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  3. SnP Files extracted from PSP simulation

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SnP Files extracted from PSP simulation

HuyDo
HuyDo over 3 years ago

Hi Cadence Forum,

I had an extracted sNp file after finishing psp simulation.
Howerver, after putting that file in an nport component, and running the sp simulation for checking.  
The S-parameters' response were different than those of the original psp simulation result.

Can anyone suggest why this discrepancy might be coming. I am using IC617 and Spectre 16.1 versions.
Thank you
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  • Andrew Beckett
    Andrew Beckett over 3 years ago

    Which interpolation method are you using for the nport component? The only way I can imagine this happening is that if you've explicitly chosen bbspice and your data has insufficient points or insufficient range, the fit that is done by the bbspice algorithm in the old version of spectre may be a poor fit (and there would have been messages in the Spectre log file to say this; that may not show up if you run spectre again though unless you add the "-cc" switch to the userCmdLineOptions field in the Setup->Environment form to force it to remove the cached data). 

    In newer Spectre versions (certainly from 20.1 onwards) the automatic methods for determining the interpolation method would have chosen linear for use when running s-parameter analysis (and you could always pick that in Spectre 16.1) which I would expect to have good match, since sp is a frequency-domain analysis and can directly use the s-parameter data without requiring a fit.

    Andrew

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  • Binhngo1210
    Binhngo1210 over 3 years ago in reply to Andrew Beckett

    Hi Andrew, sorry for squeezing into an old post. i have the same problem with touchstone file in PSP simulation. The nport/psp setting are as follows respectively but it seems a different response to what i got by psp simulation. could y recommend a solution for it? 

      

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  • Binhngo1210
    Binhngo1210 over 3 years ago in reply to Andrew Beckett

    Hi Andrew, sorry for squeezing into an old post. i have the same problem with touchstone file in PSP simulation. The nport/psp setting are as follows respectively but it seems a different response to what i got by psp simulation. could y recommend a solution for it? 

      

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  • Andrew Beckett
    Andrew Beckett over 3 years ago in reply to Binhngo1210
    Binhngo1210 said:
    Hi Andrew, sorry for squeezing into an old post. i have the same problem with touchstone file in PSP simulation. The nport/psp setting are as follows respectively but it seems a different response to what i got by psp simulation. could y recommend a solution for it?

    There's really not enough information for me to be able to make any suggestions here - I've no idea what version you're using, how big the difference you're seeing is, and so on. This is the kind of thing that seeing the actual data would really help, so please contact customer support.

    Regards,

    Andrew

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