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Using S parameter files in schematics

Question asked by rrobbi on Sep 1, 2004
This provides a good overview of how to use S parameter files in a schematic and includes an example file to look through.  For more detailed information you can look at the help files in Genesys.  The Genesys HELP section contains all of the documentation manuals, and is searchable.  Just go to Main Menu, Help, Contents, Search tab.  A good search for this topic is "device data".  The fifth topic down will be "creating new linear data files".  This will tell you all about the files themselves.

Using data files in Genesys is easy.  There are two main approaches:

1)  From the Linear Components menu, you can choose a 1,2,3...N port model and place it on your schematic.  Then double click on it and specify which file you would like it to use.  You can do this by typing the path to the file in the "filename" box or clicking the "browse" button and finding the file. [See note a]

You can use any of the linear components that have the same number of ports as your file.  They all reference the data in the same way, some just look different.  For example,  you could use one of the transistor components, "Bipolar (S-Parameters npn)", or one of the box components, "Two Port (2)", and get the same results.
(although transistors have 3 connection nodes, they are most often implemented as two port datafiles because they are measured in 2-port configuration.)

2)  Another option you have, which you can use with most any component in Genesys, is to click on the simulation tab in the component's properties window.  From there you  can select "Use __ Port" and point it to the file.  This allows you to switch back and forth between your file and the software model quickly.  For example, you could use "Bipolar  (BIPNPN)" from the linear components menu and enter the required parameters as well as pointing it to your file and, from the simulation tab, switch back and forth between using  the parameters and using the file.

Some associated notes:
a)  If your file is on a floppy disk or CD you should move it onto your hard drive.  If you leave it on a disk, the repeated delay associated with PC disk access / spinup time can be annoying.

b)  You should make sure that the s parameter file is in a plain text format and not a "Word" or other special format.  File formats that aren't plain text often contain other hidden characters (such as formatting characters) and this can cause problems reading the datafile.  Windows notepad is a good text editor to use for datafiles. (start, programs, accessories, notepad...)