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Need a lumped lossy transmission line (L, R and G) that can be coupled (Lm)

NickW

Hi,

I'm looking for a PSpice transmission line part that includes resistance, inductance, conductance (between the conductors) and also mutual inductance between multiple transmission lines.

I can't use TLOSSY because its behavior is unstable under certain conditions that I need to simulate (e.g. 1 Meg Ohm resistor in series with one of the inputs simulating a break in the circuit). To my understanding, the distributed transmission line TLOSSY (and T) use an equation to relate the ports to each other (they are not actually electrically connected).

TLUMPx would be an ideal choice, except that the Kcouple2 won't couple TLUMPx's together (I think Kcouple2 works with the distributed transmission lines T and TLOSSY only).

 T2coupled, T3coupled, etc... look promising, but I can see only a single field for mutual inductance Lm, and I need different values of Lm for different combinations of pairs of lines. I also need to couple 6 lines to each other, whereas T5coupled (couples 5 lines) is the highest in the TLINE library.

I've been working on this for several days and need to come up with a solution soon. Any suggestions will be gratefully received!

Is there a PSpice part that will model L, R, G and Lm? Or will I have to create a new custom part?

Thank you,

Nick

Parents

  • Thank you for your reply.

    I've had a look in tline.lib - the comments for 'tncoupled' say the parameters (including Lm) must be the same for all of the lines in the set. Also, coupling is modelled across adjacent lines only, whereas I need coupling between all lines. A modification to achieve this may be possible, but I'm not familiar with the format of library files (something I'll address as soon as I can).

    Unless the lumped models (TLUMP128 etc) can be coupled (I don't think they can) TLOSSY (in analog.lib) appears to be the only part that models all the features I require. I'll re-visit TLOSSY (and Kcouple2) today, and see if I can verify that I get sensible results under the input conditions in my model.

    Thanks again for your help :)

    Nick

Reply

  • Thank you for your reply.

    I've had a look in tline.lib - the comments for 'tncoupled' say the parameters (including Lm) must be the same for all of the lines in the set. Also, coupling is modelled across adjacent lines only, whereas I need coupling between all lines. A modification to achieve this may be possible, but I'm not familiar with the format of library files (something I'll address as soon as I can).

    Unless the lumped models (TLUMP128 etc) can be coupled (I don't think they can) TLOSSY (in analog.lib) appears to be the only part that models all the features I require. I'll re-visit TLOSSY (and Kcouple2) today, and see if I can verify that I get sensible results under the input conditions in my model.

    Thanks again for your help :)

    Nick

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