LoRa Devices

Semtech SX1262 LoRa transceiver 比 SX1276 新，效能較好。基於 nRF52 比基於 ESP32 省電，但較貴。

• SX1261, SX1262 and SX1268 sub-GHz radio transceivers，。
• compliance with radio regulations ETSI EN 300 220, FCC CFR 47 Part 15, China regulatory requirements and the Japanese ARIB T-108. 頻率涵蓋150MHz ~ 960MHz 支援全世界主要 sub-GHz ISM bands。
• FSK, GFSK, MSK, GMSK, LoRa and Long Range FHSS modulations。LoRa 最快 62.5kbps LoRa，FSK 最快 300kbps。
• 170dB maximum link budget (SX1262 / 68)
• +22dBm (SX1262/SX1268) 或 +15dBm (SX1261) high efficiency PA [傳送能力]
• Low RX current of 4.6mA (？？？4.2 mA of active receive current consumption)
• High sensitivity: down to -148dBm
• 88dB blocking immunity at 1MHz offset
• Co-channel rejection of 19dB in LoRa mode
• Automatic Channel Activity Detection (CAD) with ultra-fast AFC

LoRa Modulation Parameter：• Modulation BandWidth (BW_L)• Spreading Factor (SF)• Coding Rate (CR)• Low Data Rate Optimization (LDRO)

Spreading Factor (SF)：spread spectrum LoRa® modulation 是用多個 chip 代表一個 bit 資料。symbol rate (Rs)。SF = (nominal Rs)/(chip rate) = the number of symbols sent per bit of information.

Rs = BW/2^SF

SF 5 = 2⁵ = 32 chips/symbol