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IWR6843: Multiple questions

Former Member
Former Member
Part Number: IWR6843
Other Parts Discussed in Thread: DCA1000EVM

Customer is evaluating IWR6843 and has EVM that they have done some initial testing with.  Here are the questions:

Regulations : FCC regulations [ https://www.law.cornell.edu/cfr/text/47/15.255 ] contain the following two paragraphs for devices operating in the 60-64 GHz.

c (2):For fixed field disturbance sensors that occupy 500 MHz or less of bandwidth and that are contained wholly within the frequency band 61.0-61.5 GHz, the average power of any emission, measured during the transmit interval, shall not exceed 40 dBm, and the peak power of any emission shall not exceed 43 dBm. In addition, the average power of any emission outside of the 61.0-61.5 GHz band, measured during the transmit interval, but still within the 57-71 GHz band, shall not exceed 10 dBm, and the peak power of any emission shall not exceed 13 dBm.

c(3)For fixed field disturbance sensors other than those operating under the provisions of paragraph (c)(2) of this section, and short-range devices for interactive motion sensing, the peak transmitter conducted output power shall not exceed −10 dBm and the peak EIRP level shall not exceed 10 dBm.

Question 1. Looking at the 2 paragraphs above, which is the regulation that would apply to the TI system that has 4 GHz bandwidth from 60-64 GHz. The maximum output power of the TI system is 10 dBm. Can we transmit at that power over the whole bandwidth for fixed indoor sensor applications?

Question 2a.  Can we use the TI radar (IWR 6843) in both the short and long range configurations?
Question 2b. Is the maximum power radiated in each case different?
Question 2c. Can we use the maximum power in both configurations?

Question 3a. We are interested in obtaining the signal to noise ratio of the transmitter. Is there data relating to phase noise curve over the entire bandwidth that is available?
Question 3b. We are aware that the phase noise is -92 dBc at 1 MHz offset. Is there a way to calculate the total noise power over the 4GHz bandwidth?

Question 4. Do you have data or a software tool that can generate the ramp signals produced by the hardware? This ramp will be a non-idealized ramp and we would like to model its effects on system performance.

Question 5. We are aware that the board “dca1000evm” can allow us to bring radar into PC/MATLAB. But our experience so far has been that we can only record radar data first and then process the data in an off-line fashion. We have not figured a way to stream radar data in real time for processing. Could you send us instructions on how to do this, if this is feasible?

Thanks,
Brian

  • 0
    TI__Mastermind 28055 points

    Hi Brian,

    I will answer what I can but pass it over for the question on regulation.

    2a) IWR6843 can be used for human detection up to 50 meters away. We provide different configurations in the demos available on TI Resource Explorer. See the People Counting lab for short range config and the Long Range People Detection lab for a long range configuration. Our labs do not currently demonstrate this, but a device can be programmed to handle multiple chirp configurations at one time.  For an example, see the SRR demo.

    2b) We do not backoff the output power in our configurations, so the IWR6843 outputs a full 10 dBm.  See this datasheet for more information.

    2c) Maximum power works in both configurations. The long range chirp only spans about 300 MHz.

    3a) The RX noise figure is 14 dB (from the Datasheet).  System output power and noise figure will also depend on the antenna design.

    4) We do not have this software available.

    5) Generally, DCA is designed to work with Radar Studio and post process after data is captured. In the past, we have modified demos to output raw data on UART, this can then be processed with Matlab in realtime if you are wishing to test your algorithms. This will limit the data rate you can achieve.

    Regards,

    Justin

  • 0 in reply to Justin Curewitz
    TI__Mastermind 28055 points

    Hi Brian,

    Regarding question 1, the device can transmit at -10 dBm throughout the whole band (60 - 64 GHz).

    Regards,
    Justin

  • 0 in reply to Justin Curewitz
    TI__Mastermind 28055 points
    Hi Brian,

    Why does the customer need to calculate the total 4 GHz Bandwidth noise power?

    In FMCW Radar system we use the same LO for the both Tx and Rx chains. In the Rx chain we down convert through the mixer and in the mixing down conversion process same LO would be used hence correlated LO phase noise would get cancelled out.

    Regards,
    Justin
  • 0 in reply to Justin Curewitz
    Prodigy 240 points
    Justin: I still have a doubt on this: if you read the regulation clause:

    c(3)For fixed field disturbance sensors other than those operating under the provisions of paragraph (c)(2) of this section, and short-range devices for interactive motion sensing, the peak transmitter conducted output power shall not exceed −10 dBm and the peak EIRP level shall not exceed 10 dBm.

    Please note the "the peak transmitter conducted output power shall not exceed −10 dBm" clause, not "+10dBm".

    Am I interpreting this incorrectly?
  • 0 in reply to Ziyou Xiong
    TI__Mastermind 28055 points
    Hi Ziyou,

    I have confirmed that you are correct:
    If using less than 500 MHz of bandwidth, you can transmit up to 10 dBm.
    For your case of 4 GHz, you will need to stay below -10 dBm.

    Regards,
    Justin