[cheeParticipant]

Dear Damian, i have made the changes on the BER test set accordingly, but still the error persists. attached is my osd file. thanks.

[cheeParticipant]

Dear alistu, by only changing the extinction ratio of the mzm to 50dB, with the FSO deactivated, i managed to get 0 BER. the samples per bit is already set at 32.

[cheeParticipant]

Dear Damian,i am too unable to open the file as i am using trial version. my project does not have any limitation regarding MZM modulator. what is the range of extinction ratio that i can set? is there going to be other effect on the signal after i alter the extinction ratio?

[cheeParticipant]

dear alistu, i noticed that the BER value in the example u attached does not change according to the attenuation. sometimes the BER improves when i increases the attenuation or vice versa. does this means something is wrong with the simulation setup?

[cheeParticipant]

Thank you alistu. the modified BER is 0.37. stil is too high to be accepted. and i found out that even though the attenuation is only 3db and the distances is 100m, the constellation diagram at the receiver is all wrong.

[cheeParticipant]

sure thing. because i am using FSO model in Southeast Asia region, the rain rate is very high, which is why the attenuation is in the range of 50-70db\km. i would like to improve the BER to the acceptable range. if i am not mistaken. BER should be at least 10^-9 right?

[cheeParticipant]

may i know what is the parameter that affecting the BER. i tried increasing the optical amplifier gain but to no avail, the BER rate stil in the range of 0.5. is there any component that can be used to dramatically increase the BER to the acceptable range?
i noticed that in the example file OFDM Coherent Detection Single Port Single Polarization 16QAM, the BER is 0.00779. is this value acceptable?

[cheeParticipant]

yes alistu, i have the same problem too. but i noticed that if i follow the exact value from the example, then it have no problem. i wonder what is the problem. here is my system after i try to change it back to my project’s parameter. my trial license left 17 days only. please help me.

[cheeParticipant]

wow! got it. thank you very much.

[cheeParticipant]

can i know how you key in the formula in fso component?

[cheeParticipant]

i am sorry, why is the file is in doc?

[cheeParticipant]

thank you alistu. actually this is because i only have basic understanding on optisystem, so i’m not able to understand high level operation. the formula is rather simple, attenuation = 2.03(rain rate)^0.74. rain rate have one decimal place.

[cheeParticipant]

thanks alistu, do you have any more information regarding this?

[cheeParticipant]

thank you alistu. is training symbol same as pilot symbol? in the example, the number of training symbol is set at 10 but only 6 positions defined.

[cheeParticipant]

Dear alistu, i have made the amendment but still there is error in my simulation. i have already placed the subcarriers between 257-768.