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eye diagram problem

ManuelSuarez

Hi everybody,

I am suffering problems with the eye diagram in cadence.  By an unknown reason, it does not update the results.

I explain the case:

I simulate a relatively complex circuit with different outputs but, let me say i am interested in the output Out0 to simplify. When i generate the eye diagram the first time it is ok but, when i run a new simulation after modify some parameter the eye diagram is the same even when i can see clearly that the waveforms are different. Seems that for different simulations of the Out0, the eye diagram tool keeps linked to the values of the first simulation.

I have to restart cadence brake this link and get the correct eye diagram.

I use virtuoso IC6.1.6-64b.500.13.2

Some explanation for this interesting behavior?

Thanks in advance,

M

Parents

  • Not really enough information - how are you running the simulation? Is the eye diagram added as an output in ADE L/XL (if so which) or are  you generating it once and then updating it somehow? If so how?

    I think a more detailed description of how you get from A to B is needed here to understand the problem.

    Regards,

    Andrew.

  • in reply to Andrew Beckett

    Thanks for the quick answer.

    I use the analog design environment to design the digital circuits I need. I run the transient analysis of the ADE using spectre APS.  Later I plot the results through the virtuoso visualization and analysis XL. Ones the results are plotted I select the squared waveform I need. In the upper menu of the window of the Virtuoso visualization and analysis XL: Measurements>EyeDiagram.

    A window pops up and I fill the values. For the first simulation is fine.

    I always follow the same procedure:

    1-Simulation>plot signals>select signal>eye diagram(as mentioned)

    2-Circuit modification

    3-Again simulation>plot signals>select signal>eye diagram

    4-...

    Furthermore, i run a parametric simulation (two values) following the previous procedure and I get the eye diagram with as many eyes as parametric steps, that is fine. After i run a single non parametric simulation and the eye diagram corresponds to the parametric simulation.

    The problem persist when I close and reopen the ADE. I have to open and close cadence.

    I hope the information is sufficient now.

    Regards,

    M

Reply
  • in reply to Andrew Beckett

    Thanks for the quick answer.

    I use the analog design environment to design the digital circuits I need. I run the transient analysis of the ADE using spectre APS.  Later I plot the results through the virtuoso visualization and analysis XL. Ones the results are plotted I select the squared waveform I need. In the upper menu of the window of the Virtuoso visualization and analysis XL: Measurements>EyeDiagram.

    A window pops up and I fill the values. For the first simulation is fine.

    I always follow the same procedure:

    1-Simulation>plot signals>select signal>eye diagram(as mentioned)

    2-Circuit modification

    3-Again simulation>plot signals>select signal>eye diagram

    4-...

    Furthermore, i run a parametric simulation (two values) following the previous procedure and I get the eye diagram with as many eyes as parametric steps, that is fine. After i run a single non parametric simulation and the eye diagram corresponds to the parametric simulation.

    The problem persist when I close and reopen the ADE. I have to open and close cadence.

    I hope the information is sufficient now.

    Regards,

    M

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