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LMX2572: 4FSK RRC

Ryan.Bishop
Expert 3900 points
Part Number: LMX2572
Other Parts Discussed in Thread: LMX2571,

Hello,

Are there any application notes on how to generate digital modular radio (DRM) waveforms with this part?

We did find this application note on generating FSK with the LMX2571: http://www.ti.com/lit/an/snaa309/snaa309.pdf

Are there any concerns with following that app note for the LMX2572 instead? Any special considerations for this high frequency part?

We want to do 4FSK with root-raised-cosine filtering.

Thank you!
Ryan B.

  • 0
    TI__Guru* 81400 points

    Hi Ryan,

    LMX2571 does not have an embedded FSK filter, so the RRC FSK codes must be done externally. 

    Usually, the customer will use a FPGA or DSP to generate the RRC FSK codes.

    The appnote demonstrated this with a Mathlab script that generates random data --> scaled to FSK deviation --> RRC filtered --> oversampling --> convert FSK deviation to LMX2571 FSK code format.

    The Mathlab script is useful for demonstration but I believe it is not able to be imported to a FPGA or DSP. Customers have to figure out how to do it with their logic device.