BER analyzer

[Dr. Dhiman Kakati]

Hi all,

Here I am Attaching a design file that I downloaded from optiwave website the constellation points are nice. So I want to connect the BER analyzer to see the quality but I don’t know how to do it. The design is quite nice in terms of constellation poits so please anyone tell me how to connect the BER analyzer.

Regards

[alistu]

Hi Dhiman,

In order to use BER analyzer, you would have to acquire the binary input data. To do this, first you have to use a PSK decoder in each of the parallel branches. Then you can use a parallel to serial converter component to form the input data from the two parallel branches. After that, you just have to connect the input binary sequence to the upper input, the electrical signal created by passing binary input through a NRZ component to the middle input, and the output binary pulses (created by NRZ pulse generators) from the output to the lower input of the BER analyzer.

Regards

[Dr. Dhiman Kakati]

Alistu, I tried as you have mentioned as followed all steps but at BER analyzer I find onli one line and min BER=1. so Alistu did you try..?

Regards

[alistu]

Can you upload your implementation so that I would be able to check and make changes to make it work if it was possible to do so actually? It takes some time for me to implement it, so I’d rather check yours.

[Dr. Dhiman Kakati]

hi Alistu, I have attached herewith the .osd file please check and modify the required modification, I don’t know why only one line is coming instead of thick lines.

Regards

[alistu]

Thank you. I’ll try my best. In the meanwhile, I have to tell that the threshold detector settings are not set for a 4-PSK system. I think they are set for the condition with modulations with six symbols per bit. you would have to correct it by choosing one threshold and two amplitude values.

[Dr. Dhiman Kakati]

Dear Alistu,
you are right that is for 4-PSK system, I have tried using that one, actually I don’t know how to calculate the threshold value for the same. Please guide me where I can find the methodology to calculate the values, and which encoding scheme should I use there in place of PSK please let me know.

Regards.

[alistu]

In the specific case I have told you, a PSK would have two signal levels, corresponding to two states with a phase difference of 180 degrees. Therefore, the signal value is either above zero (for ‘1’, for example) and below zero (for ‘0’). So the threshold should be set at zero, a value in between. I choose the values in accordance with the values of symbols created by the PSK encoder, which I observe using M-ary visualizer. I think it is OK if you do not use the exact value as them, but still I use a value a little more than them.

[Dr. Dhiman Kakati]

Alistu you can modify the values to get the exact eye diagram, I am also trying for the same design along-with studying the component description and in the help text. Hope to solve the problem soon.

regards

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I am also facing the same problem. If you got the solution then please do share. Thank you

[Dr. Dhiman Kakati]

Dear Gokul, you can subscribe this topic. then automatically you will get notification of all the discussion answer.

Regards

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