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 how to simulate delay of a wire? 

Last post Thu, Sep 26 2013 4:54 AM by rickyuexu. 6 replies.
Started by rickyuexu 26 Sep 2013 03:03 AM. Topic has 6 replies and 421 views
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  • Thu, Sep 26 2013 3:03 AM

    • rickyuexu
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    • Joined on Sun, Jan 8 2012
    • Posts 15
    • Points 195
    how to simulate delay of a wire? Reply

    Hi all,

    We know it takes time for electrical signals to travel from one end of a wire to the other. The wavefrom seen at one end of a wire should be different from the waveform seen at the other end. How can I simulate them? At first, I though I could place two pins at the two ends. Apparently, it didn't work. Do you know any ways I can achieve that?

    Thank you very much! 

    • Post Points: 20
  • Thu, Sep 26 2013 3:35 AM

    • Marc Heise
    • Top 100 Contributor
    • Joined on Mon, May 4 2009
    • Feldkirchen, Bavaria
    • Posts 77
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    Re: how to simulate delay of a wire? Reply

     Hi,

     you need to look into transmission line simulations.  Spectre has two elements for that, mtline and tline   (spectre -h mtline/tline).

    You can find a mtline element in the analogLib.

    It's not trivial to setup.

    For some basic testing you could create a RC-ladder network as well.

     

    Regards,

    Marc

    • Post Points: 20
  • Thu, Sep 26 2013 3:53 AM

    Re: how to simulate delay of a wire? Reply

    Or if you're creating an extracted view with QRC, you could use the out-of-context probing capability to probe the net close to two different device pins on the corresponding schematic, and it will probe the signal at the corresponding locations on the RC-extracted layout.

    Regards,

    Andrew.

    • Post Points: 5
  • Thu, Sep 26 2013 4:09 AM

    • rickyuexu
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    • Joined on Sun, Jan 8 2012
    • Posts 15
    • Points 195
    Re: how to simulate delay of a wire? Reply

    Thank you, Marc and Andrew.

    Marc, with a little googling, I think the method you mentioned applies to schematic-level simulation. Is that right? I am actully trying to simulate a layout extracted view.  

    Andrew, I am simulating an extracted view (Calibre). Is it any way I can do that with Calibre, instead of QRC? Thanks.

    • Post Points: 5
  • Thu, Sep 26 2013 4:39 AM

    • rickyuexu
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    • Posts 15
    • Points 195
    Re: how to simulate delay of a wire? Reply
    OK. Now I see it doesn't matter whether I use Calibre or QRC. The thing I really need to know is "out-of-context probing", right?
    • Post Points: 20
  • Thu, Sep 26 2013 4:50 AM

    Re: how to simulate delay of a wire? Reply

    Out of context probing is only supported for Cadence extraction tools (i.e. QRC). However, if you can probe the net in the extracted view, you probably can probe the two appropriate points that you want to visualize. This is probably doable in any vendor's extracted views.

    Regards,

    Andrew.

    • Post Points: 20
  • Thu, Sep 26 2013 4:54 AM

    • rickyuexu
    • Not Ranked
    • Joined on Sun, Jan 8 2012
    • Posts 15
    • Points 195
    Re: how to simulate delay of a wire? Reply
    Thank you. I understand now.
    • Post Points: 5
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Started by rickyuexu at 26 Sep 2013 03:03 AM. Topic has 6 replies.