DBSK Modulator

[Jamal]

I am trying to implement a DBSK Modulator as shown in the Figure.
The setup is working in Optisystem7 however when I implement the same design in optiwave13, it gives an error calculating the NRZ pulse generator and cancels the simulation. Can anyone tell where the problem lies ?

Attachments:

1. 

   DBSK.png
   

[Jamal]

Also find the attached osd file of the setup

Attachments:

1. DBSK-Modulator.osd

[Damian Marek]

When you want to implement feedback you need to convert to individual bits. Check out the attached project file. I also attached an initializer which will give a first input to the XNOR.

Attachments:

1. 

   SchematicPNG.png
   

1. DBSK-Modulator1.osd

[Jamal]

Thank you Damian
This is working now

[alistu]

Hi Jamal,

You have mentioned when you implement the design in OptiSystem 13, you find this problem. Now if you don’t implement the design in the new version and just use the implementation that has been created using version 7 and run it in version 13, will you get the same error again?

[Ahmad Mahmood]

Hi alistu
Yes the error is same whether we run optisystem 7 file in version 13 or create a new project in optisystem 13. Kindly Help.

[Sasha]

Hello Ahmad,

I tried DPSK using electrical components and I am getting an output. Check whether this suits with your application.

Regards,
Sasha

Attachments:

1. dpsk.osd

[Jamal]

Hello Sasha
I tried running your osd file on optisystem 13, but there is no output at either of the Phase modulators.
Please can you look into this or tell me if I am doing something wrong?

[Ahmad Mahmood]

Hi Sasha
the circuit you suggested is giving output after setting frequency parameters but there is a problem it gives the same amount of noise at the out put. More over you set the modulation constant of Phase Modulator to 1 degree so its not giving PSK signal to get BPSK we’ll have to set it 180 degree for QPSK 90 degree and for 8 PSK 45 degree. As we required BPSK we set it to 180 degree but now changed phase of output interfere with noise and give us the disrupted output. see the modified circuit and help if you can We want refine signal without noise.

Thanks in anticipation.

Attachments:

1. 

   Signal.jpg
   

2. 

   Noise.jpg
   

3. 

   Signal-Noise.jpg
   

1. dpsk1.osd

[Sasha]

Hello Ahmad,

I tried changing the parameters in PSK modulator but noise didn’t get reduced.

[Sasha]

Hi all,

I changed the sequence length = 8 bits and then checked the output. Input from PSNR is 10101010, user defined sequence is 00000000. When I checked output at convert from Individual bits, output is 01010101. But the output of xnor should be 10101010. Can anyone please explain?

I checked the output from DBSK-modulator1.

Thanks in advance.

[Sasha]

And when I connect the binary sequence visualizer at the output of xnor gate and convert to individual bits from user defined sequence, I am not getting the output. What is the reason?

I attached a picture.

Thanks in advance.

Attachments:

1. 

   dbsk.png
   

[Ahmad Mahmood]

Hi Sasha
you should just use a sequence of 0 instead of 00000000 on user defined sequence as the initializer should just send 1 bit at start to initialize the XNOR gate after that the delayed version of output will be sent at the input of XNOR see the file attached by Damian.

[Author]

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