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Re: Tesla coil for wireless data transmission?
Original poster: "Gary Peterson" <g.peterson@xxxxxxxxxxxx>
Yes, I'm referring to "METHOD OF SIGNALING, U.S. Patent No. 723,188,
Mar. 17, 1903 and "SYSTEM OF SIGNALING, U.S. Patent No. 725,605, Apr. 14, 1903.
Regarding the definition of Spread Spectrum wireless
telecommunications, I think of this as a method in which the energy
of the transmitted electromagnetic wave is distributed up and down
within the EM spectrum, in either 1) the frequency domain or 2) the
time domain. A modern example of the first technique is Direct
Sequence-Code Division Multiple Access. While not identical to
DS-CDMA, Tesla's method of creating a wave complex through the
simultaneous operation of multiple resonators each tuned to a
different frequency also exists within this category.
The second technique is digital Frequency Hopping Spread Spectrum,
described as, "the continual switching of transmitted frequencies
based on a shared algorithm to minimize unauthorized interception or
jamming of a radio transmission." While development the technique is
often credited to Hedy Lamarr and George Antheil (SECRET
COMMUNICATIONS SYSTEM, U.S. Patent No. 2,292,387, Aug. 11, 1942), the
seed of this idea is present in the Tesla patents cited above.
Of course, the simple alternative to both of the above-described
techniques is single-frequency transmission.
Subject: Re: Tesla coil for wireless data transmission?
Original poster: Ed Phillips evp@xxxxxxxxxxx
Original poster: "Gary Peterson" g.peterson@xxxxxxxxxxxx
In response to my assertion that, "the World System was designed to
employ certain spread-spectrum principles, making available the
shorter wavelength regions of the electromagnetic spectrum." you
responded with, "Resonance and "spread spectrum" . . . are mutually
I wish to call your attention to Tesla's 1903 patents "System of
Signaling" and "Method of Signaling," patents that lay out the
basic principles of frequency-hopping and frequency-division
multiplexing in wireless spread spectrum telecommunications. In
order to provide greater security he used a wireless signal
produced on a multiple of frequencies -- the transmitter worked at
a number of separate wave lengths, like a pipe organ playing a
musical chord or, alternatively, a specific sequence of notes. On
the receiver side each one of the individual frequency components
had to be tuned in in order for the circuitry to respond.
These patents also describe the electronic AND-gate logic circuit,
a fundamental element of all present day digital computers. In
fact, on the basis of these patents the U.S. Patent Office has
asserted Tesla's priority for the invention of electronic logic
gates in general. See http://www.tfcbooks.com/articles/control.htm
for some additional words on this subject.
Are you talking about patents 723,188 and 725,605? Both are
relevant and both were granted in 1903. Guess the disparity
between us here is in the definition of spread spectrum as
contrasted to multiple-frequency modulation of one sort or another;
frequency-division multiplexing is a more accurate definition than
spread spectrum and certainly can use a bank of tuned circuits in
reception. The use of a number of different signally frequencies
and tuned receivers is certainly real enough and was practiced in
multiplexing telegraph signals by the early 1870's. That work gave
the invention of the telephone a boost but doesn't fall into the
"modern" [by that I mean the buzz words a lot of people use these
days] definition of SS. In the context of what I was thinking
spread spectrum means very wide instantaneous bandwidth of,
perhaps, 20% or more of the carrier frequency. Tuned resonators are
not useful in the reception of that kind of modulation, which
usually is carried out with a correlation receiver of some sort.