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CC1200 maximum symbol rate

Daniel M
Prodigy 80 points
Other Parts Discussed in Thread: CC1200

Hi,
According to the CC1200 datasheet, the maximum rate is 1250kbps at 4FSK modulation. So I would assume that in this case required symbol rate is 625ksps.

However, according to user manual the maximum symbol rate is 500ksps and when I try to set value higher than 500ksps in SmartRF I get error.

Could you please guide me how to get recommended registers configuration for 1250kbps rate?

Thank you in advance.

  • 0
    TI__Mastermind 39860 points

    We have tested 1.25 kbps (625 ksps) with +/-550 kHz deviation. Use SmartRF Studio and select typical setting "Symbol rate: 500 ksps, 4-GFSK, max throughput, ETSI Standard (868 MHz)". Make the following changes:

    DRATE2 D0
    DRATE1 0
    DRATE0 0
    FS_DIG0 AB
    AGC_CFG2 20
    DEVIATION_M C3

    1% BER was measured as -94 dBm.

  • 0 in reply to Sverre
    Prodigy 80 points

    Sverre, thank you for your response!

    According to the datasheet CC1200 sensitivity at 1Mbps is -97dBm. Have you measured it in the same conditions as -94dBm for 1.25Mbps? If so, do you know the reason for 3dB degradation?

  • 0 in reply to Daniel M
    TI__Mastermind 39860 points

    Everything else being equal a higher data rate will give degraded sensitivity. When I did the measurements I tested 5 samples @1.25 Mbps and got -94.125 dBm (average of the 5 samples). The same samples gave -96 dBm at 1 Mbps. For the 1.25 Mbps case we used a higher modulation index than at 1 Mbps. In theory this should gain back some of the degraded sensitivity due to increased data rate.