SPRACF4C June   2018  – January 2023 AWR1243 , AWR1443 , AWR1642 , AWR1843 , AWR1843AOP , AWR2243 , AWR2944 , AWR6843 , AWR6843AOP , IWR1843 , IWR6443 , IWR6843 , IWR6843AOP

 

  1.   Trademarks
  2. 1Introduction
    1. 1.1 Purpose of Calibrations
    2. 1.2 Purpose of Monitoring Mechanisms
  3. 2Hardware Infrastructure to Support Calibration and Monitoring
  4. 3List of Calibrations
    1. 3.1  APLL Calibration
    2. 3.2  Synthesizer VCO Calibration
    3. 3.3  LO Distribution Calibration
    4. 3.4  ADC DC Offset Calibration
    5. 3.5  HPF Cutoff Calibration
    6. 3.6  LPF Cutoff Calibration
    7. 3.7  Peak Detector Calibration
    8. 3.8  TX Power Calibration
    9. 3.9  RX Gain Calibration
    10. 3.10 IQ Mismatch Calibration
    11. 3.11 TX Phase Shifter Calibration
  5. 4Impact of Calibration on Gain and Phase
  6. 5Impact of Interference on the Calibrations and Emissions Caused Due to Calibrations
  7. 6Scheduling of Runtime Calibration and Monitoring
    1. 6.1 Selection of CALIB_MON_TIME_UNIT
    2. 6.2 Selection of CALIBRATION_PERIODICITY
    3. 6.3 Application-Controlled One Time Calibration
  8. 7Software Controllability of Calibration
    1. 7.1  Calibration and Monitoring Frequency Limits
    2. 7.2  Calibration and Monitoring TX Frequency and Power Limit
    3. 7.3  Calibration Status Reports
      1. 7.3.1 RF Initialization Calibration Completion
      2. 7.3.2 Runtime Calibration Status Report
      3. 7.3.3 Calibration/Monitoring Timing Failure Status Report
    4. 7.4  Programming CAL_MON_TIME_UNIT
    5. 7.5  Calibration Periodicity
    6. 7.6  RF Initialization Calibration
    7. 7.7  Runtime Calibration
    8. 7.8  Overriding the TX Power Calibration LUT
    9. 7.9  Overriding the RX Gain Calibration LUT
    10. 7.10 Retrieving and Restoring Calibration Data
  9. 8References
  10.   A Calibration and Monitoring Durations
    1.     A.1 Duration of Boot Time Calibrations
  11.   Revision History

3.8 TX Power Calibration

TX power calibration is carried out to ensure that the device is transmitting at exactly the specified transmit power for a given profile.

TX power calibration can be done in Open Loop Power Control (OLPC) or Closed Loop Power Control (CLPC) modes. In OLPC mode, the TX stage codes are set based on a coarse measurement and a LUT is generated for every temperature range. The final stage codes are picked from the LUT and applied to the device based on the temperature at the time of calibration.

In CLPC mode, the TX stage codes are picked from the coarse LUT as in the OLPC step. Then, the actual TX power is measured using the peak detectors and the TX stage codes are refined to achieve the desired TX power accuracy. In many cases, the CLPC mode could provide better control on the TX output power because the gains are updated based on again performing a loopback measurement. This also leads to intentional transmission on the PA and higher calibration time. Refer to the Interface Control Document for calibration times.

The LUT used for TX power calibration can be read back from the device using an API. The LUT can also be replaced with a user-programmed LUT (for example, with an LUT that was previously read back from the device). The APIs to read and write the TX power calibration LUT are covered in Section 7.8.

Note:

In CLPC mode, the LUT used for TX power calibration may be updated by the device after run time calibration events. The updated LUT can be read back from the device if needed.

TX power calibration is carried out at boot time for all enabled TXs, and can be carried out again at runtime. When recalibrating at runtime, the TX power calibration is done per-profile, per-TX.

By default, a single TX is enabled during the boot time TX power calibration. In the AWR294x, the user can select multiple TXs to be turned on at the same time to compensate for the additional supply voltage drop that might occur on the PCB due to multiple TXs being ON. This is selected using the "AWR_RF_INIT_CALIBRATION_CONF_SB API" API. Similarly for the CLPC run time calibration, multiple TXs can be configured to be ON using the "AWR_PROFILE_CONF_SB API" API.