Walter Maxwell wrote:
Cecil, when a mismatched line is matched at the input with a tuner the
reflection coefficient at the matching point in the tuner is 1.0 when the tuner
is matched, thus the re-reflected voltage wave must be equal to that of the
reflected wave. My statements are all based in these conditions.
That is NOT true of an S-parameter analysis, Walt, which is essentially
what Dr. Best is using in his article. In a system with reflections the
S-parameter reflection coefficients are NEVER equal to 1.0. How can I make
you understand that you and Dr. Best are using entirely different systems
of analysis and yours has no bearing on his.
Here's your arguments:
Steve: "It's a plant."
Walt: "No, it's a tree."
Steve: "No, no, it's a plant."
Walt: "No, no, it's a tree."
In the following matched system, the reflection coefficient in Dr. Best's
system of analysis is ALWAYS |0.5| and is NEVER 1.0. This is also true for
an S-parameter analysis. The only difference between Dr. Best's analysis
and an S-parameter analysis is that he didn't normalize his voltages to
SQRT(Z0). I presented that fact a couple of postings ago.
100W XMTR---50 ohm line---x---1/2WL 150 ohm line---50 ohm load.
Nowhere at no time is Dr. Best's reflection coefficient equal to anything
except |0.5|. It is an absolute constant whether the XMTR is off, in the
transient state, or in the steady-state. Please read this paragraph over
and over until it soaks in. In Dr. Best's system of analysis, the only
time that the reflection coefficient is 1.0 is in a system with a short,
open, or pure reactance. In his system of analysis, a reflection coefficient
of 1.0 NEVER occurs at a matched or mismatched impedance discontinuity if
the impedances are not zero or infinite (or purely reactive).
Unfortunately, my S-parameter texts are behind in Florida, and I've forgotten
the significance of the 'a' and 'b' terms.
The HP AN 95-1 ap note is available at:
http://www.sss-mag.com/pdf/hpan95-1.pdf
The S-parameter reflection coefficients are constant and do NOT change as the
reflected power changes. They are the same with no signal applied, or during
the transient state, or during the steady-state. The S-parameter reflection
coefficient is *NEVER* 1.0 when there exists an impedance discontinuity.
You and Dr. Best are NOT USING THE SAME REFLECTION COEFFICIENTS!!!!
You and Dr. Best are NOT USING THE SAME SYSTEM OF ANALYSIS!!!!
Nothing you say about your system of analysis is relevant to the
system of analysis that Dr. Best used.
--
73, Cecil
http://www.qsl.net/w5dxp
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