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Visitor II
July 15, 2021
Solved

What's the unit of the variable "deviation" in the evalAPIcommands.c file?

  • July 15, 2021
  • 1 reply
  • 629 views

In the evalAPIcommands.c file have the function "reflectedPowerTooHigh()" in the line 907. The goal of that function is to calculate the value of the reflected power and the deviation variable received this value, but don't have a comment in code say what is the unit calculated that variable, Would I like to know what is the unit of that variable percentage or dBm?

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    Best answer by Nick K

    The goal of this function is to decide if re-tuning shall be applied or not. For this the deviation between the actual measured "reflected power" and the the "reflected power" that was measured when tuned is calculated. If the diff is bigger then the deviation then re-tuning is applied. The mentioned "reflected power" here is simplified in the FW to avoid complicated math operations in FW and is the just the square sum of the measured Mixer DC level of the I and Q signals (I^2 +Q^2).

    For further details please have a look to the ST25RU3993 datasheet https://www.st.com/resource/en/datasheet/st25ru3993.pdf section 2.11.2 Reflected RF power indicator

    BR

    Nick

    1 reply

    Nick KAnswer
    ST Employee
    August 3, 2021

    The goal of this function is to decide if re-tuning shall be applied or not. For this the deviation between the actual measured "reflected power" and the the "reflected power" that was measured when tuned is calculated. If the diff is bigger then the deviation then re-tuning is applied. The mentioned "reflected power" here is simplified in the FW to avoid complicated math operations in FW and is the just the square sum of the measured Mixer DC level of the I and Q signals (I^2 +Q^2).

    For further details please have a look to the ST25RU3993 datasheet https://www.st.com/resource/en/datasheet/st25ru3993.pdf section 2.11.2 Reflected RF power indicator

    BR

    Nick