Amps
[Top] [All Lists]

[AMPS] Conjugate Matching and Efficiency

To: <amps@contesting.com>
Subject: [AMPS] Conjugate Matching and Efficiency
From: na9d@speakeasy.net (Jon Ogden)
Date: Sat, 26 May 2001 08:34:40 -0500
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."


--
FAQ on WWW:               http://www.contesting.com/FAQ/amps
Submissions:              amps@contesting.com
Administrative requests:  amps-REQUEST@contesting.com
Problems:                 owner-amps@contesting.com


<Prev in Thread] Current Thread [Next in Thread>