DPSK (BPSK) modulator using delay feedback

[Ahmad Mahmood]

I want to implement DPSK(BPSK) modulator in optisystem 13 using delay feedback loop but I dont know what component should I use in place of 1 bit delay. Moreover I cant use the output of bit sequence generator at the input of electrical XNOR gate. Balanced modulator is also not present in optisystem 13. Kindly Help and guide. Schematic is attached.

Attachments:

1. 

   DPSK-modulator.jpg
   

[alistu]

Hi Ahmad,

I think you can use “electrical delay component” for your purpose by setting the delay time a bit duration time (1/bit rate). You can use the output of bit sequence generator as the input of an electrical component by first passing it through the NRZ pulse generator. And if you address a paper related to your work, I might be able to help you with the “balanced modulator” problem.

Regards

[Ahmad Mahmood]

Thanks alistu for your valuable reply 🙂
Actually I am not implementing any paper I am to generate a DPSK(BPSK) signal for Analog to digital conversion and then again convert it to analog and detect. This is my class project. I have used the builtin DPSK modulator present in Optisystem 13 for this purpose but after DAC conversion the signal loses its phase change. My supervisor suggest me to design my own DPSK modulator and demodulator for this purpose. Now I have made the circuit as you suggested but it dont show output after XNOR gate. I found the design at the site given below. My .osd file is also attached Kindly Help. Thanks

http://www.rfwireless-world.com/Terminology/DPSK.html

Attachments:

1. DPSK-Modulator.osd

[alistu]

The problem is, by running the calculations the XOR components doesn’t get input from electrical signal delay component (or gets zero input) and so the output is always zero.There have been some other members who’ve had trouble implementing systems with feedback in Optisystem and unfortunately, I haven’t been able to help. I hope Damian will help you implement this one.

[Ahmad Mahmood]

May I invite or tag Damian on this post??? If yes then kindly guide how???

[alistu]

The Optiwave constantly and regularly check the forums during the working hours. So I think Damian will go through your topic then (This is based my my experience with the forums).

Regards

[Author]

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