on 3/9/00 11:03 PM, Carl Clawson at cclawson@transport.com wrote:
>> The amps we are dealing with here are Class AB devices and as such are
>> "pseudo-linear." S-Parameters are not valid for anything other than Class
>> A. Just using your own words.
>>
>
> Hoist by my own petard, as it were!
:-) Wasn't trying to be mean (I think you know that). Just had to get you
back! :-)
>
> Actually AB amps, thought of as "black boxes" with two ports, are as
> reasonably linear as any other amplifier, at least at the design frequency.
> It's the internal currents that are nonlinear in the extreme.
True. But how would go about measuring S-parameters on a large signal
device? I suppose you could use a large signal Z-analyzer and then do a
transformation to S-parameters........
Back in my commercial days, we were able to use external directional
couplers on our network analyzers for high power measurements. I believe
though that we did not end up getting full 4-port data that way though. We
just got S11 and S21.
How does one measure S22 and S12 at 1500 Watts! :-)
Argh! It's late! :-)
73,
Jon
KE9NA
-------------------------------------
Jon Ogden
KE9NA
Member: ARRL, AMSAT, DXCC, NRA
http://www.qsl.net/ke9na
"A life lived in fear is a life half lived."
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