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AWR2944: Temperature Compensation / Automatic Gain Adjustment

Joe Shidle
Intellectual 420 points
Part Number: AWR2944
Other Parts Discussed in Thread: AWR1243, AWR1443, AWR1642, AWR1843, AWR2243

Tool/software:

We are working with the AWR2944 and are attempting to understand how the temperature compensation and automatic gain adjustment is implemented and used.

We are noticing some anomalies during temperature testing of our proprietary board, and we would like to rule out whether or not these could be caused by the AWR2944 adjusting the receiver gain based on the operating temperature.

Is temperature compensation on by default?  If so, what are the API utilities to access this temperature compensation, for example to enable/disable it?
  • 0
    TI__Expert 5140 points

    HI,

    Someone will reach out to you about this question ASAP. 

    regards,

    Ali

  • 0 in reply to Ali Syed
    TI__Genius 13010 points

    Temp compensation is on by default. I will need to discuss internally to make sure there is an API that you can use to control it 

    -E. Shareef

  • 0 in reply to E. Shareef
    TI__Genius 13010 points

    There would be multiple LUTs for the device that I believe is controlled by Firmware. 

    https://www.ti.com/lit/an/spracv2/spracv2.pdf?ts=1678792384465

    Above document explains this in detail. 

    E. Shareef

  • 0 in reply to E. Shareef
    Intellectual 420 points

    Thank you for the response.

    We are still in the process of digesting this document, but want to clarify.  This document states that it describes "Gen1 (AWR1243, AWR1843, AWR1642, and AWR1443) and Gen2 (AWR2243) radar devices" but makes no mention of the AWR2943/2944 part.  Is the functionality described in this document 100% implemented also on the AWR2944?

    Regards,
    Joe

  • 0 in reply to Joe Shidle
    TI__Genius 13010 points

    Allow me to confirm this Joe 

    Thanks,

    E. Shareef

  • 0 in reply to E. Shareef
    Intellectual 420 points

    This document seems to describe the calibration process for generating LUTs used by the device.

    My understanding is that the LUTs can be calibrated at various points in the device's life cycle - in the TI factory which presumably generates die calibration LUTs, on power-up, during run time either by programmatic determination (e.g. "event detected, calibrate now"), regularly scheduled calibration (e.g. every 1s), and possibly others.

    Do all these calibrations affect the same LUT used by the device to perform temperature-based adjustments on the TX or RX gain?  Or are there multiple LUTs which affect the TX or RX gain simultaneously?

    This document also indicates how to enable or disable the power-up and/or run-time calibration.  But based on this document, would the TI factory LUT still be used to affect the TX or RX gain?

    How would we completely disable any LUT from being used on the AWR2944?

    Failing that, how would we generate and store a custom (non-calibrated) LUTs for the device?

  • 0 in reply to Joe Shidle
    TI__Genius 13010 points

    Hello,

    Do all these calibrations affect the same LUT used by the device to perform temperature-based adjustments on the TX or RX gain?  Or are there multiple LUTs which affect the TX or RX gain simultaneously? There are multiple LUTs for the device. 

    This document also indicates how to enable or disable the power-up and/or run-time calibration.  But based on this document, would the TI factory LUT still be used to affect the TX or RX gain? Yes it will be

    How would we completely disable any LUT from being used on the AWR2944? You wouldnt be able to disable the LUT for VCO and APLL. Others, you should be able to.

    Failing that, how would we generate and store a custom (non-calibrated) LUTs for the device? I believe this is possible, where user can set the offsets to control the temp compensation. I will need to confirm this. 

  • 0 in reply to E. Shareef
    Intellectual 420 points

    > There are multiple LUTs for the device. 

    How do the multiple LUTs interact with each other?
    Does each LUT adjust the TX or RX gain sequentially, or is each LUT used to make a "master LUT" which acts on the TX or RX gain in one operation?

    > You wouldnt be able to disable the LUT for VCO and APLL. Others, you should be able to.

    How do we disable the LUT for RX gain?

    > Failing that, how would we generate and store a custom (non-calibrated) LUTs for the device? I believe this is possible, where user can set the offsets to control the temp compensation. I will need to confirm this. 

    We would be very interested in how to perform this action, specifically a custom (non-calibrated) LUT for the TX and/or RX gain (one LUT for each).

    > Is the functionality described in this document 100% implemented also on the AWR2944?

    Were you able to confirm that this document is also relevant for the AWR2944?

    Regards,
    Joe

  • 0 in reply to Joe Shidle
    TI__Genius 13010 points

    I'm still looking into how to disable the LUT for TX and RX gain.

    -E. Shareef

  • 0 in reply to E. Shareef
    TI__Genius 13010 points

    Hello,

    Below is an excerpt from this document: www.ti.com/.../spracf4c.pdf

    The LUT used for RX gain calibration can be read back using the rlRxGainTempLutGet function. This returns the lookup table that is applied for RX gain calibration for a given profile. The function should only be called after the profile has been configured in the device.

    The LUT structure is described in the Radar Interface Control document. The LUT for a given profile consists of a set of 19 RX gain codes, each corresponding to a particular 10 degree temperature bin. Each RX gain code is further divided into an IF gain code and a RF gain code. The rlRxGainTempLutSet function can be used to replace the LUT used by the device for Rx gain calibration with a different set of gain codes.

    This function should be called once for each profile for which the LUT needs to be replaced. This function should only be called after the profile has been configured in the device.

    You can use this to override the RX Gain LUT. 

    Hope this helps,

    E. Shareef