Hi,

In reply to your first posting, I must have been half asleep
when I suggested AppCAD as a solution to your problem because
large signal impedances and s-parameters are like 'chalk and
cheese'. There isn't (as far as I know) a simple way to translate
one into the other because of the intrinsic non-linearity of DUT
parameters with respect to operating point and drive level. On
the web you should find papers dealing with this problem but the
parameters generated by the methods employed are not just a
simple mapping from S to Z.


Cheers - Joe

Joe McElvenney wrote:
Hi,

In reply to your first posting, I must have been half asleep
when I suggested AppCAD as a solution to your problem because
large signal impedances and s-parameters are like 'chalk and
cheese'. There isn't (as far as I know) a simple way to translate
one into the other because of the intrinsic non-linearity of DUT
parameters with respect to operating point and drive level. On
the web you should find papers dealing with this problem but the
parameters generated by the methods employed are not just a
simple mapping from S to Z.


This is true. Especially if you are dealing with
highly non-linear, saturated PAs and such.

Ok, but let's say i wanna design a linear, class A PA, and
i need to know Zin and Zout, so i know what to
conjugately match too. I should be able to do this
with ADS using a *.s2p file, but i haven't figured
out how to do this yet! There should be a freeware
program out there...

S.

On 24 Jan 2005 19:38:20 -0800, wrote:

Ok, but let's say i wanna design a linear, class A PA, and
i need to know Zin and Zout, so i know what to
conjugately match too. I should be able to do this
with ADS using a *.s2p file, but i haven't figured
out how to do this yet! There should be a freeware
program out there...

Checkout RFSim99. That should do what you want. Type it into Google to
find it.
--

"What is now proved was once only imagin'd." - William Blake, 1793.

Paul Burridge wrote:

On 24 Jan 2005 19:38:20 -0800, wrote:


Ok, but let's say i wanna design a linear, class A PA, and
i need to know Zin and Zout, so i know what to
conjugately match too. I should be able to do this
with ADS using a *.s2p file, but i haven't figured
out how to do this yet! There should be a freeware
program out there...


Checkout RFSim99. That should do what you want. Type it into Google to
find it.
You can try Puff

http://www.its.caltech.edu/%7Emmic/p...uffE/puffE.htm

Its a brilliant DOS based S-parameter analysis program

How ever if you are Windows savvy perhaps Serenade v8.5 from Ansoft

Regards Andrew

Who's interested in academic S-parameters at HF and with G5RV's ?