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AWR1243BOOST: Issues about the equation of the maximum range of FMCW radars

fang alton
Prodigy 170 points
Part Number: AWR1243BOOST

Hi,

I am studying the document (https://training.ti.com/sites/default/files/docs/mmwaveSensing-FMCW-offlineviewing_0.pdf).

But I am a little confused about the equation of the maximum range (page 15). 

In the third line, it says IF bandwidth is limited by the ADC sampling rate (Fs). 

However, we know that in Nyquist Theorem, sampling rate must higher than two times of the highest frequency of the IF signal.

So I think the equation has to be modified to 

Thus, the maximum range of the radar will be modified to 

Is that correct?

Thank you.

  • 0
    TI__Mastermind 24955 points
    Fang,

    The equation is correct as is and can be verified by other publications that derive FMCW radar equations. The assumption is made that you are already taking into account the highest frequency of your IF signal. Please keep in mind that the slope value does not correspond to the highest frequency in the IF signal.

    Regards,
    Kyle
  • 0 in reply to Kyle Cousino
    Prodigy 170 points

    Cousino,

    So if I use the default configuration in Radar Studio:

    Slope (MHz/us): 29.982

    Sample Rate (ksps): 10000

    Then the maximum range of the radar will be 49.995(m).

    Where 299792458 is the speed of light.

    Is that correct?

    Thank you in advance for your response.

  • 0 in reply to fang alton
    TI__Expert 5235 points

    Your calculation looks correct. On your Nyquist question, it is a natural question from the training material which does not go into details and this kind of question keeps recurring on the forum. A good response is at  There is also an application note (see section "DSP requirements") :