thesis

[seda yılmazParticipant]

hello everybody
ı have to make optical cdma. I did circuit of optical cdma and it is run but I don’ understand what I did.I don’t understand it has one or two channel.I will share my source. Please, you search my source. İs it wireless cdma or cable cdma? I think I did cable cdma but I don’t sure.I don’t understand what I did.Can you help me? I have to understand this week.
Best

Attachments:

1. 31.pdf

[RavilParticipant]

Hi Seda,

Since you are asking most of your questions about the scheme you made, can you, please, upload it? Did you make your scheme in the exact accordance with the source that you have uploaded?

[seda yılmazParticipant]

I did my scheme in the exact accordance with the my source.Only I change frequency.

[RavilParticipant]

Hi Seda,

In my opinion, you have two channels in your scheme. Each branch (represented by decoder, PIN-photodiode and subtractor) of the balance detector in your scheme defines a channel of the group signal. However, it wasn’t specified in the implementation scheme, it’s highlighted in your attached paper that designed method is applicable for cable (fiber optical CDMA) network.

+1

[RavilParticipant]

Taking a look at the attached simulation scheme, you can notice that there is an optical fiber (with the length of 5km) is used as the transmission medium. At the same time, this technique can be implemented for wireless as well.
Sorry for the delay. For some reason my answer has not been sent before! Let me know if you have any more question about the scheme!

[seda yılmazParticipant]

Hi Ravil
Thank you very much for helping. I will ask about shape of eye diagram. I will sent shape eye diagram of its in the tomorrow. My teacher is that your shape is wrong. But I think it is true. Anyway, I will ask you in detail.Thank you again.
Best

[RavilParticipant]

Hi Seda,

You are welcome! I am glad to help you with what I can. Please, feel free to send your eye diagram and I (as well as the other forum memebers) will try to help you.

[Abhishek ShramaParticipant]

Hello Seda
I am agree with Ravil,in this paper(you have attached) comparison of performance of different coding techniques and detection has been studied.Modified Double-Weight and double weight schemes used in this paper due to the advantage of less MAI and PIIN.FBG’s used to implement these code with specific chip.Rest for your eye diagram ,upload your system to better understand results.Rest Ravil explained well about fiber and wireless system.

+1

[seda yılmazParticipant]

Hi Ravil
I share my eye diagram. My teacher said that there should not be interference signals in the upper part of the eye diagrams but she said that there should not be interference signals in the side of the eye diagrams.Do you think my eye diagram is true?

Attachments:

1. eye-diagram.docx

[seda yılmazParticipant]

Hello Abhishek
Thank you for helping.

[RavilParticipant]

Hi Seda,

According to the question that your teacher asks you, does he/she mean that that “amount” of interference doesn’t correspond to your quality characteristics, i.e. Q-factor and BER? From my point of view, it looks like you should have less interference in accordance with your quality characteristics. However, I think that the threshold value might needs to be adjusted… How did you set it up? Did you just use the auto settings?