// if (i == 0) {
// qDebug("FreeDVDemod::feed: m_simpleAGC: %f", m_simpleAGC.getValue());
// }
processOneSample(ci);
m_interpolatorDistanceRemain += m_interpolatorDistance;
}
else
}
else
{
if (m_interpolator.decimate(&m_interpolatorDistanceRemain, c, &ci))
{
demod *= m_settings.m_volumeIn;
processOneSample(ci);
m_interpolatorDistanceRemain += m_interpolatorDistance;
}
pushSampleToDV((qint16) demod);
}
}
}
uint res = m_audioFifo.write((const quint8*)&m_audioBuffer[0], m_audioBufferFill);
@ -343,6 +303,62 @@ void FreeDVDemod::feed(const SampleVector::const_iterator& begin, const SampleVe
m_settingsMutex.unlock();
}
void FreeDVDemod::processOneSample(Complex &ci)
{
fftfilt::cmplx *sideband;
int n_out = 0;
int decim = 1<<(m_spanLog2 - 1);
unsigned char decim_mask = decim - 1; // counter LSB bit mask for decimation by 2^(m_scaleLog2 - 1)
n_out = SSBFilter->runSSB(ci, &sideband, true); // always USB side
for (int i = 0; i < n_out; i++)
{
// Downsample by 2^(m_scaleLog2 - 1) for SSB band spectrum display
// smart decimation with bit gain using float arithmetic (23 bits significand)
m_sum += sideband[i];
if (!(m_undersampleCount++ & decim_mask))
{
Real avgr = m_sum.real() / decim;
Real avgi = m_sum.imag() / decim;
m_magsq = (avgr * avgr + avgi * avgi) / (SDR_RX_SCALED*SDR_RX_SCALED);
m_magsqSum += m_magsq;
if (m_magsq > m_magsqPeak)
{
m_magsqPeak = m_magsq;
}
m_magsqCount++;
m_sampleBuffer.push_back(Sample(avgr, avgi));
m_sum.real(0.0);
m_sum.imag(0.0);
}
// fftfilt::cmplx z = sideband[i];
// Real demod = (z.real() + z.imag()) * 0.7;
Real demod = sideband[i].real(); // works as good
if (m_agcActive)
{
m_simpleAGC.feed(demod);
demod *= (m_settings.m_volumeIn * 3276.8f) / m_simpleAGC.getValue(); // provision for peak to average ratio (here 10) compensated by m_volumeIn
// if (i == 0) {
// qDebug("FreeDVDemod::feed: m_simpleAGC: %f", m_simpleAGC.getValue());
// }
}
else
{
demod *= m_settings.m_volumeIn;
}
pushSampleToDV((qint16) demod);
}
}
void FreeDVDemod::start()
{
applyChannelSettings(m_inputSampleRate, m_inputFrequencyOffset, true);

1
plugins/channelrx/demodfreedv/freedvdemod.h
View File

@ -417,6 +417,7 @@ private:
void applySettings(const FreeDVDemodSettings& settings, bool force = false);
void applyAudioSampleRate(int sampleRate);
void applyFreeDVMode(FreeDVDemodSettings::FreeDVMode mode);
void processOneSample(Complex &ci);
void webapiFormatChannelSettings(SWGSDRangel::SWGChannelSettings& response, const FreeDVDemodSettings& settings);
void webapiFormatChannelReport(SWGSDRangel::SWGChannelReport& response);
void webapiReverseSendSettings(QList<QString>& channelSettingsKeys, const FreeDVDemodSettings& settings, bool force);