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129 lines
4.5 KiB
C++
129 lines
4.5 KiB
C++
///////////////////////////////////////////////////////////////////////////////////
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// Copyright (C) 2012 maintech GmbH, Otto-Hahn-Str. 15, 97204 Hoechberg, Germany //
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// written by Christian Daniel //
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// (c) 2014 Modified by John Greb
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// //
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// This program is free software; you can redistribute it and/or modify //
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// it under the terms of the GNU General Public License as published by //
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// the Free Software Foundation as version 3 of the License, or //
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// //
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// This program is distributed in the hope that it will be useful, //
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// but WITHOUT ANY WARRANTY; without even the implied warranty of //
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the //
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// GNU General Public License V3 for more details. //
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// //
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// You should have received a copy of the GNU General Public License //
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// along with this program. If not, see <http://www.gnu.org/licenses/>. //
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///////////////////////////////////////////////////////////////////////////////////
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#include <QTime>
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#include <stdio.h>
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#include "ssbdemod.h"
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#include "audio/audiooutput.h"
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#include "dsp/dspcommands.h"
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MESSAGE_CLASS_DEFINITION(SSBDemod::MsgConfigureSSBDemod, Message)
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SSBDemod::SSBDemod(AudioFifo* audioFifo, SampleSink* sampleSink) :
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m_sampleSink(sampleSink),
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m_audioFifo(audioFifo)
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{
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m_Bandwidth = 5000;
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m_volume = 2.0;
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m_sampleRate = 96000;
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m_frequency = 0;
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m_nco.setFreq(m_frequency, m_sampleRate);
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m_interpolator.create(16, m_sampleRate, 5000);
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m_sampleDistanceRemain = (Real)m_sampleRate / 48000.0;
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m_lowpass.create(21, 48000, 5000);
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m_audioBuffer.resize(512);
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m_audioBufferFill = 0;
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m_undersampleCount = 0;
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}
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SSBDemod::~SSBDemod()
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{
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}
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void SSBDemod::configure(MessageQueue* messageQueue, Real Bandwidth, Real volume)
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{
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Message* cmd = MsgConfigureSSBDemod::create(Bandwidth, volume);
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cmd->submit(messageQueue, this);
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}
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void SSBDemod::feed(SampleVector::const_iterator begin, SampleVector::const_iterator end, bool positiveOnly)
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{
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Complex ci;
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bool consumed;
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for(SampleVector::const_iterator it = begin; it < end; ++it) {
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Complex c(it->real() / 32768.0, it->imag() / 32768.0);
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c *= m_nco.nextIQ();
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consumed = false;
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// could squelch audio if RTL_SDR samplerate is not being fully decimated.
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if(m_interpolator.interpolate(&m_sampleDistanceRemain, c, &consumed, &ci)) {
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Real demod = ci.imag() + ci.real();
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demod = 32768.0 * m_lowpass.filter(demod * 0.7);
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// Downsample by 4x for audio display
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if (!(m_undersampleCount++ & 3))
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m_sampleBuffer.push_back(Sample(demod, 0.0));
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qint16 sample = (qint16)(demod * m_volume);
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m_audioBuffer[m_audioBufferFill].l = sample;
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m_audioBuffer[m_audioBufferFill].r = sample;
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++m_audioBufferFill;
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if(m_audioBufferFill >= m_audioBuffer.size()) {
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uint res = m_audioFifo->write((const quint8*)&m_audioBuffer[0], m_audioBufferFill, 1);
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m_audioBufferFill = 0;
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}
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m_sampleDistanceRemain += (Real)m_sampleRate / 48000.0;
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}
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}
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if(m_audioFifo->write((const quint8*)&m_audioBuffer[0], m_audioBufferFill, 0) != m_audioBufferFill)
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;//qDebug("lost samples");
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m_audioBufferFill = 0;
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if(m_sampleSink != NULL)
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m_sampleSink->feed(m_sampleBuffer.begin(), m_sampleBuffer.end(), true);
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m_sampleBuffer.clear();
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}
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void SSBDemod::start()
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{
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}
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void SSBDemod::stop()
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{
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}
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bool SSBDemod::handleMessage(Message* cmd)
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{
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if(DSPSignalNotification::match(cmd)) {
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DSPSignalNotification* signal = (DSPSignalNotification*)cmd;
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qDebug("%d samples/sec, %lld Hz offset", signal->getSampleRate(), signal->getFrequencyOffset());
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m_sampleRate = signal->getSampleRate();
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m_nco.setFreq(-signal->getFrequencyOffset(), m_sampleRate);
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m_interpolator.create(16, m_sampleRate, m_Bandwidth);
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m_sampleDistanceRemain = m_sampleRate / 48000.0;
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cmd->completed();
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return true;
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} else if(MsgConfigureSSBDemod::match(cmd)) {
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MsgConfigureSSBDemod* cfg = (MsgConfigureSSBDemod*)cmd;
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m_Bandwidth = cfg->getBandwidth();
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m_interpolator.create(16, m_sampleRate, m_Bandwidth);
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m_lowpass.create(21, 48000, cfg->getBandwidth());
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m_volume = cfg->getVolume();
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m_volume *= m_volume * 0.1;
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cmd->completed();
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return true;
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} else {
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if(m_sampleSink != NULL)
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return m_sampleSink->handleMessage(cmd);
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else return false;
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}
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}
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