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AWR2944EVM: Dependence on RF parameters and calibration errors during calibration

Katherine Wang
Intellectual 2210 points
Part Number: AWR2944EVM

Hi Team,

There is no detailed description of the starting frequency, bandwidth, and slope used during calibration in the calibration document. So I have the following questions.

1. Is constant frequency calibration required during calibration?

2. How does the choice of center frequency during calibration affect PS INL?

3. Since the calibration itself also has the problem of jitter in the measurement data, does the calibration operation require N times of calibration to obtain the expectation?

4. If N operations are required, what is the value range of N?

5. Is this measurement noise Gaussian, and can we use the mean instead of the expectation?

Kind regards,

Katherine

  • 0
    TI__Intellectual 1815 points

    Hi Katherine,

    1. Are all the questions related to phase shifter calibration only or all the calibrations?

    2. Do the questions refer to factory calibration procedure? Procedure mentioned in https://www.ti.com/lit/an/spracv2/spracv2.pdf .

    I hope the customer is referring to the application note: https://www.ti.com/lit/an/spracf4c/spracf4c.pdf.

    Regards,

    Swati

  • 0 in reply to Swati Hans
    TI__Intellectual 2210 points

    Hi Swati,

    Swati Hans said:
    1. Are all the questions related to phase shifter calibration only or all the calibrations?

    1. All the above questions are related to phase shifter and antenna phase calibration

    Swati Hans said:
    2. Do the questions refer to factory calibration procedure?

    2. The questions refer to the project calibration mentioned in the spracv2 document

    Regards,

    Katherine

  • 0 in reply to Katherine Wang
    TI__Intellectual 1815 points

    Hi Katherine,

    Please find the answers below:

    1. Is constant frequency calibration required during calibration? – You can use a chirp signal for calibration. Constant frequency (0 slope) is not necessary.
    2. How does the choice of center frequency during calibration affect PS INL? – As we move farther from the calibration frequency, the accuracy of the phase shifter calibration degrades. Hence, the user should always perform phase shifter calibration with the user in-field profile frequency.
    3. As the calibration itself also has the problem of jitter in the measurement data, does the calibration operation require N times of calibration to obtain the expectation? – Doing the calibration N times would ideally lead to less measurement inaccuracy and noise. It would be recommended to check whether the IF tone for phase shifter calibration measurement has a good SNR (>40dB), and if that is the case, then even 1 time calibration is good enough.
    4. If N operations are required, what is the value range of N?- Answered above
    5. Is this measurement noise Gaussian, and can we use the mean instead of the expectation?- Can you elaborate on the question?
    6. During the calibration/restore process of the TX phase shifter, the document does not require us to perform INL correction on the measured PS Cal Result Array DegreeTXm (0 to 63) value, but only requires us to save and restore it to the AWR device . So how does the AWR device correct the INL caused by the phase shift? According to this process, the AWR device can completely complete this process automatically. Why do we need to implement this process manually? –
      1. Based on the restored PS Cal Result Array DegreeTXm (0 to 63) value, the device internally computes the required correction settings
      2. Can you specify the process that you are mentioning?

    Regards,

    Swati