Circuit Models
Creating a Circuit Model
In order to allow the
modeling of more complex passive components, e.g. filter elements such
as ferrite beads, you can create, edit and simulate circuit models.
These circuits models
may consist out of 31 individual elements (R, L, C, connections and transmission
lines), which may be composed by using a grid-based editor.
On New
Model  , set the Kind to "Equival.-Cir."
and Type to "Circuit",
please choose a name for your new circuit model (the name has to end with
"_cir").
On "OK", the
new model is added to the list of models. In order to fill this new circuit
model with some content, you may now Open
the selected model description.
Editing Circuit Models
On opening a selected
circuit model, a grid based editor allows you to create a circuit model,
containing up to 31 elements and up to 14 external
nodes. The dialog title shows the model name and the related project
tree (Site or Project).
You may place one of
R, L, C, TL, or a direct connection at any of the edges within the grid,
by pressing the RMB. By choosing "None" you may delete a previously
set element. Initially, default values
are set for the introduced elements. These are:
R = 1 Ohm,
L = 1 nH,
C = 1 pF,
TL: Z=50 Ohm and TD = 666.66 ps delay.
The transmission line
(TL) parameter are equivalent to a 100mm long track segment, as used in
the Scenario Editor as well.
In
order to connect the model with the outside world, e.g. within the Scenario
Editor, you have to define External nodes.
By clicking on the named nodes at the outer boundary of the grid, you
can toggle their status from internal
to external. This can also be
done by a RMB click. It is not possible to make any unnamed node from
the inner area of the grid to be an "External" node, which can
be connected from the outside.
The name of the external
nodes can easily be edited just by clicking on the name (initially a number
1,2,..., 20), e.g. to "GND", or "Input". In the same
way you can edit the values and names of the individual elements. For
further reference, you may also add comments in the Comment field on the
bottom of the dialog.
Please note, that the
names of the individual elements and nodes have to be unique. The names
of the elements have to start with "R", "L", "C",
or "TL", respectively and must not exceed 64 characters in total.
 
Limitations
Due to the nature of
the grid based model editor and the model usage within the circuit model
editor, a few limitations apply.
Two
or more External nodes must not be connected, directly. Only
named nodes can become an external node. All
elements have to be connected with other elements, or to an external node. Allowed
value ranges of the individual elements:
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