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AWR2944: ADC data bit error for RX1&3 when using DCA1000

Geogia
Prodigy 170 points
Part Number: AWR2944


Hi All

For AWR2944 OF our radar board, we use DCA1000 to transmit raw ADC data, the Rx1 and Rx3 have bit error, but Rx2 and Rx4 do not have bit error.

I have three questions:

1. Why only RX1 AND 3 have bit error, Do Rx1 and 3 in the same LVDS lane? and RX2 and 4 in the other LVDS lane?

2. When the LVDS wire length is 0.5 meters, it has little possibility of bit error. When using 2 meters lvds wire, it has high possibility of bit error. is there any method?

3. is there any chance that the bit error is related with the air temperature?

thx

  • 0
    TI__Mastermind 36195 points

    Hello Geogia,

    Can you also confirm that this spike is only in the LVDS received data. Can you compare first the data you receive in the ADC buffer and the data over the LVDS and compare?
    That will help in identifying the root cause.
    I want to understand how you are classifying this as a bit error?
    Also are you seeing the bit error always in the same position?
    Can you first let me know how are you using interleaved or non-interleaved data?

    Regards,
    Saswat Kumar

  • 0 in reply to Saswat Kumar
    Prodigy 170 points

    Hi Kumar

    When using 0.3m lvds wire, there is no bit error; when using 1 m lvds wire, there are bit errors;

    The bit error has no relation with position;

    what do you mean  interleaved or non-interleaved data?

  • 0 in reply to Geogia
    TI__Mastermind 36195 points

    Hello Geogia,

    As there are only 2 lanes, the way the data is arranged in the ADC matters how it goes over the LVDS lanes. But as you confirmed it doesn't get corrupted with a shorter line, so those details don't matter.
    Let me assign this to a hardware expert.

    Regards,
    Saswat Kumar

  • 0 in reply to Geogia
    TI__Mastermind 30925 points

    Hello,

    What cable are you using to transmit over 1m? 

    You probably are encountering some signal integrity issues over longer distances. Do you have anyway to measure the eye diagram with the short and long cable?

    Regards,

    Adrian