[Duy Le NguyenParticipant]

Hi Quang Hoang, are you okay with your problem?
I don’t have Optisystem here on my computer. So I cant remember the option to resolve this problem.
If you want me help, you can email to me at zzdragonzz291@gmail.

Regards!

[Duy Le NguyenParticipant]

Hi hosam!
This because the start bits and the end bits of BER analyzer. You should set those values to 1024 bits.
Regards.

[Duy Le NguyenParticipant]

Hi umer!
Did you mean the bandwidth of the bandpass filter in WDM Mux and Demux blocks?

[Duy Le NguyenParticipant]

Hi Gokul.
I’m working on sample file.
Thank you for your answer. Now i knew it is wrong result on OS12 blocks.

[Duy Le NguyenParticipant]

Hi Gede

Did you put Optical Spectrum Analyzer at the end of Fiber?
In my project, OSA can show the FWM effect.
Or you can try to increase no. of channel or reduce channel spacing.

Thanks

[Duy Le NguyenParticipant]

Hi Gokul.I’m using Optisystem ver 14.0.0.48, maybe it’s the reason you can’t open that file. But you can open OFDM modulation file in your sample folder and try to change the CP point.

I’m using OS12 component because OS13 block give too good constellation result, although have some mistakes in my system.

I didn’t change any parameters except CP points at OFDM modulator and demodulator because I want to know the effect of CP to the system. And I think we will have the better result but it isn’t true?

Regard!

[Duy Le NguyenParticipant]

Hi Gokul. Yes, BER was zero before insertion of CP. And I worked on the OFDM 12OS. You can check the attached file below ( I modified CP points to 128)

Attachments:

1. OFDM-Modulator.osd

[Duy Le NguyenParticipant]

Hi Fady.
You can see it in the RF sectrum analyzer after the Quadrature Modulator. But I don’t know the reason, I’m beginer.
And you can go through the follow link. Gokul has the same question.
http://staging.optiwave.com/forums/topic/ofdm-4qam-ssb-with-os12-and-os13/
If you know the answer, please feedback to me.
Thanks and regards.

[Duy Le NguyenParticipant]

Hi Rajguru!
Thank you so much for your reply. But I resolved that issue. I tried to decrease the channel spacing from 100 GHz to 50 GHz, so it’s ok. Now I’m trying to use 16-QAM in my system.
And can I have another question? At the beginning, i worked in OFDM modulation sample, and I tryied to increase bit rate from 10 Ghz to 30 GHz, then I modified some parameters but the result is so bad. If you worked on same problem, could you give me some hints?

I’m very appreciated for your help? I’m still a newbie.
I attached my osd file below.
Best regards.

Attachments:

1. OFDM-Modulator1.osd

[Duy Le NguyenParticipant]

Hi Rajguru!
Can i ask one question? I’m studying about OFDM-WDM system so I’m making a project – 4QAM Direct detecter OFDM WDM with 16 channels. The results from 1st channel to 10th channel seem ok. But from 12-16th channel, the results aren’t good.
What parameter i should change?

Thanks and regards.

[Duy Le NguyenParticipant]

Hi Hamza!
You can’t extend your license by download the software on another ID and install on same computer. You must lease it by year.
Regards.

[Duy Le NguyenParticipant]

Hi Fady.
The center freq. of RF Quadrature modulator is 2.5GHz and freq. of CW laser is 193.1 THz, so we have center freq. of filter is 193.1025THz.
Regards.

[Duy Le NguyenParticipant]

Hi Gokul!
I don’t work on the new OFDM modulation. But see it if it can help you.
http://staging.optiwave.com/forums/topic/what-is-happening/

Regards.

[Duy Le NguyenParticipant]

Hi Gokul!
Sorry, but can i ask one question? Why in the DD-OOFDM sample we can choose the frequency of Quadrature Modulator is 7.5 GHz and the cut off frequency of low-pass filter is 0.62*bit rate.

Thanks and regards.

[Duy Le NguyenParticipant]

Hi Dihiman.

I’m very appreciated for you help. And how about the symbol rate you mentioned in previous comment.

and in the quadrature modulator try to set frequency same as symbol rate, in most of the cases I found better results by doing so.

Regards,
Dhiman

Is it OFDM symbols?

Regards.