Constellation map phase shift

[boldooParticipant]

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:

1. 

   phase-shifted.png
   

[Damian MarekParticipant]

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