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LP-CC1312R7: Spurious, adjacent channel leakage power, and selectivity at 1200 MHz

Genius 5320 points
Part Number: LP-CC1312R7
Other Parts Discussed in Thread: CC1312R7

Hi experts,

My customer is using the LP-CC1312R7 evaluation board to check its performance.

As an evaluation for use in the ARIB-STD-T67 1200 MHz band, we used the LP-CC1312R7 and RFStudio to output a GFSK signal at 1216-1217 MHz and measured that signal, but had problems with the following points.
1) Transmit power is only about 1mW at 10mW setting.
2) Spurious must be less than -36dB relative to the carrier, but only just under the standard at -36dB.
3) Adjacent channel leakage power must be -40dB or less relative to transmit power, but only -37dB can be obtained.

Q1:To solve these problems, do I need to modify the CC1312R7 settings or external circuits?
(In the related thread, it was only the transmit power, so I just wanted to be sure.)
https://e2e.ti.com/support/wireless-connectivity/sub-1-ghz-group/sub-1-ghz/f/sub-1-ghz-forum/987966/launchxl-cc1312r1-change-the-txpower

Also they have tested the reception performance, but the signal selectivity for the reception frequency ±12.5 kHz does not seem to be good, and the reception sensitivity drops when the received signal and the ±12.5 kHz interference signal are input simultaneously.

Q2:They think the selectivity can be improved if the BPF bandwidth for reception can be narrowed, but is there such a setting for CC1312R7?

Best regards,
O.H

  • The Launchpad is optimized for the 868 MHz and 915 MHz band. If you want to use 1200 MHz and T67 you most likely have to make a custom board that is optimized for the band in question. 

  • Hi O.H.,

    To add to the post above:

    1. You would need to both optimise the BoM and the settings. We do not currently have a reference design for the 1.216-1.217 GHz band (or PA table settings) and have not performed characterisation within this frequency range so far. The factors you mentioned (for both TX and RX) will be affected by the output matching network.
    2. It is likely that finding a BoM that is optimised for the desired band would have the largest effect on performance.

    Regards,

    Zack 

  • Hi,

    Sorry for the late reply. I understood that there is no reference in the 1200 MHz band.

    Thanks to both of you for your support.

    Best regards,
    O.H