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TLK2501: PRBS 2^7-1 bit pattern information and receive error detect time in PRBS enable MODE

F.N
Expert 8760 points
Part Number: TLK2501

Hi team,

My customer wants to know the following information.

(1)TLK2501 PRBS 2^7-1 bit pattern

(2)Recieve error detect time(from bad PRBS pattern incoming to outputting PRBS_PASS deassert)
    in PRBS enable MODE

If you have the imformation, please let me know them.

Best regards,
Fumio Nakano

  • 0
    TI__Genius 16150 points
    Hi F.N,

    Sorry for the delayed response. PRBS 2^7-1 bit pattern built-in the TLK2501 has 127 number of bits (128-2 = 126 bits).

    Regarding the error detect time, please let me verify with the team. ASAP I will be back with the answer.

    Thanks,
    Luis Omar Moran
    High Speed Interface
    SWAT Team
  • 0 in reply to Luis Omar Moran
    TI__Expert 8760 points

    Hi Moran-san,

    Thank you for your reply.

    The customer wants to get PRBS 2^7-1 bit based pattern.
    So, I genarated this pattern.  Please look into this:PRBS-2^7-1pat-Gen.xlsx
    Is this pattern correct? Please let me know.

    Regarding the error detect time, I will wait for the answer.
    Thank you for your cooperation.

    Best regards,
    Fumio Nakano

  • 0 in reply to F.N
    TI__Genius 16150 points
    Hi Fumio-san,

    The pattern that you generated looks fine. Could you clarify why customer does not use the TLK2501's PRBS generator?

    Please let me push the team to get the error detect time.

    Thanks,
    Luis Omar Moran
    High Speed Interface
    SWAT Team
  • 0 in reply to F.N
    TI__Genius 16150 points
    Hello Fumio-san,

    The error counters can then be read after a certain duration of time to calculate the BER. The right duration will depend on the serial data rate, the BER target to which you are measuring, and the amount of confidence you need in the BER measurement. For example, if the serial rate is 5 Gbps and you want to verify that the BER is better than 1E-12 with 95% confidence, you would need to read zero errors after about 10 minutes (3E12 bit times). A good calculator tool can be found here: www.jittertime.com/.../bercalc.shtml.

    Thanks,
    Luis
  • 0 in reply to Luis Omar Moran
    TI__Expert 8760 points

    Hi Moran-san,

    Thank you for the answer.

    I have questions.

    PRBS_PASS will not output LOW immediately when an error occurs in PRBS enable MODE?
    Does that mean the customer have to wait 3E12 bit times to get PRBS_PASS LOW output?

    The customer wants to know the time from detecting the first error to outputting PRBS_PASS LOW
    in PRBS enable MODE.

    Please let me know.

    Best regards,
    Fumio Nakano

  • 0 in reply to F.N
    TI__Genius 16150 points
    Hello Fumio-san,

    Sorry for the confusion. Basically the PRBS verifier in the TLK2501 will trigger PRBS_PASS to go high as soon as a valid PRBS pattern is detected. It does not need to keep track of all 2^7-1 bits to do this, since PRBS patterns can be generated by an algorithm. The verifier just needs to be able to read in the first several bits, compute what the next bit should be, then compare it to the value that is being received. As soon as an invalid bit is detected, the PRBS_PASS indicator will go low.

    Thanks,
    Luis
  • 0 in reply to Luis Omar Moran
    TI__Expert 8760 points

    Hi Moran-san,

    Your answer is very useful.
    Thank you!!

    Best regards,
    Fumio Nakano