On Thu, 30 Jun 2005 00:22:48 GMT, james wrote:

In electrical engineering it is the instantaneous power density of two
signals passing at the same spot from two directions. That is called
Convolution.

Hi James,

No, it is called Superposition, and that is done only with voltage or
current. What you are describing may be associated with the Fourier
convolution of power series - an entirely different field (and not
even additive).

73's
Richard Clark, KB7QHC

On Wed, 29 Jun 2005 17:31:36 -0700, Richard Clark
wrote:

On Thu, 30 Jun 2005 00:22:48 GMT, james wrote:

In electrical engineering it is the instantaneous power density of two
signals passing at the same spot from two directions. That is called
Convolution.

Hi James,

No, it is called Superposition, and that is done only with voltage or
current. What you are describing may be associated with the Fourier
convolution of power series - an entirely different field (and not
even additive).

73's
Richard Clark, KB7QHC
*****

Okay maybe I am not expressing my self correctly and right now I don't
realy have the time or patience to look back through my old text
books. It has been several years since I have done a lot of RF work
and some things are not as fresh in my mind. It does seem like the
less you use the more you forget or have trouble explaining what you
think.

Most of my work lately has been away from RF.

james

On Thu, 30 Jun 2005 01:02:06 GMT, james wrote:



Most of my work lately has been away from RF.

Uh huh. And do you drive a Kenworth or a Volvo?

Richard Clark wrote:
On Thu, 30 Jun 2005 00:22:48 GMT, james wrote:


In electrical engineering it is the instantaneous power density of two
signals passing at the same spot from two directions. That is called
Convolution.


Hi James,

No, it is called Superposition, and that is done only with voltage or
current. What you are describing may be associated with the Fourier
convolution of power series - an entirely different field (and not
even additive).

73's
Richard Clark, KB7QHC

Convolution is a mathematical stunt you can perform with
two functions: f(x)* g(x) = (integral from 0 to x) f(t)g(x-t) dt.
At least that's how it's explained in Schaum's Outline book
_Differential Equations_. It's pretty tough to see how it relates
to power in a transmission line. Maybe someone has a use for it
there.
73,
Tom Donaly, KA6RUH

On Thu, 30 Jun 2005 01:30:39 GMT, "Tom Donaly"
wrote:


Convolution is a mathematical stunt you can perform with
two functions: f(x)* g(x) = (integral from 0 to x) f(t)g(x-t) dt.
At least that's how it's explained in Schaum's Outline book
_Differential Equations_. It's pretty tough to see how it relates
to power in a transmission line. Maybe someone has a use for it
there.
73,
Tom Donaly, KA6RUH
****

Yes Tom

Convultion was the wrong term to use. I made a mistake because i type
as i think and on occasion hit send before i reread what i have
written.

I still contend that a sinusoidal wave travelling down a coax is
comprised of perpendicular(orthogonal) E and H fields. The these
vector fields that induce sinusodial current and voltage potential
vectors in and between the shield and center conductors as the wave
travels. Both the source and reflected waves are comprised of two
vector fields, E and H. Granted this is true only when the load
reflection coefficient is not zero. In that case of zero, then there
is no reflected power.

It is possible to derive from the vector current and vector voltage a
magnitude of those vectors and thus a produce two scalar quantities
that can be pluged into Ohm's Law and derive an instantaineous power
at a given time and position on the coax. That both source and
reflected sinusoidal current and voltage can have derived scalar
values. These values can be directly added.

This all started from an SWR question. I contend that the
instantaineous power at any given time and position of the coax can be
expressed as the sum of the magnitudes or scalar quantities of the
source and reflected powers. If you are wanting just the magnitudes of
the power, then this should work.

james