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IWRL6432BOOST: The chirp repetition period () Calculation issue

Aditya Shah
Intellectual 390 points
Part Number: IWRL6432BOOST

Hi,
In reference to the MotionPresenceDetectionDemo_TuningGuide.pdf under ti\MMWAVE_L_SDK_05_02_00_02\docs, I have some queries:

  • The chirp repetition period () is (idle1+idle2+2ramp) for two TX antennas (TX=2), where idle1 and idle2 are the idle times per chirp (see Figure 8)  (Page-64)
  • How the Tidle1 and Tidle2 is defined in the config file?
  • Can you give the supportive mapping/calculation?
  • 0
    Intellectual 390 points

    Tr calculation doesn't match here

  • 0 in reply to Aditya Shah
    Intellectual 390 points

    In pdf, it says the chirp repetition period () is (idle1+idle2+2ramp)

    but in the estimator app it says


     

    Please convey the correct formulation, and its mapping to config

  • 0 in reply to Aditya Shah
    TI__Expert 4448 points

    Hi,

    I will confirm with our expert to make sure there is no inaccuracy in the calculation. 

    But the Sensing Estimator tool is assuming that idle1 = idle2, i.e. the chirp idle times are equal between the two TX chirps. This value comes from chirpTimingCfg's chirpIdleTime field. Thus, when using 2Tx antennas,

    if idle1 = idle2 = idle, then

    (idle1+idle2+2ramp) = (2*idle + 2*ramp) = 2*(idle+ramp) = numTxAntennas*(idle + ramp)

    If using just 1Tx, then the equation still holds, numTxAntennas*(idle + ramp).

    Now that I've explained that, let me confirm the assumption that idle1 = idle2 in the TDM and BPM schemes.

    Regards,
    Luke

  • 0 in reply to Luke Rouleau
    Intellectual 390 points

    Thanks for the reply.
    The formulation you described doesn't come the same way in the app.
    I tried with the MotionDetect.cfg in the Sensing Estimator tool and auto-populated the fields.

    Here Tr=200

    Idle Time=6

    Ramp end time=28

    Tx=2

    Expected Tr= 2*(6+28) which is not equal to 200

  • 0 in reply to Aditya Shah
    TI__Intellectual 790 points

    Hello Aditya.

    In 6432 SDK, we have two chirping modes: (1) normal mode, (2) burst mode. Please refer to 'Section 3.1.3 Frame Configuration' of the 'MotionPresenceDetectionDemo_TuningGuide.pdf' for more details. You can also refer to 'Section 4 Chirp Configuration Modes' of the 'MotionPresenceDetectionDemo_documentation.pdf'.

    In normal mode, we only have 1 burst (which is the limit), where each chirp in the burst is uniform in time (i.e., idle1 = idle2). In this case, the chirp repetition period formula is valid (numTxAntennas*(idle + ramp)).

    But in burst mode, we have multiple bursts, where each burst has numTxAntennas chirps (which is the limit). In this mode, the chirp repetition period becomes equal to the burst period, which is configured in 'frameCfg 2 0 200 64 100 0'. In this mode, idle2 is still the same one configured in 'chirpTimingCfg 6 32 0 40 60.5', but idle1 is internally computed by 'burstPeriod - idle2 - numTxAntennas(ramp)'. These are explained in the documents above.

    The mmWave sensing estimator explains the meaning of chirp repetition period for normal mode, but it internally computes the correct value depending on the configured one.

    I hope this answer makes it clear. Please let us know if you have further questions.

    Regards.

    Muhammet