On Jun 21, 9:04*am, Cecil Moore wrote:
On Jun 20, 8:03*pm, Keith Dysart wrote:

1. Please explain how inserting the circulator did not change
* *the circuit conditions. The generator went from delivering
* *0W to delivering 50W.

The generator went from experiencing total destructive interference to
experiencing zero interference. Of course, the entire purpose of
inserting the circulator is to cause the generator to see 50 ohms as a
load impedance.

Along with the other use for circulators: To present an impedance
match to the reflected wave so that it will not be re-reflected.

2. Where do you think the 50W being dissipated in the circulator
* *termination resistor is coming from? The line? Or the
* *generator (which is now outputting 50W)?

TV ghosting experiments will verify that the signal being dissipated
in the circulator load resistor has made a round trip from the
generator to the end of the N(1/2WL) stub and back to the circulator.

It is not clear why you think this verifies something.

Enhancing the details slightly of the generator in the original
example: The generator is constructed using the Thevenin model
of a source followed by a 50ohm resistor.

With the circulator, there is no re-reflection at the driven
end of the line, 50W is dissipated in the circulator
resistor and 50W is dissipated in the source resistor.

Without the circulator, there is no re-reflection and nothing is
dissipated in the source resistor (and there is no circulator
resistor).

The dissipation seems to correlate much more strongly with the
circuit design than it does with the magnitude of the "reflected
power".

Please don't insult our intelligence by arguing that is not a steady-
state condition.

Well you are right, it is not steady-state when there is modulation,
but modulation does not affect the examples I have provided.

....Keith

PS: For further understanding, substitute a Norton style generator,
then do it again for both kinds of generators but with the end
of the line shorted yielding more examples where the "reflected
power" does not correlate with the dissipation.