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First changes for correlation of D-Star.

This commit is contained in:
Jonathan Naylor 2017-07-02 17:57:17 +01:00
parent ae9e35ccad
commit 5d74c2f7bf
3 changed files with 145 additions and 78 deletions
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3
DStarDefines.h
View File

@ -22,13 +22,14 @@
const unsigned int DSTAR_RADIO_BIT_LENGTH = 5U; // At 24 kHz sample rate
const unsigned int DSTAR_HEADER_LENGTH_BYTES = 41U;
const unsigned int DSTAR_HEADER_LENGTH_BITS = DSTAR_HEADER_LENGTH_BYTES * 8U;
const unsigned int DSTAR_FEC_SECTION_LENGTH_BYTES = 83U;
const unsigned int DSTAR_FEC_SECTION_LENGTH_BITS = 660U;
const unsigned int DSTAR_FEC_SECTION_LENGTH_SAMPLES = DSTAR_FEC_SECTION_LENGTH_BITS * DSTAR_RADIO_BIT_LENGTH;
const unsigned int DSTAR_DATA_LENGTH_BYTES = 12U;
const unsigned int DSTAR_DATA_LENGTH_BITS = DSTAR_DATA_LENGTH_BYTES * 8U;
const unsigned int DSTAR_DATA_LENGTH_SAMPLES = DSTAR_DATA_LENGTH_BITS * DSTAR_RADIO_BIT_LENGTH;
const uint8_t DSTAR_EOT_BYTES[] = {0x55, 0x55, 0x55, 0x55, 0xC8, 0x7A, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};
const unsigned int DSTAR_EOT_LENGTH_BYTES = 6U;

159
DStarRX.cpp
View File

@ -22,12 +22,6 @@
#include "DStarRX.h"
#include "Utils.h"
const unsigned int BUFFER_LENGTH = 200U;
const uint32_t PLLMAX = 0x10000U;
const uint32_t PLLINC = PLLMAX / DSTAR_RADIO_BIT_LENGTH;
const uint32_t INC = PLLINC / 32U;
const unsigned int MAX_SYNC_BITS = 50U * DSTAR_DATA_LENGTH_BITS;
const unsigned int SYNC_POS = 21U * DSTAR_DATA_LENGTH_BITS;
@ -245,14 +239,22 @@ const uint16_t CCITT_TABLE[] = {
0xf78fU, 0xe606U, 0xd49dU, 0xc514U, 0xb1abU, 0xa022U, 0x92b9U, 0x8330U,
0x7bc7U, 0x6a4eU, 0x58d5U, 0x495cU, 0x3de3U, 0x2c6aU, 0x1ef1U, 0x0f78U};
const uint16_t NOENDPTR = 9999U;
CDStarRX::CDStarRX() :
m_pll(0U),
m_prev(false),
m_rxState(DSRXS_NONE),
m_patternBuffer(0x00U),
m_rxBuffer(),
m_rxBufferBits(0U),
m_dataBits(0U),
m_bitBuffer(),
m_buffer(),
m_bitPtr(0U),
m_dataPtr(0U),
m_startPtr(NOENDPTR),
m_endPtr(NOENDPTR),
m_syncPtr(NOENDPTR),
m_minSyncPtr(NOENDPTR),
m_maxSyncPtr(NOENDPTR),
m_maxCorr(0),
m_lostCount(0U),
m_countdown(0U),
m_mar(0U),
m_pathMetric(),
m_pathMemory0(),
@ -275,12 +277,17 @@ m_dcState()
void CDStarRX::reset()
{
m_pll = 0U;
m_prev = false;
m_rxState = DSRXS_NONE;
m_patternBuffer = 0x00U;
m_rxBufferBits = 0U;
m_dataBits = 0U;
m_dataPtr = 0U;
m_bitPtr = 0U;
m_maxCorr = 0;
m_startPtr = NOENDPTR;
m_endPtr = NOENDPTR;
m_syncPtr = NOENDPTR;
m_minSyncPtr = NOENDPTR;
m_maxSyncPtr = NOENDPTR;
m_lostCount = 0U;
m_countdown = 0U;
m_rssiAccum = 0U;
m_rssiCount = 0U;
}
@ -303,45 +310,38 @@ void CDStarRX::samples(const q15_t* samples, const uint16_t* rssi, uint8_t lengt
m_rssiAccum += rssi[i];
m_rssiCount++;
bool bit = samples[i] < (q15_t) (dc_level >> 16);
q15_t sample = samples[i] - q15_t(dc_level >> 16);
if (bit != m_prev) {
if (m_pll < (PLLMAX / 2U))
m_pll += INC;
else
m_pll -= INC;
}
m_bitBuffer[m_bitPtr] <<= 1;
if (sample < 0)
m_bitBuffer[m_bitPtr] |= 0x01U;
m_prev = bit;
m_pll += PLLINC;
if (m_pll >= PLLMAX) {
m_pll -= PLLMAX;
m_buffer[m_dataPtr] = sample;
switch (m_rxState) {
case DSRXS_NONE:
processNone(bit);
break;
case DSRXS_HEADER:
processHeader(bit);
processHeader(sample);
break;
case DSRXS_DATA:
processData(bit);
processData(sample);
break;
default:
processNone(sample);
break;
}
}
m_dataPtr++;
if (m_dataPtr >= DSTAR_FRAME_LENGTH_SAMPLES)
m_dataPtr = 0U;
m_bitPtr++;
if (m_bitPtr >= DSTAR_RADIO_BIT_LENGTH)
m_bitPtr = 0U;
}
}
void CDStarRX::processNone(bool bit)
void CDStarRX::processNone(q15_t sample)
{
m_patternBuffer <<= 1;
if (bit)
m_patternBuffer |= 0x01U;
// Fuzzy matching of the frame sync sequence
if (countBits32((m_patternBuffer & FRAME_SYNC_MASK) ^ FRAME_SYNC_DATA) <= FRAME_SYNC_ERRS) {
DEBUG1("DStarRX: found frame sync in None");
@ -379,12 +379,8 @@ void CDStarRX::processNone(bool bit)
}
}
void CDStarRX::processHeader(bool bit)
void CDStarRX::processHeader(q15_t sample)
{
m_patternBuffer <<= 1;
if (bit)
m_patternBuffer |= 0x01U;
WRITE_BIT2(m_rxBuffer, m_rxBufferBits, bit);
m_rxBufferBits++;
@ -411,12 +407,8 @@ void CDStarRX::processHeader(bool bit)
}
}
void CDStarRX::processData(bool bit)
void CDStarRX::processData(q15_t sample)
{
m_patternBuffer <<= 1;
if (bit)
m_patternBuffer |= 0x01U;
WRITE_BIT2(m_rxBuffer, m_rxBufferBits, bit);
m_rxBufferBits++;
@ -536,6 +528,71 @@ void CDStarRX::writeRSSIData(unsigned char* data)
m_rssiCount = 0U;
}
bool CDStarRX::correlateDataSync()
{
if (countBits32((m_bitBuffer[m_bitPtr] & DSTAR_SYNC_SYMBOLS_MASK) ^ DSTAR_SYNC_SYMBOLS) <= MAX_SYNC_SYMBOLS_ERRS) {
uint16_t ptr = m_dataPtr + DSTAR_FRAME_LENGTH_SAMPLES - DSTAR_SYNC_LENGTH_SAMPLES + DSTAR_RADIO_SYMBOL_LENGTH;
if (ptr >= DSTAR_FRAME_LENGTH_SAMPLES)
ptr -= DSTAR_FRAME_LENGTH_SAMPLES;
q31_t corr = 0;
for (uint8_t i = 0U; i < YSF_SYNC_LENGTH_SYMBOLS; i++) {
q15_t val = m_buffer[ptr];
switch (DSTAR_SYNC_SYMBOLS_VALUES[i]) {
case +1:
corr -= val;
break;
default:
corr += val;
break;
}
ptr += DSTAR_RADIO_SYMBOL_LENGTH;
if (ptr >= DSTAR_FRAME_LENGTH_SAMPLES)
ptr -= DSTAR_FRAME_LENGTH_SAMPLES;
}
if (corr > m_maxCorr) {
uint16_t startPtr = m_dataPtr + DSTAR_FRAME_LENGTH_SAMPLES - DSTAR_SYNC_LENGTH_SAMPLES + DSTAR_RADIO_SYMBOL_LENGTH;
if (startPtr >= DSTAR_FRAME_LENGTH_SAMPLES)
startPtr -= DSTAR_FRAME_LENGTH_SAMPLES;
m_maxCorr = corr;
m_lostCount = MAX_SYNC_FRAMES;
m_syncPtr = m_dataPtr;
m_startPtr = startPtr;
m_endPtr = m_dataPtr + DSTAR_FRAME_LENGTH_SAMPLES - DSTAR_SYNC_LENGTH_SAMPLES - 1U;
if (m_endPtr >= DSTAR_FRAME_LENGTH_SAMPLES)
m_endPtr -= DSTAR_FRAME_LENGTH_SAMPLES;
return true;
}
}
}
return false;
}
void CDStarRX::samplesToBits(uint16_t start, uint16_t count, uint8_t* buffer, uint16_t offset)
{
for (uint16_t i = 0U; i < count; i++, offset++) {
q15_t sample = m_buffer[start];
if (sample < 0)
WRITE_BIT2(buffer, offset, true);
else
WRITE_BIT2(buffer, offset, false);
start += DSTAR_RADIO_SYMBOL_LENGTH;
if (start >= DSTAR_FRAME_LENGTH_SAMPLES)
start -= DSTAR_FRAME_LENGTH_SAMPLES;
}
}
bool CDStarRX::rxHeader(uint8_t* in, uint8_t* out)
{
int i;

27
DStarRX.h
View File

@ -37,13 +37,19 @@ public:
void reset();
private:
uint32_t m_pll;
bool m_prev;
DSRX_STATE m_rxState;
uint32_t m_patternBuffer;
uint8_t m_rxBuffer[100U];
unsigned int m_rxBufferBits;
unsigned int m_dataBits;
uint32_t m_bitBuffer[DSTAR_RADIO_BIT_LENGTH];
q15_t m_buffer[DSTAR_FEC_SECTION_LENGTH_SAMPLES];
uint16_t m_bitPtr;
uint16_t m_dataPtr;
uint16_t m_startPtr;
uint16_t m_endPtr;
uint16_t m_minSyncPtr;
uint16_t m_maxSyncPtr;
uint16_t m_syncPtr;
q31_t m_maxCorr;
uint16_t m_lostCount;
uint8_t m_countdown;
unsigned int m_mar;
int m_pathMetric[4U];
unsigned int m_pathMemory0[42U];
@ -56,9 +62,12 @@ private:
arm_biquad_casd_df1_inst_q31 m_dcFilter;
q31_t m_dcState[4];
void processNone(bool bit);
void processHeader(bool bit);
void processData(bool bit);
void processNone(q15_t sample);
void processHeader(q15_t sample);
void processData(q15_t sample);
bool correlateFrameSync();
bool correlateDataSync();
void samplesToBits(uint16_t start, uint16_t count, uint8_t* buffer, uint16_t offset);
void writeRSSIHeader(unsigned char* header);
void writeRSSIData(unsigned char* data);
bool rxHeader(uint8_t* in, uint8_t* out);