On Mar 29, 6:41 pm, Cecil Moore wrote:
Keith Dysart wrote:
Have you computed the correct result then?

Yes, the results are identical with or without
the 1WL of 75 ohm lossless line, exactly as the
theory predicts it should be.

This is clearly not correct. Without the 75 Ohm line the first
reflection does not arrive back at the generator for 62 cycles.
With the 75 Ohm line, the first reflection arrives back at the
generator after only two cycles. The response is not at all
the same, though I agree, they do arrive at the same steady
state condition.

The discontinuity between the 450 Ohm line and the 75 Ohm line
produces a re-reflection back towards the load, which is one of
the two sources of ghosts in your experiment, the other being
the 75 Ohm line connection to the 450 Ohm generator. Remember
that any impedance discontinuity produces a reflection. Without
the 75 Ohm line, there are no reflections back towards the load
and no ghosts (i.e. for the original experiment).

So the two experiments are clearly different. For the experiment
without the 75 Ohm line (i.e. the original example), can you
derive the magnitude of the re-reflected voltage that reaches
the load and creates a ghost?

If so, please let us know the magnitude and how to derive it.

Have you read w2du's web page yet?

Yes, but it is discussing, as its title clearly states, "Additional
Experimental Evidence Proving Existence of Conjugate Match and
Non-Dissipative Source Resistance In RF Power Amplifiers".
I find it not applicable to the experiment at hand since we
are neither discussing a reasonable implementation of an
RF Power Amplifier nor is there a conjugate match.

Regardless, the real question is can you compute the magnitude
of the re-reflection when it reaches the load and what is the
methodology? (And please do not modify the experiment to do so.)

....Keith