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Questions Regarding UXPI Presentation on PAM4 versus NRZ




    All:

    During my presentation to the Backplane Ethernet Study Group, there
were two questions for which I did not have an immediate answer.  These
are answered below.  I don't remember the exact wording of the second
question, but I think I have paraphrased it correctly.

    Thank you for the opportunity to make this presentation.  The UXPI
group and its member companies look forward to working with IEEE to
create a succesful
standard.

    Regards,

    Steve A.

    1.    Q: What jitter was assumed in the stat eye analyses?  A:
DJ=0.3 UIpp, RJ = 0.0152 UI RMS.

    2.    Q: Is the figure of page 7 correct?  This is the figure that
plots vertical eye openings of PAM4 and NRZ versus bit rate.  The text
states that this results from "Transmission line analysis".  A: We
neglected to say that this also includes equalization.  The equalization
is linear.  It partially corrects the transmission line response so that
the resulting channel has a -3 dB bandwidth of 3 GHz.  This same
equalization was used for both PAM4 and NRZ.
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