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AWR1642BOOST: Why does the distance corresponding to the beat frequency for 2Rx or 4Rx to be shrink into 1/2 or 1/4 compared with 1Rx respectively ?

A-Kai
Intellectual 310 points
Part Number: AWR1642BOOST
Other Parts Discussed in Thread: AWR1642, UNIFLASH

Hi ,

   We modify mss.c of mem_capture code to capture raw data for 1TX_1Rx, 1Tx_2Rx, 1Tx_4Rx and 2Tx_1Rx, 2Tx_2Rx , 2Tx_4Rx and analyze them with matlab.

   We found the result of 1Tx_1Rx and 2Tx_1Rx are correct to meet the center distance about 1m between detected target and AWR1642EVM. 

   But the distance for 1Tx_2Rx or 2Tx_2Rx will be shortened to 1/2 compared with the distance of 1Tx_1Rx or 2Tx_1Rx. As for the distance of 1Tx_4Rx or 2Tx_4Rx will be shortened to 1/4.

   The test setup and result are as follows.

    1. Fixed AWR1642EVM with tape on small chair

    2. Fixed single detected target, wood, whose center distance to AWR1642EVM is about 100 cm.
    3. Use mem_capture to  capture raw data with ccs_debug mode for  1TX_1Rx, 1Tx_2Rx, 1Tx_4Rx and 2Tx_1Rx, 2Tx_2Rx , 2Tx_4Rx respectively and save data.
        We will use 2Tx_1Rx, 2Tx_2Rx, 2Tx_4Rx  as examples to show the test result.
        The modified mss.c of mem_capture for 2Tx_4Rx are as follow. As for 1Rx or 2Rx  , we just modify chCfg->rxChannelEn =2 (1Rx) or 6(2Rx).
         
                
    4. The test result for 2Tx_1Rx, 2Tx_2Rx and 2Tx_4Rx  with 30cm range resolution are as follows:
        1. 2Tx_1Rx: distance 1.28 m , show 2 chirps result as follows: correct  
           
         2. 2Tx_2Rx: distance shrink 1/2 to 0.6399 m , show 2 chirps result as follows: Fail
            
         3. 2Tx_4Rx: distance shrink 1/4 to 0.32 m ,  and has another peak at about 20.8m, show 2 chirps result as follows: Fail 
          
   5. The captured raw data  are 256 samples @ 5400 KHz sampling rate, 44 chirps x 2 Tx = 88 chirps, 1 frame, Complex x1, IQ format , length is always x4 for max 4Rx. 
        In addition, the data arrangement refer to the section 4, swra581b.pdf
        1. 2Tx_1Rx raw data:  256*88 IQ data + 256*88*3 zero data2T1R_100cm_wood1_center_f1.dat 
       2. 2Tx_2Rx raw data: 256*88*2 IQ data + 256*88*2 zero data
          2T2R_100cm_wood1_center_f1.dat
       
       3. 2Tx_4Rx raw data: 256*88 *4 IQ data
         2T4R_100cm_wood1_center_f1.dat
 
 Question:
    1. Why does the distance corresponding to the beat frequency for 2Rx or 4Rx to be shrink into 1/2 (2Rx) or 1/4 (4Rx) compared with 1Rx respectively no matter whether 2Tx or 1Tx ?
    2. What’s the Rx data arrangement for 2Rx and 4Rx on gDataCube of mem_capture on CCS?  The captured data follow up the Fig.6 and equation 3 in the section 4 of swra581b.pdf, right?
         
  Thanks for your help.
  Best Regards,
  A-Kai
  • 0
    TI__Guru 69990 points

    Hi,

    I would request you to check the same experiment with mmWave Studio. 

    Or use mmw demo with the same configuration and plot on mmwave demo visualizer to check this issue.

    Regards,

    Jitendra

  • 0 in reply to Jitendra Gupta
    Intellectual 310 points

    Hi, 

      I use mmWave demo visualizer or studio postproc to test  2Tx_1Rx , 2Tx_2Rx and 2Tx_4Rx.

     All distance are correct. So  forget the wrong distance issue of mem_capture for 2Rx and 4Rx.

     Thanks for your help.

    Best Regards,

     A-Kai

  • 0 in reply to A-Kai
    Intellectual 310 points

    Hi,
    I recently used awr1642 to collect raw adc data. Now there is a problem. I hope you can help me. I modified the chirp and frame parameter configuration in mss.c and loaded the .xe file to mss and dss, and When I clicked the run button, an error occurred, causing the board to disconnect directly. What is the problem?

  • 0 in reply to user5912247
    TI__Guru 69990 points

    Does this happens every time you connect, load and execute from CCS?

    You need to give a delay b/w power cycle and CCS core connect. Make sure that you have flashed ccsdebug.bin (hopefully you have done that).

    Regards,

    Jitendra

  • 0 in reply to Jitendra Gupta
    Intellectual 310 points

    Dear Jit

    Yes, you are right, I am sure I loaded the ccsdeug.bin file on uniflash, and ccs reports the error you see every time you debug.

  • 0 in reply to user5912247
    TI__Guru 69990 points

    What is the change you made? I hope earlier it was working with you (as per your first post).

    Make sure that you have change the SOP settings to functional mode (SOP0:1, SOP1:0, SOP2:0) on EVM after you flash the ccsdebug.bin file to it.

    And as another option try to flash the mmw demo image and check that application is able to boot in functional mode (to confirm the device functionality in SOP-4 mode).

    You need to trace back to find out if you did some change in SW/HW.

    Regards,

    Jitendra