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CC1200: Avoiding the integer boundary

Part Number: CC1200

Hello,

Are the following limitations for avoiding the integer boundary problem fixed in new hardware revisions?

Table 4.14 of the CC1200’s Data Sheet

“It is expected that there will be degraded sensitivity at multiples of XOSC/2 in RX, and an increase in spurious emissions when the RF Crystal frequency 38.4 40 MHz channel is close to multiples of XOSC in TX. We recommend that the RF channel is kept RX_BW/2 away from XOSC/2 in RX, and that the level of spurious emissions be evaluated if the RF channel is closer than 1 MHz to multiples of XOSC in TX.”

What could you recommend to avoid this problem when CC1200 is used?

Thanks,

Alex

  • This is a fundamental RF issue since a spur on n*clock frequency will end up in the middle of the channel and hence degrade the performance some. We have not done any changes on CC1200 since the device was released.

    Either you can look inot not using the channels in question or try to adjust the xtal frequency some if you need to operate on a given channel and don't want poorer perfromance on this channel.

  • Thank you, TER.

    I'm not sure how Frequency Offset (registers FREQOFF1, FREQOFF0) is implemented in CC1200. If some frequency e.g. Fo should be avoided, is it possible to set up radio frequency (Fo-Foffset) for CC1200 and compensate it by +Foffset?

    Thanks,

    Merry Christmas and Happy New Year!

      

  • I would do it on a higher level. You should probably set the protocol not to use a given channel.