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IWR1642: Configuring 2 radar modules : DCA1000EVM plus IWR1642 X2 to work together with external trigger one as transmitter and the other as receiver.

Part Number: IWR1642
Other Parts Discussed in Thread: DCA1000EVM,

I have 2 radar modules both working with IWR1642 as frontend both has DCA1000EVM as interface to the computer, I use 2 computers to control the 2 DCA1000EVM cards, I configure the modules to start Tx/Rx cycle from the same external trigger. We get different distance in the same configuration each time we apply trigger in compare to one radar module working in both Tx and Rx mode that gives same result each time. What do you Think is the reason for the different results? Is it because the both internal clocks use to transmit and receive are not in phase with each other?  Is it possible to configure them to be in phase with each other? How do I define the 2 Radars to work correctly - one in Tx mode and the other in Rx mode?

  • HI, there:

    Can you provide more details for different detected distance?  

    1) The ground truth?  is it exactly the same distance from the target to both modules? 

    2) Systematic range offset, there will be about 7cm in systematic range offset that you can calibrate out.  So what is the range and range difference in your test?

    3) If you programmed the one module at a time, do you still observe the different distance for the target detection?   

    Regarding 2 radar working in phase, please check out our cascade radar system.  You need to use the same clock to both radar system.  And you need to lay out antenna design carefully to use RX channel from both devices together. 

    Best,

    Zigang

  • Hello zigang,

    In regrading to your questions:

    1. Yes it approximal the same distance to both modules.
    2. We get different ranges up to X10 distance, and the reading is unstable -each frame we get different distance.
    3. If we check each modules separately both work good and stable.  

    What do you recommend is the best way to supply the same clock for 2 separate modules?

  • HI, Israel:

    One possible is that one of the system is experiencing interference from the other sensor.   Maybe the trigger to one of the system is delayed a tiny little bit more and falls into the detectable delay of the other sensor.   Is it possible to swap the trigger setting between the two subsystem and see whether you observe the other way, or change the trigger delay to see whether it goes away.  Besides it is possible to change the direction of the sensor so that they are not facing with each other?  

    I am not sure about your question at the end.  What do you trying to achieve?  Please go through a users guide of the cascade system https://www.ti.com/lit/ug/swru553a/swru553a.pdf?ts=1646853990592&ref_url=https%253A%252F%252Fwww.ti.com%252Ftool%252FMMWCAS-RF-EVM .  And see whether that is what you are looking for. 

    Best,

    Zigang

  • OR you can try to use different RF frequency band to avoid interference.  It may involve redesign your chirp configuration.

    Best,

    Zigang