NucleoTNC/TNC/M17Demodulator.cpp

531 wiersze
14 KiB
C++

// Copyright 2020-2021 Rob Riggs <rob@mobilinkd.com>
// All rights reserved.
#include "AudioLevel.hpp"
#include "M17Demodulator.h"
#include "Util.h"
#include "main.h"
#include "stm32l4xx_hal.h"
#include <algorithm>
#include <array>
#include <cstdint>
namespace mobilinkd { namespace tnc {
//m17::Indicator lsf_indicator{GPIOB, GPIO_PIN_0};
//m17::Indicator dcd_indicator{GPIOA, GPIO_PIN_2};
//m17::Indicator str_indicator{GPIOA, GPIO_PIN_7};
void M17Demodulator::start()
{
SysClock72();
#if defined(HAVE_LSCO)
HAL_RCCEx_DisableLSCO();
#endif
demod_filter.init(m17::rrc_taps_f15);
passall(kiss::settings().options & KISS_OPTION_PASSALL);
polarity = kiss::settings().rx_rev_polarity() ? -1 : 1;
audio::virtual_ground = (VREF + 1) / 2;
hadc1.Init.OversamplingMode = ENABLE;
if (HAL_ADC_Init(&hadc1) != HAL_OK)
{
CxxErrorHandler();
}
ADC_ChannelConfTypeDef sConfig;
sConfig.Channel = AUDIO_IN;
sConfig.Rank = ADC_REGULAR_RANK_1;
sConfig.SingleDiff = ADC_SINGLE_ENDED;
sConfig.SamplingTime = ADC_SAMPLETIME_12CYCLES_5;
sConfig.OffsetNumber = ADC_OFFSET_NONE;
sConfig.Offset = 0;
if (HAL_ADC_ConfigChannel(&hadc1, &sConfig) != HAL_OK)
CxxErrorHandler();
startADC(1499, ADC_BLOCK_SIZE);
// getModulator().start_loopback();
dcd_off();
}
void M17Demodulator::update_values(uint8_t index)
{
correlator.apply([this,index](float t){dev.sample(t);}, index);
dev.update();
idev = dev.idev() * polarity;
sync_sample_index = index;
}
void M17Demodulator::dcd_on()
{
// Data carrier newly detected.
INFO("dcd = %d", int(dcd.level() * 100));
dcd_ = true;
sync_count = 0;
dev.reset();
framer.reset();
decoder.reset();
missing_sync_count = 0;
// dcd_indicator.off();
}
void M17Demodulator::dcd_off()
{
// Just lost data carrier.
INFO("dcd = %d", int(dcd.level() * 100));
dcd_ = false;
demodState = DemodState::UNLOCKED;
// dcd_indicator.on();
adc_timing_adjust = 0;
prev_clock_estimate = 1.;
}
void M17Demodulator::initialize(const q15_t* input)
{
static constexpr float scale = 1.f / 2560.f;
for (size_t i = 0; i != ADC_BLOCK_SIZE; i++) {
demod_buffer[i] = float(input[i]) * scale;
}
auto filtered = demod_filter(demod_buffer.data());
for (size_t i = 0; i != ADC_BLOCK_SIZE; ++i)
{
auto filtered_sample = filtered[i];
correlator.sample(filtered_sample);
}
}
void M17Demodulator::update_dcd(const q15_t* input)
{
static constexpr float inv = 1.0 / 2048.0;
if (!dcd_ && dcd.dcd())
{
dcd_on();
need_clock_reset_ = true;
}
else if (dcd_ && !dcd.dcd())
{
dcd_off();
}
for (size_t i = 0; i != ADC_BLOCK_SIZE; ++i)
{
dcd(input[i] * inv);
}
}
[[gnu::noinline]]
void M17Demodulator::do_unlocked()
{
// We expect to find the preamble immediately after DCD.
if (missing_sync_count < 1920)
{
missing_sync_count += 1;
auto sync_index = preamble_sync(correlator);
auto sync_updated = preamble_sync.updated();
if (sync_updated)
{
sync_count = 0;
missing_sync_count = 0;
need_clock_reset_ = true;
dev.reset();
update_values(sync_index);
sample_index = sync_index;
demodState = DemodState::LSF_SYNC;
INFO("P sync %d", sync_index);
}
return;
}
// Otherwise we start searching for a sync word.
auto sync_index = lsf_sync(correlator);
auto sync_updated = lsf_sync.updated();
if (sync_updated)
{
sync_count = 0;
missing_sync_count = 0;
need_clock_reset_ = true;
dev.reset();
update_values(sync_index);
sample_index = sync_index;
demodState = DemodState::FRAME;
if (sync_updated < 0)
{
sync_word_type = M17FrameDecoder::SyncWordType::STREAM;
INFO("S sync %d", int(sync_index));
}
else
{
sync_word_type = M17FrameDecoder::SyncWordType::LSF;
INFO("L sync %d", int(sync_index));
}
}
sync_index = packet_sync(correlator);
sync_updated = packet_sync.updated();
if (sync_updated < 0)
{
sync_count = 0;
missing_sync_count = 0;
need_clock_reset_ = true;
dev.reset();
update_values(sync_index);
sample_index = sync_index;
demodState = DemodState::FRAME;
sync_word_type = M17FrameDecoder::SyncWordType::BERT;
INFO("B sync %d", int(sync_index));
}
}
/**
* Check for LSF sync word. We only enter the DemodState::LSF_SYNC state
* if a preamble sync has been detected, which also means that sample_index
* has been initialized to a sane value for the baseband.
*/
[[gnu::noinline]]
void M17Demodulator::do_lsf_sync()
{
float sync_triggered = 0.;
float bert_triggered = 0.;
if (correlator.index() == sample_index)
{
sync_triggered = preamble_sync.triggered(correlator);
// INFO("PSync = %d", int(sync_triggered));
if (sync_triggered > 0.1)
{
ITM_SendChar('.');
return;
}
sync_triggered = lsf_sync.triggered(correlator);
bert_triggered = packet_sync.triggered(correlator);
if (bert_triggered < 0)
{
missing_sync_count = 0;
need_clock_update_ = true;
update_values(sample_index);
demodState = DemodState::FRAME;
sync_word_type = M17FrameDecoder::SyncWordType::BERT;
INFO("+b sync");
}
else if (std::abs(sync_triggered) > 0.1)
{
missing_sync_count = 0;
need_clock_update_ = true;
update_values(sample_index);
INFO("LSync = %d", int(sync_triggered));
if (sync_triggered > 0)
{
demodState = DemodState::FRAME;
sync_word_type = M17FrameDecoder::SyncWordType::LSF;
INFO("+l sync %d", int(sample_index));
}
else
{
demodState = DemodState::FRAME;
sync_word_type = M17FrameDecoder::SyncWordType::STREAM;
INFO("+s sync %d", int(sample_index));
}
}
else if (++missing_sync_count > 192)
{
demodState = DemodState::UNLOCKED;
INFO("l unlock %d", int(missing_sync_count));
missing_sync_count = 0;
}
else
{
update_values(sample_index);
}
}
}
/**
* Check for a stream sync word (LSF sync word that is maximally negative).
* We can enter DemodState::STREAM_SYNC from either a valid LSF decode for
* an audio stream, or from a stream frame decode.
*
*/
[[gnu::noinline]]
void M17Demodulator::do_stream_sync()
{
uint8_t sync_index = lsf_sync(correlator);
int8_t sync_updated = lsf_sync.updated();
sync_count += 1;
if (sync_updated < 0)
{
missing_sync_count = 0;
if (sync_count > 70)
{
update_values(sync_index);
sync_word_type = M17FrameDecoder::SyncWordType::STREAM;
demodState = DemodState::FRAME;
INFO("s sync %d", int(sync_index));
}
return;
}
else if (sync_count > 87)
{
update_values(sync_index);
missing_sync_count += 1;
if (missing_sync_count < MAX_MISSING_SYNC)
{
sync_word_type = M17FrameDecoder::SyncWordType::STREAM;
demodState = DemodState::FRAME;
INFO("s unsync %d", int(missing_sync_count));
}
else
{
demodState = DemodState::LSF_SYNC;
INFO("s unlock");
}
}
}
/**
* Check for a packet sync word. DemodState::PACKET_SYNC can only be
* entered from a valid LSF frame decode with the data/packet type bit set.
*/
[[gnu::noinline]]
void M17Demodulator::do_packet_sync()
{
auto sync_index = packet_sync(correlator);
auto sync_updated = packet_sync.updated();
sync_count += 1;
if (sync_count > 70 && sync_updated)
{
missing_sync_count = 0;
update_values(sync_index);
sync_word_type = M17FrameDecoder::SyncWordType::PACKET;
demodState = DemodState::FRAME;
INFO("k sync");
return;
}
else if (sync_count > 87)
{
missing_sync_count += 1;
if (missing_sync_count < MAX_MISSING_SYNC)
{
sync_word_type = M17FrameDecoder::SyncWordType::PACKET;
demodState = DemodState::FRAME;
INFO("k unsync");
}
else
{
demodState = DemodState::UNLOCKED;
INFO("k unlock");
}
}
}
/**
* Check for a bert sync word.
*/
[[gnu::noinline]]
void M17Demodulator::do_bert_sync()
{
auto sync_index = packet_sync(correlator);
auto sync_updated = packet_sync.updated();
sync_count += 1;
if (sync_count > 70 && sync_updated < 0)
{
missing_sync_count = 0;
update_values(sync_index);
sync_word_type = M17FrameDecoder::SyncWordType::BERT;
INFO("b sync");
demodState = DemodState::FRAME;
}
else if (sync_count > 87)
{
missing_sync_count += 1;
if (missing_sync_count < MAX_MISSING_SYNC)
{
sync_word_type = M17FrameDecoder::SyncWordType::BERT;
demodState = DemodState::FRAME;
INFO("b unsync");
}
else
{
demodState = DemodState::UNLOCKED;
INFO("b unlock");
}
}
}
[[gnu::noinline]]
void M17Demodulator::do_frame(float filtered_sample, hdlc::IoFrame*& frame_result)
{
if (correlator.index() != sample_index) return;
float sample = filtered_sample - dev.offset();
sample *= idev;
auto n = mobilinkd::llr<float, 4>(sample);
int8_t* tmp;
auto len = framer(n, &tmp);
if (len != 0)
{
need_clock_update_ = true;
std::copy(tmp, tmp + len, buffer.begin());
auto valid = decoder(sync_word_type, buffer, frame_result, ber);
INFO("demod: %d, dt: %7d, evma: %5d, dev: %5d, freq: %5d, index: %d, %d, %d ber: %d",
int(decoder.state()), int(clock_recovery.clock_estimate() * 1000000),
int(dev.error() * 1000), int(dev.deviation() * 1000),
int(dev.offset() * 1000),
int(sample_index), int(clock_recovery.sample_index()), int(sync_sample_index),
ber);
switch (decoder.state())
{
case M17FrameDecoder::State::STREAM:
demodState = DemodState::STREAM_SYNC;
break;
case M17FrameDecoder::State::LSF:
// If state == LSF, we need to recover LSF from LICH.
demodState = DemodState::STREAM_SYNC;
break;
case M17FrameDecoder::State::BERT:
demodState = DemodState::BERT_SYNC;
break;
default:
demodState = DemodState::PACKET_SYNC;
break;
}
sync_count = 0;
switch (valid)
{
case M17FrameDecoder::DecodeResult::FAIL:
WARN("decode invalid");
if (frame_result && !passall_)
{
hdlc::release(frame_result);
frame_result = nullptr;
}
break;
case M17FrameDecoder::DecodeResult::EOS:
demodState = DemodState::LSF_SYNC;
INFO("EOS");
break;
case M17FrameDecoder::DecodeResult::OK:
break;
case M17FrameDecoder::DecodeResult::INCOMPLETE:
break;
}
}
}
hdlc::IoFrame* M17Demodulator::operator()(const q15_t* input)
{
static int16_t initializing = 10;
hdlc::IoFrame* frame_result = nullptr;
// We need to pump a few frames through on startup to initialize
// the demodulator.
if (__builtin_expect((initializing), 0))
{
--initializing;
initialize(input);
return frame_result;
}
// str_indicator.on();
update_dcd(input);
if (!dcd_)
{
dcd.update();
// str_indicator.off();
return frame_result;
}
// Do adc_micro_adjustment() here?
// adc_micro_adjustment();
static constexpr float scale = 1.f / 2560.f;
for (size_t i = 0; i != ADC_BLOCK_SIZE; i++) {
demod_buffer[i] = float(input[i]) * scale;
}
auto filtered = demod_filter(demod_buffer.data());
// getModulator().loopback(filtered);
for (size_t i = 0; i != ADC_BLOCK_SIZE; ++i)
{
auto filtered_sample = filtered[i];
correlator.sample(filtered_sample);
if (correlator.index() == 0)
{
if (need_clock_reset_)
{
clock_recovery.reset();
need_clock_reset_ = false;
sample_index = sync_sample_index;
adc_timing_adjust = 0;
}
else if (need_clock_update_) // must avoid update immediately after reset.
{
clock_recovery.update();
uint8_t clock_index = clock_recovery.sample_index();
uint8_t clock_diff = std::abs(sample_index - clock_index);
uint8_t sync_diff = std::abs(sample_index - sync_sample_index);
bool clock_diff_ok = clock_diff <= 1 || clock_diff == 9;
bool sync_diff_ok = sync_diff <= 1 || sync_diff == 9;
if (clock_diff_ok) sample_index = clock_index;
else if (sync_diff_ok) sample_index = sync_sample_index;
// else unchanged.
need_clock_update_ = false;
}
}
clock_recovery(filtered_sample);
if (demodState != DemodState::UNLOCKED && correlator.index() == sample_index)
{
dev.sample(filtered_sample);
}
switch (demodState)
{
case DemodState::UNLOCKED:
// In this state, the sample_index is unknown. We need to find
// a sync word to find the proper sample_index. We only leave
// this state if we believe that we have a valid sample_index.
do_unlocked();
break;
case DemodState::LSF_SYNC:
do_lsf_sync();
break;
case DemodState::STREAM_SYNC:
do_stream_sync();
break;
case DemodState::PACKET_SYNC:
do_packet_sync();
break;
case DemodState::BERT_SYNC:
do_bert_sync();
break;
case DemodState::FRAME:
do_frame(filtered_sample,frame_result);
break;
}
}
dcd.update();
// str_indicator.off();
return frame_result;
}
}} // mobilinkd::tnc