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Why i am getting two eye diagrams for Gaussian Mono Cycle Pulse ?

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(joined October 2014)
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Hi every one !
Hope u r fine.

I am using Gaussian Mono cycle pulse in my research work. But when i want to analyze and measure BER of Gaussian Mono Cycle pulse (fig attached below) by using BER Analyzer then i got “Two Eye diagrams” as shown in fig below.

I am getting these two Eye Diagrams because BER analyzer in Opti sys took negative and positive going cycles of Gaussian Monocycle a separate signals. Therefore BER analyzer made two eye diagrams one for each cycle.

But this is wrong, because BER analyzer should analyze and measure BER for Gaussian mono cycle as a one complete signal rather than take two components of Gaussian mono cycle signal separately. Further, it must display findings and result in only one eye diagram.

Therefore, Can some body tell me how to make BER Analyzer able to take Gaussian mono cycle one complete signal and display result in one Eye Diagram.

I will be very thankful to you for your kind response.
P.S i am transmitting NRZ data from transmitting side.
Best Regards

Responses (23):

    • #18565
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      Ibn Aziz
      Participant

      Hi every one !
      Hope u r fine.

      I am using Gaussian Mono cycle pulse in my research work. But when i want to analyze and measure BER of Gaussian Mono Cycle pulse (fig attached below) by using BER Analyzer then i got “Two Eye diagrams” as shown in fig below.

      I am getting these two Eye Diagrams because BER analyzer in Opti sys took negative and positive going cycles of Gaussian Monocycle a separate signals. Therefore BER analyzer made two eye diagrams one for each cycle.

      But this is wrong, because BER analyzer should analyze and measure BER for Gaussian mono cycle as a one complete signal rather than take two components of Gaussian mono cycle signal separately. Further, it must display findings and result in only one eye diagram.

      Therefore, Can some body tell me how to make BER Analyzer able to take Gaussian mono cycle one complete signal and display result in one Eye Diagram.

      I will be very thankful to you for your kind response.
      P.S i am transmitting NRZ data from transmitting side.
      Best Regards

    • #18580
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      Damian Marek
      Participant

      It might not be possible to calculate the BER from the eye diagram alone. Could you please attach your project file?

      Thanks

    • #18581
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      Ibn Aziz
      Participant

      Damian thanks alot for responding, file is attached below.

      Damian I need to find both Eye diagram and BER but first problem is that i am getting 2 eye diagrams which should be only one (further detail is discussed above).Hw can i come out of this ?

      2. Kindly guide me how will i measure BER for such scenario or when i am using Gaussian Mono cycle pulse signal ??

      P.s I am using Opti sys 7

      Best Regards
      Stay Bless

      • #18584
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        Damian Marek
        Participant

        Hello,

        What type of eye diagram are you expecting for the Gaussian Mono Cycle? Fundamentally, the modulation schemes are different between a NRZ pulse and the monocycle gaussian format. From the eye diagram it looks exactly as I would expect it to considering the modulation type and the input electrical signal.

        Our BER Analyzer assumes an NRZ or RZ modulation format and calculates the BER from the eye diagram based on that, which of course does not apply to this application. In your case the best bet is to use the BER Visualizer for a quick visualization of the signal, but I think for a rigorous BER calculation you will need to use the BER Test Set. There are plenty of topics on the forum on the use of the BER Test Set if you are unfamiliar with it.

        Regards

    • #18587
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      Ibn Aziz
      Participant

      Thanks Damian for your kind elaboration !

      I am expecting a general eye diagram which works for all NRZ scheme (which don’t have any negative portion or down word slop as shown in above attachment) but as u stated above, it will not apply here.

      Actually from the transmitting side i am sending NRZ data but in return at receiver side i am getting Gaussian mono cycle. So when i plot Eye diagram i should get eye diagram like all NRZ data but i didn’t get that shape because BER analyzer understand only RZ or NRZ type data.

      ok Damian I will use BER visualizer and BER Test Set to find the require Eye diagram and BER. I hope it will work.

      I am very thankful to you Damian, u always there to help any community member.

      Best Regards

      • #18589
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        Damian Marek
        Participant

        You are most welcome! The alternative is to perform some type of analog demodulation to revert back to an NRZ format.

    • #18590
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      Ibn Aziz
      Participant

      Yes Damian, i will have to bring it back to NRZ format. Actually Damian i tried absolute component in my work to clip off negative cycle which brings signal to its original form and helps to measure BER. But in this way the only anomaly i will have, is in amplitude of the signal.

      And Damian if u know any type of analog demodulation (for example ??) that helps to regenerate NRZ fromat signal also share.

      Best Regards

    • #18611
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      Ibn Aziz
      Participant

      Dear Damian as i am using Opti sys 7, so according to my knowledge there is no such component like BER Test Set is available in it but if any such component in opti sys 7 who has some functionality resembling BER Test Set plz share.

      I will be very thankful to you.

      Best Regards

      • #18636
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        Damian Marek
        Participant

        You should be able to change the Algorithm for the BER Analyzer from Gaussian to Measured mode.

    • #18671
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      Ibn Aziz
      Participant

      Damian Thanks alot for your reply.

      Damian i read your similar suggestion in many other forum topics in which u suggested the similar approach but u didn’t share how can we change BER anlyzer algorithm from Gaussian to measured mode ??

      i have gone through the many tutorials and help doc but couldn’t find any way…

      Kindly any one who knows the procedure or method to change BER analyzer algorithm from Gaussian to Measured mode for Opti sys 7 plzz share.

      I will be very thankful to you for your kind suggestions.

      Best Regards

      • #18936
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        Damian Marek
        Participant

        Right-click the component choose Component Properties. Change the Algorithm from Gaussian to Measured.

        Cheers!

    • #18954
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      Ibn Aziz
      Participant

      Thanks Alot Damian for your kind response !

      But there is no such option like “Measured” over there. I am sharing in below pic all options which i get after scrolling down. kindly tell me how can i use measured value in BER analyzer.

      Regards

      Attachments:
      • #18978
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        Damian Marek
        Participant

        Oh sorry about that. I forgot you are using OptiSystem 7. I am not sure what components were available in that version you might try the BER Test Set if it there.

    • #19298
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      Dear Aziz,

      The two eye diagrams because you are working in ( BI-PHASE ) modulation format. The analyzer takes the complete cycle not only the positive or negative part of signal. BUT, these two diagrams one for ( 1 and 0) which are represented by a monocycle and its reflection

      IF you work in ON-OFF keying modulation format you will get one eye diagram. as attached pic

      Attachments:
    • #19302
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      Find also these waveforms of BPM and OOK modulation formats. You can notice the change in the phase of monocycle signal in BPM according to the input binary data.

      Attachments:
    • #19336
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      Ibn Aziz
      Participant

      Thanks a lot Dear Jaffar for your kind response,

      1. I am working in Uni-phase modulation format and u can verify it from the signal graph attached above (I am also attaching it below).
      That’s the problem I don’t know why i am still getting two eye diagram ?

      2. I’m using NRZ pulse generator and always work in On Off keying format (I am attaching project file where u can verify it)

      Further, just for verification, Can u tell me how can I set On off keying in Opti sys 7 because there is no option about OOK modulation format in my setup.

      3. As I could not get any solution to this problem so I decided to transmit only “Gaussian pulses” in UWB over fiber transmission instead of “Gaussian mono cycle pulse”, Is this right or wrong decision ?

      4. I am searching different references where they have used Gaussian pulses in UWB over fiber transmission but could not find any good reference from reputable confreres/ journals like JLT, OFC etc.

      Have u notice any work/research paper/ journal which had used Gaussian pulses in UWBoF transmission ?? kindly share it.

      i am thankful to you for ur participation at post.
      Best Regards

    • #19355
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      Dear Aziz

      Unfortunately now I do not have optisystem to check your system. I am sure there is a small error somewhere. you can attach the photo of optisystem design so I can comment on it. I have four papers about UWB signal generation from monocycle to fifth-order derivative Gaussain pulses operated with OOK and BPM modulation formats and all implemented in Optisystem.

      It is incorrect to transmit Gaussian pulses for UWB communication. The UWB signal must be Gaussian monocycle or higher order derivative of Gaussian pulse for example Doublet or Triplet so that the power spectrum density will be comply with FCC mask..
      This link is my latest paper published in British journal regarding the optical generation of Gaussian monocycle and doublet pulses with OOK and BPM modulation.

      http://article.sapub.org/10.5923.j.optics.20150501.02.html

    • #19417
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      Ibn Aziz
      Participant

      Thanks a lot Jaffar for your kind participation,

      I am attaching picture of my setup and also the paper which I am simulating (the setup diagram is at page 4 of research paper), u can check them in below attachment.

      Kindly comment where I am getting wrong so that I beocome able to find BER and eye diagram, because still I have not found any solution to this problem.

      I have saved your paper but did not studied due to difference in working domain but now I will study them, to get an idea of how u have done calculation of BER and eye diagram in Opti sys for mono and duplet pulses.

      I don’t know why your upper shared link is not working, kindly email me your paper at engr.bilalaziz@gmail.com.

      Best Regards

    • #19422
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      Dear Mr.Aziz

      Here is my paper and I received your system. I will check it and respond as soon as possible.

    • #19444
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      Ibn Aziz
      Participant

      ok thanks alot Jaffar,

      i will wait for ur response.

      Best Regards

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