on 5/26/01 4:20 AM, Steve Thompson at g8gsq@qsl.net wrote:
>> What do you mean "doesn't the source have to be a transmission line?"
>
> Nothing personal here, Jon, but I can't think of any other way to put it. In
> my mind, I can't see how you can have or measure forward and reflected power
> without a transmission line somewhere. Doesn't reflected power only happen
> when the termination on a transmission line doesn't equal Zo. I'm wide open
> to correction here.
S-Parameters can be used and applied to any n port device. If our box is a
transmitter, it will only have one port. Therefore, the only S parameter we
can measure is S11.
You don't have to have a transmission line although those usually are
involved in S parameter measurements. Any device can have S parameters
defined for it. They may not be the best or most appropriate, but since S
parameters are based on Z parameters and all the others, they are still
applicable.
You can model inductances and capacitances via transmission lines as well.
Again, I point to microwave applications where that's all that is used are
transmission line elements.
>>
>> A series C can indeed do what you say. However, a true series C does not
>> dissipate energy but stores it.
>
> Indeed. The point I intended to make was that there are situations and
> impedances where simple impedance calculations are intuitively more useful
> than s parameters, but it didn't come over as clearly as I intended.
I'd most definitely agree. I think we are saying the same thing but from
different angles or view points.
73,
Jon
NA9D
-------------------------------------
Jon Ogden
NA9D (ex: 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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