haphazard waveform

[jyoti raina]

helo evryone..
i am facing a prblm.. i dont know why my mux’ed signal is like this..it is very haphazard and not so clear…i m designing a four channel wdm system.. i hv taken a sample frm the example folder and it was for 16 channel wdm system..thr i checked the waveform was clear havng 16 distinct signals..bt nw whn i changd it to 4 channel wdm..the ber got betr bt now this happens.
check the picture plz and help plz..
thanx in advance

Attachments:

1. 

   test.jpg
   

[Damian Marek]

Your filter settings in the Mux and Demu are probably not set correctly for the new channel positions.

Make sure they match

[jyoti raina]

hi Damian sir.. thanx fr replying to my query.
what is the thing i hv to do to set them right.. do i hv to change filter setting of wdm mux demux only or the all filters frm the receiver side..i m also using low pass bessel filtr with order 4..
i ll try to check and see this..anywyz thanx agn fr the kind help.

[Dr. Dhiman Kakati]

Hello Jyoti Raina,
Damian has suggested what you can look into, and without looking at your design and component parameters its difficult to give a fruitful solution. If it is possible please upload your design file. Thanking you..

Regards,
Dhiman

[jyoti raina]

hi dhiman sir..thanx for replying.
I hv taken an example from the optiwave samples for wdm systems.. it had 16 channels.. i changed it to 4 channels so that i could start frm basic..
when changing to 4 channel i got this waveform which is different from the one i got when i simulated the sample example..
now i ll try changing the filter as suggested by damian sir.. i hope it works well.. anyway thanx a lot

[Dr. Dhiman Kakati]

You are most welcome and Thank you Jyoti for making me clear, I will lok into the same example and try to modify as you are doing and let you know if i succeed.

Regards,
Dhiman

[Dr. Dhiman Kakati]

Hello Jyoti Raina,
I have modified the 16 channel NRZ ideal WDM design from the library to have 4 channel at the input and find acceptable BER and Q-factor. Please have a look into this design attached herewith and respective wavelength wavelength snapshot.

The modification I have done here are following,

the transmitter output changed from 16 to 4.

deleted unnecessary blocks.

fiber centre wavelength to 1563 nm.

Dispersion compensation fiber reference wavelength to 1563 nm.

WDM demux output wavelength to the 1st two transmitted wavelength i.e. 1565 nm and 1563 nm.

Thats all.

Thanking you..

Regards,
Dhiman

Attachments:

1. 

   11111111111111111111111.jpg
   

1. 4Ch-NRZ-Ideal.osd

[jyoti raina]

Thanx Dhiman sir..

[SAHIL SINGH]

Hello Jyoti Raina,

I agree with Dhiman kakati that without looking at your design and component parameters its difficult to give exact or workable solution. Try uploading your .osd file so that forum members can provide you with the optimum possible solution… Thanking you..

Regards

Sahil Singh

[jyoti raina]

hi sahil singh.. thanx for ur reply i am grateful to you.
I already mentioned that i have modified the sample example from 16 channel to 4 channel system rest i have kept the same…
i tried increasing the length..stil i vil try to upload the sample file fr ur convenience so dat u cud see what is wrong with it..
plz see i am uploading it with this comment of myn. thanx in advance

Attachments:

1. test2.osd

[burhan num mina llah]

hello jyoti raina

Try uploading your .osd file in order to get a better of your problem and also try to upload a screenshot of the wdm mux setting and that of wdm demux. so that the help for you would be presize enough .

Regards

Burhan

[jyoti raina]

hi burhan mam…thanx for ur kind reply n time.
i hv already uploaded the sample simulation file..just change the no of channels from 16 to 4..rest i hv kept same almost..
i wil be grateful if u see why this type of behaviour aftr the mux. i vil be looking forward to ur reply.
thanx in advance

[SAHIL SINGH]

Hi Jyoti Raina,

What i think is that Atul Sharmas comments are showing awaiting moderation becausw he might be new to the optiwave forum and has not been yet approved by the optiwave team to comment on the forum… They will first check whether his comment is appropriate so as to allow him on the forum.. After approval you and all other forum members will be able to see his comments for sure… So you must wait sometime… Hope this helps

Regards

Sahil Singh

[jyoti raina]

Thanx everyone for ur help..my signal waveforms got finer when i changed many things… Thanx dhiman sir for ur kind efforts…
this is my new waveform..i think it is correct noww…i guess..
thanx once agn

Attachments:

1. 

   test1.jpg
   

[Dr. Dhiman Kakati]

You are most welcome Jyoti Raina, The spectrum image you have attached here is quite Good as there is no overlapping now. I think you should get better result now but one thing i need to mention that how much frequency separation you are giving to get this Spectrum at the WDM mux output because if you give more than a limit you will not be able to transmit longer distance. Thanks for uploading.

Regards,
Dhiman

[jyoti raina]

Thanx Dhiman sir for ur kind reply..i think u are asking about the frequency spacing??
i am giving 100 Ghz spacing between the four transmitted frequencies…i am also using wdm mux with 15 Ghz bandwidth..bcoz somewhere on the forum i read it gives u better results so i increazed it to 15 which i think is nt dat much…i hope i am not doing wrong…dhiman sir i hv one query abt plotting graphs for all 4 receivers on the same graph for ber abd q factr…bt m nt able to do it at a time fr all..cn u plz tel me if i can do it..i vil b very much thankful…thanx in advnce

[Dr. Dhiman Kakati]

Hi Jyoti,
Thank you so much for providing with the values. regarding your query,you need to find all the respective values and make a table in Microsoft excel and from there you can plot all of them as per your wish, There are many videos in youtube where it is nicely explained. Just do a search “how to plot a graph in excel” and thats done. remember you need to pres and hold control button for doing in case of multiple graph.

Regards,
Dhiman

[jyoti raina]

Thanx fr d help Dhiman sir..it was very helpful indeed..

[aasif bashir dar]

hi joyti raina,
i thick you must know what is awaiting moderation because you also have gone the same stage while joining and posting in optiwave forum for the first time as the recruit,,
any ways awaiting moderation means the checking the first post of newly joining member in optiwave forum by the optiwave admin.. it takes the 24 hourss… after that the post gets shown on the forum.
with regards

[jyoti raina]

sry aasif sir i din know..thanx fr tht info

[aasif bashir dar]

hi joyti raina,
your query related to awaiting moderation answered in reply no #34250
with regards

[SAHIL SINGH]

Hi Jyoti Raina,

As far as awaiting moderation is concerned that is allready mentioned in the previous comments…

Regards

Sahil Singh

[SAHIL SINGH]

Hi Jyoti Raina,

You are welcome.. This forum is meant to help each other and share our valuable information and experience.. Thanks Optiwave forum..

Regards
Sahil Singh

[jyoti raina]

hi atul sharma..thanx fr reply bt what is awaiting moderation?
n sorry by mistake i hit the like button..no option of unlike..by mistake.
thanx anyway

[Dr. Dhiman Kakati]

Hi Jyoti,
please refer to the answer at reply no 34250, provided by Aashif Bashir Dar. and the like button is for supporting the answer or the answer that solved your problem.

Regards,
Dhiman

[jyoti raina]

thank u ol for the help…i am really thankful to ol people n the forum..

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