- This topic has 7 replies, 2 voices, and was last updated 6 years, 6 months ago by
zheng kai.
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January 1, 1970 at 12:00 am #81237
Adalberto Weissmuller
Member(Awaiting moderation)
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January 1, 1970 at 12:00 am #83841
Adalberto Weissmuller
Member(Awaiting moderation)
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January 16, 2018 at 7:12 am #47375
zheng kai
ParticipantHi!
Using MATLAB compnent dispersion compensation, the result is wrong.
Dispersion compensation expression:H’=exp(j*w^2*beta2*L/2)
use SSMF,:beta2 =-20 L=200km, Not considering attenuation and non-linearityMATLAB code:
OutputPOrt1 = InputPort1;
for i = 1:length(InputPort1.Sampled.Signal)
OutputPort1.Sampled.Signal(i)=InputPort1.Sampled.Signal(i)*exp(1j*beta2*L/2*InputPort1.Sampled.Frequency(i)*InputPort1.Sampled.Frequency(i));
endWhere is wrong? ? ? Why can not compensate
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January 17, 2018 at 8:17 am #47420
Mohamed A. A. Abouseif
Participantsend both matlab file and .osd file in compressed folder, I might be able to help
thanks
Mohamed Abouseif -
January 17, 2018 at 8:53 pm #47427
zheng kai
Participantzip file
Attachments:
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January 18, 2018 at 2:57 pm #47439
Mohamed A. A. Abouseif
ParticipantHi Zheng,
I have checked you project,
I think I got the error.
note that the output of PIN photodetector is time domain signal. so you can not multiply time domain with transfer function in frequency domain!!
So the solution, you have to
convert the output of PIN to frequency domain then multiply by H(omega).
hope that helps,
thanks
Mohamed Abouseif -
January 18, 2018 at 10:25 pm #47440
zheng kai
ParticipantHi Mohamed Abouseif,
Sampled signal domain is frequency in MATLAB Component.
Can you give me a solution? -
January 18, 2018 at 10:52 pm #47441
zheng kai
ParticipantHi Mohamed Abouseif,
I try to fft transform PIN output, and then multiplied by H, the result is wrong. -
January 19, 2018 at 7:38 am #47454
Mohamed A. A. Abouseif
ParticipantZheng,
you need to pay attention about domain of calculation.
after fft pls make sure to compare it with actual frequency domain of the input. in other words, try with something known first (for example Gaussian pulse, or anything similar..) then do the multiplication also make sure again from the results (it is as simple as multiplication)
then return back to time domain by ifft, again make sure from the output is correct. then afterwards, use this matlab component in your project.
be patient in checking each step. keep in your mind it is just a multiplication process!!!! but in frequency domain -
January 19, 2018 at 9:32 pm #47466
zheng kai
ParticipantHi Mohamed Abouseif,
Do you have any documentation on multiplying the frequency domain?
Let me refer to it,I am very anxious to use this project。
thanks
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