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AWR1642BOOST: The difference between the radar equation and measured data of SNR

Jacki Hsu
Intellectual 330 points
Part Number: AWR1642BOOST


Hi TI team,

According to the radar equation for SNR calculation TI applied as below, the SNR is about 17dB.

I set up the radar emulator with the same parameter but the SNR is only -9dB calculated from the measured data. ("2-D FFT SNR" - "processor gain")

Why is there a such difference between them?

Is the SNR restricted by the ADC?

I think the reason is the signal is still under the noise floor of ADC but I'm not sure on that.

Thank you.

Jacki Hsu

  • 0
    TI__Guru**** 150364 points

    Hi,

    The SNR computed using the radar equation assumes that there is only thermal noise in the system.

    The noise in a real system, especially in a static case is mostly due to clutter and not thermal noise. So, the radar equation SNR computation will not be a good estimate.

    In addition to this, as you mentioned, in a real system there is ADC noise, post processing noise...

    Thank you

    Cesar

  • 0 in reply to Cesar
    Intellectual 330 points

    Hi Cesar,

    Thanks for your description.

    By the way, when  I estimated the thermal noise, I'm not sure the definition of bandwidth. (N = kTB)

    Is the bandwidth a ADC sampling rate or the inverse of total chirp time (ramp end time * chirp number) ?

    Thank you.

    Jacki Hsu

  • 0 in reply to Jacki Hsu
    TI__Guru**** 150364 points

    The Bandwidth is defined as

    B = S * Tadc * Nadcsamples

    S = frequency slope
    Tadc = ADC sampling period (1/ADC sampling frequency)
    Nadcsamples = # of ADC samples

    Thank you

    Cesar