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Improve the P25 sync positioning.

This commit is contained in:
Jonathan Naylor 2017-02-05 19:33:52 +00:00
parent ec5100bf6f
commit 4221ac45b1
2 changed files with 27 additions and 18 deletions
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42
P25RX.cpp
View File

@ -45,9 +45,10 @@ m_buffer(),
m_bitPtr(0U), m_bitPtr(0U),
m_dataPtr(0U), m_dataPtr(0U),
m_endPtr(NOENDPTR), m_endPtr(NOENDPTR),
m_syncPtr(NOENDPTR),
m_minSyncPtr(NOENDPTR), m_minSyncPtr(NOENDPTR),
m_maxSyncPtr(NOENDPTR), m_maxSyncPtr(NOENDPTR),
m_hdrSyncPtr(NOENDPTR),
m_lduSyncPtr(NOENDPTR),
m_maxCorr(0), m_maxCorr(0),
m_lostCount(0U), m_lostCount(0U),
m_countdown(0U), m_countdown(0U),
@ -71,7 +72,8 @@ void CP25RX::reset()
m_maxCorr = 0; m_maxCorr = 0;
m_averagePtr = 0U; m_averagePtr = 0U;
m_endPtr = NOENDPTR; m_endPtr = NOENDPTR;
m_syncPtr = NOENDPTR; m_hdrSyncPtr = NOENDPTR;
m_lduSyncPtr = NOENDPTR;
m_minSyncPtr = NOENDPTR; m_minSyncPtr = NOENDPTR;
m_maxSyncPtr = NOENDPTR; m_maxSyncPtr = NOENDPTR;
m_centreVal = 0; m_centreVal = 0;
@ -148,11 +150,11 @@ void CP25RX::processNone(q15_t sample)
m_averagePtr = 0U; m_averagePtr = 0U;
// These are the sync positions for the following LDU after a HDR // These are the sync positions for the following LDU after a HDR
m_minSyncPtr = m_syncPtr + P25_HDR_FRAME_LENGTH_SAMPLES - 1U; m_minSyncPtr = m_hdrSyncPtr + P25_HDR_FRAME_LENGTH_SAMPLES - 1U;
if (m_minSyncPtr >= P25_LDU_FRAME_LENGTH_SAMPLES) if (m_minSyncPtr >= P25_LDU_FRAME_LENGTH_SAMPLES)
m_minSyncPtr -= P25_LDU_FRAME_LENGTH_SAMPLES; m_minSyncPtr -= P25_LDU_FRAME_LENGTH_SAMPLES;
m_maxSyncPtr = m_syncPtr + P25_HDR_FRAME_LENGTH_SAMPLES + 1U; m_maxSyncPtr = m_hdrSyncPtr + P25_HDR_FRAME_LENGTH_SAMPLES + 1U;
if (m_maxSyncPtr >= P25_LDU_FRAME_LENGTH_SAMPLES) if (m_maxSyncPtr >= P25_LDU_FRAME_LENGTH_SAMPLES)
m_maxSyncPtr -= P25_LDU_FRAME_LENGTH_SAMPLES; m_maxSyncPtr -= P25_LDU_FRAME_LENGTH_SAMPLES;
@ -174,15 +176,15 @@ void CP25RX::processHdr(q15_t sample)
if (m_dataPtr == m_maxSyncPtr) { if (m_dataPtr == m_maxSyncPtr) {
bool isSync = false; bool isSync = false;
if (m_minSyncPtr < m_maxSyncPtr) { if (m_minSyncPtr < m_maxSyncPtr) {
if (m_syncPtr >= m_minSyncPtr && m_syncPtr <= m_maxSyncPtr) if (m_lduSyncPtr >= m_minSyncPtr && m_lduSyncPtr <= m_maxSyncPtr)
isSync = true; isSync = true;
} else { } else {
if (m_syncPtr >= m_minSyncPtr || m_syncPtr <= m_maxSyncPtr) if (m_lduSyncPtr >= m_minSyncPtr || m_lduSyncPtr <= m_maxSyncPtr)
isSync = true; isSync = true;
} }
DEBUG4("P25RX, sync position in HDR, pos/min/max", m_syncPtr, m_minSyncPtr, m_maxSyncPtr);
if (isSync) { if (isSync) {
uint16_t ptr = m_syncPtr + P25_LDU_FRAME_LENGTH_SAMPLES - P25_HDR_FRAME_LENGTH_SAMPLES - P25_SYNC_LENGTH_SAMPLES - 1U; DEBUG4("P25RX, sync position in HDR, pos/min/max", m_lduSyncPtr, m_minSyncPtr, m_maxSyncPtr);
uint16_t ptr = m_hdrSyncPtr + P25_LDU_FRAME_LENGTH_SAMPLES - P25_HDR_FRAME_LENGTH_SAMPLES - P25_SYNC_LENGTH_SAMPLES - 1U;
if (ptr >= P25_LDU_FRAME_LENGTH_SAMPLES) if (ptr >= P25_LDU_FRAME_LENGTH_SAMPLES)
ptr -= P25_LDU_FRAME_LENGTH_SAMPLES; ptr -= P25_LDU_FRAME_LENGTH_SAMPLES;
@ -203,8 +205,8 @@ void CP25RX::processHdr(q15_t sample)
m_centreVal >>= 4; m_centreVal >>= 4;
m_thresholdVal >>= 4; m_thresholdVal >>= 4;
DEBUG4("P25RX: sync found in Hdr (best) pos/centre/threshold", m_syncPtr, m_centreBest, m_thresholdBest); DEBUG4("P25RX: sync found in Hdr (best) pos/centre/threshold", m_hdrSyncPtr, m_centreBest, m_thresholdBest);
DEBUG4("P25RX: sync found in Hdr pos/centre/threshold", m_syncPtr, m_centreVal, m_thresholdVal); DEBUG4("P25RX: sync found in Hdr pos/centre/threshold", m_hdrSyncPtr, m_centreVal, m_thresholdVal);
uint8_t frame[P25_HDR_FRAME_LENGTH_BYTES + 1U]; uint8_t frame[P25_HDR_FRAME_LENGTH_BYTES + 1U];
samplesToBits(ptr, P25_HDR_FRAME_LENGTH_SYMBOLS, frame, 8U, m_centreVal, m_thresholdVal); samplesToBits(ptr, P25_HDR_FRAME_LENGTH_SYMBOLS, frame, 8U, m_centreVal, m_thresholdVal);
@ -216,11 +218,11 @@ void CP25RX::processHdr(q15_t sample)
serial.writeP25Hdr(frame, P25_HDR_FRAME_LENGTH_BYTES + 1U); serial.writeP25Hdr(frame, P25_HDR_FRAME_LENGTH_BYTES + 1U);
} }
m_minSyncPtr = m_syncPtr + P25_LDU_FRAME_LENGTH_SAMPLES - 1U; m_minSyncPtr = m_lduSyncPtr + P25_LDU_FRAME_LENGTH_SAMPLES - 1U;
if (m_minSyncPtr >= P25_LDU_FRAME_LENGTH_SAMPLES) if (m_minSyncPtr >= P25_LDU_FRAME_LENGTH_SAMPLES)
m_minSyncPtr -= P25_LDU_FRAME_LENGTH_SAMPLES; m_minSyncPtr -= P25_LDU_FRAME_LENGTH_SAMPLES;
m_maxSyncPtr = m_syncPtr + 1U; m_maxSyncPtr = m_lduSyncPtr + 1U;
if (m_maxSyncPtr >= P25_LDU_FRAME_LENGTH_SAMPLES) if (m_maxSyncPtr >= P25_LDU_FRAME_LENGTH_SAMPLES)
m_maxSyncPtr -= P25_LDU_FRAME_LENGTH_SAMPLES; m_maxSyncPtr -= P25_LDU_FRAME_LENGTH_SAMPLES;
@ -263,14 +265,14 @@ void CP25RX::processLdu(q15_t sample)
m_centreVal >>= 4; m_centreVal >>= 4;
m_thresholdVal >>= 4; m_thresholdVal >>= 4;
DEBUG4("P25RX: sync found in Ldu (best) pos/centre/threshold", m_syncPtr, m_centreBest, m_thresholdBest); DEBUG4("P25RX: sync found in Ldu (best) pos/centre/threshold", m_lduSyncPtr, m_centreBest, m_thresholdBest);
DEBUG4("P25RX: sync found in Ldu pos/centre/threshold", m_syncPtr, m_centreVal, m_thresholdVal); DEBUG4("P25RX: sync found in Ldu pos/centre/threshold", m_lduSyncPtr, m_centreVal, m_thresholdVal);
m_minSyncPtr = m_syncPtr + P25_LDU_FRAME_LENGTH_SAMPLES - 1U; m_minSyncPtr = m_lduSyncPtr + P25_LDU_FRAME_LENGTH_SAMPLES - 1U;
if (m_minSyncPtr >= P25_LDU_FRAME_LENGTH_SAMPLES) if (m_minSyncPtr >= P25_LDU_FRAME_LENGTH_SAMPLES)
m_minSyncPtr -= P25_LDU_FRAME_LENGTH_SAMPLES; m_minSyncPtr -= P25_LDU_FRAME_LENGTH_SAMPLES;
m_maxSyncPtr = m_syncPtr + 1U; m_maxSyncPtr = m_lduSyncPtr + 1U;
if (m_maxSyncPtr >= P25_LDU_FRAME_LENGTH_SAMPLES) if (m_maxSyncPtr >= P25_LDU_FRAME_LENGTH_SAMPLES)
m_maxSyncPtr -= P25_LDU_FRAME_LENGTH_SAMPLES; m_maxSyncPtr -= P25_LDU_FRAME_LENGTH_SAMPLES;
} }
@ -357,7 +359,7 @@ bool CP25RX::correlateSync()
m_thresholdBest = threshold; m_thresholdBest = threshold;
m_centreBest = centre; m_centreBest = centre;
m_lostCount = MAX_SYNC_FRAMES; m_lostCount = MAX_SYNC_FRAMES;
m_syncPtr = m_dataPtr; m_lduSyncPtr = m_dataPtr;
// This is the position of the end of a normal LDU // This is the position of the end of a normal LDU
m_endPtr = m_dataPtr + P25_LDU_FRAME_LENGTH_SAMPLES - P25_SYNC_LENGTH_SAMPLES - 1U; m_endPtr = m_dataPtr + P25_LDU_FRAME_LENGTH_SAMPLES - P25_SYNC_LENGTH_SAMPLES - 1U;
@ -366,6 +368,8 @@ bool CP25RX::correlateSync()
// These are the positions of the sync in the following LDU if the HDR is present // These are the positions of the sync in the following LDU if the HDR is present
if (m_state == P25RXS_NONE) { if (m_state == P25RXS_NONE) {
m_hdrSyncPtr = m_dataPtr;
m_minSyncPtr = m_dataPtr + P25_HDR_FRAME_LENGTH_SAMPLES - 1U; m_minSyncPtr = m_dataPtr + P25_HDR_FRAME_LENGTH_SAMPLES - 1U;
if (m_minSyncPtr >= P25_LDU_FRAME_LENGTH_SAMPLES) if (m_minSyncPtr >= P25_LDU_FRAME_LENGTH_SAMPLES)
m_minSyncPtr -= P25_LDU_FRAME_LENGTH_SAMPLES; m_minSyncPtr -= P25_LDU_FRAME_LENGTH_SAMPLES;
@ -443,6 +447,9 @@ void CP25RX::writeSync(uint16_t start)
q15_t sync[P25_SYNC_LENGTH_SYMBOLS]; q15_t sync[P25_SYNC_LENGTH_SYMBOLS];
for (uint16_t i = 0U; i < P25_SYNC_LENGTH_SYMBOLS; i++) { for (uint16_t i = 0U; i < P25_SYNC_LENGTH_SYMBOLS; i++) {
if (i == (P25_SYNC_LENGTH_SYMBOLS - 1U))
DEBUG4("P25RX: sync1/sync2/start", m_hdrSyncPtr, m_lduSyncPtr, start);
sync[i] = m_buffer[start]; sync[i] = m_buffer[start];
start += P25_RADIO_SYMBOL_LENGTH; start += P25_RADIO_SYMBOL_LENGTH;
@ -453,3 +460,4 @@ void CP25RX::writeSync(uint16_t start)
serial.writeSamples(STATE_P25, sync, P25_SYNC_LENGTH_SYMBOLS); serial.writeSamples(STATE_P25, sync, P25_SYNC_LENGTH_SYMBOLS);
} }
#endif #endif

3
P25RX.h
View File

@ -45,7 +45,8 @@ private:
uint16_t m_endPtr; uint16_t m_endPtr;
uint16_t m_minSyncPtr; uint16_t m_minSyncPtr;
uint16_t m_maxSyncPtr; uint16_t m_maxSyncPtr;
uint16_t m_syncPtr; uint16_t m_hdrSyncPtr;
uint16_t m_lduSyncPtr;
q31_t m_maxCorr; q31_t m_maxCorr;
uint16_t m_lostCount; uint16_t m_lostCount;
uint8_t m_countdown; uint8_t m_countdown;