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Normal WideFM demod.

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This commit is contained in:
John Greb 2014-12-24 00:47:16 +00:00
parent 346260eb25
commit a7bc5d649e
1 changed files with 8 additions and 16 deletions
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24
plugins/channel/wfm/wfmdemod.cpp
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@ -51,26 +51,21 @@ void WFMDemod::configure(MessageQueue* messageQueue, Real afBandwidth, Real volu
cmd->submit(messageQueue, this); cmd->submit(messageQueue, this);
} }
/*
* Experimental. Code taken from RTL_FM does not work as well here as it does there.
*/
void WFMDemod::feed(SampleVector::const_iterator begin, SampleVector::const_iterator end, bool positiveOnly) void WFMDemod::feed(SampleVector::const_iterator begin, SampleVector::const_iterator end, bool positiveOnly)
{ {
qint16 sample; qint16 sample;
double meansqr = 1.0; Real x, y, demod;
for(SampleVector::const_iterator it = begin; it < end; ++it) { for(SampleVector::const_iterator it = begin; it < end; ++it) {
Real a = m_scale * m_this.real() * (m_last.imag() - it->imag()); x = it->real() * m_last.real() + it->imag() * m_last.imag();
Real b = m_scale * m_this.imag() * (m_last.real() - it->real()); y = it->real() * m_last.imag() - it->imag() * m_last.real();
m_last = m_this; m_last = Complex(it->real(), it->imag());
m_this = Complex(it->real(), it->imag()); demod = atan2(y, x);
Complex e(b - a, 0);
Complex c;
meansqr += it->real() * it->real() + it->imag() * it->imag();
Complex e(demod, 0);
Complex c;
if(m_interpolator.interpolate(&m_sampleDistanceRemain, e, &c)) { if(m_interpolator.interpolate(&m_sampleDistanceRemain, e, &c)) {
// TODO: Volume is a function of bandwidth sample = (qint16)(c.real() * 100 * m_volume * m_volume);
sample = (qint16)(c.real() * m_volume * m_volume);
m_sampleBuffer.push_back(Sample(sample, sample)); m_sampleBuffer.push_back(Sample(sample, sample));
m_audioBuffer[m_audioBufferFill].l = sample; m_audioBuffer[m_audioBufferFill].l = sample;
m_audioBuffer[m_audioBufferFill].r = sample; m_audioBuffer[m_audioBufferFill].r = sample;
@ -91,9 +86,6 @@ void WFMDemod::feed(SampleVector::const_iterator begin, SampleVector::const_iter
if(m_sampleSink != NULL) if(m_sampleSink != NULL)
m_sampleSink->feed(m_sampleBuffer.begin(), m_sampleBuffer.end(), true); m_sampleSink->feed(m_sampleBuffer.begin(), m_sampleBuffer.end(), true);
m_sampleBuffer.clear(); m_sampleBuffer.clear();
// moving average auto-gain
m_scale = 0.8 * m_scale + 0.2 * ( end - begin) * 20.0 / meansqr;
} }
void WFMDemod::start() {} void WFMDemod::start() {}