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IWR1443: TX and RX pins, a few questions for start of application development

Bart
Expert 6460 points
Part Number: IWR1443

Team,

a few questions from our customer, can you please help?

1. Which pins should I use as a transmitter (TX) and as a receiver (RX), if I only want to use one of each pins?

2. If we can summarize 3 channels power, can we use 3 transmitter pin to give out the same signal to get better performance?

3. If we only want to use one pin to transmit and one for the receiving what should we do with the rest of the RX/TX pins?
    Should we ground it or leave it alone?
    Should we forbid it somehow the other outputs to minimize the power consumption? If yes, how?

4. How the device should be used to minimize the power consumption?

5. Can we use a non-active RX input as a 50Ohm EOL resistor? For example for a separator?

Thank you,
Best regards

  • 0
    TI__Mastermind 37500 points

    Hello,

    1. The Tx and Rx pins can be assigned within the Mmwave SDK.   Typically to place them close together for a single Tx and single Rx, Rx4 and Tx1.

        There is no requirement.

    2. Yes you can transmit upto 2 Tx simulateneous with the IWR1443, using the RF 1.3v.   This increases the Transmit power, but you are transmitting from two antennas.   If you use a power combiner, can be transmitted from one antenna.   Within the design of the patch antenna array, there is also Tx to Rx leakage.  Increasing the Tx power without increasing the Tx-Rx leakage is beneficial.

    3. The Tx pins that are not used can be left open.  The Rx pins that are not used should be connected to GND through a 50 ohm resistor, we are not expecting RF transmission so a standard resistor is OK.   The Rx inputs are AC coupled.  The Tx power is limited through the selection of Tx and Rx used in the Mmwave SDK, see Table 1 in the Mmwave SDK user Guide. (doc folder)

    4. There are several strategies for minimizing power consumption (they need to be studied for your use case)

       -  Using the Sensing Estimator, adjust the Tx and Rx antenna gain, note that for specific Max Range, and RCS values the amount of time (number of chirps)

           needed varies.    While you can increase the integration time, this also directly increases the Mmwave sensor power.

       -  In your use case, combining 2 Rx can increase the peak detected to signal floor.

       -  the algorithm used for detection, and tracking can be reviewed for optimization

      -   circuit board RF trace routing, RF laminate material used, RF signal attenuation reduces the available Tx output power, or Rx input signal

       -  the Low Voltage power supply can be modified to be more efficient 

        note: these are all based on describing your use case, testing, and tradeoffs 

    5. Yes you can, its not recommended though.  

    Regards,

    Joe Quintal

       

  • 0 in reply to Radio-Joe
    TI__Expert 6460 points

    Hi Joe,

    thanks for your detailed feedback, it helps a lot. Just two more questions:

    a) In the lab0004_high_accuracy_14xx_pjt there are two profiles: profile_2db and profile_2de - Can you advise what's the difference between those?

    b) We're looking for the lens on the attached png. Do you have a detailed description of this lens? Like diameter, 3D model, etc.

  • 0 in reply to Bart
    TI__Mastermind 37500 points
    Hello,
    If you compare the two files, you will find that the profile configuration is different.
    Using table 1 in the Mmwave SDK User guide, the number of DFE samples per chirp is different, the synthesizer slope is different,
    and the Rx LNA gain is different. Typically the synthesizer slope changes the distance/ FFT bin. The zoom function provides more resolution
    between the Range FFT output points.

    The Lens, is to convert the 120 degree azimuth by 45 degree elevation antenna, into something like 5-20 degrees for a level sensing application. Thor Labs has 40mm and 80mm dielectric lens on their website. Note: normally the dielectric lens and patch antenna are designed for a specific range of operation. Level Gauge applications would like to have a ~5 degree Field of View.

    Regards,
    Joe Quintal