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 nport Issue 

Last post Tue, Mar 25 2008 10:37 AM by archive. 3 replies.
Started by archive 25 Mar 2008 10:37 AM. Topic has 3 replies and 1819 views
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  • Tue, Mar 25 2008 10:37 AM

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    nport Issue Reply

    I am simulating n4port element in spectre. My s-parameter file is in spectre format. I am using linear Interpolation. For my setup, I have a AC source connected to port 1+ as my input. I am doing AC frequency analysis and observing output at other 3 ports. I do not get any output on ports 2, 3 and 4. I see the entire signal on port 1-. Can you tell what my problem could be?

    Let me know if you need anymore information.

    Chintan Shah
    chshah@ncsu.edu


    Originally posted in cdnusers.org by shahch31
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  • Wed, Mar 26 2008 3:00 PM

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    RE: nport Issue Reply

    This is almost certainly because you've not terminated the nport with sensible impedances. The s-parameters were probably measured assuming 50-ohm (or something similar) ports - you can see this by looking in the s-parameter file.

    If you connect an ac vsource directly to an nport pin, it's going to do all sorts of horrid and unrealistic things.

    I just tried doing it, and I got similar results to what you describe, so I'm assuming you've just connected the circuit up inappropriately.

    Regards,

    Andrew.


    Originally posted in cdnusers.org by adbeckett
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  • Wed, Mar 26 2008 3:33 PM

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    RE: nport Issue Reply

    I figured out what my problem was. I needed to ground the negative terminal and on the positive terminal connect a pdc source on all 4 ports which would allow me to run a s-parameter simulation. I was not successful with running transient but I am assuming you won't be able to run transient for a nport element. Thank you for looking into this problem.

    Thanks,
    Chintan


    Originally posted in cdnusers.org by shahch31
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  • Wed, Mar 26 2008 3:52 PM

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    RE: nport Issue Reply

    I also got the transient simulation working. I forgot to include the model file. I connected a 50 Ohm resistor at the input and all the outputs. Thanks again for your help.

    Thanks,
    Chintan


    Originally posted in cdnusers.org by shahch31
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Started by archive at 25 Mar 2008 10:37 AM. Topic has 3 replies.