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sdrangel/plugins/channel/wfm/wfmdemod.cpp
2014-11-21 15:41:58 +00:00

118 lines
4.2 KiB
C++

///////////////////////////////////////////////////////////////////////////////////
// Copyright (C) 2012 maintech GmbH, Otto-Hahn-Str. 15, 97204 Hoechberg, Germany //
// written by Christian Daniel //
// //
// This program is free software; you can redistribute it and/or modify //
// it under the terms of the GNU General Public License as published by //
// the Free Software Foundation as version 3 of the License, or //
// //
// This program is distributed in the hope that it will be useful, //
// but WITHOUT ANY WARRANTY; without even the implied warranty of //
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the //
// GNU General Public License V3 for more details. //
// //
// You should have received a copy of the GNU General Public License //
// along with this program. If not, see <http://www.gnu.org/licenses/>. //
///////////////////////////////////////////////////////////////////////////////////
#include <QTime>
#include <stdio.h>
#include "wfmdemod.h"
#include "audio/audiooutput.h"
#include "dsp/dspcommands.h"
MESSAGE_CLASS_DEFINITION(WFMDemod::MsgConfigureWFMDemod, Message)
WFMDemod::WFMDemod(AudioFifo* audioFifo, SampleSink* sampleSink) :
m_sampleSink(sampleSink),
m_audioFifo(audioFifo)
{
m_volume = 2.0;
m_sampleRate = 250000;
m_frequency = 0;
m_nco.setFreq(m_frequency, m_sampleRate);
m_interpolator.create(16, m_sampleRate, 16000);
m_sampleDistanceRemain = (Real)m_sampleRate / 48000.0;
m_audioBuffer.resize(256);
m_audioBufferFill = 0;
}
WFMDemod::~WFMDemod()
{
}
void WFMDemod::configure(MessageQueue* messageQueue, Real afBandwidth, Real volume)
{
Message* cmd = MsgConfigureWFMDemod::create(afBandwidth, volume);
cmd->submit(messageQueue, this);
}
void WFMDemod::feed(SampleVector::const_iterator begin, SampleVector::const_iterator end, bool positiveOnly)
{
Complex ci;
bool consumed;
qint16 sample;
Real demod;
for(SampleVector::const_iterator it = begin; it < end; ++it) {
Complex c(it->real() , it->imag());
Complex d = c * conj(m_lastSample);
m_lastSample = c;
demod = atan2(d.imag(), d.real()) * (1 /M_PI);
Complex e(demod, 0);
consumed = false;
if(m_interpolator.interpolate(&m_sampleDistanceRemain, e, &consumed, &ci)) {
sample = (qint16)(3000.0 * ci.real() * m_volume);
m_sampleBuffer.push_back(Sample(sample, sample));
m_audioBuffer[m_audioBufferFill].l = sample;
m_audioBuffer[m_audioBufferFill].r = sample;
++m_audioBufferFill;
if(m_audioBufferFill >= m_audioBuffer.size()) {
uint res = m_audioFifo->write((const quint8*)&m_audioBuffer[0], m_audioBufferFill, 1);
if(res != m_audioBufferFill)
qDebug("lost %u samples", m_audioBufferFill - res);
m_audioBufferFill = 0;
}
m_sampleDistanceRemain += (Real)m_sampleRate / 48000.0;
}
}
if(m_audioFifo->write((const quint8*)&m_audioBuffer[0], m_audioBufferFill, 0) != m_audioBufferFill)
qDebug("lost samples");
m_audioBufferFill = 0;
if(m_sampleSink != NULL)
m_sampleSink->feed(m_sampleBuffer.begin(), m_sampleBuffer.end(), true);
m_sampleBuffer.clear();
}
void WFMDemod::start() {}
void WFMDemod::stop() {}
bool WFMDemod::handleMessage(Message* cmd)
{
if(DSPSignalNotification::match(cmd)) {
DSPSignalNotification* signal = (DSPSignalNotification*)cmd;
qDebug("%d samples/sec, %lld Hz offset", signal->getSampleRate(), signal->getFrequencyOffset());
m_sampleRate = signal->getSampleRate();
m_interpolator.create(16, m_sampleRate, m_afBandwidth);
m_sampleDistanceRemain = m_sampleRate / 48000.0;
cmd->completed();
return true;
} else if(MsgConfigureWFMDemod::match(cmd)) {
MsgConfigureWFMDemod* cfg = (MsgConfigureWFMDemod*)cmd;
m_afBandwidth = cfg->getAFBandwidth();
m_interpolator.create(16, m_sampleRate, m_afBandwidth);
m_volume = cfg->getVolume();
cmd->completed();
return true;
} else {
if(m_sampleSink != NULL)
return m_sampleSink->handleMessage(cmd);
else return false;
}
}