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IWR1843AOP: How to Apply Chirp-Based Phase Shift to Transmit Antennas

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Prodigy 50 points
Part Number: IWR1843AOP

Tool/software:

To the TI Support Team,

Thank you for your support.

Please note that this message was translated using AI.

We are currently evaluating the chirp-based phase shifter feature using mmWave Studio, DCA1000, and IWR1843AOP.

[Request]
We would like to use the “Chirp based Phase Shifter” feature in BPMConfig.

[Steps Taken]
We connected the DCA1000 and IWR1843AOP to mmWave Studio.
First, we enabled “Per Chirp Phase Shifter En” in the Radar Miscellaneous Control section of the StaticConfig tab.
Next, we configured the phase shift settings. For a simplified functional check, we set the following parameters:

[13:32:09] [RadarAPI]: ar1.ChirpConfig(0, 0, 0, 0, 0, 0, 0, 1, 0, 0)
[13:32:09] [RadarAPI]: Status: Passed
[13:32:09] [RadarAPI]: ar1.ChirpConfig(1, 1, 0, 0, 0, 0, 0, 0, 1, 0)
[13:32:09] [RadarAPI]: Status: Passed
[13:32:09] [RadarAPI]: ar1.ChirpConfig(2, 2, 0, 0, 0, 0, 0, 0, 0, 1)
[13:32:09] [RadarAPI]: Status: Passed

[13:33:10] [RadarAPI]: ar1.SetPerChirpPhaseShifterConfig(0, 0, 20, 0, 0)
[13:33:10] [RadarAPI]: Status: Passed
[13:33:10] [RadarAPI]: ar1.SetPerChirpPhaseShifterConfig(1, 1, 0, 20, 0)
[13:33:10] [RadarAPI]: Status: Passed
[13:33:10] [RadarAPI]: ar1.SetPerChirpPhaseShifterConfig(2, 2, 0, 0, 20)
[13:33:10] [RadarAPI]: Status: Passed

Next, we acquired ADC data using the following steps under Capture and Post Processing in the SensorConfig tab:
DCA1000 ARM → Trigger Frame → Stop Frame → PostProc

We have attached the result. In the attached screenshot, although we expected phase shifts to be applied, the phase shift values for all TX antennas remain “0” across all chirps.

PostProc

[Questions]

  1. How can we correctly use the chirp-based phase shift feature?

    Are the procedures we followed correct?

  2. Is it possible to confirm that the phase shifts have been properly applied within mmWave Studio?
    (For example, as shown in the attached screenshot, is it not possible to determine whether the phase shift is working correctly just by checking the “txPhaseShifter(deg)” values?)

We do have access to evaluation equipment such as a radar target simulator, but it is not readily available for use at the moment. Therefore, we would like to know if there is any way to verify the phase shifts using only mmWave Studio.

Before submitting this question, we referred to the following E2E thread and applied the suggested configurations. However, the phase shift still does not appear to be applied correctly, so we are reaching out for further guidance:
https://e2e.ti.com/support/sensors-group/sensors/f/sensors-forum/1422818/iwr6843isk-ods-chirp-based-phase-shifter-in-tdm-mode/5463923?tisearch=e2e-sitesearch&keymatch=chirp%252520phase#5463923

Thank you very much for your support.

Best regards,

  • 0
    TI__Mastermind 40515 points

    Hi, there:

    I would not trust the phase information listed in the postProc figure below.  It may have some limitations.   Did you process your data and checked the real and imaginary part of the signal for different chirps and did you observe any change?  One suggestion from me is to program the chirps to use the same TX, and just change the phase shifting value, to see any relative change in phase cross different chirp. 

    Best,

    Zigang

  • 0 in reply to zigang Yang
    Prodigy 50 points

    Dear Zigang,

    Thank you for your reply.

    >　Did you process your data and checked the real and imaginary part of the signal for different chirps and did you observe any change?

    Not yet. I wanted to run the system on my desk first and make sure the configuration was set correctly before conducting experiments using an anechoic chamber or evaluation equipment. In the PostProc image I attached, the area around the IWR1843AOP was cluttered with various objects, so even if I processed the raw data, I wouldn’t have been able to obtain meaningful results.

    Moving forward, I plan to prepare a more suitable measurement environment and then process the actual raw data to observe any changes.

    >　One suggestion from me is to program the chirps to use the same TX, and just change the phase shifting value, to see any relative change in phase cross different chirp.

    Thank you very much for this valuable suggestion. I will configure the system to use simultaneous transmission from all TXs while varying only the phase shift values. I plan to apply this configuration and conduct measurements in an anechoic chamber at a later time.

    Best regards.