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); } } }