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  • RZ line coding

    From [email protected]@21:1/5 to All on Fri Sep 7 05:05:28 2018
    Hi

    A very big hello to Huub if he reads me.

    Do you know a signal that is using RZ line coding?

    Thanks,
    Michelot

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  • From Huub van Helvoort@21:1/5 to You on Fri Sep 7 21:28:14 2018
    Bonsoir Michelot,



    You wrote:

    A very big hello to Huub if he reads me.

    Very nice to hear from you again ;-D

    Do you know a signal that is using RZ line coding?

    I don't know any RZ signals. The reason that they are not used
    may be that the line rate is twice the datarate.

    More common is bipolar-RZ. Used in early PCM as AMI coding in US/ANSI
    T1, and improved HDB3 in European/ETSI E1.
    (HDB3 coding is used to avoid sending more than 3 conscutive "0")

    See also: https://en.wikipedia.org/wiki/Return-to-zero

    Best regards, Huub.


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  • From Michelot@21:1/5 to All on Sat Sep 8 11:59:04 2018
    Bonsoir Huub,

    A great pleasure to read your reply.

    You're rignt. In optical fiber, it seems that RZ is not used. We only see NRZ.

    I just discovered, in G.959.1(04/2016), Appendix VI, this text:

    "A future revision of this Recommendation is expected to contain specifications for single-channel IrDIs with a bit rate/line coding of RZ 40G. These applications are expected to show a higher tolerance to PMD than shown by applications with a bit rate/
    line coding of NRZ 40G".

    Perhaps, for the decoding, the expanding time due to the dispersion has less effect onto 0,33 UI pulses than complete UI pulses. The overlap between received pulses, with the sequence (1 - 0 - 1) can be better controlled.

    Best regards, Michelot

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  • From Huub van Helvoort@21:1/5 to All on Sun Sep 9 00:10:46 2018
    Bonsoir Michelot,

    Because you mention 40G signals, here is a tutorial
    discussing RZ and NRZ for 40G.
    Conclusion NRZ is better.

    https://optiwave.com/resources/applications-resources/optical-system-comparison-of-rz-and-nrz-modulation-formats-for-40-gbs-systems/

    Kind regards, Huub.

    ---
    A great pleasure to read your reply.

    You're rignt. In optical fiber, it seems that RZ is not used. We only see NRZ.

    I just discovered, in G.959.1(04/2016), Appendix VI, this text:

    "A future revision of this Recommendation is expected to contain specifications for single-channel IrDIs with a bit rate/line coding of RZ 40G. These applications are expected to show a higher tolerance to PMD than shown by applications with a bit rate/
    line coding of NRZ 40G".

    Perhaps, for the decoding, the expanding time due to the dispersion has less effect onto 0,33 UI pulses than complete UI pulses. The overlap between received pulses, with the sequence (1 - 0 - 1) can be better controlled.

    Best regards, Michelot



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  • From [email protected]@21:1/5 to All on Mon Sep 10 05:19:55 2018
    Bonjour Huub,

    Many thanks for this document. I have to read it.

    Kind regards,
    Michelot

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