On Mar 29, 10:55 pm, Cecil Moore wrote:
Keith Dysart wrote:
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.

I am only talking about steady-state so the conditions are
indeed identical, as I stated.

That does cause some difficulties since we are discussing ghosts,
clearly a transient phenomenom. Remember the question: What is
the magnitude of the first re-reflection to reach the load?

So the two experiments are clearly different.

No, technical theory says they have to be the same in the
steady-state condition. Saying they are different violates
the laws of physics.

Thank you for agreeing that they are different for the non-steady
state situation under discussion.

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.

That you find it "not applicable" is part of your problem.
You ignore reality in favor of your wet dreams. That's your
choice but please don't try to convince the rest of the
world to join you. The impedance seen by the reflections is
NOT the 450 ohm resistor. The impedance seen by the reflections
is the V/I ratio of the source.

But what a surprise, that is 450 Ohms. Try plotting it. Compute
the slope.

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.)

I have asked you before - please provide me a math model of the
source and I will be more than glad to do so. Hint: Handwaving
the existence of a source is not acceptable. Where's the beef?

Sure, why not? Just for fun let's do the Norton model for the
generator. A 2 Amp ideal current source in parallel with a
450 Ohm resistor. Recall that an ideal current source has an
infinite impedance and adjusts its voltage to whatever is necessary
to cause 2 Amps to flow. This is quite a simple model and
EXACTLY models the generator because it is the same as the
definition of the generator used in the experiment. It is
quite amenable to analysis.

Remember that the question to be answered is: What is the
magnitude of the first re-reflection to reach the load?

Use the methodology of your choice, but you can't make any
changes to the circuit since such changes might alter the
transient behaviour. Hints:
- steady state analysis is unlikely to work since the
question is about the transient behaviour.
- for a methodology that works try googling lattice diagrams.
These are specifically applicable to the transient behaviour
of a system.

And to get any marks at all, show your work along with the answer.

Good luck.

....Keith