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https://github.com/f4exb/sdrangel.git
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147 lines
6.3 KiB
C++
147 lines
6.3 KiB
C++
///////////////////////////////////////////////////////////////////////////////////
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// Copyright (C) 2019 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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// (at your option) any later version. //
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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_CHIRPCHATDEMODSINK_H
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#define INCLUDE_CHIRPCHATDEMODSINK_H
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#include <vector>
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#include <queue>
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#include "dsp/channelsamplesink.h"
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#include "dsp/nco.h"
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#include "dsp/interpolator.h"
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#include "dsp/fftwindow.h"
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#include "util/message.h"
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#include "util/movingaverage.h"
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#include "chirpchatdemodsettings.h"
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class BasebandSampleSink;
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class FFTEngine;
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namespace ChirpChatDemodMsg {
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class MsgDecodeSymbols;
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}
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class MessageQueue;
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class ChirpChatDemodSink : public ChannelSampleSink {
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public:
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ChirpChatDemodSink();
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~ChirpChatDemodSink();
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virtual void feed(const SampleVector::const_iterator& begin, const SampleVector::const_iterator& end);
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bool getDemodActive() const { return m_demodActive; }
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void setDecoderMessageQueue(MessageQueue *messageQueue) { m_decoderMsgQueue = messageQueue; }
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void setSpectrumSink(BasebandSampleSink* spectrumSink) { m_spectrumSink = spectrumSink; }
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void applyChannelSettings(int channelSampleRate, int bandwidth, int channelFrequencyOffset, bool force = false);
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void applySettings(const ChirpChatDemodSettings& settings, bool force = false);
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double getCurrentNoiseLevel() const { return m_magsqOffAvg.instantAverage() / (1<<m_settings.m_spreadFactor); }
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double getTotalPower() const { return m_magsqTotalAvg.instantAverage() / (1<<m_settings.m_spreadFactor); }
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private:
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enum ChirpChatState
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{
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ChirpChatStateReset, //!< Reset everything to start all over
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ChirpChatStateDetectPreamble, //!< Look for preamble
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ChirpChatStatePreambleResyc, //!< Synchronize with what is left of preamble chirp
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ChirpChatStatePreamble, //!< Preamble is found and look for SFD start
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ChirpChatStateSkipSFD, //!< Skip SFD
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ChirpChatStateReadPayload,
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ChirpChatStateTest
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};
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ChirpChatDemodSettings m_settings;
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ChirpChatState m_state;
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bool m_demodActive;
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ChirpChatDemodMsg::MsgDecodeSymbols *m_decodeMsg;
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MessageQueue *m_decoderMsgQueue;
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int m_bandwidth;
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int m_channelSampleRate;
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int m_channelFrequencyOffset;
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unsigned int m_chirp;
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unsigned int m_chirp0;
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static const unsigned int m_requiredPreambleChirps = 4; //!< Number of chirps required to estimate preamble
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static const unsigned int m_maxSFDSearchChirps = 8; //!< Maximum number of chirps when looking for SFD after preamble detection
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static const unsigned int m_fftInterpolation = 2; //!< FFT interpolation factor (usually a power of 2)
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FFTEngine *m_fft;
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FFTEngine *m_fftSFD;
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int m_fftSequence;
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int m_fftSFDSequence;
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FFTWindow m_fftWindow;
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Complex *m_downChirps;
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Complex *m_upChirps;
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Complex *m_spectrumLine;
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unsigned int m_fftCounter;
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int m_argMaxHistory[m_requiredPreambleChirps];
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unsigned int m_argMaxHistoryCounter;
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unsigned int m_preambleHistory[m_maxSFDSearchChirps];
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unsigned int m_syncWord;
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double m_magsqMax;
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MovingAverageUtil<double, double, 10> m_magsqOnAvg;
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MovingAverageUtil<double, double, 10> m_magsqOffAvg;
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MovingAverageUtil<double, double, 10> m_magsqTotalAvg;
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std::queue<double> m_magsqQueue;
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unsigned int m_chirpCount; //!< Generic chirp counter
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unsigned int m_sfdSkip; //!< Number of samples in a SFD skip or slide (1/4) period
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unsigned int m_sfdSkipCounter; //!< Counter of skip or slide periods
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NCO m_nco;
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Interpolator m_interpolator;
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Real m_sampleDistanceRemain;
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Real m_interpolatorDistance;
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BasebandSampleSink* m_spectrumSink;
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Complex *m_spectrumBuffer;
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unsigned int m_nbSymbols; //!< Number of symbols = length of base FFT
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unsigned int m_nbSymbolsEff; //!< effective symbols considering DE bits
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unsigned int m_fftLength; //!< Length of base FFT
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unsigned int m_interpolatedFFTLength; //!< Length of interpolated FFT
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int m_deLength; //!< Number of FFT bins collated to represent one symbol
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int m_preambleTolerance; //!< Number of FFT bins to collate when looking for preamble
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void processSample(const Complex& ci);
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void initSF(unsigned int sf, unsigned int deBits, FFTWindow::Function fftWindow); //!< Init tables, FFTs, depending on spread factor
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void reset();
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unsigned int argmax(
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const Complex *fftBins,
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unsigned int fftMult,
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unsigned int fftLength,
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double& magsqMax,
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double& magSqTotal,
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Complex *specBuffer,
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unsigned int specDecim
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);
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unsigned int argmaxSpreaded( //!< count energy in adjacent bins for same symbol (needs DE bits > 0)
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const Complex *fftBins,
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unsigned int fftMult,
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unsigned int fftLength,
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double& magsqMax,
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double& magsqNoise,
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double& magSqTotal,
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Complex *specBuffer,
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unsigned int specDecim
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);
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void decimateSpectrum(Complex *in, Complex *out, unsigned int size, unsigned int decimation);
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int toSigned(int u, int intSize);
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unsigned int evalSymbol(unsigned int rawSymbol);
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};
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#endif // INCLUDE_CHIRPCHATDEMODSINK_H
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