The Rest of the Story
 

On Mar 25, 10:28 am, Cecil Moore wrote:
Keith Dysart wrote:
Read it as Pr.correction(t) to emphasize that it is not
average power of which I am writing. Then it is not
interference.

That statement makes it obvious that you don't understand
interference. When instantaneous values are being used,
if [V1(t)^2 + V2(t)^2] NOT= [V1(t) + V2(t)]^2, then
interference is present. Did you miss Physics 201?

Let us build a slightly better example that complies with
your "NOT =" expression above.

+-----------------------------------+
| |
Vs1(t) = 141.4cos(wt) \
| = 100 Vrms Rload /
| 50 ohms \
Vs2(t) = 70.7cos(wt) /
| = 50 Vrms |
+-----------------------------------+

Using superposition the contribution from source 1 is
Vload.s1 = 100 Vrms
Iload.s1 = 2 Arms
and from source 2 is
Vload.s2 = 50 Vrms
Iload.s2 = 1 Arms
combining
Vload = 150 Vrms
Iload = 3 Arms

From
Pload = Vload * Iload
= 150 * 3
= 450 Waverage

As can be seen, this example satisfies your requirement
for interference:
[V1(t)^2 + V2(t)^2] NOT= [V1(t) + V2(t)]^2

Computing the imputed powers for the waves from each source
we have
Pload.s1 = 100 * 2
= 200 Waverage
Pload.s2 = 50 * 1
= 50 Waverage
To obtain the power in the load from these imputed powers
we need to use
Pload = Pload.s1 + Pload.s2 + Pload.correction
450 = 200 + 50 + Pload.correction
200 = Pload.correction

From previous analysis
Pcorrection = 2 * sqrt(P1 * P2)cos(theta)
(the cos(theta) term is appropriate here because these
are average powers being used)
Pcorrection = 2 * sqrt(10000) * 1
= 200
as required from above.

So according to your energy analsysis, the power in
the load comes from
the wave from source 1 = 200 W
the wave from source 2 = 50 W
"interference energy" = 200 W
for a total of
450 W as required.

Now if the 200 W from the wave from source 1 and the
50 W from the wave from source 2 represent actual
energy flows, then the "interference energy" must
also be an actual energy flow to satisfy conservation
of energy.

What element provides the energy for this "interference
energy" flow? Note that in this analysis, this energy
is an average energy flow, so it can not be saved during
part of the cycle and returned during another part.

In other posts, you have suggested that this would be
a constructive interference energy and that there would
be an equal destructive interference energy to provide
it. If you still claim this, where is this destructive
interference happening?

....Keith

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Gene Fuller wrote:
In any case, you answered my question. "Wave reflection model" means
nothing beyond ordinary electromagnetic theory. Big deal.

It is a big deal when someone asserts that there is
no energy in a reflected EM wave or that the energy
in a reflected EM wave doesn't have to be conserved
or that a reflected wave doesn't obey the rules
of the wave reflection model.
--
73, Cecil http://www.w5dxp.com

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"Jim, K7JEB" wrote in message
...
....This
source was used in optical processors for synthetic-aperture
imagery back in the 50's....

That should have read "synthetic-aperture radar imagery"...
Just trying to not let my mind outrun my typing speed.
K7JEB

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Cecil Moore wrote:
Gene Fuller wrote:
I did a little bit of the cheap modern day replacement for research by
Googling "wave reflection model". Some 455 references came back.

That's strange. When I did the identical thing, 1,970,000
references came back. Wonder what is wrong with your computer?

I used the quote marks around the words and got 266 references.
Few of them, other than yours, relate to electronics at all, much less
radio.

Dave K8MN

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Keith Dysart wrote:
You should consider that perhaps your inability to
identify the element and its energy function really
calls into question your concept of "interference
energy" being stored and returned later.

I have previously multiple times identified the element
as the network reactance and pointed you to a reference.

If you were asking me to teach you the English
language on r.r.a.a, you would get the same response.

I suppose, if you want to rename superposition as interference.
But none of my basic circuit theory books use the word
interference when discussing superposition.

I'm not renaming superposition. I'm using the
definition of "interference" provided by Hecht
in "Optics". Superposition can occur with or
without interference. The present discussion is
about superposition with interference present.
Interference is just a word which identifies
the special case of superposition that is
under discussion.

If the powers imputed to the constituent voltages of
superposition did represent actual energy flows, then
you would be able to simply add them to get the total
flow, since energy can not be created or destroyed.

There you go again, confusing power and energy.
There is *NO* conservation of power principle.
Until you give up on superposing powers, you
are doomed to failure. There is absolutely nothing
wrong with storing energy and turning it into
power later in time. Do you think that backup
storage batteries are a violation of the
conservation of energy principle?

The fact that a correction needs to be applied when
adding them is proof that they can not be actual energy
flows.

There is *NO CORRECTION TO THE ENERGY COMPONENTS*. There
is only a correction to the power components to account
for the time the energy is being stored before it is
dissipated. You really need to learn the difference
between energy and power.

You should take this as a reason to
call into question the whole idea that this "interference
energy" is an actual energy flow.

Your argument is not with me - it is with experts
like Eugene Hecht. Please read his *57 page* Chapter
9 on "Interference" and then get back to us. With 57
pages devoted to the subject, Hecht doesn't seem to
share your problems with it.

If *your* "wave reflection model" includes the idea that
Pref always represents an actual energy flow, then *your*
"wave reflection model" is wrong.

When you can prove that reflected traveling waves contain
zero energy, i.e. that ExH=0, I will accept your assertion
but not before. Exactly how does a TDR detect zero energy?

In fact, the thing you need to do is forget the transmission
line and deal with light waves encountering boundaries with
different indexes of refraction. The problem is identical,
but dealing with light out in the open prohibits you from
pushing your mashed-potatoes energy religion.
--
73, Cecil http://www.w5dxp.com

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Keith Dysart wrote:
What element provides the energy for this "interference
energy" flow? Note that in this analysis, this energy
is an average energy flow, so it can not be saved during
part of the cycle and returned during another part.

Already answered a few postings ago. Sorry you
missed it. Here it is again:

Here are the basic principles:

When destructive interference occurs, there is "extra"
energy left over from that isolated event. That energy
must go somewhere. Here are the possibilities in a
typical lossless RF transmitting system.

1. The source can throttle back on its energy output
to compensate for the destructive interference energy.

2. Reactive components can store the destructive
interference energy and return it to the network at
a later time.

3. In the absence of (1) and (2) above, an RF energy
wave is launched in a direction that allows the
"extra" energy to leave the destructive event area.

When constructive interference occurs, there is "missing"
energy needed to be supplied into that isolated event. That
energy must come from somewhere. Here are the possibilities
in a typical lossless RF transmitting system.

1. The source can simply supply the energy needed by
the constructive interference event.

2. Reactive components can return stored energy to
the network.

3. In the absence of (1) and (2) above, constructive
interference energy *must* be supplied in real time
by destructive interference between two other waves.
--
73, Cecil http://www.w5dxp.com

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Keith Dysart wrote:
Now if the 200 W from the wave from source 1 and the
50 W from the wave from source 2 represent actual
energy flows, then the "interference energy" must
also be an actual energy flow to satisfy conservation
of energy.

One other observation: Although the interference model
will work for a lumped circuit example, there is no
reason to use it as it complicates the computations
and adds nothing to the solution. The wave reflection
model also works for circuits but there is simply no
good reason to use it for lumped circuit analysis.

Where interference becomes a useful tool is when it
happens away from any compensating source. An analysis
of the interference of two EM light waves in free space
far removed from any source leaves us with two constant
sources of energy, the total energy of which has to go
somewhere. The following two web pages tell us exactly
where the energy goes.

http://www.mellesgriot.com/products/optics/oc_2_1.htm

http://micro.magnet.fsu.edu/primer/j...ons/index.html

Your theory seems to require that the EM waves must
know beforehand whether to carry energy or not from
a star light years away. You apparently have invented
a rather curious "smart wave theory".

The question is: How did those two interfering waves
from Alpha Centauri know whether to arrive at the
planet Earth ten years later carrying ExH energy
or not carrying ExH energy?
--
73, Cecil http://www.w5dxp.com

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Keith Dysart wrote:
Let us build a slightly better example that complies with
your "NOT =" expression above.

Your constant voltage sources are NOT a better example
and not even a good example. To confront the subject
being discussed, you should use constant power sources.

The reason is obvious. A constant steady-state EM
wave is a constant average power source, not a constant
voltage source. Constant voltage source examples
just won't do.

Try your example with constant power sources and
see what happens.
--
73, Cecil http://www.w5dxp.com

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On Mar 26, 11:43*am, Cecil Moore wrote:
Keith Dysart wrote:
You should consider that perhaps your inability to
identify the element and its energy function really
calls into question your concept of "interference
energy" being stored and returned later.

I have previously multiple times identified the element
as the network reactance and pointed you to a reference.

Indeed you have, but you have not answered the second clause
in the question. Until you can provide the energy flow
function of the element you claim is storing the energy
there is no reason to believe that it is the element.

Can it be that hard to provide the function?
Or perhaps the element you have identified does not have
the appropriate energy flow function? (It doesn't.)

I suppose, if you want to rename superposition as interference.
But none of my basic circuit theory books use the word
interference when discussing superposition.

I'm not renaming superposition. I'm using the
definition of "interference" provided by Hecht
in "Optics". Superposition can occur with or
without interference. The present discussion is
about superposition with interference present.
Interference is just a word which identifies
the special case of superposition that is
under discussion.

Sure. OK.

If the powers imputed to the constituent voltages of
superposition did represent actual energy flows, then
you would be able to simply add them to get the total
flow, since energy can not be created or destroyed.

There you go again, confusing power and energy.
There is *NO* conservation of power principle.

Conservation of energy arises from the inability
to create or destroy energy. Energy can only flow from
one element to another.

This requires that the sum of the flows out of the
elements providing energy equals the sum of the flows
into the elements receiving the energy. Choose
whatever name you want for it, but this is the
reason that
Ps(t) must equal Prs(t) + Pg(t)

And it is just as powerful a concept as conservation
of energy since it follows directly from that principle.

The fact that a correction needs to be applied when
adding them is proof that they can not be actual energy
flows.

There is *NO CORRECTION TO THE ENERGY COMPONENTS*. There
is only a correction to the power components to account
for the time the energy is being stored before it is
dissipated. You really need to learn the difference
between energy and power.

And we are still waiting for the energy flow function
for the element that you claim is doing the storing
of the energy.

You should take this as a reason to
call into question the whole idea that this "interference
energy" is an actual energy flow.

Your argument is not with me - it is with experts
like Eugene Hecht. Please read his *57 page* Chapter
9 on "Interference" and then get back to us. With 57
pages devoted to the subject, Hecht doesn't seem to
share your problems with it.

Actually, we are debating *your* interpretation.

If *your* "wave reflection model" includes the idea that
Pref always represents an actual energy flow, then *your*
"wave reflection model" is wrong.

When you can prove that reflected traveling waves contain
zero energy, i.e. that ExH=0, I will accept your assertion
but not before.

You see. There you go again. Refusing to set aside an
assumption, even temporarily. It does make it difficult
to explore alternate explanations if you stop before you
start.

Exactly how does a TDR detect zero energy?

Does it detect energy? Are you sure?
Or is it voltage that it detects? Or current?

In fact, the thing you need to do is forget the transmission
line and deal with light waves encountering boundaries with
different indexes of refraction. The problem is identical,
but dealing with light out in the open prohibits you from
pushing your mashed-potatoes energy religion.

No. Light, in a 3 dimensional space and at such high frequency
makes the math and measurements so complicated that it is
extremely difficult to follow the energy. Much better to learn
from a one-dimensional transmission line and then see if the
solutions also apply to light. Which they do. But the analysis
is tractable in a transmission line.

...Keith

The Rest of the Story
 

On Mar 26, 11:49*am, Cecil Moore wrote:
Keith Dysart wrote:
What element provides the energy for this "interference
energy" flow? Note that in this analysis, this energy
is an average energy flow, so it can not be saved during
part of the cycle and returned during another part.

Already answered a few postings ago. Sorry you
missed it. Here it is again:

Since there was no destructive interference in the example,
the rest of your post is snipped as being a non-sequitor.

...Keith