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Constellation map phase shift

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(joined October 2014)
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Hi all,

I configured 16QAM transmitter and fiber, filter, DCFiber and receiver. But in receiver, constellation map phase shifted.

i think reason is dispersion of fiber. right?

how to restore square 16QAM? which parameter affecting to phase shift? please share me your idea.

please check photo

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Responses (1):

    • #15265
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      boldoo
      Participant

      Hi all,

      I configured 16QAM transmitter and fiber, filter, DCFiber and receiver. But in receiver, constellation map phase shifted.

      i think reason is dispersion of fiber. right?

      how to restore square 16QAM? which parameter affecting to phase shift? please share me your idea.

      please check photo

      Attachments:
    • #15279
      Profile Photo
      Damian Marek
      Participant

      Rotation of the diagram is due to an ordered phase shift. You can use a Digital Signal Processing component to reset the phase or you could manually add your own phase shift component and set it to rotate the constellation back to the correct position.

      +3

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