HOW RFTOOL CONFIGURES ITS NETWORKS ??

Hi,

I am trying to set up an RF Filter comprising of R,L,C Components. However, in "Rftool" "RF Components pane" it is NO CLEARLY defined what is meant by a "series" or a "parallel newtork" .A network has TWO -PORTS , so, how do you add a "series network" ?? And what about adding a "parallel network" ?? How can we get a clear picture what they mean ??

Furthermore, when you go to add components inside each network ,are these meant connected in successive order as you enter them ?

I am really confused with Rftool !In the Help menu they write various generalities but no specific circuit example ! Any one has worked out any application with it ??

Is there a way to VIRTUALLY visualize the set-up circuit as is e.g with Powerlib ?? Any one has aworked out example to send me ??

Many thanks in advance ,

                                                  El