mirror of
https://github.com/f4exb/sdrangel.git
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223 lines
6.3 KiB
C++
223 lines
6.3 KiB
C++
///////////////////////////////////////////////////////////////////////////////////
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// Copyright (C) 2015 Edouard Griffiths, F4EXB. //
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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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#ifndef INCLUDE_AMDEMOD_H
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#define INCLUDE_AMDEMOD_H
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#include <dsp/basebandsamplesink.h>
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#include <QMutex>
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#include <vector>
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#include "dsp/nco.h"
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#include "dsp/interpolator.h"
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#include "dsp/movingaverage.h"
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#include "dsp/agc.h"
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#include "dsp/bandpass.h"
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#include "audio/audiofifo.h"
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#include "util/message.h"
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class AMDemod : public BasebandSampleSink {
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Q_OBJECT
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public:
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AMDemod();
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~AMDemod();
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void configure(MessageQueue* messageQueue, Real rfBandwidth, Real volume, Real squelch, bool audioMute, bool bandpassEnable);
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virtual void feed(const SampleVector::const_iterator& begin, const SampleVector::const_iterator& end, bool po);
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virtual void start();
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virtual void stop();
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virtual bool handleMessage(const Message& cmd);
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double getMagSq() const { return m_magsq; }
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bool getSquelchOpen() const { return m_squelchOpen; }
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void getMagSqLevels(double& avg, double& peak, int& nbSamples)
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{
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avg = m_magsqCount == 0 ? 1e-10 : m_magsqSum / m_magsqCount;
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peak = m_magsqPeak == 0.0 ? 1e-10 : m_magsqPeak;
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nbSamples = m_magsqCount == 0 ? 1 : m_magsqCount;
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m_magsqSum = 0.0f;
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m_magsqPeak = 0.0f;
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m_magsqCount = 0;
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}
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private:
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class MsgConfigureAMDemod : public Message {
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MESSAGE_CLASS_DECLARATION
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public:
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Real getRFBandwidth() const { return m_rfBandwidth; }
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Real getVolume() const { return m_volume; }
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Real getSquelch() const { return m_squelch; }
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bool getAudioMute() const { return m_audioMute; }
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bool getBandpassEnable() const { return m_bandpassEnable; }
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static MsgConfigureAMDemod* create(Real rfBandwidth, Real volume, Real squelch, bool audioMute, bool bandpassEnable)
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{
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return new MsgConfigureAMDemod(rfBandwidth, volume, squelch, audioMute, bandpassEnable);
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}
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private:
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Real m_rfBandwidth;
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Real m_volume;
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Real m_squelch;
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bool m_audioMute;
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bool m_bandpassEnable;
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MsgConfigureAMDemod(Real rfBandwidth, Real volume, Real squelch, bool audioMute, bool bandpassEnable) :
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Message(),
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m_rfBandwidth(rfBandwidth),
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m_volume(volume),
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m_squelch(squelch),
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m_audioMute(audioMute),
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m_bandpassEnable(bandpassEnable)
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{ }
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};
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enum RateState {
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RSInitialFill,
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RSRunning
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};
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struct Config {
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int m_inputSampleRate;
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qint64 m_inputFrequencyOffset;
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Real m_rfBandwidth;
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Real m_squelch;
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Real m_volume;
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quint32 m_audioSampleRate;
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bool m_audioMute;
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bool m_bandpassEnable;
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Config() :
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m_inputSampleRate(-1),
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m_inputFrequencyOffset(0),
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m_rfBandwidth(-1),
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m_squelch(0),
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m_volume(0),
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m_audioSampleRate(0),
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m_audioMute(false),
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m_bandpassEnable(false)
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{ }
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};
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Config m_config;
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Config m_running;
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NCO m_nco;
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Interpolator m_interpolator;
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Real m_interpolatorDistance;
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Real m_interpolatorDistanceRemain;
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Real m_squelchLevel;
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uint32_t m_squelchCount;
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bool m_squelchOpen;
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double m_magsq;
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double m_magsqSum;
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double m_magsqPeak;
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int m_magsqCount;
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MovingAverage<double> m_movingAverage;
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SimpleAGC m_volumeAGC;
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Bandpass<Real> m_bandpass;
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AudioVector m_audioBuffer;
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uint m_audioBufferFill;
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AudioFifo m_audioFifo;
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QMutex m_settingsMutex;
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void apply();
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void processOneSample(Complex &ci)
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{
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Real magsq = ci.real() * ci.real() + ci.imag() * ci.imag();
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magsq /= (1<<30);
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m_movingAverage.feed(magsq);
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m_magsq = m_movingAverage.average();
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m_magsqSum += magsq;
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if (magsq > m_magsqPeak)
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{
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m_magsqPeak = magsq;
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}
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m_magsqCount++;
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if (m_magsq >= m_squelchLevel)
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{
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if (m_squelchCount <= m_running.m_audioSampleRate / 10)
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{
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if (m_squelchCount == m_running.m_audioSampleRate / 20) {
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m_volumeAGC.fill(1.0);
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}
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m_squelchCount++;
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}
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}
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else
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{
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if (m_squelchCount > 1)
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{
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m_squelchCount -= 2;
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}
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}
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qint16 sample;
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if ((m_squelchCount >= m_running.m_audioSampleRate / 20) && !m_running.m_audioMute)
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{
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Real demod = sqrt(magsq);
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m_volumeAGC.feed(demod);
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demod = (demod - m_volumeAGC.getValue()) / m_volumeAGC.getValue();
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if (m_running.m_bandpassEnable)
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{
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demod = m_bandpass.filter(demod);
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demod /= 301.0f;
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}
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Real attack = (m_squelchCount - 0.05f * m_running.m_audioSampleRate) / (0.05f * m_running.m_audioSampleRate);
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sample = (0.5 - demod) * attack * 2048 * m_running.m_volume;
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m_squelchOpen = true;
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}
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else
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{
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sample = 0;
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m_squelchOpen = false;
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}
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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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{
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uint res = m_audioFifo.write((const quint8*)&m_audioBuffer[0], m_audioBufferFill, 10);
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if (res != m_audioBufferFill)
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{
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qDebug("AMDemod::feed: %u/%u audio samples written", res, m_audioBufferFill);
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}
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m_audioBufferFill = 0;
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}
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}
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};
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#endif // INCLUDE_AMDEMOD_H
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