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IWR1642: SDK demo steepest acceptable ramp

Massimo Liistro
Prodigy 190 points
Part Number: IWR1642

Hi,

I would like to use the SDK demo (02_00_00_04) to perform static measurements.

I've generated a profile with the mmWave Demo Visualizer (2.0.0) and set the RX gain to maximum (48dB) to best see the filters contribution.

The result is in the following picture. We can clearly see the contribution of the filters on the noise (green dots, 1000 frames average).

I would like to perform the closest measurements but inside the band of the filters (that would be ~2m here). That implies to use the steepest ramp possible : 100MHz/us. However, as I am working in the 76-77GHz band, I cannot generate a profile with this value with the Visualizer. I've tried to generate one, modify the ramp value to 100, adapt the number of samples but to no avail : the radar get stuck.

What are the profile constraints for the SDK demo ?

Best regards,

Massimo

  • 0
    TI__Expert 7510 points

    Dear Massimo:

    The maximum ramp rate according to the IWR1642 is 100MHz/us as you stated, but there may be other factors which depending on the use case might make it lower. I am linking you a link to an estimator tool which generates a configuration file(.cfg) according to the constraints you put in with your use case. Play around with this and see how high you can make your ramp rate.

    https://dev.ti.com/gallery/view/mmwave/mmWaveSensingEstimator/ver/1.4.0/

    Best regards,

    Connor Desmond

  • 0 in reply to Connor Desmond
    Prodigy 190 points

    Hi Connor,

    I've tried the mmwave sensing estimator but it generates invalid profiles for the SDK demo.

    The main issue seems to be that at least 64 samples are needed per chirp while the estimator can give values lower.

    As the max sampling frequency for complex is 6.25MS/s, this yields a minimum ramp endtime of 64/6.25MHz = 10.24us.

    10.24us * 100MHz/us > 1GHz, so I cannot use the steepest ramp with a 1GHz bandwidth.

    I will try to fit the best ramp and timing parameters.

    Thanks anyway for the help.