Keith Dysart wrote:
Now you have me quite confused. One moment you agree that
your claim is mere numerical eqivalency and the next you
seem to again be claiming that the energy in the reflected
wave is dissipated in the source resistor.
I have never used the words "mere numerical equivalency"
so I have never claimed any such thing. The energy in
the reflected wave is dissipated in the source resistor
but you are confused about the timing of that dissipation.
It doesn't happen when you are saying it happens. Some
magnitude of energy is stored and dissipated later in
the same cycle.
Your analysis so far has completely ignored
*one additional source of instantaneous energy*, namely
the reactive component in the network, i.e. the reactance
of the transmission line. When you account for the temporary
storing of the intra-cycle destructive interference energy
in the transmission line followed by its later release as
constructive interference, you will find that all of the
energy in the reflected wave is dissipated in the source
resistor.
During part of a cycle, energy is lost from the source
resistor into the transmission line. During the following
part of the same cycle, that same energy is recovered
from the transmission line back to the source resistor.
instantaneous power dissipated in the source resistor =
1. instantaneous forward power plus
2. instantaneous reflected power plus
3. instantaneous interference (can be plus or minus)
Your calculations so far have completely ignored that
third term which is a source (or sink) of energy depending
upon what part of the cycle exists.
--
73, Cecil
http://www.w5dxp.com