Arpad- I would define a "Port" as being defined by two "Terminals or nodes". One of the nodes would be a 'signal' node and the other would be a 'reference' node. As I mentioned when I brought up this topic several days ago, some n-port models (n >= 2) contain but a single reference for all ports, while some conform to the tradional definition of an n-port and provide a reference for each port. If your model has a reference for each port then you will have 2*n terminals for an n-port. If your model only allows a single reference for all ports then you will have n+1 terminals or nodes. And yes you are correct, depending on how your n-port model handles the refererence node issue, the way the n-port model may be used may be restricted for certain purposes. As Marek Schmidt-Szalowski pointed out this morning, by utilizing a"perfect" transformer (perhaps an Hspice E elment) you may convert a 3 terminal 2-port to a 4 terminal 2-port. -Ray Anderson > >I would like someone to give us a definition of "port". > >The reason I am asking for this is because I think there >is an important detail that makes things confusing in these >responses. Is a port just one node, *assuming* a universal, >global reference (as in SPICE node 0)? Or does a port >consist of two nodes, neither one of which is GND (node 0) >between which the measurements are done with respect to >each other? The first one could also be called single=20 >ended, and the second one differential. There may be far >reaching implications depending on how we define "port". > >Arpad ------------------------------------------------------------------ To unsubscribe from si-list: si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field or to administer your membership from a web page, go to: //www.freelists.org/webpage/si-list For help: si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field List archives are viewable at: //www.freelists.org/archives/si-list or at our remote archives: http://groups.yahoo.com/group/si-list/messages Old (prior to June 6, 2001) list archives are viewable at: http://www.qsl.net/wb6tpu