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CC1125 Sensitivity

Hi,

When MODCFG_DEV_E.MOD_FORMAT set to 2-(G)FSK modulation and frequency deviation set to ¼ of symbol rate,it is the MSK modulation.When I use MSK modulation and symbol rate set to 9600,the receive sensitivity reach -114dBm.but when symbol rate is 19200,the receive sensitivity only -108dBm.it is normal taht sensitivity will decrease when symbol rate increase,but if it is too much from -114dBm to -108dBm?And,how to implove receive sensitivity when symbol rate is 19200?

Thanks.

  • Datarate 9600 bps, deviation 2400 Hz : 99% OBW 10320 (given GFSK)

    Datarate 19200 bps, deviation 4800 Hz : 99% OBW 20640 (given GFSK)

    => You need 2x Rx bandwidth to receive the highest datarate compared to the lowest datarate which gives a 3 dB loss in sensitivity. Higher datarate using the same Rx BW will also give poorer sensitivity,.

    Why do you need MSK? What are your goal/ design restrictions? As and example we have measured on 19.2 kbps, 7.2 kHz 4 GFSK and gotten -113 dBm sensitivity.