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IWR1843: Where should Self-Calibration be carried out.

Part Number: IWR1843

Tool/software:

Hello,

I would like to clarify the following points regarding the Self-Calibration function of the IWR1843:

  • Whether Self-Calibration is carried out when the Self-Calibration is enabled.
  • Where should the Self-Calibration be carried out.

Based on the document SPRACF4C, I have summarized our understanding in Table 1 and Table 2 respectively.
Please confirm if our understanding is correct.
If there are any mistakes or additional information needed, please refer to the attached Excel sheet, which serves as the basis for the tables, and make any necessary corrections or additions.

Self-Calibration.xlsx

Best regards,
Yasuaki

  • Hi

    Thanks for your query. Please allow us a couple of days to respond.

    Regards

  • Hi

    Table 1 correctly depicts the calibration done during boot time and run time

    Below appnote povides more details about the calibration in TI mmwave devices

    https://www.ti.com/lit/an/spracf4c/spracf4c.pdf?ts=1727949516303&ref_url=https%253A%252F%252Fwww.google.com%252F

    Below appnote provides details about the tests done at factory and during field

    https://www.ti.com/lit/an/spracx7/spracx7.pdf?ts=1727949604241&ref_url=https%253A%252F%252Fwww.google.com%252F

    In Table 2

    Location for boot time calibration is correct. It is recommended that factory saved values are restored for rx gain, rx iq mismatch and tx phase shifter.

    But during run time calibration, it is recommended that rx gain be done on field 

    Regards 

  • Hi,

    Sorry for the delayed response.
    Thank you for your answers.
    I have revised Table 2. Please check it.

    I have some questions regarding the implementation of Self-Calibration for RX Gain, RX IQ Mismatch, and TX Phase Shifter using the mmWave API (ti/control/mmwave/mmwave.h).
    When running Self-Calibration in Field Operation according to the revised Table 2, are the following argument settings and execution methods correct?
    If any are incorrect, please provide the corrections.

    • API MMWave_open()
      - Arg MMWave_OpenCfg>useCustomCalibration: set true
      - Arg MMWave_OpenCfg>customCalibrationEnableMask:
          - 10bit(RX Gain Cal) : set 1(Enable)
          - 11bit(Tx Phase Cal): set 0(Disable)
          - 12bit(RX IQMM Cal) : set 0(Disable)
      - Arg MMWave_CalibrationData: set factory saved values
    • API MMWave_start()
      - Arg MMWave_CalibrationCfg>MMWave_ChirpCalibrationCfg>enableCalibration: set true
      - Arg MMWave_CalibrationCfg>MMWave_ChirpCalibrationCfg>enablePeriodicity: set true
    • API MMWave_addProfile()
      - Arg rlProfileCfg_t>pfCalLutUpdate:
          - 1bit(Retain RxCal LUT): set 1(Do not Update RX calibration LUT)
    • API rlRxGainTempLutSet(): should be issued after MMWave_addProfile()

    Best regards,
    Yasuaki

  • Hello,

    Could you please provide answers next Tuesday?
    Alternatively, by when could you provide the answers?

    Best regards,
    Yasuaki

  • Hi

    Periodic calibration should not be enabled, Run time calibration should be rerun only when there is change in temperature by 40 degrees Celsius.

    If periodic calibration is enabled, it will change the gain codes and tx power so that there will be slight variation for reading from time to time.

    Updated table is correct

    Rest of the sequence is ok

    Regards

  • Hi,

    Thank you for your reply.
    A few things have come up that I would like to confirm.

    Q1:
    When there is a temperature change of 40 degrees Celsius, should the RX gain code be updated similarly to the gain codes of TX power?
    For example, we would like to know whether the gain code (LUT) should be updated periodically to ensure there is not much difference in the target signal strength between -40 degrees and 105 degrees.

    Q2:
    Based on your response, how should I correct the red text in my second comment?
    Is it sufficient to simply change "MMWave_ChirpCalibrationCfg>enablePeriodicity: set true" to "false"?

    Q3:
    Is it possible to configure the control for automatically running runtime calibration after a 40 degrees Celsius temperature change in the SDK?

    Q4:
    If the answer to Q3 is no, I believe we need to detect the temperature change and perform the runtime calibration ourselves.
    Is there a way for us to perform or schedule the calibration at any arbitrary timing after MMWave_start()?
    Or do we need to stop the RF output by executing MMWave_stop() or similar commands?

    Best regards,
    Yasuaki

  • Hi

    Q1:Running the runtime calibration with Rx gain and Tx power enabled will repopulate the codes. There is no need to update anything manually

    Q2: MMWave_ChirpCalibrationCfg>enablePeriodicity should be false

    Q3 : You will have to write the code to measure temperature and enable the runtime config. There is no prebuilt function that you can use

    Q4: You will have to stop RF output using MMWave_stop() before you execute runtime calibration. Once the calibration is done, you can restart the RF output

    Regards