Constellation diagram of BPSK and QPSK

[Abhilash Achanta]

Hi all,

I am doing an analysis of different modulation schemes in an RoF link.

For BPSK and QPSK I am getting a very bad constellation at the transmitter end itself(Screenshots of layout and visualizer attached). What could the problem be ?

Appreciate your help.

Attachments:

1. 

   BPSK.png
   

2. 

   QPSK.png
   

3. 

   Simulation_layout.png
   

[adnan sabbar]

Kindly attach your optisystem file to solve your problem

[Abhilash Achanta]

Hi Adnan,
The constellation diagrams at the transmitter end are okay now.

At the receiver end, BPSK and 8-QAM are not as expected.

Please find screen shots and simulation file attached.

Thanks for the help.

Attachments:

1. 

   8-QAM_constellation_at_receiver.png
   

2. 

   BPSK-1.png
   

1. 8QAM.osd
2. BPSK.osd

[Damian Marek]

Start from one of our square 8QAM examples, it looks like you modified one of our Star QAM, as the the QAM Sequence generator is set to Star type of constellation.

[Abhilash Achanta]

Damian,

I checked the graphs that are generated in OFDM demodulation component and they resemble 8-QAM scheme (I saw one of your post which says this, Thanks!)

Please find the constellation diagram attached

Attachments:

1. 

   8-QAM.png
   

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