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AWR1642BOOST: TX disabled but still get data captured on TSW1400EVM

Part Number: AWR1642BOOST
Other Parts Discussed in Thread: AWR1642

Dear TI support , I have TSW1400EVM , MMWAVE DEVPACK and AWR1642BOOST connected together. (and also Radar Studio v1.7.4.0 + High Speed Data converter Pro v4.70

For a "sanity check" from the radar studio i turned off all the 2 TX and turn on only 1 RX. (using the GUI, unticked Tx1 and Tx2, ticked Rx1)  (then RF Init).

I then do other config accordingly, then finally Trigger a "frame" (which should not exist as there is no TX). i did however get some capture data back. Any idea why? Was Tx not properly disabled?

I am also exploring a possibility of using this settings and "sniffer" (receive only) hence why all TX was turned off. Here's the radar studio log, binary capture file, and also screen shot attached as zip file.

awr1642notx.zip Thanks

  • Hello Ucu,
    If you don't enable any Tx and try to capture data over LVDS/CSI2 then, in this case, AdcBuff will have some junk data. As Rx is on and it'll capture signal which is falling on antenna and after digital conversion AdcBuff will have some garbage data which you might be capturing over TSW1400EVM.

    Regards,
    Jitendra
  • Hi Jitendra, thanks for your reply.

    Yes i am aware that there could be some garbage/noise(/) there but assuming that there are not many or probably no signal in the range of 76-81Ghz, it may be a bit unlikely? .

    I will analyse the data anyway today and confirm later.

    In any cases, would you be able to confirm the understanding below

    Q1.  TX can be definitely turned off by unticking TX1 and TX2 and then subsequently do "RF Init'?  any other command required to make sure its off?

    I don't have any equipment yet here that can physically check the presence or not presence of the RF signal. Thanks

    Q2 as ADC is sampling the IF signal that is the result of mixing TX and RX (ref: the block diagram of the chip), would it be correct to say that i could expect  the RX signal sampled by the ADC, in absence of TX?

    Again i am trying to use this as a "sniffer"/"analyzer"  to be used for the time being before a proper high end measurement system from Rohde and Schwarz arrives next year

    Thanks

    Regards

  • Hello Ucu,

    In the channel Configuration and in the chirpConfig also select none of Tx option, these two will make sure that all TX are off.

    When you turned off all Tx and in the chirping mode PA will be off (no signal transmitted) but internally it'll be mixed with the signal generated by LO generator and the received signal. So effectively you can use this as an analyzer.

    Regards,

    Jitendra

  • Thanks Jitendra, oh that means it will still be mixed with something (signal from LO)! Do you think it can still be used as an "analyser"? When i say "analyser", what i mean is to capture radar transmission from *another* AWR1642 , positioned in the vicinity. I thought this would only be possible if TX LO is off?(is it possible to turn it off?-probably by programming/writing to a certain register?


    Regards