US 802429 A
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Description (OCR text may contain errors)
No. 802,429. PATENTED OCT. 24, 1905. J. S. STONE.
APPLICATION FILED JUNE 24, 1905.
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No. 802,429. PATENTED 00124, 1905. J. S. STONE.
APPLICATION FILED JUNE 24, 1905.
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6 015V MID/1X) WIN p mam/vi W No. 802,429. PATENTED 0m. 24, 1905. J.S.STONE.
APPLICATION FILED JUNE 24,1905.
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No. 802,429. PATENTED 09124, 1905 J. S. STONE.
APPLICATION FILED JUNE 24,1905.
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NTTED STATES PATENT OFFTOE.
JOHN STONE STONE, OF CAMBRIDGE, MASSACHUSETTS, ASSIGNOR TO WILLIAM W. SWAN, TRUSTEE, OF BOSTON, MASSACHUSETTS.
Specification of Letters Patent.
Patented Oct. 24, 1905.
Original application filed May 10, 1906, Serial No. 259,841. Divided and this application filed June 24, 1905. Serial No. 266,858.
To (all whom it may concern:
Be it known that I, JOHN STONE STONE, a citizen of the United States, and a resident of Cambridge, in the county of Middlesex and State of Massachusetts, have invented a certain new and useful Improvement in Space Telcgraphy, of which the following is a specification.
My invention relates to the art of transmitting intelligence from one station to another by means of electromagnetic waves without the use of wires to guide the waves to their destination; and it relates more particularly tomethods of such transmission in which the electromagnetic waves are developed by producing electric vibrations or oscillations in an elevated conductor, preferably vertically elevated.
The general object of the present invention is to realize a multiplex system of space telegraphy in which the transmitting stations may selectively transmit their signals each to a particular receiving station simultaneously or otherwise without mutual interference; and it comprises improvements in electrical apparatus and circuit arrangements whereby methods of electrical selection and distribution may be carried into effect. By means of such apparatus and circuit arrangements electromagnetic waves of different definite frequencies or rates of vibration, free or unguided except by the surface of the earth, may be simultaneously or individually developed and the energy of said waves selectively absorbed and utilized.
The fundamental underlying principles of the present invention have been fully set forth in my Letters Patent Nos. 714,756, 737,170 and 767,994, to which reference may be had for a more detailed description of the broad principles involved, as well as for the general construction of the apparatus employed, than is necessary to set forth herein.
For selectively transmitting and receiving the energy of electromagnetic signal waves of different definite frequencies simultaneously or individually, I associate with the transmitting and receiving elevated conductors closed persistently-oscillating circuits, each attuned to a different one of said frequencies, in the manner more fully described in my aforesaid Letters Patent No. 714,756, and illustrated in Figs. l3, l4, l5, l6 and 17 thereof, and in Letters Patent No. 737,170 and illustrated in Figs. 1, 2, 3 and 4 thereof. These closed persistently-oscillating circuits when used for developing persistent trains of simple harmonic electromagnetic signal waves are termed sonorous circuits, and when they are used for selectively absorbing the energy of the oscillations resulting from the impingement of such waves upon an elevated receiving conductor they are termed resonant circuits. As pointed out in my Letters Patent Nos. 714,756 and 767,975, in order that the oscillations developed in an elevated transmitting conductor may be of great amplitude, the frequency of the impressed force may be made to correspond to the fundamental or to the odd harmonies of the elevated transmitting conductor system and, in order that abrupt or impulsive electric forces impinging upon an elevated receiving conductor may not cause a response of the associated resonant receiving circuit, the elevated receiving conductor system may be given natural rates of vibration which are different from that to which said associated resonant receiving circuit is attuned by any of the means disclosed in my Letters Patent No. 767,994, or in my application serial number 194,649, filed Feb. 23, 1904, which means, in general, comprise circuits containing capacity and inductance associated with the receiving conductor and which for thefrequency of a persistent train of waves the energy of which is to be received have a reactance equal but opposite in sign to the reactance of the elevated conductor per 86.
The,.particularobject of the present invention consists in increasing the efliciency of multiplex systems of the general type illustrated in my Letters Patent above referred to. In other Words, whereas heretofore with this organization of circuits 1 have used an aperiodic elevated conductor, I find that it is of advantage to employ an elevated conductor system which is selectively responsive to impressed forces of the several frequencies employed in the multiplex transmission.
The invention may best be understood by having reference to the drawings which accompany and form a part of this specification and which diagrammatically illustrate organizations of apparatus and circuits whereby the hereinbefore stated objects may be realized in practice.
In the drawings,
Figs. 1 and 3 represent in diagram multiplex space telegraph transmitting systems.
Figs. 2 and 4 represent in diagram multiplex space telegraph receiving systems.
Figs. 5 and 6 are curves hereinafter referred to in the explanation of the theory of operation of the systems shown in Figs. 1, 2, 3 and 4.
In the figures,
V is an elevated conductor.
E is an earth connection.
G C 01 C2 C" 1 are condensers.
L1 L2 L1 L are inductance coils.
M M M1 M1 M2 M2 M" M aretransformers which may be step-up transformers or step-down transformers as desired, though in general in the transmitting system the transformers M1 M1 are step-up transformers, and in the receiving system the transformers M2 M2 are either step-up or stepdown transformers.
11 L &c. are transformer primaries.
I2 12 &c. are transformer secondaries.
K K are electro-receptive devices herein shown as bolometer fine wires or strips.
T T are electric translating or signal-indicating devices which may be telephone receivers.
B B are batteries.
A A are alternating current generators or other suitable sources of vibratory current.
Z," are keys.
8 s are spark gaps.
The circuits 5 C L, s C 11 are sonorous or persistently oscillating circuits at the transmitting station adapted to develop in the elevated transmitting conductor system forced simple harmonic electrical oscillations of different definite frequencies, and the circuits K 0 I2, K O I2, K CH L1, K 01 L1, are resonantor persistently oscillating circuits at the receiving station adapted to selectively respond to oscillations of said definite frequencies. Each of the aforesaid sonorous or resonant circuits is made the equivalent of a circuit having a single degree of freedom by any of the methods described in my prior patents. In the particular embodiments of the present invention which are illustrated in Figs. 1, 2, 3 and 4, the particular method employed for rendering each sonorous or reso' nant circuit the equivalent of a circuit having a single degree of freedom consists in so associating such circuits With the respective elevated conductors by means of a trans former of large magneticleakage that the mutual energy of each circuit with respect to the other circuits of the system is made small compared with the self energy of said circuit in the manner described in my prior patents, although it is to be understood that any of the other methods previously described by me for effecting such loose inductive coupling of the closed and open oscillators may be employed,
for example that of swamping the efi ect of the mutual inductance between such closed and open oscillators by means of an auxiliary loading coil.
In that embodiment of my invention shown in Fig. 2, the circuits C M? Mg and G" Mi M3 are resonant weeding out circuits such as described in my aforesaid prior patents and each is attuned to the frequency to which its associated resonant receiving circuit is made resonant.
In Figs. 1 and 2 the circuits L1 ()1 and L2 C2 are parallel branch circuits such as described in my Letters Patent No. 767,99I, each of which, as shown, contains a condenser in one branch and an inductance coil in the other branch, although I am notlimited to this particular form of parallel branch circuit, but may employ one having a plurality of condensers and coils in each branch as set forth more fully in said patent. As more particularly pointed out in Letters Patent No. 767,994l, the reactance of the loop circuits L1 C1 and L2 02 as measured at their points of connection with the elevated conductor system will vary with the frequency of the oscillations developed in such system, being for certain frequencies the reactance of an equivalent condenser and for other frequencies the reactance of an equivalent coil.
Reference may now be had to Fig. 5, which consists of curves drawn to rectangular coordinates, in which the ordinates represent reactance and the abscissae represent frequency. The curves (1) (2) and (3) respectively, represent the variation with frequency of the reactances of the elevated conductor per se, the loop circuit 01 L1 and the loop circuit C2 L. For a more comprehensive interpretation of this figure and of Fig. 6 than need be given in this specification reference may be had to my Letters PatentNo. 767,994. It should be understood that the curves shown in Figs. 5 and 6 are not drawn to scale but are based upon computations made for actual circuits Which I have employed and that such computations have been checked experimentally.
It will be observed that for two frequencies n and '71. the algebraic sum of the ordinates of the curves (1), (2), (3) is zero, and therefore the elevated conductor system will be highly responsive to persistent oscillating electric forces of said frequencies, as shown at n and 77/ in Fig; 6, which is a curve drawn to rectangular co-ordinates in which the ordinates represent current amplitude and the abscissae represent frequency.
In Fig. 5, 72.1 represents the frequency to which the circuit C1L1 responds when isolated; 21-1 represents the frequency to which the circuit C2 L2 responds when isolated; and m, m", m, respectively represent the fundamental, the iirst even harmonic and the first ITO odd harmonic of the elevated conductor per se when isolated. 92/ represents the pronounced natural rate of vibration of the elevated conductor system and the curve in Fig. 6 shows the maximum corresponding to this frequency at a on the aXis of abscissze. Gurrents of this frequency a are developed in the elevated conductor system when abrupt or impulsive forces impinge upon the vertical and this frequency represents therefore one, and the most pronounced, natural rate of vibration of the elevated conductor system for such forces. The maximum at a" in the curve shown in Fig. 6 need not be considered when the elevated conductor system is employed for transmitting electromagnetic waves; and, as more fully pointedout in Letters Patent No. 767,994, when the elevated conductor system is employed for absorbing the energy of electromagnetic waves, any abrupt or impulsive electric forces which may impinge upon the vertical create natural oscillations in the elevated conductor system which do not effect the response of the associated resonant receiving circuitbecause a by far greater amount of energy is absorbed and redistributed by said natural oscillations as shown by the far greater area inclosed between the curve whose maximum ordinate is shown at a and its abseissae, and because such natural oscillations are of frequencies different from those to which the resonant reeeiving circuit or circuits is attuned. In other words, referring more particularly to Fig. 2, when impulsive forces act upon the vertical wire, the latter tends to respond only to its own natural rates of vibration as affected by the associated circuits, that is to say, it tends to oscillate at periodicity a and at the upper harmonics. Such forces acting upon the vertical wire have little tendency to develop oscillations of the natural periods of the loop circuits as affected by their connection with. the vertical, namely, the periods 02/ and a, and the receivers which are associated respectively with said loop circuits are therefore protected from the effects of such impulsive forces.
From the foregoing description of Figs. 1 and 2 and the discussion of Figs. 5 and 6, it will be obvious that by depressing either key Z: or 7r, persistent trains of simple harmonic electrical oscillations of frequencies a and a will be developed in the elevated transmitting conductor system, and that the reaetance of the elevated transmitting conductor system will be Zero for both of these frequencies. Also it will readily be apparent that when the keys 7 and L are simultaneously depressed and the persistent trains of simple harmonic electrical oscillations are simultaneously developed in the elevated transmitting conductor system, the reactance of the elevated transmitting conductor system will be Zero for both i of these frequencies.
When persistent trains of simple harmonic electromagnetic waves of frequency a or a impinge upon the elevated receiving conductor and create therein persistent trains of simple harmonic electrical oscillations of corresponding frequency, it will be obvious that the reactance of the elevated receiving conductor system will be zero for both of these frequencies. and that if the resonant receiving circuits be attuned to either one of said frequencies the electro-receptive devices K or K will be operated. Also it will readily be apparent that if such persistent trains of simple harmonic electrical oscillations of said frequenciesbe simultaneously developed in the elevated receiving conductor system, the reactance of the elevated receiving conductor system will be zero for both of these frequencies, and that the electro-receptive devices K and K included in the resonant receiving circuits will simultaneously be operated, each by the oscillations to the frequency of which the resonant circuit including it is attuned.
If, however, abrupt or impulsive electric forces impinging upon the elevated receiving conductor cause the elevated conductor system to execute natural oscillations, these oscillations will be of frequenciesill adapted to effect the response of either resonant receiving circuit because, as above explained, the frequencies of such natural oscillations will be different from the frequencies to which the resonant receiving circuits respectively are attuned.
Although for the purposes of illustrating my invention 1 have shown and described two persistently oscillating circuits and two loop circuits associated with the elevated conductor system, it is to be understood that I am not limited to such construction because a larger number of persistently oscillating circuits may be employed and for each such circuit so employed a loop circuit may be associated with the elevated conductor system.
Although I have herein shown and described the persistently oscillating circuits inductively associated with the elevated conductor system, it is to be understood that 1 am not limited to such construction because such circuits may be couductively connected thereto in the manner described in my prior patents.
In Figs. 3 and a l have shown, for the purpose of more completely disclosing the invention, a modification of the systems above described,and this mod ification consists in ind uctively associating the loop circuits 12" C1 and 12' G2 with the elevated conductor by means of the transformers M and M' respectively. The principle involved in this arrangement of circuits has been fully set forth in my application serial number 194,6et9, filed February 23, 1904, and therefore need not be repeated herein, it being sufficient to state that said circuits so inductively react upon the elevated 1 conductor system that the reactance of the transmitting elevated conductor system is rendered zero for the persistent trains of simple harmonic electrical oscillations of the frequencies impressed thereon by the sonorous circuits 5 O 11 and s C 1'1; and that the reactance of the receiving elevated conductor system is rendered zero for persistent trains of simple harmonic electrical oscillations of the frequencies developed therein by persistent trains of simple harmonic electromagnetic waves to the frequency of which the resonant receiving circuits K C I2 and K 0' 1'2 respectively, are attuned.
It will be readily apparent that, as in the systems illustrated in Figs. 1 and 2, the oscillations may be simultaneously developed in the elevated conductor systems of Figs. 3 and 4, as well as individually.
I make no claim in the present application to an apparatus whereby the method hereinafter claimed may be carried into effect as such apparatus forms the subject matter of my application Serial No. 259,841, filed May 10, 1905, of which this application is a division.
It will be understood that many variations and modifications may be made in the systems herein specifically described without departing from the spirit of myinveution and therefore I do not limit my claims to the specific embodiments of the present broad invention disclosed; but
I claim broadly as my invention 1. The method of giving an elevated conductor system a plurality of rates of vibration for persistent trains of electrical oscillations of different definite frequencies which consists in rendering the reactance of the elevated conductor system zero for persistent trains of electrical oscillations of said frequencies.
2. The method of simultaneously developing persistent trains of forced simple harmonic electrical oscillations of a number of different definite frequencies in an elevated conductor system which consists in causing each one of a like number of circuits to so react upon the elevated conductor system as to balance, each by its own reactance for persistent trains of oscillations of aditferent one of said frequencies, the reactance of the rest of the elevated conductor system.
1n testimony whereof I have hereunto subscribed my name this 16th day of June, 1905.
JOHN STONE STONE.
BRAINERD T. JUDKINs, GEORGIA A. HIGGINS.