Original poster: "Gary Peterson" <g.peterson@xxxxxxxxxxxx> Ed,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.
Best regards, Gary
Subject: Re: Tesla coil for wireless data transmission? Original poster: Ed Phillips evp@xxxxxxxxxxxOriginal poster: "Gary Peterson" g.peterson@xxxxxxxxxxxx
Ed,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 incompatible."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.Most sincerely, Gary Peterson
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.Ed