• State TI Thinks Resolved
  • Locked Locked
  • Replies 5 replies
  • Answers 2 answers
  • Subscribers 30 subscribers
  • Views 2506 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

IWR1443: FMCW radar wavelength of the signal

Eric Wolf
Prodigy 120 points
Part Number: IWR1443

Hello,

In a FMCW radar system, the angle is estimated by receiving the reflected signal from the object using multiple receivers that are spaced apart with a distance ‘d’. The signal arriving at each of the successive
receivers is delayed by d*sin(θ) and this “delay” causes a phase shift of 2π d*sin(θ)/λ. This phase shift between each of the receivers is used to estimate the angle (θ) of the object.

ƛ → Wavelength of the signal used

I would like to know how much the wavelength is here？Assume that the transmitted signal is from 77 GHz to 81 GHz.

Some documents say that the wavelength corresponds to the carrier frequency.In there Is the carrier frequency at 77GHz?

Thanks

  • 0
    TI__Mastermind 22155 points

    Hello Eric,

    Similar post is already answered in below post

    Thanks,

    Raghu

    ---------------------------------------------------------------------------------------------------------

    Please click the Verify Answer button on this post if it answers your question.

    ----------------------------------------------------------------------------------------------------------

  • 0 in reply to Raghunandan Kamath
    Prodigy 120 points
    Hello Raghu,

    if I set the transmitted signal is from 80 GHz to 81 GHz. Is the value of Lambda in the angle formula still 3.8mm(corresponding 79GHz)?

    Thank you very much
  • Former Member
    0 Former Member in reply to Eric Wolf

    Hello Eric,

    By angle formula are you referring to the lambda used for max unambiguous angular range calculation? 

    Best,

    Amanda

  • 0 in reply to Former Member
    Prodigy 120 points

    Hello Amanda，

    You said no problem.I would like to make sure that the wavelength used in the formula corresponds to which frequency.

    for the IWR1443，Whether the lambda used in angle formula is related to the starting frequency and the termination frequency of the chirp signal, or it  is always fixed  at 3.8 cm(79GHZ)?

  • 0 in reply to Eric Wolf
    TI__Prodigy 565 points

    Hi Eric,

    You can use the wave length corresponding to the mid-point of the sweep [ So for a chirp from  77-79 GHz, ,you can use the wavelenght at 78 GHz].

    Note that since the bandwidth (2GHz in this case), quite small compared to the center frequency (78), the result of the calculation will not be very sensitive to the exact value of lambda used.

    Sandeep