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Different curve for log(BER)

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(joined December 2015)
Participant

Hi All,

Is there any one know why are the curve of log(BER) different in the picture that is attached.

BER-1 and Eye diagram-1 are from one of the Optisystem 13 samples example.
BER-2 and Eye diagram-2 are from my design.

and which curve is good

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Responses (3):

    • #29058
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      Hi All,

      Is there any one know why are the curve of log(BER) different in the picture that is attached.

      BER-1 and Eye diagram-1 are from one of the Optisystem 13 samples example.
      BER-2 and Eye diagram-2 are from my design.

      and which curve is good

      Attachments:
    • #29060
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    • #29069
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      Alessandro Festa
      Participant

      Hi Mohamed,

      for which particular design/example are these curves?

      Regards,

      Alessandro

    • #29074
      Profile Photo

      Hi Alessandro

      Thanks for your reply. The example is WDM PON from Metro and Access system folder. My project is
      CO-OFDM. I know they are different design, but I just want to know why both
      of them has different shape of BER curve while they have almost the same
      value.and is mine is consider as good or not.

      I already get the explanation from optisystem support team, and here their answer

      “The reason your eye diagram looks like this is its connected after the
      decoder and the NRZ generator, which means your signals can only have “zero”
      or “one” and that’s why they look ideal. For a more accurate view of the eye
      diagram, you have to connect the visualizer before a decision has been made
      on the electrical signal. However, you can’t really do that on the OFDM
      because the output is not actually electrical. The decision is made inside
      the OFDM component.

      By the way, you are using our old OFDM component, which to be perfectly
      honest, is not very good. For better results, please switch to our latest
      OFDM components. They are a huge improvement over the old ones. I think you
      have to be using at least OptiSystem 13.0.3 for them.”

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