Subject: Re Frequency, what's that? (fwd)
Date: Thu, 4 Dec 1997 092218 -0600 (CST)
From: "Roy L. Beavers" <rbeavers@mail.llion.org>
To: emfguru@hotmail.com
--------------------------------------------------
Hi everybody:
I very much appreciate Clas discussion below (in response to one
of my statements).
Also, not being mentioned again -- but very relevant -- is the role
of _transients and harmonics_ in the "real world"; but they are not being
factored into much of our research!!!
Let us be careful not to interpret "mother nature" in terms of OUR
delineations of reality.... Sometimes limited by what we can do or cannot
do in the laboratory!!!..... We must put forth more effort to examine
this EMF phenomenon in terms of "mother nature's reality." In truth, OUR
perceptions of how nature works are still confined by a vast universe of
ignorance..... If we try to interpret the EMF/biology paradigm merely
by what we _already know_ about biology or physics, we may too narrowly
restrict the possible answers.
[In connection with the last comment, I will soon be forwarding a news
item which reports on some recent biological research that suggests we may
be in error, for example, when we 'assume' (as many have done in EMF
sessions I have attended) that the locus of damaging activity by the EMF
upon the cell MUST be WITHIN the cell rather then upon its surface......
Recent biological research is finding that the _immune system_ can be
affected by proteins on the cell membrane called "chemokines"..... This
is of some significance because some (mostly the physics community) have
contended that the EMF being experienced in the "real world" is too weak
to penetrate the cell membrane, therefore it is too weak to do any harm....
See:
Clas has a good message below, don't miss it........
Cheerio......
Roy Beavers (EMFguru)
rbeavers@llion.org..............http://www.feb.se/EMF-L/EMF-L.html
................................It is better to light a single candle ...
than to curse the darkness...............................................
---------- Forwarded message ----------
Date: Thu, 04 Dec 1997 14:00:37 +0100
From: Clas Tegenfeldt
To: "Roy L. Beavers"
Subject: Re: Frequency, what's that?
At 19:50 1997-12-03 -0600, Beavers wrote:
>Are we not becoming guilty of assigning characteristics to those bands
>which "mother nature" knows nothing about and could not care less???
The concept of frequency is an artificial parameter, in the real world
signals have a time-varying shape and thus a range of (time-varying)
frequencies. You cannot from a combination of frequencies alone reshape
the signal, you need more information than that (phase and amplitude).
Let me tell you that a perfect method to get really confused in the real
world of EMFs is to measure power density at a point of a field
or frequency distribution (harmonic contents or spectral analysis).
Many have tried, many have failed, to make any sense of it (sense in the
meaning of understanding cause and effect of biological interactions with
EMFs).
Since we see so many reports about various biological effects using
signals of all kinds and frequencies we maybe have to rethink our
simplified use of a single frequency as a measure of a signal?
Some seem still to think this is all about amplitude or power, but that
is just not so, there are too many contradicting reports to justify
that thesis. It is quite safe to say that we know there are non-thermal
effects, so this isn't about cooking is it?
Some seem obsessed with the concept of frequency and talk about low or
high frequency, but what "frequency" does a GSM signal have? You just
can't say it is 900 MHz or 217 Hz, so what is it? Of course it is a mess
of various frequencies, and to make matters worse the frequency contents
may vary with time (as it does for AM signals). What about experiments where
the effects of a 60 Hz sine wave magnetic field does not give as much
response as a 60 Hz sine wave magnetic field switched on and off regularly?
Say this switching occurs at 0.1 Hz, does that mean I would get the same
response by a 0.1 Hz sine wave magnetic field? Most probably /not/!
Fields are like an ocean, think about the task:
"I want you to make a measurement of the atlantic ocean!"
What parameters do you deem important to measure? Temperature?
If so where? Everywhere? Mean temperature or minimum/maximum?
Temperature over time? Or is it wave height? Wave length? Number of
waves per second? Direction of wave travel or wave front? Is it the
small superimposed high frequency waves or the large slow ones?
Tide water variations? Water depth? What about wind speed that
creates the waves? What about crossing waves?
I would like to mention that the ocean is a surface but EMFs travel
in three dimensional space and in addition you have both a
electric and magnetic vector component at each points in space, those
vectors have a length and direction that varies in time.
Just a tiny little bit more complex isn't it?
We could set up a contest in thinking up as many ways as possible to
describe subsets of parameters, but the contest would never ever end...
Back to frequency, OK spectrum analysers are good tools, but so are
oscilloskopes, voltmeters, circle saws and my favorite hammer!
Fourier analysis is a good show, but there are a reason that
wavelets have become popular and important tools in just a few
years. Fourier analysis has been around since 18:th century and
wavelets just for roughly ten years, it is seldom a mathematical tool
goes from theory to practice that fast. The reason is that the
frequency distribution (fourier) does not contain time information
and that is a big problem in many cases for real signals which
vary in time. Wavelets are local in both time and frequency and
offers new methods to look at signals. For those who haven't
used wavelets yet, take a look. (a warning though, the mathematics
is gruesome).
There is nothing wrong using frequency, but don't expect /the/ answer
to lie there.
Clas Tegenfeldt ,,,
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Archive provided courtesy of WaveGuide, http://www.wave-guide.org
Reprinted with permission of Roy Beavers, http://www.feb.se/EMF-L/EMF-L.html