• State Resolved
  • Locked Locked
  • Replies 6 replies
  • Answers 2 answers
  • Subscribers 32 subscribers
  • Views 200 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

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.

IWR1843BOOST: Questions about whether the initial phase of the baseband signal of IWR1843 is stable

Stong Zhang
Prodigy 40 points
Part Number: IWR1843BOOST
Other Parts Discussed in Thread: IWR1843

Tool/software:

Hello, I would like to ask if the initial phase of the baseband signal of TI's IWR1843 is fixed. My current scenario is: there are two IWR1843s that need to transmit and receive FMCW signals simultaneously to implement a coherent distributed radar system. But I don't know whether the initial phases of the baseband signals of the two radars are consistent. If not, can I assume that the phase difference is consistent? Is there a manual I can refer to?

  • 0
    TI__Mastermind 33230 points

    Hi,

    If you want to use two radar synchronously to modulate and demodulate each others signals, you will need to cascade them together. See our user guide here. You cannot use 1843 for this - you will have to use 2243.

    https://www.ti.com/tool/MMWCAS-RF-EVM

    Best,

    Nate

  • 0 in reply to Nathan Block
    Prodigy 40 points

    Thank you for your quick reply.
    But what I want is actually a distributed radar. As far as I know, 2243 is a monostatic radar integrated on a board. What I want to achieve is actually a long-range radar (maybe the distance between the two radars is 5m) that can modulate and demodulate each other. I wonder if TI has related equipment

  • 0 in reply to Nathan Block
    Prodigy 40 points

    Hi, 

    I would like to know whether the initial phase difference between the two radars is fixed in the distributed radar scenario I mentioned. If it is fixed, it may be eliminated by software.

    Best,

    Zst

  • 0 in reply to Stong Zhang
    TI__Mastermind 33230 points

    Hi,

    This isn't feasible. The two radars need to be time synchronized so their TX and RX frequencies will mix down to something within the IF bandwidth. Since the TX and RX have frequency slopes in the range of 10+ MHz/usec and the IF bandwidth is 10 MHz, the two radars will need to be time-synchronized to <1 usec. This is why cascade is needed.

    Best,

    Nate

  • 0 in reply to Nathan Block
    Prodigy 40 points

    Hi, Nathan

    In fact, I have achieved simultaneous triggering of about 1ns through hardware triggering + FPGA, so the synchronization problem of the Chirp has been solved. But the main problem now is whether the initial phase of the baseband FMCW signal is fixed. If the initial phase of the Chirp signal sent each time is not fixed, it cannot be corrected by software. Because if the initial phases of the two radar baseband signals are fixed, they can be corrected directly by software. If the initial phase difference is not fixed, the intermediate frequency signal obtained will be completely chaotic and incomprehensible. In this case, it is indeed impossible for the two IWR1843s to realize a coherent distributed radar system.

    Best,

    Zst

  • +1 in reply to Stong Zhang
    TI__Intellectual 2520 points

    Hi Zst, 

    The IWR1843 is not capable of fixing the phase of the FMCW baseband signal, and thus you will not be able to acchieve a coherent distributed radar with it. 

    Thanks!

    Blake