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CC1101: CC1101 attenuation value tolerance?

Andreas Paulin
Prodigy 235 points
Part Number: CC1101

We are using the Close-in attenuation as described in AppNote DN010/SWRS061I.
The selectable values in Register FIFOTHR.CLOSE_IN_RX[1:0] are 0dB, 6dB, 12dB and 18dB.
These attenuations are marked as TYPICAL values.
We are using these values to calculate the real RSSI before switching on the 18dB attenuation but we find
differences here and there. It seems that these are related to tolerances in those attenuation values.

Do you have any tolerance values defined, how far the real attenuation value can differ from the typical values?

Kind regards

Andreas Paulin

  • 0
    TI__Mastermind 27145 points

    Hi,

    How did you test those values?

    Did you do conductive tests? if not, please do conductive tests.

    What is the tolerance you observed?

    Those values are typical.

    Thanks,

    PM

  • 0 in reply to PM
    TI__Mastermind 27145 points

    Hi,

    Any update on this one?

    Thanks,

    PM

  • 0 in reply to PM
    Prodigy 235 points

    Hi, PM,

    we found a strange difference between the RSSI during reception of a packet without using attenuation and the RSSI after using attenuation and then subtracting (adding) the 18dB attenuation from the RSSI value.
    We have no precise values, RSSI is changing, but our observations is about +/- 3db deviation. And we found the attenuation values (0dB, 6dB, 12dB and 18dB) defined as TYPICAL. So i was asking, if there's a tolerance from the typical values defined somewhere, just to make shure.

    Btw.. what does 'conductive test' mean in this case?

    Regards

    Andreas

  • 0 in reply to Andreas Paulin
    TI__Mastermind 27145 points

    Hi,

    The RSSI accuracy within +/- 3dB is Normal. So, this is not a problem.

    Conductive means connect the Board (RF Port) to the Test Equipment with the Cable (RF Cable) for testing purpose. This way  we can measure proper levels. 

    Where as in Radiative tests ( Radiation from Antenna - wireless), the signal varies a lot and also the measurement values won't be accurate.

    Thanks,

    PM