mirror of
https://github.com/f4exb/sdrangel.git
synced 2025-10-30 12:30:20 -04:00
97 lines
3.5 KiB
C++
97 lines
3.5 KiB
C++
///////////////////////////////////////////////////////////////////////////////////
|
|
// Copyright (C) 2018 Edouard Griffiths, F4EXB //
|
|
// //
|
|
// Symbol synchronizer or symbol clock recovery mostly encapsulating //
|
|
// liquid-dsp's symsync "object" //
|
|
// //
|
|
// 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 "symsync.h"
|
|
|
|
SymbolSynchronizer::SymbolSynchronizer()
|
|
{
|
|
// For now use hardcoded values:
|
|
// - RRC filter
|
|
// - 4 samples per symbol
|
|
// - 5 symbols delay filter
|
|
// - 0.5 filter excess bandwidth factor
|
|
// - 32 filter elements for the internal polyphase filter
|
|
m_sync = symsync_crcf_create_rnyquist(LIQUID_FIRFILT_RRC, 4, 5, 0.5f, 32);
|
|
// - 0.02 loop filter bandwidth factor
|
|
symsync_crcf_set_lf_bw(m_sync, 0.01f);
|
|
// - 4 samples per symbol output rate
|
|
symsync_crcf_set_output_rate(m_sync, 4);
|
|
m_syncSampleCount = 0;
|
|
}
|
|
|
|
SymbolSynchronizer::~SymbolSynchronizer()
|
|
{
|
|
symsync_crcf_destroy(m_sync);
|
|
}
|
|
|
|
Real SymbolSynchronizer::run(const Sample& s)
|
|
{
|
|
unsigned int nn;
|
|
Real v = -1.0f;
|
|
liquid_float_complex y = (s.m_real / SDR_RX_SCALEF) + (s.m_imag / SDR_RX_SCALEF)*I;
|
|
symsync_crcf_execute(m_sync, &y, 1, m_z, &nn);
|
|
|
|
for (unsigned int i = 0; i < nn; i++)
|
|
{
|
|
if (nn != 1) {
|
|
qDebug("SymbolSynchronizer::run: %u", nn);
|
|
}
|
|
|
|
if (m_syncSampleCount % 4 == 0) {
|
|
v = 1.0f;
|
|
}
|
|
|
|
if (m_syncSampleCount < 4095) {
|
|
m_syncSampleCount++;
|
|
} else {
|
|
qDebug("SymbolSynchronizer::run: tau: %f", symsync_crcf_get_tau(m_sync));
|
|
m_syncSampleCount = 0;
|
|
}
|
|
}
|
|
|
|
return v;
|
|
}
|
|
|
|
liquid_float_complex SymbolSynchronizer::runZ(const Sample& s)
|
|
{
|
|
unsigned int nn;
|
|
liquid_float_complex y = (s.m_real / SDR_RX_SCALEF) + (s.m_imag / SDR_RX_SCALEF)*I;
|
|
symsync_crcf_execute(m_sync, &y, 1, m_z, &nn);
|
|
|
|
for (unsigned int i = 0; i < nn; i++)
|
|
{
|
|
if (nn != 1) {
|
|
qDebug("SymbolSynchronizer::run: %u", nn);
|
|
}
|
|
|
|
if (m_syncSampleCount == 0) {
|
|
m_z0 = m_z[i];
|
|
}
|
|
|
|
if (m_syncSampleCount < 3) {
|
|
m_syncSampleCount++;
|
|
} else {
|
|
m_syncSampleCount = 0;
|
|
}
|
|
}
|
|
|
|
return m_z0;
|
|
}
|