+ Post New Thread
Results 1 to 13 of 13
  1. #1
    Newbie level 4
    Points: 1,398, Level: 8

    Join Date
    Apr 2005
    Posts
    5
    Helped
    0 / 0
    Points
    1,398
    Level
    8

    what is the eye pattern in digital communication ?

    Dear Sir,
    I wanted to know what is the eye pattern in digital communication and how it is useful for our receiver quality measurements.
    Thanks
    Pardeep

  2. #2
    Member level 4
    Points: 2,239, Level: 10

    Join Date
    Mar 2005
    Posts
    72
    Helped
    11 / 11
    Points
    2,239
    Level
    10

    eye pattern oscilloscope

    in digital communications, we have either a pulse of one or a pulse of zero.
    if you superimpose these two pulses on each other for several times, you will get a pattern like an eye (take into consideration that a pluse is not a sharp rect and has a rise and fall time).
    if you have noise on your pulses, it is called that the sye closes.
    this noise can either change the pulse amplitude which results in the closure of the eye as you push the upper sides of the sye.
    if you have a noise that changes the timing of the pulses, you will have a jitter that will close your eye form left and right side.
    i will attach a photo describing this concept later.
    I do not have it now with me.


    3 members found this post helpful.

    •   Alt26th May 2005, 16:34

      advertising

        
       

  3. #3
    Member level 4
    Points: 1,675, Level: 9

    Join Date
    Dec 2004
    Posts
    71
    Helped
    3 / 3
    Points
    1,675
    Level
    9

    eye diagram digital communication

    In short, eye diagrams are used to check for ISI i.e intersymbol interference in a digital communication system. ISI can be removed by a process that is referred to as equalization.



  4. #4
    Member level 4
    Points: 2,239, Level: 10

    Join Date
    Mar 2005
    Posts
    72
    Helped
    11 / 11
    Points
    2,239
    Level
    10

    how to generate eye patern?

    hi!
    this is a photo on eye diagram.
    rgs


    4 members found this post helpful.

  5. #5
    Full Member level 3
    Points: 2,037, Level: 10

    Join Date
    Dec 2004
    Posts
    188
    Helped
    3 / 3
    Points
    2,037
    Level
    10

    plot eye pattern

    Eye diagram is the data transtion of the digital signal for testing whether the device is pass the protocal or not.
    It is for testing the falling time/rising time/hold time.... of the device.



    •   Alt3rd June 2005, 01:58

      advertising

        
       

  6. #6
    Member level 2
    Points: 1,592, Level: 9

    Join Date
    Mar 2005
    Posts
    42
    Helped
    1 / 1
    Points
    1,592
    Level
    9

    eye pattern in digital communication

    Yeh eye diagram tell you that how much ISI will be present at the receiver side....You just have to see in your eye diagram that at ur sampling point how much is the eye opening.If the eye opening is wider then means less or no ISI or otherwise...



    •   Alt28th June 2005, 16:45

      advertising

        
       

  7. #7
    Advanced Member level 2
    Points: 4,439, Level: 15

    Join Date
    Oct 2004
    Posts
    521
    Helped
    29 / 29
    Points
    4,439
    Level
    15

    eye diagram+digital communication

    Who you can generate it with HSPICE?



  8. #8
    Full Member level 3
    Points: 2,614, Level: 11

    Join Date
    Oct 2004
    Posts
    169
    Helped
    27 / 27
    Points
    2,614
    Level
    11

    isi eye pattern

    An oscilloscope display in which a pseudorandom digital data signal from a receiver is repetitively sampled and applied to the vertical input, while the data rate is used to trigger the horizontal sweep.
    Note: System performance information can be derived by analyzing the display. An open eye pattern corresponds to minimal signal distortion. Distortion of the signal waveform due to intersymbol interference and noise appears as closure of the eye pattern.



  9. #9
    Banned
    Points: 4,334, Level: 15

    Join Date
    Jan 2007
    Posts
    208
    Helped
    26 / 26
    Points
    4,334
    Level
    15

    how to plot eye pattern of a modulation scheme

    can any body tell how to calcultae the eye mask values.



  10. #10
    Newbie level 2
    Points: 1,030, Level: 7

    Join Date
    Mar 2007
    Posts
    2
    Helped
    0 / 0
    Points
    1,030
    Level
    7

    eye pattern matlab

    Hi,

    i have noticed one thing while ploting eye pattern in matlab that eye pattern varies for same modulation scheme and same sample to symbol ratio.
    how is it so when same specs are used for particular modulation scheme.

    regards



  11. #11
    Full Member level 1
    Points: 1,926, Level: 10
    Robinenemy's Avatar
    Join Date
    Jul 2006
    Posts
    110
    Helped
    27 / 27
    Points
    1,926
    Level
    10

    eye pattern diagram

    Horizontal opening of the eye signifies the timing jitters
    and vertical opening of the eye determines the diffrence between the logic High and logic low in case of the Digital Communication System.


    1 members found this post helpful.

  12. #12
    Junior Member level 1
    Points: 1,313, Level: 8

    Join Date
    Apr 2006
    Posts
    15
    Helped
    2 / 2
    Points
    1,313
    Level
    8

    how to create eye pattern

    hi pardeep

    you can use hspice to generate

    * Eye Diagrams
    * This type of diagram is to reduce a large amount of data to
    * one frame. Data from a fixed period is superimposed upon
    * itself.
    *
    * An e source is setup to create a sawtooth.
    * The sawtooth period is the window to be plotted, eyewidth. i.e. if
    * you are looking at a periodic signal and want to know if the
    * period or amplitude drifts over a large time, then the
    * eyewidth is set to the period of the data to be plotted and
    * superimposed.
    *
    * In this example, Y is a damped sin wave at 1 Mhz. X is a 5 Mhz
    * sin wave. The eyewidth is set to 2 Mhz. (Look at the difference
    * between 2Mhz and 1Mhz as an experiment).
    *
    * To view output in Meta-Waves, place signal T on the x axis and plot either
    * X or Y on the y axis. For the damped sin wave, notice that the
    * frequency is constant but that the amplitude obviously decays.
    * This is a view of all periods super-imposed on each other.
    *
    * Plot X, Y vs Time,
    * X, or Y vs T
    *
    * Only 4 lines are needed to add eye diagrams to a circuit:
    * Here they are:
    * .Param EyeWidth = 2.0x $ Bandwidth
    * eT T 0 Vol='(TIME*EyeWidth)-int((TIME*EyeWidth))'
    * rT T 0 1k
    * .Option Post

    .Param EyeWidth = 1.0x $ Bandwidth

    * a clever alternative here is to set .Param Eyewidth = '1/<clock_period>'

    vX X 0 Sin ( 0v 3v 1xHz )
    vY Y 0 Sin ( 0v 1v 1xHz 0s 500k )

    * Simple time manipulation to create a sawtooth pattern
    eT T 0 Vol='(TIME*EyeWidth)-int((TIME*EyeWidth))'

    rX X 0 1k
    rY Y 0 1k
    rT T 0 1k



    .Tran 10ns 10us
    .Option Post=2
    .End
    ************************************************** *****


    1 members found this post helpful.

  13. #13
    Newbie level 4
    Points: 406, Level: 4

    Join Date
    Oct 2010
    Posts
    5
    Helped
    0 / 0
    Points
    406
    Level
    4

    Re: how to create eye pattern

    How do you measure the init point



+ Post New Thread
Please login