View Single Post
  #94   Report Post  
Old June 9th 05, 07:29 PM
Jim Kelley
 
Posts: n/a
Default



Cecil Moore wrote:

Jim Kelley wrote:

Cecil Moore wrote:

Of course, my statement is related to steady-state. I don't
see anything worth responding to, Jim. Where's the beef?



The problem is that there should only be a 1 second lapse of time
between the beginning of gozinta at 100 Joules/sec and the beginning
of comezouta at 100 Joules/sec. At what point is the additional 2
seconds worth of energy fed into the system?



During the power-on transient phase. The load rejects half the incident
power. To keep things simple, assume a very smart fast tuner. After
one second, the feedline will contain 100 joules. The load will have
accepted zero joules. After two seconds, the feedline will contain the
100 joules generated plus 50 joules rejected by the load and the load
will have accepted 50 joules. Already the feedline contains 150 joules
while the source is putting out 100 joules per second. After 'n'
seconds, the line contains 300 joules, 100 from the source and 200
rejected by the load during the power-on transient stage.

seconds forward energy reflected energy load power
1 100 0 0
2 100 50 50
3 150 50 50
4 150 75 75
5 175 75 75
6 175 87.5 87.5
7 187.5 87.5 87.5
8 187.5 93.75 93.75
9 193.75 93.75 93.75
10 193.75 96.875 96.875
n 200 100 100

After 10 seconds the source has output 1000 joules. The load
has accepted 709.375 joules. 290.625 joules are already stored
in the feedline on the way to 300 joules during steady-state.
This is simple classical reflection model stuff.


If a load in rejecting half its incident power, the steady-
state reflected power will equal the steady-state load
power. The steady-state forward power will be double
either one of those.


It really is an interesting theory. And I'm willing to concede on a
certain point here. If we were to fit a curve to the data in your far
right side column, what we have is a dispersion curve. That is a
predictable phenomenon, most easily observable on long transmission
lines. However as this is not actual data, an important column is
missing. A column marked 'energy from source' is crucial to proving
your point. Without running the experiment and taking the data we can't
really know how much energy would be in any of the columns at any given
time. When we assume what that energy might be, we run the risk of
making an ass out of u and me. Well, mostly u. :-)

73, AC6XG