implementation of DPSK in SCM

[Debanjan Sarkar]

Hi all
I have implemented DPSK in SCM from the example as given in example for ASK.
But I am not getting the output. Please share your knowledge and also find the attachment.
Thank you

[Debanjan Sarkar]

Hi all..waiting for your reply.

[Aadil Raza]

Can you please share the clear snapshot of your design ? Because I have version 7 only

[Dr. Dhiman Kakati]

Dear Debanjan,
can you upload the paper which you are trying to implement because the modulating signal seems a little bit complex so that i can check the modification required.

Regards

[Dr. Dhiman Kakati]

Hi Debanjan, I somehow managed to get the output bit stream but the 3R generator generator and the BER analyzer after the NRZ encoder you should not use here, If the circuit is correct I would suggest you to use the BER test set for calculating the Q-factor, BER etc. if you want to use the BER analyzer then you have to use it after the Quadrature demodulator along with 3R generator. Thanks. I have attached here with the modified design i will be confirmed after you upload your paper trying to realize.

Regards,
Dhiman

[alistu]

Hi Dhiman,

I ran the modified file and did not manage to see the result. Then I used BER Test Set to see the number of error bits. I am getting BER of about 0.5 which corresponds to signal corruption. Does the problem still exist or should I do something, like a change in the settings, to be able to see the result? Thank you.

Regards

[Dr. Dhiman Kakati]

Hi Alistu, definitely you can modify the design to have the better results.

Regards.

[alistu]

Actually I couldn’t! And I have doubts about using threshold detectors that Debanjan has used for DPSK. So I asked about the result you have obtained and it is a normal thing in these forums. BTW, the decision component used was set for BPSK, so I changed it to PSK with 3 bits per symbol on differential coding and yet did not manage to get results.

Regards

[Debanjan Sarkar]

sorry for late reply. Actually i have taken the concept from radio over fiber scm ask.osd as given in example.
Thanks

[alistu]

The reason for not getting any results in the output was simply the fact that the threshold levels were chosen in a way that all the signal was located in the zero zone. So you only need to change the threshold to see signal in output. However, I didn’t manage to get acceptable results after this, even though I compared your system with the sample you have addressed. I will let you know in case.

[Debanjan Sarkar]

ok thank you..alistu

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