mirror of
https://github.com/f4exb/sdrangel.git
synced 2024-11-26 09:48:45 -05:00
124 lines
4.1 KiB
C++
124 lines
4.1 KiB
C++
//////////////////////////////////////////////////////////////////////////////////////////////////////////////
|
|
// Copyright (C) 2021 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 <algorithm>
|
|
#include <QMutexLocker>
|
|
|
|
#include "dcsdetector.h"
|
|
|
|
DCSDetector::DCSDetector() :
|
|
m_bitIndex(0.0),
|
|
m_sampleRate(48000),
|
|
m_eqSamples(nullptr),
|
|
m_high(0.0f),
|
|
m_low(0.0f),
|
|
m_mid(0.0f),
|
|
m_prevSample(0.0f),
|
|
m_dcsWord(0)
|
|
{
|
|
setBitrate(134.3);
|
|
setEqWindow(23);
|
|
}
|
|
|
|
bool DCSDetector::analyze(Real *sample, unsigned int& dcsCode)
|
|
{
|
|
QMutexLocker mlock(&m_mutex);
|
|
bool codeAvailable = false;
|
|
|
|
if (!m_eqSamples) {
|
|
return false;
|
|
}
|
|
// Equalizer
|
|
m_eqSamples[m_eqIndex++] = *sample;
|
|
|
|
if (m_eqIndex == m_eqSize)
|
|
{
|
|
m_high = *std::max_element(m_eqSamples, m_eqSamples + m_eqSize);
|
|
m_low = *std::min_element(m_eqSamples, m_eqSamples + m_eqSize);
|
|
m_mid = (m_high + m_low) / 2.0f;
|
|
// qDebug("DCSDetector::analyze: %f %f %f", m_low, m_mid, m_high);
|
|
m_eqIndex = 0;
|
|
}
|
|
|
|
// Edge detection
|
|
if (((m_prevSample < m_mid) && (*sample >= m_mid)) || ((m_prevSample > m_mid) && (*sample <= m_mid))) {
|
|
m_bitIndex = 0.0;
|
|
}
|
|
|
|
// Symbol detection
|
|
m_prevSample = *sample;
|
|
float fprev = m_bitIndex;
|
|
m_bitIndex += m_bitsPerSample;
|
|
|
|
if ((fprev < 0.5f) && (m_bitIndex >= 0.5f)) // mid point detection
|
|
{
|
|
unsigned int bit = *sample > m_mid ? 1 : 0; // always work in positive mode
|
|
m_dcsWord = (bit << 23) + (m_dcsWord >> 1);
|
|
|
|
if (((m_dcsWord >> 9) & 0x07) == 4) // magic signature
|
|
{
|
|
codeAvailable = m_golay2312.decodeParityFirst(&m_dcsWord);
|
|
|
|
if (codeAvailable) {
|
|
dcsCode = m_dcsWord & 0x1FF;
|
|
}
|
|
}
|
|
}
|
|
|
|
if (m_bitIndex > 1.0f) {
|
|
m_bitIndex -= 1.0f;
|
|
}
|
|
|
|
return codeAvailable;
|
|
}
|
|
|
|
void DCSDetector::setBitrate(float bitrate)
|
|
{
|
|
m_bitrate = bitrate;
|
|
m_bitsPerSample = m_bitrate / m_sampleRate;
|
|
m_samplesPerBit = m_sampleRate / m_bitrate;
|
|
}
|
|
|
|
void DCSDetector::setSampleRate(int sampleRate)
|
|
{
|
|
m_sampleRate = sampleRate;
|
|
m_bitsPerSample = m_bitrate / m_sampleRate;
|
|
m_samplesPerBit = m_sampleRate / m_bitrate;
|
|
}
|
|
|
|
void DCSDetector::setEqWindow(int nbBits)
|
|
{
|
|
QMutexLocker mlock(&m_mutex);
|
|
|
|
m_eqBits = nbBits;
|
|
m_eqSize = (int) m_samplesPerBit * m_eqBits;
|
|
|
|
if (m_eqSamples) {
|
|
delete[] m_eqSamples;
|
|
}
|
|
|
|
m_eqSamples = new float[m_eqSize];
|
|
m_eqIndex = 0;
|
|
}
|
|
|
|
DCSDetector::~DCSDetector()
|
|
{
|
|
if (m_eqSamples) {
|
|
delete[] m_eqSamples;
|
|
}
|
|
}
|