## [eispice] Re: py2port

• From: Charles Eidsness <charles@xxxxxxxxxxxxxxxxxxxxx>
• To: eispice@xxxxxxxxxxxxx
• Date: Tue, 11 Mar 2008 13:53:17 -0400

```Thanks Matt, it's something I've wanted to write for a couple years now, ever
since I read Howard Johnson's "High Speed Signal Propagation" and finally found
some time.

That line connects a W element to the end of the two-port chain. The W element
is a lossy transmission line model. The arguments are (kind of similar to the
SPICE W-Element model):

length -- length of T-Line (inches)
L -- inductance per meter (H/m)
C -- capacitance per meter (C/m)
R0 -- series resistance per meter (Ohm/m) -- default = 0
G0 -- parallel conductance per meter (S/m) -- default = 0
Rs -- skin effect resistance (Ohm/(m*sqrt(Hz)) -- default = 0
Gd -- dielectric loss conductance (S/(m*Hz) -- default = 0

You can use a tool like mmtl (http://mmtl.sourceforge.net/) to calculate the
arguments for arbitrary t-line geometries.

There is also a simple non-lossy t-line model that's easier to use called "T"
with these arguments:

length -- length of T-Line (inches)
Zc -- characteristic impedance (Ohms)
er -- permitivity (unitless) -- default = 4.3

For some more examples you can try:

import py2port

help(pytport.twoport)
help(pytport.W)
help(pytport.T)

Cheers,
Charles

Matt Ettus wrote:
> Charles Eidsness wrote:
>> Hi All,
>>
>> This isn't eispice news but I just released a new tool called py2port. It
>> can be
>> used to perform two-port and one-port linear circuit analysis. I thought the
>> members on the eispice list might be interested. You can find it here:
>>
>> http://www.thedigitalmachine.net/py2port.html
>>
>> If you have any comments, questions, or concerns please let me know.
>>
>
> Charles,
>
> Very cool work.  I like the PRBS part especially.  Can you tell me what
> this line is:
>
> |cct += py2port.W(10, 6.35011e-7, 5.10343e-11, 0.0, 0.0, 0.0, 0.0)
>
> It looks like it adds a component, but I don't know what a W is.
>
> Matt
>
> |
>
>
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