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not clear 16APSK

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(joined October 2014)
Participant

Dear all,

attached pic is actually 16APSK, but it looks very bad cause of Dispersion effect. How can I fix this? is there any better way?

Responses (7):

    • #15324
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      boldoo
      Participant

      Dear all,

      attached pic is actually 16APSK, but it looks very bad cause of Dispersion effect. How can I fix this? is there any better way?

    • #15422
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      Damian Marek
      Participant

      Hi Boldoo,

      I simulated your project again with the fibers and amplifiers off and the constellation came out properly. Although I don’t think it is a traditional 16-PSK constellation it still looks good.

      The fibers and amplifiers are the agents which cause the distortion here. Try a DCF to get a better result.

      Regards

      Attachments:
    • #15558
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      Ravil
      Participant

      I have a question about 2dB power level sent through 16km fiber to receiver: did you consider the sensitivity limits of your detector?

      +1
    • #15578
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      boldoo
      Participant

      first amplifier is 0db. second amplifier is 2dB through 16km fiber. you mean it is too low?

      how to set sensitivity limits?

    • #15580
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      boldoo
      Participant

      Amplifier 2 db is too low. it should more than 10dB, right? what does it mean Power parameter of Receiver?

    • #15610
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      Ravil
      Participant

      Not exactly. I’m suggesting you to consider the level of overload signal for your receiver. The matter is that all receivers, in general, are working in dynamic range -15-25dB and if your input power will be bigger than higher limit, your receiver will become saturated which will bring you nonlinear distortion and information quality will degrade.

    • #15611
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      Ravil
      Participant

      Levels of 0dB and 2dB accordingly are used, in general, for fiber spans with length of 80-160km which gives power level at the receiver within the dynamic range…

    • #15612
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      Ravil
      Participant

      For better explanation I can refer you book “Fiber optic communication” G. Agarwal…

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