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AWR1243: Parameters about ADC and IF chain

徐志伟 xu
Prodigy 30 points
Part Number: AWR1243

HI,

       When i calculate the full-scale input level of ADC, I do not find the parameters of Vpp and Rin( Input Impedance ) of ADC. 

        And in the Receive channel , whether there is an  antialiasing filter? Can you share me the information about performance of  the filter?

Best Regards,

Zachary

  • 0
    TI__Guru 58035 points
    Hello Zachary,
    We are looking into your query. We will get back to you on this soon.

    regards,
    Vivek
  • 0 in reply to Vivek Dham
    TI__Guru 58035 points

    Hello Zachary,

    The full scale signal corresponds to 1V at the ADC input. So depending on your configuration (12/14/16bits) the swing corresponding to the each LSB would change. You can back calculate the signal from ADC voltage to LNA input by multiplying the RX chain gain that is set. 

    The anti aliasing filter is adjusted based on the sampling rate configured. The pass band allows a bandwidth of 90% of Nyquist frequency. ie 0.9*(fs/2) in case of real mode and 0.9*fs incase of complex 1x mode.  

    Below is an example filter response with a 10Mbps sampling rate (real mode).

    Regards,

    Vivek

  • 0 in reply to Vivek Dham
    Prodigy 30 points

     Hi, Vivek

            Thank you for your response. 

           1.  Is the voltage 1V  difference ? And in AWR1243, the A2D resolution is only 12bits ? 

           2.  How many of the impedance in ADC?

           3. In analog IF stages include high-pass filtering. There is only the parameter of  HPF Corner Frequencies. How about the attenuation of HPF? 

    Regards,

    Zachary

  • 0 in reply to 徐志伟 xu
    TI__Guru 58035 points
    Hello Zachary,
    The AWR1243 supports 12/14/16 bit options. You can use either of the three. The ADC impedance , single/differential design etc. are our internal design details which we cannot share.

    There are two HPFs and each of the HPF has 20dB/decade rolloff beyond the corner frequency programmed by the user.

    Regards,
    Vivek
  • 0 in reply to Vivek Dham
    Prodigy 30 points

    Hello， Vivek

          Thanks very much.

          From the reply, I think that the power of target will not exceed the full scale input level of ADC, even a truck is very near to my radar system; that's right? 

          And when I calculate the sensitivity of receiver, it's only determined by system noise ( system noise plus SNR )? 

    Regards

    Zachary

  • 0 in reply to 徐志伟 xu
    TI__Guru 58035 points
    Hello Zachary,
    You are right, in most practical use case other vehicles would not saturate the ADC. But if you place a radar behind a case or bumper , for example, you need to make sure the material used for the case /bumper is not a very strong reflector. Since this would be very close the radar (few cms max) this needs to be considered.
    As you pointed out the sensitivity of the receiver would be governed by the receiver's noise figure and the detection threshold (SNR) used in the algorithm to detect a peak as an object.

    Regards,
    Vivek