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  3. Automatically switch between "sparameter" view and "rfm...

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Automatically switch between "sparameter" view and "rfm" view

amitG22
amitG22 2 months ago

Hello Community, 

When I generate sparameter files through EMX, EMX generates the sparameter views that is basically a touchstone file. There is in essence no separate schematic with a nport component. This works well except when you want to run transient simulation. Then, spectre tries to generate bbspice models for all these sparameter views. Now, I don't want spectre to generate its own models (why not is not relevant for my question). I want to generate my own RFM models and want spectre to use them during transient simulation without creating a separate schematic with a nport component and pointing to a rfm file. This is tedious and doesn't scale well when you are working on a big project. 


My question is : Is it possible to do this with spectre in an elegant manner instead of all the tedious manual work? 

A snapshot of the view generated by EMX : 


If it indeed turns out that its possible to "hack" the normal WoW and force spectre to use my own RFM models then the following information may be handy : In the linux directory structure, I have a folder that is exactly the same as the name of the sparameter view. Within it, next to the sparam.snp file I have placed my sparam.rfm file. 

Thanks in advance for all your tips/tricks and suggestions. 

Regards,
Amit

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  • JankoK
    JankoK 5 days ago

    Hi Amit,

    You probably figured it out by now, but just in case...

    Answer: Yes, it is possible. You can literally just point to your RFMs from nports. In case you need to create your RFMs, we got you covered there too... that's the fitting part of our S-parameter Quality Checking and Fitting Tool. 

    SPECTRE® S-Parameter Quality Checking and Fitting Tool

    From IC23.1 ISR11, you have in the GUI too. It super easy to use:

    How to use 'S-Parameter Quality Checking and Fitting Tool' and 'Comparison Tool' of SPECTRE in Virtuoso CIW

    Have fun!

    /Janko

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  • amitG22
    amitG22 4 days ago in reply to JankoK

    Hi JankoK,

    Thanks for your response. 

    As I already mentioned in my post, creating separate views with nports and then pointing it to the RFM files may work on a simple test-bench but doesnt work so well in a real transceiver design with multiple passive cells, where each cell has to be extracted over 5 BE corners and at least 3 temperatures. And then imagine creating 15 such cell views with nports pointing to RFM files and 15 cell views with just the EMX spar views. It is a nightmare and just doesn't work. 

    Regarding the RFM file generation, as far as I understood, the quality checking tool doesn't output a rfm file that we can directly use. 

    Regards,
    Amit

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  • JankoK
    JankoK 4 days ago in reply to amitG22

    Hi Amit,

    For the first problem... I think that's what MDIF format is for. The tool supports it. You should be able to run the fitting and get your RFMs over corners. To be honest, I haven't tested that functionality myself, but you can find the workflow described here:

    Generate and Simulate MDIF Files with EMX and Virtuoso ADE Corners

    The quality of your RFMs will depend on the quality of your S-parameters and fitting. There are also a few fitting options to play with. Anyway, you should be able to use them with Spectre, that's the whole idea, to make life easier for you and the simulator. Please ping your local support for more detailed investigation or file an official case on our support (ASK) page. 

    BR

    /Janko

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  • amitG22
    amitG22 4 days ago in reply to JankoK

    Hello Janko,

    No I have never used MDIF myself. But that's a good suggestion. We will need to evaluate it and we can then use it in our future projects. It can help with maintaining all these different views more efficiently. Thanks for this tip.

    Regards,
    Amit

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