275 lines
8.2 KiB
C++
275 lines
8.2 KiB
C++
///////////////////////////////////////////////////////////////////////////////////
|
|
// Copyright (C) 2012 maintech GmbH, Otto-Hahn-Str. 15, 97204 Hoechberg, Germany //
|
|
// written by Christian Daniel //
|
|
// //
|
|
// 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/>. //
|
|
///////////////////////////////////////////////////////////////////////////////////
|
|
|
|
#include <QTime>
|
|
#include <stdio.h>
|
|
#include <complex.h>
|
|
#include "nfmdemod.h"
|
|
#include "audio/audiooutput.h"
|
|
#include "dsp/dspcommands.h"
|
|
#include "dsp/pidcontroller.h"
|
|
|
|
MESSAGE_CLASS_DEFINITION(NFMDemod::MsgConfigureNFMDemod, Message)
|
|
|
|
NFMDemod::NFMDemod(AudioFifo* audioFifo, SampleSink* sampleSink) :
|
|
m_sampleSink(sampleSink),
|
|
m_audioFifo(audioFifo)
|
|
{
|
|
m_config.m_inputSampleRate = 500000;
|
|
m_config.m_inputFrequencyOffset = 0;
|
|
m_config.m_rfBandwidth = 12500;
|
|
m_config.m_afBandwidth = 3000;
|
|
m_config.m_squelch = -40.0;
|
|
m_config.m_volume = 2.0;
|
|
m_config.m_audioSampleRate = 44100;
|
|
|
|
apply();
|
|
|
|
m_audioBuffer.resize(16384);
|
|
m_audioBufferFill = 0;
|
|
|
|
m_movingAverage.resize(16, 0);
|
|
}
|
|
|
|
NFMDemod::~NFMDemod()
|
|
{
|
|
}
|
|
|
|
void NFMDemod::configure(MessageQueue* messageQueue, Real rfBandwidth, Real afBandwidth, Real volume, Real squelch)
|
|
{
|
|
Message* cmd = MsgConfigureNFMDemod::create(rfBandwidth, afBandwidth, volume, squelch);
|
|
cmd->submit(messageQueue, this);
|
|
}
|
|
|
|
float arctan2(Real y, Real x)
|
|
{
|
|
Real coeff_1 = M_PI / 4;
|
|
Real coeff_2 = 3 * coeff_1;
|
|
Real abs_y = fabs(y) + 1e-10; // kludge to prevent 0/0 condition
|
|
Real angle;
|
|
if( x>= 0) {
|
|
Real r = (x - abs_y) / (x + abs_y);
|
|
angle = coeff_1 - coeff_1 * r;
|
|
} else {
|
|
Real r = (x + abs_y) / (abs_y - x);
|
|
angle = coeff_2 - coeff_1 * r;
|
|
}
|
|
if(y < 0)
|
|
return(-angle);
|
|
else return(angle);
|
|
}
|
|
|
|
Real angleDist(Real a, Real b)
|
|
{
|
|
Real dist = b - a;
|
|
|
|
while(dist <= M_PI)
|
|
dist += 2 * M_PI;
|
|
while(dist >= M_PI)
|
|
dist -= 2 * M_PI;
|
|
|
|
return dist;
|
|
}
|
|
|
|
void NFMDemod::feed(SampleVector::const_iterator begin, SampleVector::const_iterator end, bool firstOfBurst)
|
|
{
|
|
Complex ci;
|
|
bool consumed;
|
|
|
|
if(m_audioFifo->size() <= 0)
|
|
return;
|
|
|
|
if(m_audioFifo->getSampleRate() != m_config.m_audioSampleRate) {
|
|
m_config.m_audioSampleRate = m_audioFifo->getSampleRate();
|
|
apply();
|
|
}
|
|
|
|
if(firstOfBurst) {
|
|
if(m_audioFifo->isStopped()) {
|
|
if(m_audioFifo->fill() >= m_audioFifo->size() / 8.0) {
|
|
m_audioFifo->setStopped(false);
|
|
m_interpolatorRegulation = 0.9999;
|
|
}
|
|
} else {
|
|
Real err = (Real)m_audioFifo->fill() / ((Real)m_audioFifo->size() / 9.0);
|
|
if(err < 0.999)
|
|
err = 0.999;
|
|
else if(err > 1.001)
|
|
err = 1.001;
|
|
|
|
m_interpolatorRegulation = (m_interpolatorRegulation * 400.0 + err * 1.0) / 401.0;
|
|
|
|
if(m_interpolatorRegulation < 0.99)
|
|
m_interpolatorRegulation = 0.99;
|
|
else if(m_interpolatorRegulation > 1.01)
|
|
m_interpolatorRegulation = 1.01;
|
|
}
|
|
m_interpolatorDistance = m_interpolatorRegulation * (Real)m_running.m_inputSampleRate / (Real)m_running.m_audioSampleRate;
|
|
}
|
|
|
|
for(SampleVector::const_iterator it = begin; it != end; ++it) {
|
|
Complex c(it->real() / 32768.0, it->imag() / 32768.0);
|
|
c *= m_nco.nextIQ();
|
|
|
|
consumed = false;
|
|
while(!consumed) {
|
|
if(m_interpolator.interpolate(&m_interpolatorDistanceRemain, c, &consumed, &ci)) {
|
|
m_sampleBuffer.push_back(Sample(ci.real() * 32767.0, ci.imag() * 32767.0));
|
|
|
|
m_movingAverage.feed(ci.real() * ci.real() + ci.imag() * ci.imag());
|
|
if(m_movingAverage.average() >= m_squelchLevel)
|
|
m_squelchState = m_running.m_audioSampleRate/ 20;
|
|
|
|
qint16 sample;
|
|
|
|
m_squelchState = 999;
|
|
if(m_squelchState > 0) {
|
|
m_squelchState--;
|
|
/*
|
|
Real argument = arg(ci);
|
|
Real demod = argument - m_lastArgument;
|
|
m_lastArgument = argument;
|
|
*/
|
|
|
|
Complex d = conj(m_lastSample) * ci;
|
|
m_lastSample = ci;
|
|
Real demod = atan2(d.imag(), d.real());
|
|
//Real demod = arctan2(d.imag(), d.real());
|
|
/*
|
|
Real argument1 = arg(ci);//atan2(ci.imag(), ci.real());
|
|
Real argument2 = m_lastSample.real();
|
|
Real demod = angleDist(argument2, argument1);
|
|
m_lastSample = Complex(argument1, 0);
|
|
*/
|
|
|
|
|
|
demod /= M_PI;
|
|
|
|
demod = m_lowpass.filter(demod);
|
|
|
|
if(demod < -1)
|
|
demod = -1;
|
|
else if(demod > 1)
|
|
demod = 1;
|
|
|
|
demod *= m_running.m_volume;
|
|
sample = demod * 32700;
|
|
|
|
} else {
|
|
sample = 0;
|
|
qDebug("!!!");
|
|
}
|
|
|
|
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, 1);
|
|
if(res != m_audioBufferFill)
|
|
qDebug("lost %u audio samples", m_audioBufferFill - res);
|
|
m_audioBufferFill = 0;
|
|
}
|
|
|
|
m_interpolatorDistanceRemain += m_interpolatorDistance;
|
|
}
|
|
}
|
|
}
|
|
if(m_audioBufferFill > 0) {
|
|
uint res = m_audioFifo->write((const quint8*)&m_audioBuffer[0], m_audioBufferFill, 1);
|
|
if(res != m_audioBufferFill)
|
|
qDebug("lost %u samples", m_audioBufferFill - res);
|
|
m_audioBufferFill = 0;
|
|
}
|
|
|
|
if(m_sampleSink != NULL)
|
|
m_sampleSink->feed(m_sampleBuffer.begin(), m_sampleBuffer.end(), firstOfBurst);
|
|
m_sampleBuffer.clear();
|
|
}
|
|
|
|
void NFMDemod::start()
|
|
{
|
|
m_squelchState = 0;
|
|
m_audioFifo->clear();
|
|
m_audioFifo->setStopped(true);
|
|
m_interpolatorRegulation = 0.9999;
|
|
m_interpolatorDistance = 1.0;
|
|
m_interpolatorDistanceRemain = 0.0;
|
|
m_lastSample = 0;
|
|
}
|
|
|
|
void NFMDemod::stop()
|
|
{
|
|
}
|
|
|
|
bool NFMDemod::handleMessage(Message* cmd)
|
|
{
|
|
if(DSPSignalNotification::match(cmd)) {
|
|
DSPSignalNotification* signal = DSPSignalNotification::cast(cmd);
|
|
|
|
m_config.m_inputSampleRate = signal->getSampleRate();
|
|
m_config.m_inputFrequencyOffset = signal->getFrequencyOffset();
|
|
apply();
|
|
cmd->completed();
|
|
return true;
|
|
} else if(MsgConfigureNFMDemod::match(cmd)) {
|
|
MsgConfigureNFMDemod* cfg = MsgConfigureNFMDemod::cast(cmd);
|
|
m_config.m_rfBandwidth = cfg->getRFBandwidth();
|
|
m_config.m_afBandwidth = cfg->getAFBandwidth();
|
|
m_config.m_volume = cfg->getVolume();
|
|
m_config.m_squelch = cfg->getSquelch();
|
|
apply();
|
|
return true;
|
|
} else {
|
|
if(m_sampleSink != NULL)
|
|
return m_sampleSink->handleMessage(cmd);
|
|
else return false;
|
|
}
|
|
}
|
|
|
|
void NFMDemod::apply()
|
|
{
|
|
|
|
if((m_config.m_inputFrequencyOffset != m_running.m_inputFrequencyOffset) ||
|
|
(m_config.m_inputSampleRate != m_running.m_inputSampleRate)) {
|
|
m_nco.setFreq(-m_config.m_inputFrequencyOffset, m_config.m_inputSampleRate);
|
|
}
|
|
|
|
if((m_config.m_inputSampleRate != m_running.m_inputSampleRate) ||
|
|
(m_config.m_rfBandwidth != m_running.m_rfBandwidth)) {
|
|
m_interpolator.create(16, m_config.m_inputSampleRate, m_config.m_rfBandwidth / 2.2);
|
|
m_interpolatorDistanceRemain = 0;
|
|
m_interpolatorDistance = 1.0;
|
|
}
|
|
|
|
if((m_config.m_afBandwidth != m_running.m_afBandwidth) ||
|
|
(m_config.m_audioSampleRate != m_running.m_audioSampleRate)) {
|
|
m_lowpass.create(21, m_config.m_audioSampleRate, m_config.m_afBandwidth);
|
|
}
|
|
|
|
if(m_config.m_squelch != m_running.m_squelch) {
|
|
m_squelchLevel = pow(10.0, m_config.m_squelch / 20.0);
|
|
m_squelchLevel *= m_squelchLevel;
|
|
}
|
|
|
|
m_running.m_inputSampleRate = m_config.m_inputSampleRate;
|
|
m_running.m_inputFrequencyOffset = m_config.m_inputFrequencyOffset;
|
|
m_running.m_rfBandwidth = m_config.m_rfBandwidth;
|
|
m_running.m_squelch = m_config.m_squelch;
|
|
m_running.m_volume = m_config.m_volume;
|
|
m_running.m_audioSampleRate = m_config.m_audioSampleRate;
|
|
}
|