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sdrangel/plugins/channel/tetra/tetrademod.cpp
2014-06-15 09:32:25 +01:00

107 lines
3.5 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 <stdio.h>
#include "tetrademod.h"
#include "dsp/dspcommands.h"
MessageRegistrator TetraDemod::MsgConfigureTetraDemod::ID("MsgConfigureTetraDemod");
static FILE* f = NULL;
TetraDemod::TetraDemod(SampleSink* sampleSink) :
m_sampleSink(sampleSink)
{
m_sampleRate = 500000;
m_frequency = 0;
m_nco.setFreq(m_frequency, m_sampleRate);
m_interpolator.create(32, 32 * m_sampleRate, 36000);
m_sampleDistanceRemain = (Real)m_sampleRate / 36000.0;
}
TetraDemod::~TetraDemod()
{
}
void TetraDemod::configure(MessageQueue* messageQueue)
{
Message* cmd = MsgConfigureTetraDemod::create();
cmd->submit(messageQueue, this);
}
void TetraDemod::feed(SampleVector::const_iterator begin, SampleVector::const_iterator end, bool positiveOnly)
{
size_t count = end - begin;
Complex ci;
bool consumed;
for(SampleVector::const_iterator it = begin; it < end; ++it) {
Complex c(it->real() / 32768.0, it->imag() / 32768.0);
c *= m_nco.nextIQ();
consumed = false;
if(m_interpolator.interpolate(&m_sampleDistanceRemain, c, &consumed, &ci)) {
m_sampleBuffer.push_back(Sample(ci.real() * 32768.0, ci.imag() * 32768.0));
m_sampleDistanceRemain += (Real)m_sampleRate / 36000.0;
}
}
if(f != NULL) {
fwrite(&m_sampleBuffer[0], m_sampleBuffer.size(), sizeof(m_sampleBuffer[0]), f);
}
if(m_sampleSink != NULL)
m_sampleSink->feed(m_sampleBuffer.begin(), m_sampleBuffer.end(), positiveOnly);
m_sampleBuffer.clear();
}
void TetraDemod::start()
{
}
void TetraDemod::stop()
{
}
bool TetraDemod::handleMessage(Message* cmd)
{
if(cmd->id() == DSPSignalNotification::ID()) {
DSPSignalNotification* signal = (DSPSignalNotification*)cmd;
qDebug("%d samples/sec, %lld Hz offset", signal->getSampleRate(), signal->getFrequencyOffset());
m_sampleRate = signal->getSampleRate();
m_nco.setFreq(-signal->getFrequencyOffset(), m_sampleRate);
m_interpolator.create(32, m_sampleRate, 25000 / 2);
m_sampleDistanceRemain = m_sampleRate / 36000.0;
cmd->completed();
return true;
} else if(cmd->id() == MsgConfigureTetraDemod::ID()) {
if(f == NULL) {
f = fopen("/tmp/tetra.iq", "wb");
qDebug("started writing samples");
} else {
fclose(f);
f = NULL;
qDebug("stopped writing samples");
}
} else {
return false;
}
}