void CYSFRX::processNone(q15_t sample)
{
m_symbolBuffer <<= 1;
if (sample < 0)
m_symbolBuffer |= 0x01U;
m_symbols[m_symbolPtr] = sample;
// Fuzzy matching of the data sync bit sequence
if (countBits32((m_symbolBuffer & YSF_SYNC_SYMBOLS_MASK) ^ YSF_SYNC_SYMBOLS) <= SYNC_SYMBOL_ERRS) {
q15_t max = -16000;
q15_t min = 16000;
for (uint8_t i = 0U; i < YSF_SYNC_LENGTH_SYMBOLS; i++) {
q15_t val = m_symbols[i];
if (val > max)
max = val;
if (val < min)
min = val;
}
q15_t centre = (max + min) >> 1;
q31_t v1 = (max - centre) * m_scale;
q15_t threshold = q15_t(v1 >> 15);
uint16_t ptr = m_symbolPtr + 1U;
if (ptr >= YSF_SYNC_LENGTH_SYMBOLS)
ptr = 0U;
for (uint8_t i = 0U; i < YSF_SYNC_LENGTH_SYMBOLS; i++) {
q15_t sample = m_symbols[ptr] - centre;
if (sample < -threshold) {
m_bitBuffer <<= 2;
m_bitBuffer |= 0x01U;
} else if (sample < 0) {
m_bitBuffer <<= 2;
m_bitBuffer |= 0x00U;
} else if (sample < threshold) {
m_bitBuffer <<= 2;
m_bitBuffer |= 0x02U;
} else {
m_bitBuffer <<= 2;
m_bitBuffer |= 0x03U;
}
ptr++;
if (ptr >= YSF_SYNC_LENGTH_SYMBOLS)
ptr = 0U;
}
// Fuzzy matching of the data sync bit sequence
if (countBits64((m_bitBuffer & YSF_SYNC_BITS_MASK) ^ YSF_SYNC_BITS) <= SYNC_BIT_START_ERRS) {
DEBUG5("YSFRX: sync found in None min/max/centre/threshold", min, max, centre, threshold);
for (uint8_t i = 0U; i < YSF_SYNC_LENGTH_BYTES; i++)
m_buffer[i] = YSF_SYNC_BYTES[i];
m_centre = centre;
m_threshold = threshold;
m_lostCount = MAX_SYNC_FRAMES;
m_bufferPtr = YSF_SYNC_LENGTH_BITS;
m_state = YSFRXS_DATA;
io.setDecode(true);
io.setADCDetection(true);
}
}
void CDMRSlotRX::correlateSync(q15_t sample)
{
m_bitBuffer[m_bitPtr] <<= 1;
if (sample < 0)
m_bitBuffer[m_bitPtr] |= 0x01U;
uint8_t errs = countBits32((m_bitBuffer[m_bitPtr] & DMR_SYNC_SYMBOLS_MASK) ^ DMR_MS_DATA_SYNC_SYMBOLS);
// The voice sync is the complement of the data sync
bool data = (errs <= MAX_SYNC_SYMBOLS_ERRS);
bool voice = (errs >= (DMR_SYNC_LENGTH_SYMBOLS - MAX_SYNC_SYMBOLS_ERRS));
if (data || voice) {
uint16_t ptr = m_dataPtr - DMR_SYNC_LENGTH_SAMPLES + DMR_RADIO_SYMBOL_LENGTH;
q31_t corr = 0;
q15_t min = 16000;
q15_t max = -16000;
uint32_t mask = 0x00800000U;
for (uint8_t i = 0U; i < DMR_SYNC_LENGTH_SYMBOLS; i++, mask >>= 1) {
bool b = (DMR_MS_DATA_SYNC_SYMBOLS & mask) == mask;
if (m_buffer[ptr] > max)
max = m_buffer[ptr];
if (m_buffer[ptr] < min)
min = m_buffer[ptr];
if (data)
corr += b ? -m_buffer[ptr] : m_buffer[ptr];
else // if (voice)
corr += b ? m_buffer[ptr] : -m_buffer[ptr];
ptr += DMR_RADIO_SYMBOL_LENGTH;
}
if (corr > m_maxCorr) {
q15_t centre = (max + min) >> 1;
q31_t v1 = (max - centre) * SCALING_FACTOR;
q15_t threshold = q15_t(v1 >> 15);
uint8_t sync[DMR_SYNC_BYTES_LENGTH];
uint16_t ptr = m_dataPtr - DMR_SYNC_LENGTH_SAMPLES + DMR_RADIO_SYMBOL_LENGTH;
samplesToBits(ptr, DMR_SYNC_LENGTH_SYMBOLS, sync, 4U, centre, threshold);
if (data) {
uint8_t errs = 0U;
for (uint8_t i = 0U; i < DMR_SYNC_BYTES_LENGTH; i++)
errs += countBits8((sync[i] & DMR_SYNC_BYTES_MASK[i]) ^ DMR_MS_DATA_SYNC_BYTES[i]);
if (errs <= MAX_SYNC_BYTES_ERRS) {
DEBUG5("DMRSlotRX: data sync found slot/pos/centre/threshold", m_slot ? 2U : 1U, m_dataPtr, centre, threshold);
m_maxCorr = corr;
m_centre = centre;
m_threshold = threshold;
m_control = 0x40U;
m_endPtr = m_dataPtr + DMR_SLOT_TYPE_LENGTH_SAMPLES / 2U + DMR_INFO_LENGTH_SAMPLES / 2U - 1U;
DEBUG3("DMRSlotRX: slot/endPtr", m_slot ? 2U : 1U, m_endPtr);
}
} else { // if (voice)
uint8_t errs = 0U;
for (uint8_t i = 0U; i < DMR_SYNC_BYTES_LENGTH; i++)
errs += countBits8((sync[i] & DMR_SYNC_BYTES_MASK[i]) ^ DMR_MS_VOICE_SYNC_BYTES[i]);
if (errs <= MAX_SYNC_BYTES_ERRS) {
DEBUG5("DMRSlotRX: voice sync found slot/pos/centre/threshold", m_slot ? 2U : 1U, m_dataPtr, centre, threshold);
m_maxCorr = corr;
m_centre = centre;
m_threshold = threshold;
m_control = 0x20U;
m_endPtr = m_dataPtr + DMR_SLOT_TYPE_LENGTH_SAMPLES / 2U + DMR_INFO_LENGTH_SAMPLES / 2U - 1U;
DEBUG3("DMRSlotRX: slot/endPtr", m_slot ? 2U : 1U, m_endPtr);
}
}
}
