0
\$\begingroup\$

Can someone please explain what's the difference between a symmetric vs unsymmetric transmission line model ?

The normal un-symmetric one has R and L in series with G, C in parallel. While the symmetric model has the R and L divided in two halves and distributed on the two sides of the parallel G and C. Unsymmetric

Symmetric

Is there any advantage what so ever of representing the same thing two different ways? We can get to the telegrapher's equations either way, so what's the point? Is it that the transmission line model should represent the line as being same from either point?

\$\endgroup\$
0
\$\begingroup\$

The difference is in relation to ground / common signal. For example asymmetrical TL is realized by coaxial cable where the shield is grounded. Symmetrical TL can be realized by "twisted pair" or "open twin lead" where neither signal path is directly grounded / has same relation to ground.

\$\endgroup\$
  • \$\begingroup\$ Thank you for replying. Can you please elaborate a little bit ? How does distributing the elements change the relation to the ground? I've added pictures of the models to make things clear. \$\endgroup\$ – Hasnain Abdur Rehman Sep 20 '18 at 18:48
0
\$\begingroup\$

One is only meaningful when driven from one end, the other can be driven from both ends with the same effect (talking about voltage sources, but not necessarily only them). In terms of derivation, sure, one is redundant; in terms of simulation, it's a different thing.

\$\endgroup\$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.