sdrangel/plugins/channelrx/demodam/amdemod.h

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6.4 KiB
C++

///////////////////////////////////////////////////////////////////////////////////
// Copyright (C) 2015 Edouard Griffiths, F4EXB. //
// //
// 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/>. //
///////////////////////////////////////////////////////////////////////////////////
#ifndef INCLUDE_AMDEMOD_H
#define INCLUDE_AMDEMOD_H
#include <dsp/basebandsamplesink.h>
#include <QMutex>
#include <vector>
#include "dsp/nco.h"
#include "dsp/interpolator.h"
#include "dsp/movingaverage.h"
#include "dsp/agc.h"
#include "dsp/bandpass.h"
#include "audio/audiofifo.h"
#include "util/message.h"
class AMDemod : public BasebandSampleSink {
Q_OBJECT
public:
AMDemod();
~AMDemod();
void configure(MessageQueue* messageQueue, Real rfBandwidth, Real volume, Real squelch, bool audioMute, bool bandpassEnable);
virtual void feed(const SampleVector::const_iterator& begin, const SampleVector::const_iterator& end, bool po);
virtual void start();
virtual void stop();
virtual bool handleMessage(const Message& cmd);
double getMagSq() const { return m_magsq; }
bool getSquelchOpen() const { return m_squelchOpen; }
void getMagSqLevels(double& avg, double& peak, int& nbSamples)
{
avg = m_magsqCount == 0 ? 1e-10 : m_magsqSum / m_magsqCount;
peak = m_magsqPeak == 0.0 ? 1e-10 : m_magsqPeak;
nbSamples = m_magsqCount == 0 ? 1 : m_magsqCount;
m_magsqSum = 0.0f;
m_magsqPeak = 0.0f;
m_magsqCount = 0;
}
private:
class MsgConfigureAMDemod : public Message {
MESSAGE_CLASS_DECLARATION
public:
Real getRFBandwidth() const { return m_rfBandwidth; }
Real getVolume() const { return m_volume; }
Real getSquelch() const { return m_squelch; }
bool getAudioMute() const { return m_audioMute; }
bool getBandpassEnable() const { return m_bandpassEnable; }
static MsgConfigureAMDemod* create(Real rfBandwidth, Real volume, Real squelch, bool audioMute, bool bandpassEnable)
{
return new MsgConfigureAMDemod(rfBandwidth, volume, squelch, audioMute, bandpassEnable);
}
private:
Real m_rfBandwidth;
Real m_volume;
Real m_squelch;
bool m_audioMute;
bool m_bandpassEnable;
MsgConfigureAMDemod(Real rfBandwidth, Real volume, Real squelch, bool audioMute, bool bandpassEnable) :
Message(),
m_rfBandwidth(rfBandwidth),
m_volume(volume),
m_squelch(squelch),
m_audioMute(audioMute),
m_bandpassEnable(bandpassEnable)
{ }
};
struct AudioSample {
qint16 l;
qint16 r;
};
typedef std::vector<AudioSample> AudioVector;
enum RateState {
RSInitialFill,
RSRunning
};
struct Config {
int m_inputSampleRate;
qint64 m_inputFrequencyOffset;
Real m_rfBandwidth;
Real m_squelch;
Real m_volume;
quint32 m_audioSampleRate;
bool m_audioMute;
bool m_bandpassEnable;
Config() :
m_inputSampleRate(-1),
m_inputFrequencyOffset(0),
m_rfBandwidth(-1),
m_squelch(0),
m_volume(0),
m_audioSampleRate(0),
m_audioMute(false),
m_bandpassEnable(false)
{ }
};
Config m_config;
Config m_running;
NCO m_nco;
Interpolator m_interpolator;
Real m_interpolatorDistance;
Real m_interpolatorDistanceRemain;
Real m_squelchLevel;
uint32_t m_squelchCount;
bool m_squelchOpen;
double m_magsq;
double m_magsqSum;
double m_magsqPeak;
int m_magsqCount;
MovingAverage<double> m_movingAverage;
SimpleAGC m_volumeAGC;
Bandpass<Real> m_bandpass;
AudioVector m_audioBuffer;
uint m_audioBufferFill;
AudioFifo m_audioFifo;
QMutex m_settingsMutex;
void apply();
void processOneSample(Complex &ci)
{
Real magsq = ci.real() * ci.real() + ci.imag() * ci.imag();
magsq /= (1<<30);
m_movingAverage.feed(magsq);
m_magsq = m_movingAverage.average();
m_magsqSum += magsq;
if (magsq > m_magsqPeak)
{
m_magsqPeak = magsq;
}
m_magsqCount++;
if (m_magsq >= m_squelchLevel)
{
if (m_squelchCount <= m_running.m_audioSampleRate / 10)
{
if (m_squelchCount == m_running.m_audioSampleRate / 20) {
m_volumeAGC.fill(1.0);
}
m_squelchCount++;
}
}
else
{
if (m_squelchCount > 1)
{
m_squelchCount -= 2;
}
}
qint16 sample;
if ((m_squelchCount >= m_running.m_audioSampleRate / 20) && !m_running.m_audioMute)
{
Real demod = sqrt(magsq);
m_volumeAGC.feed(demod);
demod /= m_volumeAGC.getValue();
if (m_running.m_bandpassEnable)
{
demod = m_bandpass.filter(demod);
demod /= 301.0f;
}
Real attack = (m_squelchCount - 0.05f * m_running.m_audioSampleRate) / (0.05f * m_running.m_audioSampleRate);
sample = (0.5 - demod) * attack * 2048 * m_running.m_volume;
m_squelchOpen = true;
}
else
{
sample = 0;
m_squelchOpen = false;
}
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, 10);
if (res != m_audioBufferFill)
{
qDebug("AMDemod::feed: %u/%u audio samples written", res, m_audioBufferFill);
}
m_audioBufferFill = 0;
}
}
};
#endif // INCLUDE_AMDEMOD_H