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AWR6843AOP: Enable BPM function in AWR6843AOP

JINHYUN JEONG
Prodigy 220 points
Part Number: AWR6843AOP
Other Parts Discussed in Thread: AWRL6432, AWR6843

Tool/software:

Dear TI experts

Hello, 

I plan to use the knowledge i learned from AWRL6432 to use it in AWR6843AOP. 

Also, i used a demo and as i intended the demo only processes signals with HWA within MSS without using DSS.

So i am curious whether the functions are possible or not.

0. Implementation possibility.

- is it possible to create a radarcube using BPM in AWR6843AOP like AWRL6432?

( Tx1+ Tx2 / Tx1-Tx2  )

Addition and subtraction method using phase difference

1. BPM 

i want to use BPM because there is an SNR gain.

i am trying it using that profile.  (  profile-2dbpm.cfg), So i would like to check if radar transmission method operates in BPM ,

is there a way to check?

2. Using 3 Rx antenna.

AWR6843AOP has 3Tx / 4Rx, but i would like to use 2tx / 3Rx.

is it possible to use 3Rx? 

Accroding to rangeprohwa code ( Screen shot) , It i use 3 Rx, the error occurs.

Please share your opinon.

Thanks

BEST Regards

JINHYUN JEONG

  • 0
    Prodigy 220 points

    **********************+ Question*************************

    3. ADC format

    AWRL6432 ADC format is Real  , So is it possible to set Real in AWR6843 ADC foramt ?  

  • 0 in reply to JINHYUN JEONG
    TI__Genius 13276 points

    Hey Jinhyun,

    Thanks for reaching out regarding your implementation questions. I will need a day or two to look into the first set of questions, but for the last question, there is no real format ADC data for 6843. However, you could implement this yourself by taking the real part of all samples from the radar cube - should be the upper halfword of each sample if little endian.

    Regards,

    Kristien 

  • 0 in reply to Kristien Everett
    Prodigy 220 points

    Hey Kristien,

    i am looking forward to your reply.

    Thanks

    Best regards.

  • 0
    TI__Intellectual 2600 points

    Hello ,

    Could you please provide your help on here?

    Regards,

    Victor Park

  • 0 in reply to JINHYUN JEONG
    TI__Genius 13276 points

    Hey Jinhyun,

    I apologize for the delay in getting back to you. I will answer your questions below:

    0. The radar cube formats for AWR6843AOP should match the formats for AWRL6432. The only difference is that AWRL6432 has one additional format that roughly consists of a chirp, antenna, range structure.

    1. The easiest way would be to set up a corner reflector or other strong reflective object in boresight of the sensor and use the DCA1000 to capture raw ADC data when device is configured in TDM and then comparing that to data in BPM. The BPM data should be roughly 3 dB stronger.

    If you wanted to measure the BPM signal propagated through space, that would be much more difficult as it would involve expensive equipment for down converting the high frequency chirp signal and then measuring the power or frequency spectrum.

    2. There are two reasons why using 3 Rx antennas may not work. The main reason why it shouldn't work at all is that the ping/pong EDMA scheme only supports 2 and 4 Rx antennas. Additionally, a few of the processing steps are usually optimized for virtual antenna arrays that are multiples of 4. However, there should be a default case that is unoptimized and used in the event that the virtual antennas are not a multiple of 4.

    Regards,

    Kristien

  • 0 in reply to Kristien Everett
    Prodigy 220 points

    Hi Kristien,

    About Question 2, AWRL 6432 also has 3 Rx, i don't understand why EDMA works on even RX antennas.

    i think the ADC buffer for the 6432 will be formed as above, isn't it?

    (The adc value will be a complex value, unlike 6432, but in range dpu only real values among the complex value will be performed by HWA.)

    i also optimized virtual antenna like 6432.

    +) Could you also check the profile for BPM method?

    ChannelCfg 7 5 0

    (Tx0 / Tx2 Enable  | Rx0 / Rx1 / Rx2 Enable)

    Chrip Cfg

    0 0 0 0 0 0 0 5

    1 1 0 0 0 0 0 5 

    (Tx 0 / Tx 2 Enable)

    Bpm cfg

    -1 1 0 1

    If i set it like this, is is correct that the opposite phase of the first chirp is transmitted in the second Chrip?

    Thanks

    Best regards

    JINHYUN JEONG

  • 0 in reply to JINHYUN JEONG
    TI__Genius 13276 points

    Hey Jinhyun,

    I will loop in one of our engineers that might be able to comment more on the EDMA and ADC buffer. They should reach out to you within the next day or two.

    Thank you for your patience,

    Kristien

  • 0 in reply to JINHYUN JEONG
    TI__Mastermind 40495 points

    Hi: Jinhyun:

    i think the ADC buffer for the 6432 will be formed as above, isn't it?

    (The adc value will be a complex value, unlike 6432, but in range dpu only real values among the complex value will be performed by HWA.)

    It seems that you are trying to enable the 6843 in complex mode, and then use only the real portion of it.  But this is not the right way.  Because the ADC output in real mode is not equal to the real portion of ADC output in complex mode (there is some frequency shift and downsampling in ADC complex mode in digital logic).   

    You will need to program the AWR6843 ADC in real mode.  But the AWR6843 demo does not really support real ADC mode.   Let us continue the discussion through email thread. 

    +) Could you also check the profile for BPM method?

    Inside AWR6843 OOB demo (with DSP), the bpmCfg is supported. 

    1) With this bpmCfg CLI, the RF frontend will program the BPM chirp configuration through MMWave_addBpmChirp

    2) at the same time, the signal processing chain will support bpm demodulation (in doppler FFT procedure).

    As the AWR6843AOP OOB does not support bpmCfg, it does not really enable bpm mode in radar frontend, nor apply bpm demodulation in the signal chain.  So, you will need to add the support yourself in the similar manner as in AWR6843 demo (with DSP)

    Best,

    Zigang