Hi !
I read the datasheet, and it says:
"The receive chain comprises a differential low-noise amplifier (LNA), a down-converter to
low-IF by mixer operation in quadrature configuration".
1. What is the GAIN and the NF of the diff. LNA ?
1.a Is it also the NF of the LORA ?
2. Can I add another amplifier (LNA) at the input ?
Thanks,
Kosta
Hello
The NF has been measured following the procedure described below using the RSSI:
SNR_in = pwr_in_RX+ 174 = 94dB
SNR_out= RSSI (gene ON) – RSSI (gene OFF) + 10*log (BW)
NF=SNR_in – SNR_out.
NF doesn't depend on modulation.
For example:
For a frequency of 868 MHz
Gain = 41 at 25° and 3.3V (highest LNA gain step).
NF = 5.6 at 25° and 3.3V SMPS ON
For the external LNA: for low data rate or high SF (for LoRa) I'm not sure it's interesting, for higher data rate it should be possible to gain several dB of sensitivity, in fact I don't see why it should not be possible.
Best Regards.
STTwo-32
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