SWRA682 December   2020 CC1310 , CC1312PSIP , CC1312R , CC1314R10 , CC1350 , CC1352P , CC1352P7 , CC1352R , CC1354P10 , CC1354R10

 

  1.   Trademarks
  2. 1 Introduction
  3. 2 Recommended Test Setup
  4. 3 Overrides
  5. 4 Find the Needed RX BW
  6. 5 How to Set the Deviation
  7. 6 Theoretical Sensitivity
  8. 7 Determine AGC_REF Level
  9. 8 Determine Anti-Aliasing BW
  10. 9 Determine PA Ramp Settings
  11. 10Intermediate Frequency (IF)
  12. 11LNA Ib Offset
  13. 12Sensitivity and Selection of Sync Word
  14. 13Narrowband
    1. 13.1 Frequency Offset Tolerance
    2. 13.2 Low Datarate
    3. 13.3 Phase Noise
  15. 14RSSI Offset

6 Theoretical Sensitivity

Before starting to measure RF performance, it is recommended to calculate the theoretical sensitivity to be able to know if the measured sensitivity is as expected. To get close to the theoretical value, use BER = 1%. It is possible to calculate the relation between PER and BER using Equation 3.

Equation 3. PER = 1 - (1- BER)N

where, N is the total packet length in number of bits including payload and CRC. For sensitivity measurements it is recommended to compare the number of received packets without error vs. the number of transmitted packets.

The theoretical sensitivity is:

Equation 4. -174 dBm/Hz + NF + 10∗log10(RX BW) + SNR

where,

  • -174 dBm: Thermal noise in a 1 Hz bandwidth
  • NF: Noise figure. Noise of all stages referred to the input in a 1 Hz bandwidth
  • RX BW: Receiver filter bandwidth
  • SNR: Signal-to-noise ratio required by demodulator
  • Sum of the first three terms is the total integrated noise in the system and is called the noise floor.
  • NF can be set to 7 dB in the calculations. This is set mainly by the LNA.
  • SNR is dependent of modulation format and modulation index. For 2-(G)FSK with h = 1 and BER = 1% assume SNR = 7 dB