mirror of
https://github.com/f4exb/sdrangel.git
synced 2024-11-17 13:51:47 -05:00
287 lines
7.4 KiB
C++
287 lines
7.4 KiB
C++
///////////////////////////////////////////////////////////////////////////////////
|
|
// Copyright (C) 2019 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 //
|
|
// (at your option) any later version. //
|
|
// //
|
|
// 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 <QDebug>
|
|
#include <stdio.h>
|
|
|
|
#include "dsp/dsptypes.h"
|
|
#include "dsp/basebandsamplesink.h"
|
|
|
|
#include "lorademodsink.h"
|
|
|
|
const int LoRaDemodSink::DATA_BITS = 6;
|
|
const int LoRaDemodSink::SAMPLEBITS = LoRaDemodSink::DATA_BITS + 2;
|
|
const int LoRaDemodSink::SPREADFACTOR = (1 << LoRaDemodSink::SAMPLEBITS);
|
|
const int LoRaDemodSink::LORA_SFFT_LEN = (LoRaDemodSink::SPREADFACTOR / 2);
|
|
const int LoRaDemodSink::LORA_SQUELCH = 3;
|
|
|
|
LoRaDemodSink::LoRaDemodSink() :
|
|
m_spectrumSink(nullptr)
|
|
{
|
|
m_Bandwidth = LoRaDemodSettings::bandwidths[0];
|
|
m_channelSampleRate = 96000;
|
|
m_channelFrequencyOffset = 0;
|
|
m_nco.setFreq(m_channelFrequencyOffset, m_channelSampleRate);
|
|
m_interpolator.create(16, m_channelSampleRate, m_Bandwidth/1.9);
|
|
m_sampleDistanceRemain = (Real) m_channelSampleRate / m_Bandwidth;
|
|
|
|
m_chirp = 0;
|
|
m_angle = 0;
|
|
m_bin = 0;
|
|
m_result = 0;
|
|
m_count = 0;
|
|
m_header = 0;
|
|
m_time = 0;
|
|
m_tune = 0;
|
|
|
|
loraFilter = new sfft(LORA_SFFT_LEN);
|
|
negaFilter = new sfft(LORA_SFFT_LEN);
|
|
mov = new float[4*LORA_SFFT_LEN];
|
|
history = new short[1024];
|
|
finetune = new short[16];
|
|
}
|
|
|
|
LoRaDemodSink::~LoRaDemodSink()
|
|
{
|
|
delete loraFilter;
|
|
delete negaFilter;
|
|
delete [] mov;
|
|
delete [] history;
|
|
delete [] finetune;
|
|
}
|
|
|
|
void LoRaDemodSink::dumpRaw()
|
|
{
|
|
short bin, j, max;
|
|
char text[256];
|
|
|
|
max = m_time / 4 - 3;
|
|
|
|
if (max > 140) {
|
|
max = 140; // about 2 symbols to each char
|
|
}
|
|
|
|
for ( j=0; j < max; j++)
|
|
{
|
|
bin = (history[(j + 1) * 4] + m_tune ) & (LORA_SFFT_LEN - 1);
|
|
text[j] = toGray(bin >> 1);
|
|
}
|
|
|
|
prng6(text, max);
|
|
// First block is always 8 symbols
|
|
interleave6(text, 6);
|
|
interleave6(&text[8], max);
|
|
hamming6(text, 6);
|
|
hamming6(&text[8], max);
|
|
|
|
for ( j=0; j < max / 2; j++)
|
|
{
|
|
text[j] = (text[j * 2 + 1] << 4) | (0xf & text[j * 2 + 0]);
|
|
|
|
if ((text[j] < 32 )||( text[j] > 126)) {
|
|
text[j] = 0x5f;
|
|
}
|
|
}
|
|
|
|
text[3] = text[2];
|
|
text[2] = text[1];
|
|
text[1] = text[0];
|
|
text[j] = 0;
|
|
|
|
qDebug("LoRaDemodSink::dumpRaw: %s", &text[1]);
|
|
}
|
|
|
|
short LoRaDemodSink::synch(short bin)
|
|
{
|
|
short i, j;
|
|
|
|
if (bin < 0)
|
|
{
|
|
if (m_time > 70) {
|
|
dumpRaw();
|
|
}
|
|
|
|
m_time = 0;
|
|
return -1;
|
|
}
|
|
|
|
history[m_time] = bin;
|
|
|
|
if (m_time > 12)
|
|
{
|
|
if (bin == history[m_time - 6])
|
|
{
|
|
if (bin == history[m_time - 12])
|
|
{
|
|
m_tune = LORA_SFFT_LEN - bin;
|
|
j = 0;
|
|
|
|
for (i=0; i<12; i++) {
|
|
j += finetune[15 & (m_time - i)];
|
|
}
|
|
|
|
if (j < 0) {
|
|
m_tune += 1;
|
|
}
|
|
|
|
m_tune &= (LORA_SFFT_LEN - 1);
|
|
m_time = 0;
|
|
return -1;
|
|
}
|
|
}
|
|
}
|
|
|
|
m_time++;
|
|
m_time &= 1023;
|
|
|
|
if (m_time & 3) {
|
|
return -1;
|
|
}
|
|
|
|
return (bin + m_tune) & (LORA_SFFT_LEN - 1);
|
|
}
|
|
|
|
int LoRaDemodSink::detect(Complex c, Complex a)
|
|
{
|
|
int p, q;
|
|
short i, result, negresult, movpoint;
|
|
float peak, negpeak, tfloat;
|
|
float mag[LORA_SFFT_LEN];
|
|
float rev[LORA_SFFT_LEN];
|
|
|
|
loraFilter->run(c * a);
|
|
negaFilter->run(c * conj(a));
|
|
|
|
// process spectrum twice in FFTLEN
|
|
if (++m_count & ((1 << DATA_BITS) - 1)) {
|
|
return m_result;
|
|
}
|
|
|
|
movpoint = 3 & (m_count >> DATA_BITS);
|
|
|
|
loraFilter->fetch(mag);
|
|
negaFilter->fetch(rev);
|
|
peak = negpeak = 0.0f;
|
|
result = negresult = 0;
|
|
|
|
for (i = 0; i < LORA_SFFT_LEN; i++)
|
|
{
|
|
if (rev[i] > negpeak)
|
|
{
|
|
negpeak = rev[i];
|
|
negresult = i;
|
|
}
|
|
|
|
tfloat = mov[i] + mov[LORA_SFFT_LEN + i] +mov[2 * LORA_SFFT_LEN + i]
|
|
+ mov[3 * LORA_SFFT_LEN + i] + mag[i];
|
|
|
|
if (tfloat > peak)
|
|
{
|
|
peak = tfloat;
|
|
result = i;
|
|
}
|
|
|
|
mov[movpoint * LORA_SFFT_LEN + i] = mag[i];
|
|
}
|
|
|
|
p = (result - 1 + LORA_SFFT_LEN) & (LORA_SFFT_LEN -1);
|
|
q = (result + 1) & (LORA_SFFT_LEN -1);
|
|
finetune[15 & m_time] = (mag[p] > mag[q]) ? -1 : 1;
|
|
|
|
if (peak < negpeak * LORA_SQUELCH)
|
|
{
|
|
result = -1;
|
|
}
|
|
|
|
result = synch(result);
|
|
|
|
if (result >= 0) {
|
|
m_result = result;
|
|
}
|
|
|
|
return m_result;
|
|
}
|
|
|
|
void LoRaDemodSink::feed(const SampleVector::const_iterator& begin, const SampleVector::const_iterator& end)
|
|
{
|
|
int newangle;
|
|
Complex ci;
|
|
|
|
m_sampleBuffer.clear();
|
|
|
|
for (SampleVector::const_iterator it = begin; it < end; ++it)
|
|
{
|
|
Complex c(it->real() / SDR_RX_SCALEF, it->imag() / SDR_RX_SCALEF);
|
|
c *= m_nco.nextIQ();
|
|
|
|
if (m_interpolator.decimate(&m_sampleDistanceRemain, c, &ci))
|
|
{
|
|
m_chirp = (m_chirp + 1) & (SPREADFACTOR - 1);
|
|
m_angle = (m_angle + m_chirp) & (SPREADFACTOR - 1);
|
|
Complex cangle(cos(M_PI*2*m_angle/SPREADFACTOR),-sin(M_PI*2*m_angle/SPREADFACTOR));
|
|
newangle = detect(ci, cangle);
|
|
|
|
m_bin = (m_bin + newangle) & (LORA_SFFT_LEN - 1);
|
|
Complex nangle(cos(M_PI*2*m_bin/LORA_SFFT_LEN),sin(M_PI*2*m_bin/LORA_SFFT_LEN));
|
|
m_sampleBuffer.push_back(Sample(nangle.real() * 100, nangle.imag() * 100));
|
|
m_sampleDistanceRemain += (Real) m_channelSampleRate / m_Bandwidth;
|
|
}
|
|
}
|
|
|
|
if (m_spectrumSink) {
|
|
m_spectrumSink->feed(m_sampleBuffer.begin(), m_sampleBuffer.end(), false);
|
|
}
|
|
}
|
|
|
|
void LoRaDemodSink::applyChannelSettings(int channelSampleRate, int bandwidth, int channelFrequencyOffset, bool force)
|
|
{
|
|
qDebug() << "LoRaDemodSink::applyChannelSettings:"
|
|
<< " channelSampleRate: " << channelSampleRate
|
|
<< " channelFrequencyOffset: " << channelFrequencyOffset;
|
|
|
|
if((channelFrequencyOffset != m_channelFrequencyOffset) ||
|
|
(channelSampleRate != m_channelSampleRate) || force)
|
|
{
|
|
m_nco.setFreq(-channelFrequencyOffset, channelSampleRate);
|
|
}
|
|
|
|
if ((channelSampleRate != m_channelSampleRate) || force)
|
|
{
|
|
qDebug() << "LoRaDemodSink::applyChannelSettings: m_interpolator.create";
|
|
m_interpolator.create(16, channelSampleRate, bandwidth / 1.9f);
|
|
m_sampleDistanceRemain = (Real) channelSampleRate / bandwidth;
|
|
}
|
|
|
|
m_channelSampleRate = channelSampleRate;
|
|
m_Bandwidth = bandwidth;
|
|
m_channelFrequencyOffset = channelFrequencyOffset;
|
|
}
|
|
|
|
void LoRaDemodSink::applySettings(const LoRaDemodSettings& settings, bool force)
|
|
{
|
|
qDebug() << "LoRaDemodSink::applySettings:"
|
|
<< " m_centerFrequency: " << settings.m_centerFrequency
|
|
<< " m_bandwidthIndex: " << settings.m_bandwidthIndex
|
|
<< " m_spread: " << settings.m_spread
|
|
<< " m_rgbColor: " << settings.m_rgbColor
|
|
<< " m_title: " << settings.m_title
|
|
<< " force: " << force;
|
|
|
|
m_settings = settings;
|
|
}
|