mirror of https://github.com/f4exb/sdrangel.git
375 lines
10 KiB
C++
375 lines
10 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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// //
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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 <QDebug>
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#include <stdio.h>
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#include <complex.h>
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#include "nfmdemod.h"
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#include "nfmdemodgui.h"
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#include "audio/audiooutput.h"
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#include "dsp/channelizer.h"
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#include "dsp/pidcontroller.h"
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#include "dsp/dspengine.h"
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static const Real afSqTones[2] = {1200.0, 6000.0}; // {1200.0, 8000.0};
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MESSAGE_CLASS_DEFINITION(NFMDemod::MsgConfigureNFMDemod, Message)
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NFMDemod::NFMDemod() :
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m_ctcssIndex(0),
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m_sampleCount(0),
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m_afSquelch(2, afSqTones),
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m_squelchOpen(false),
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m_audioFifo(4, 48000),
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m_settingsMutex(QMutex::Recursive)
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{
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setObjectName("NFMDemod");
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m_config.m_inputSampleRate = 96000;
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m_config.m_inputFrequencyOffset = 0;
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m_config.m_rfBandwidth = 12500;
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m_config.m_afBandwidth = 3000;
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m_config.m_squelch = -30.0;
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m_config.m_volume = 2.0;
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m_config.m_ctcssOn = false;
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m_config.m_audioSampleRate = DSPEngine::instance()->getAudioSampleRate();
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apply();
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m_audioBuffer.resize(1<<14);
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m_audioBufferFill = 0;
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m_movingAverage.resize(16, 0);
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m_agcLevel = 0.003; // 0.003
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//m_AGC.resize(480, m_agcLevel, 0, 0.1*m_agcLevel);
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m_AGC.resize(240, m_agcLevel*m_agcLevel, 0.3);
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m_ctcssDetector.setCoefficients(3000, 6000.0); // 0.5s / 2 Hz resolution
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m_afSquelch.setCoefficients(24, 48000.0, 5, 1); // 4000 Hz span, 250us
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m_afSquelch.setThreshold(0.001);
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DSPEngine::instance()->addAudioSink(&m_audioFifo);
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}
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NFMDemod::~NFMDemod()
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{
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DSPEngine::instance()->removeAudioSink(&m_audioFifo);
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}
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void NFMDemod::configure(MessageQueue* messageQueue,
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Real rfBandwidth,
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Real afBandwidth,
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Real volume,
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Real squelch,
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bool ctcssOn)
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{
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Message* cmd = MsgConfigureNFMDemod::create(rfBandwidth,
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afBandwidth,
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volume,
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squelch,
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ctcssOn);
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messageQueue->push(cmd);
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}
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float arctan2(Real y, Real x)
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{
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Real coeff_1 = M_PI / 4;
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Real coeff_2 = 3 * coeff_1;
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Real abs_y = fabs(y) + 1e-10; // kludge to prevent 0/0 condition
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Real angle;
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if( x>= 0) {
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Real r = (x - abs_y) / (x + abs_y);
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angle = coeff_1 - coeff_1 * r;
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} else {
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Real r = (x + abs_y) / (abs_y - x);
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angle = coeff_2 - coeff_1 * r;
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}
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if(y < 0)
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return(-angle);
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else return(angle);
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}
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Real angleDist(Real a, Real b)
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{
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Real dist = b - a;
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while(dist <= M_PI)
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dist += 2 * M_PI;
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while(dist >= M_PI)
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dist -= 2 * M_PI;
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return dist;
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}
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void NFMDemod::feed(const SampleVector::const_iterator& begin, const SampleVector::const_iterator& end, bool firstOfBurst)
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{
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Complex ci;
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m_settingsMutex.lock();
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for (SampleVector::const_iterator it = begin; it != end; ++it)
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{
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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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{
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if (m_interpolator.interpolate(&m_interpolatorDistanceRemain, c, &ci))
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{
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m_sampleBuffer.push_back(Sample(ci.real() * 32767.0, ci.imag() * 32767.0));
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qint16 sample;
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//m_AGC.feed(abs(ci));
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//ci *= (m_agcLevel / m_AGC.getValue());
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m_AGC.feed(ci);
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// demod
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/*
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Real argument = arg(ci);
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Real demod = argument - m_lastArgument;
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m_lastArgument = argument;
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*/
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/*
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// Original NFM
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Complex d = conj(m_m1Sample) * ci;
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Real demod = atan2(d.imag(), d.real());
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demod /= M_PI;
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*/
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/*
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Real argument1 = arg(ci);//atan2(ci.imag(), ci.real());
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Real argument2 = m_lastSample.real();
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Real demod = angleDist(argument2, argument1);
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m_lastSample = Complex(argument1, 0);
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*/
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// Alternative without atan - needs AGC
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// http://www.embedded.com/design/configurable-systems/4212086/DSP-Tricks--Frequency-demodulation-algorithms-
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Real ip = ci.real() - m_m2Sample.real();
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Real qp = ci.imag() - m_m2Sample.imag();
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Real h1 = m_m1Sample.real() * qp;
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Real h2 = m_m1Sample.imag() * ip;
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Real demod = (h1 - h2) * 10000;
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m_m2Sample = m_m1Sample;
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m_m1Sample = ci;
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m_sampleCount++;
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// AF processing
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if(m_afSquelch.analyze(&demod))
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{
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m_squelchOpen = m_afSquelch.open();
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}
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if (m_squelchOpen)
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{
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if (m_running.m_ctcssOn)
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{
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Real ctcss_sample = m_lowpass.filter(demod);
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if ((m_sampleCount & 7) == 7) // decimate 48k -> 6k
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{
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if (m_ctcssDetector.analyze(&ctcss_sample))
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{
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int maxToneIndex;
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if (m_ctcssDetector.getDetectedTone(maxToneIndex))
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{
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if (maxToneIndex+1 != m_ctcssIndex)
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{
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m_nfmDemodGUI->setCtcssFreq(m_ctcssDetector.getToneSet()[maxToneIndex]);
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m_ctcssIndex = maxToneIndex+1;
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}
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}
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else
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{
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if (m_ctcssIndex != 0)
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{
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m_nfmDemodGUI->setCtcssFreq(0);
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m_ctcssIndex = 0;
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}
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}
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}
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}
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}
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if (m_running.m_ctcssOn && m_ctcssIndexSelected && (m_ctcssIndexSelected != m_ctcssIndex))
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{
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sample = 0;
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}
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else
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{
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demod = m_bandpass.filter(demod);
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demod *= m_running.m_volume;
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sample = demod * ((1<<15)/301); // denominator = bandpass filter number of taps
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}
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m_AGC.openedSquelch();
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}
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else
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{
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if (m_ctcssIndex != 0)
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{
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m_nfmDemodGUI->setCtcssFreq(0);
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m_ctcssIndex = 0;
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}
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m_AGC.closedSquelch();
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sample = 0;
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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("NFMDemod::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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m_interpolatorDistanceRemain += m_interpolatorDistance;
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}
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}
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}
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if (m_audioBufferFill > 0)
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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("NFMDemod::feed: %u/%u tail samples written", res, m_audioBufferFill);
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}
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m_audioBufferFill = 0;
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}
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m_sampleBuffer.clear();
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m_settingsMutex.unlock();
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}
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void NFMDemod::start()
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{
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m_audioFifo.clear();
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m_m1Sample = 0;
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}
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void NFMDemod::stop()
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{
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}
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bool NFMDemod::handleMessage(const Message& cmd)
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{
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qDebug() << "NFMDemod::handleMessage";
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if (Channelizer::MsgChannelizerNotification::match(cmd))
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{
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Channelizer::MsgChannelizerNotification& notif = (Channelizer::MsgChannelizerNotification&) cmd;
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m_config.m_inputSampleRate = notif.getSampleRate();
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m_config.m_inputFrequencyOffset = notif.getFrequencyOffset();
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apply();
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qDebug() << "NFMDemod::handleMessage: MsgChannelizerNotification: m_inputSampleRate: " << m_config.m_inputSampleRate
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<< " m_inputFrequencyOffset: " << m_config.m_inputFrequencyOffset;
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return true;
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}
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else if (MsgConfigureNFMDemod::match(cmd))
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{
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MsgConfigureNFMDemod& cfg = (MsgConfigureNFMDemod&) cmd;
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m_config.m_rfBandwidth = cfg.getRFBandwidth();
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m_config.m_afBandwidth = cfg.getAFBandwidth();
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m_config.m_volume = cfg.getVolume();
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m_config.m_squelch = cfg.getSquelch();
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m_config.m_ctcssOn = cfg.getCtcssOn();
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apply();
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qDebug() << " - MsgConfigureNFMDemod: m_rfBandwidth: " << m_config.m_rfBandwidth
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<< " m_afBandwidth: " << m_config.m_afBandwidth
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<< " m_volume: " << m_config.m_volume
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<< " m_squelch: " << m_config.m_squelch
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<< " m_ctcssOn: " << m_config.m_ctcssOn;
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return true;
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}
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else
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{
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return false;
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}
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}
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void NFMDemod::apply()
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{
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if ((m_config.m_inputFrequencyOffset != m_running.m_inputFrequencyOffset) ||
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(m_config.m_inputSampleRate != m_running.m_inputSampleRate))
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{
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m_nco.setFreq(-m_config.m_inputFrequencyOffset, m_config.m_inputSampleRate);
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}
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if ((m_config.m_inputSampleRate != m_running.m_inputSampleRate) ||
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(m_config.m_rfBandwidth != m_running.m_rfBandwidth))
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{
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m_settingsMutex.lock();
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m_interpolator.create(16, m_config.m_inputSampleRate, m_config.m_rfBandwidth / 2.2);
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m_interpolatorDistanceRemain = 0;
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m_interpolatorDistance = (Real) m_config.m_inputSampleRate / (Real) m_config.m_audioSampleRate;
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m_settingsMutex.unlock();
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}
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if ((m_config.m_afBandwidth != m_running.m_afBandwidth) ||
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(m_config.m_audioSampleRate != m_running.m_audioSampleRate))
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{
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m_settingsMutex.lock();
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m_lowpass.create(301, m_config.m_audioSampleRate, 250.0);
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m_bandpass.create(301, m_config.m_audioSampleRate, 300.0, m_config.m_afBandwidth);
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m_settingsMutex.unlock();
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}
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if (m_config.m_squelch != m_running.m_squelch)
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{
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m_squelchLevel = pow(10.0, m_config.m_squelch / 10.0);
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m_squelchLevel *= m_squelchLevel;
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m_afSquelch.setThreshold(m_squelchLevel);
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m_afSquelch.reset();
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}
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m_running.m_inputSampleRate = m_config.m_inputSampleRate;
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m_running.m_inputFrequencyOffset = m_config.m_inputFrequencyOffset;
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m_running.m_rfBandwidth = m_config.m_rfBandwidth;
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m_running.m_afBandwidth = m_config.m_afBandwidth;
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m_running.m_squelch = m_config.m_squelch;
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m_running.m_volume = m_config.m_volume;
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m_running.m_audioSampleRate = m_config.m_audioSampleRate;
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m_running.m_ctcssOn = m_config.m_ctcssOn;
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}
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