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DSSS modulation of CC1310

Nomo
Guru 16800 points
Other Parts Discussed in Thread: CC1310

Hello,

I have two questions for the DSSS modulation (long-range mode) of CC1310.

1. Is there any documentation to use the DSSS modulation of CC1310?
   I cannot understand how to set the RF parameter (ex. Deviation, RX Filter BW, and Symbol Rate).

2. Let me know the target application of the DSSS modulation.

Best Regards,

Nomoto

  • 0
    TI__Mastermind 39860 points
    From e2e.ti.com/.../509875 "The LRM scheme in the CC1310 comprises of a convolutional encoder of rate ½ is followed by a direct sequence spreader (DSSS) with variable spreading length. The output of that module is finally fed to the 2-(G)FSK modulator. The modulation kernel (symbol rate, frequency deviation) can be user defined."

    In SmartRF Studio you can change the spreading (use the "Override Editor"):
    0x505C,0x0000; 1 x spreading
    0x505C,0x0100; 2 x spreading
    0x505C,0x0303; 4 x spreading
    0x505C,0x073C; 8 x spreading

    In SmartRF Studio there is an LRM example. 10 ksps, 8 x spreading yielding a bit rate of 625 bps. You can change the spreading to achieve 1.25 kbps, 2.5 kbps or 5 kbps.

    If you want other symbol rates simply enter this into Studio. Change the deviation to get a modulation index = 1 (i.e. deviation = symbol rate/2). Scale the RX BW to fit the transmitted signal BW. Approximation: RX BW > symbol rate + 2 x deviation + 4 x Crystal error (in ppm) x RF frequency (in MHz)

    Target application? Cases where you need long range (i.e. best sensitivity)