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Improving D-Star detection

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This commit is contained in:
Andy CA6JAU 2017-05-25 23:46:16 -04:00
parent 3c63ed1314
commit 5684499b5f
7 changed files with 31 additions and 4 deletions
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21
DStarRX.cpp
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@ -30,6 +30,11 @@ const unsigned int SYNC_POS = 21U * DSTAR_DATA_LENGTH_BITS;
const unsigned int SYNC_SCAN_START = SYNC_POS - 3U;
const unsigned int SYNC_SCAN_END = SYNC_POS + 3U;
// D-Star preamble sequence (only 32 bits of 101010...)
const uint32_t PREAMBLE_MASK = 0xFFFFFFFFU;
const uint32_t PREAMBLE_DATA = 0xAAAAAAAAU;
const uint8_t PREAMBLE_ERRS = 2U;
// D-Star bit order version of 0x55 0x55 0x6E 0x0A
const uint32_t FRAME_SYNC_DATA = 0x00557650U;
const uint32_t FRAME_SYNC_MASK = 0x00FFFFFFU;
@ -284,9 +289,21 @@ void CDStarRX::processNone(bool bit)
if (bit)
m_patternBuffer |= 0x01U;
// Fuzzy matching of the preamble sync sequence
if (countBits32((m_patternBuffer & PREAMBLE_MASK) ^ PREAMBLE_DATA) <= PREAMBLE_ERRS) {
DEBUG1("DStarRX: preamble detected, fuzzy");
// Extend scan period in D-Star, once preamble is detected
m_modeTimerCnt = 0;
m_rxState = DSRXS_NONE;
return;
}
// 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");
DEBUG1("DStarRX: found frame sync in None, fuzzy");
::memset(m_rxBuffer, 0x00U, DSTAR_FEC_SECTION_LENGTH_BYTES);
m_rxBufferBits = 0U;
@ -297,7 +314,7 @@ void CDStarRX::processNone(bool bit)
// Exact matching of the data sync bit sequence
if (countBits32((m_patternBuffer & DATA_SYNC_MASK) ^ DATA_SYNC_DATA) == 0U) {
DEBUG1("DStarRX: found data sync in None");
DEBUG1("DStarRX: found data sync in None, exact");
io.setDecode(true);