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IWR1642BOOST: Traffic Monitoring Demo - FFT Windowing

Andrew Chadwick
Prodigy 120 points
Part Number: IWR1642BOOST
Other Parts Discussed in Thread: TIDEP-0090

Hi,

I'm looking at the source code for the Traffic Monitoring demo, downloaded with the mmWave Industrial Toolbox v2.3.0 [mmwave_industrial_toolbox_2_3_0\labs\lab0013_traffic_monitoring_16xx].  I believe this is identical to the TIDEP-0090 design files [TIDCDG5D] which I've also downloaded.

If I understand correctly: the number of ADC samples processed per chirp and the number of chirps per frame are set up from the configuration file.  In the examples provided, this is 312 samples/chirp and 32 chirps/frame [mmw_tm_demo_ph2.cfg] or 256 samples/chirp and 118 chirps/frame [mmw_tm_demo_longRange.cfg]

However... the FFT window functions appear to be hard-coded in dss_data_path.c, with half-lengths of 16 for the 1D window, and 4 for the 2D window, and corresponding numbers of hard-coded coefficients.

It therefore looks like there are not enough window coefficients to apply in RADARDEMO_rangeProc_priv.c or RADARDEMO_dopplerProc_priv.c, when looping over the requested number of samples / chirps (and the code will overrun the window coefficient arrays)?

Please can someone explain what I'm missing, why are the window lengths apparently fixed and less than the expected input data lengths?  I've found the MmwDemo_genWindow function in the MMW SDK (v1.01.00.02) source code, but can't see that is used in this demo?

Thanks.

  • Former Member
    0 Former Member
    Hello Andrew,

    Yes the lab and TIDEP-0090 are currently identical. In the future, all updates to the Traffic Monitoring demo software can be downloaded from the industrial toolbox. You are correct that this demo does not use the SDK windowing function. Instead, in the docs folder of the rangeProc module, there is a high level block diagram of the process implemented. The windowing function should scale with the number of ADC bits. For more details, I have reached out to the team and will follow up with you as soon as possible.

    Thanks,
    Amanda
  • 0
    TI__Guru 50240 points
    We apologize that we were not able to provide you a timely answer.
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