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AWR1642BOOST: + DCA1000 EVM : Precise equation for modeling of IF complex baseband signal

Part Number: AWR1642BOOST

Hi TI Team;

I am working with AWR1642BOOST EVM (ES2.0) and DCA1000 EVM.

I am working on complex 2x ADC data and working on its basic study and evaluation and I am using mmwave Studio.

I am trying to model, as precisely, as possible, the complex baseband IF signal and then comparing it with the real time field data that I have gathered. However, my simulation results are not matching the actual field data. I suspect the problem with the forms of IF complex baseband equations that I am using.

I have come across some different forms of equations for IF complex baseband signal for FMCW radar. There are some differences which depend on how the relevant author is presenting the scenario. I am deliberately not giving some examples.

Can you please advise the as much precise, as possible, the form of equation that represents the IF complex baseband signal. I will appreciate if you could refer relevant TI document(s) and even some other literature that you think most closely describes the equation / model used by TI.

By the way, please note that both the phase and the magnitude of those complex number are important for me.

Thanks and regards

  • Hi,

    Please give me a few days to check with our design team what information is available regarding the baseband.

    Thank you

    Cesar

  • Hi Cesar,

    Just a polite reminder on the above request, though I know you would already working on it.

    regards

  • Hi,

    Thank you for the reminder.

    I am still waiting on the answer from the design team. Unfortunately some of the baseband information is proprietary.

    Let me ping them again

    Cesar

  • I have an answer to start with. Please review it and please provide us with more details

    thank you
    Cesar

    >> I am trying to model, as precisely, as possible, the complex baseband IF signal and then comparing it with the real time field data that I have gathered. However, my simulation results are not matching the actual field data. 

    It is not fully clear to us the nature of the issue you are facing. 

    For a static object, the IF signal would correspond to a tone at a beat frequency fb = 2*R*S/c, where R is the distance to the target, S is the chirp slope and c is the speed of light.

    So, you can expect that the IF signal in complex baseband mode would be y(n) = A*exp{(2*pi*(2*R*S/c)*n/Fs)+q}, where A is the amplitude that depends on various factors including RCS, Fs is the output sampling rate, and theta is a random phase.

    Can you confirm that you are able to see such a tone, matching the above model, for a static object?

     

    >> By the way, please note that both the phase and the magnitude of those complex number are important for me.

    The magnitude of the tone would depend on various factors – including Tx output power, antenna gain, roundtrip path loss based on the distance, RCS of the object, Rx gain.

    The absolute phase of the tone is typically not relevant in most use-cases, and it is often the ‘delta phase change’ across successive chirps, and across antennas, that is used to compute the speed and angle of arrival of the target.

     

  • Hi Cesar ,

    Thank you very much for your above reply.

    I am working on it and will get back to soon with details.

    Thanks and regards

  • Thank you

     cesar