N. ‘TESLA.
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`PATENTED MAR. 17, 1903.
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`METHOD OF SIGNALING.
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`APPLE 1012
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`c UNITnD STATES PATENT OFFICE.
`
`NIKOLA TESLA, OENEW YURK, N. Y.
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`METHOD OF SIGNALING.
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`SPECIFICATION forming part of Letters Patent N0. 723,188, dated March 17, 19b3.
`Original application filed July 16, 1900. Serial No. 23.847. Divided and this application filed June 14. 1901. Serial
`No. 64.522.
`(No model.)
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`To all whom in 7nd,] concern.-
`Be it known that I, NIKOLA TESLA, a citi-
`_zen of the United States, residing in the bor-
`ough of Manhattan, in the city, county, and
`State of New York, have invented certain
`new and useful Improvements in Methods of
`Signaling, of which the following is a speci-
`fication, reference being had to the drawings
`accompanying and forming a part of the
`same.
`
`In certain systems for transmitting intelli-
`gible messages or governing the movements
`and operations of distant automata electrical
`impulses or disturbances produced by suit-
`‘ able apparatus are conveyed through the nat-
`ural media to a receiving-circuit capable of
`responding to the impulses, and thereby ef-
`fecting the control of other appliances. Gen-
`erally a special device, highly sensitive, is
`connected to the receiving-circuit, which in
`order to render it still more susceptible and
`to reduce the liability of its being affected
`by extraneous disturbances is carefully ad-
`justed so as to be in tune with the transmit-
`ter. By a- scientific design of the sending
`and receiving circuits and other apparatus
`and skilful adjustment of the same these
`objects may be in a nieasureattainedg but
`in long experience I have found that not-
`wilhstan ding all constructive ad vantages and
`experimental resources this method is in
`many cases inadequate. Thus while I have
`succeeded in so operating selectively under
`certain favorable conditions more than one
`hundred receivers in most cases it is prac-
`ticable to work successfully but a few,-V the
`number rapidly diminishing as, either owing
`to great distance or other causes, the energy
`available in the tuned circuits becomes
`smaller and the receivers necessarily more
`delicate. Evidently a circuit however Well
`constructed and adjusted to respond exclu-
`sively tovibrations of one period is apt to
`be affected by higher harmonics and still
`more so by lower ones.
`“Then the oscilla-
`tions are of a very high frequency, the num-
`- ber of the eflective harmonics may be large
`and the receiver consequently easily dis-
`turbed by extraneous influences to such an
`extent that when very short waves, such as
`those produced by Hertzian spark apparatus,
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`are used little advantage in this respect is to
`be derived from tuning the circuits.
`It be-
`ing an imperative requirement in most prac-
`tical applicalions of such systems of signal-
`ing or intelligence transmission that the sig-
`nals or messages should be exclusive or pri-
`vate, it is highly desirable to do away with
`the above limitations, especially in View of
`the fact which I have observed that the in-
`fluence of powerful electrical disturbances
`upon sensitive receivers extends even on
`land to distances of many hundreds of miles,
`and consequently, in accordance with theory,
`still farther on sea. To overcome these draw-
`backs and to enable a great number of trans-
`mitting and receiving stations to be operated
`selectively and exclusively and without any
`danger of the signals or messages being dis-
`turbed, intercepted, or interfered with in any
`way is the object of my present invention-
`Broadly stated, this invention consists in
`generating two or more kinds or classes of
`disturbances or impulses of distinctive char-
`acter with respect to their effect upon a re-
`ceiving-circuit and operating thereby a dis-
`tant receiver which comprises two or more
`-circuits, each of which is tuned to respond
`exclusively to the disturbances or impulses
`.of one kind or class and so arranged that the
`operation of the receiver is dependent upon
`their conjoint or resultant action.
`By employing only two kinds of disturb-
`ances or series of impulses instead of one, as
`has heretofore been done, to operate a re-
`ceiver of this kind I have found that safety
`against the disturbing influences of other
`sources is increased to such an extent that I
`believe this number to be amply suffieient in
`most cases for rendering the exchange of sig-
`nals or messages reliable and exclusive; but
`in exceptional
`instances a greater number
`may be used and a degree of safety against
`m utual and extraneous interference attained,
`such as is comparable to that afforded by a
`combination-lock; The liability of a receiver
`being affected by disturbances emanating
`from other sources, as well as that of the sig-
`nals or messages being received by instru-
`ments for which they are not intended, may,
`however, be reduced not only by an increased
`number of the cooperative disturbances or
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`723,188
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`choice ' nance with its secondary system, as I have
`eries of impulses; but also byjudicious
`explained in other patents granted to me;
`of the same and order in which they are made
`The briish-liolders B’ and B2 are capable in-1
`I to act upon the receiver;
`-
`dependently of angular and, if necessaryi;
`Evidently there are a great many ways of
`also of lateral adjustment, so that any desired
`generating impulses or disturbances at any
`order of succession or any difference of time
`wave length, wave form, number or order of
`interval between the discharges occurring in
`succession, or ofany special character, such
`the two primary circuits may be obtained,
`as will be capable of fulfilling the require-
`The condensers being energized from a suit-
`ments above stated, and there are also many
`able scurce S, preferably of high potential,
`ways in which such impulses or disturbances
`and the disk D being rotated, its projections
`may be made to cooperate and to cause the
`or teeth p p coming at periodically-recurring
`receiverto be actuated, and inasmuch as the
`intervals in very close proximity to or, as the
`skill and practical knowledge in these novel
`case may be, in contact with conducting rods
`fields can only be acquired by long experience
`or brushes n ‘It cause the condensers to be
`the degree of safety and perfection attained
`discharged in rapid succession through t_heir
`will necessarily depend upon the ability and
`respective circuits.
`In this manner the two
`resource of the expert who applies myinven-
`secondary systems D’ S’ E and D” S2 E are set
`tion; but in order to enable the same to be
`in vibration and oscillate freely each at its
`successfully practiced by any person pos-
`proper rate for a certain period of time at
`sessed only of the more general knowledge
`every discharge. The two vibrations are im-
`and experience in these branches I shall de-
`pressed upon the ground through the-plate
`scribe the simplest plan of carrying it out
`E and spread to a distance reaching the re-
`which is at present. known to me.
`ceiving’-station, which has two similar cir-
`Fora better understanding of the subject
`cuits or systems 6 8’ cl’ and c 32 (l2, arranged
`reference is now made to the accompanying
`and connected in the same manner and tuned
`drawings, in which—-
`to the systems at the sending-station, so that
`Figures 1 and 2 represent diagrammatic-
`each responds exclusively to one of the two
`ally an apparatus and circuit connections em-
`vibrations produced by the transmitting ap-
`ployed at the sending and receiving stations,
`paratus. The saine rules of adjustment are
`respectively, for the practice of my invention;
`observed with respect
`to the receiving-cir-
`and Figs. 3, 4, and 5, modified means which
`cuits, care being furthermore taken that the
`maybe employed in the practical application
`tuning is effected when all the apparatus is
`of the invention.
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`connected to the circuits and placed in posi-
`In Fig. 1, S’ ‘2 are two spirally—wound coils
`tion, as any change may more or less modify
`' or conductors connected with their inner ends
`the vibration. Each of the receiving-coils 3’
`to preferably elevated terminals D’ and D2,
`and siis shunted bya local circuit containing,
`respectively, and with their outer ends to an
`respectively, sensitive devices Ct’ cg, batteries
`earth-plate E. These two coils, conductors,
`I)’ b?, adjustable resistances 7*’ 7'2, and sensi-
`or systems D’ S’ E and D2 S2 E have different
`tive relays R’ R2, all
`joined in series, as
`and suitably-chosen periods of vibra_tion,and,
`shown. The precise connections and ar-
`as pointed out in other patents relating to my
`raiigements of the various receiving instru-
`system of energy and intelligence transmis-
`ments are largely immaterial and may be
`sion, their lengths should be" such that the
`varied in many ways. The sensitive cle-
`points of maxim um pressure developed there-
`vices CL’ CI/2 may be any of
`the well-known
`in coincide with the elevated terminals D’
`devices of this kind-—as, for example, two
`D2. By suitably-chosen periods of vibration
`conducting—torminals separated by a minute
`such periods are meant as will secure the
`air-gap or a thin film of dielectric which is
`greatest safetyagainstinterference, both inu-
`strained or weakened by a battery or other
`tiial and extraneous. The two systems may
`ineaus to the point of breaking down and
`have electrical hscillatioiis impressed upon
`gives way to the slightest disturbing influ-
`them _in_ any desired manner coirveniently by
`ence.
`Its return to the normal sensitive state
`energizing them: through primaries P'_and P2,
`may be secured by momentarily interrupting
`placed in proximity to them. Adjustable
`the battery-circuits after each operation or
`inductances L’ and L2 are preferably included
`otherwise. The relays R’ R2 have armatures
`in the primary circuits chiefly for the pur-
`Z’ Z2, which are connected by a wire 10 and
`pose}otf.01~egulfit:pg‘t1herates toll‘ the p_rima_ry
`when attracted establish electrical contacts
`nsci a 1 ns.
`n , ie< rawings
`iese primaries
`at c’ and c2, thus closing a circuit containing
`P’ and P2 surround the coils S’ S2 and are
`a battery Z23 and adjustable resistance r3 and
`joinec in series through the inductances L’
`a relay R3. From the above description it
`L2, conductor F, condensers C’ and C2, brush-
`will be readily seen that the relay R3 will be
`holders B’ and B2, and a toothed disk D,
`operated only when both contacts 0’ and of are
`which is connected to the conductor F and, if
`closed.
`desired, also to theground-plate E, as shown,
`The apparatus at the sending-station may
`two independent primary circuits being thus
`be controlled in any suitable manner—as, for
`formed. The condensers C’ and C2 are of
`instance, by momentarily closing the circuit
`such capacity and the inductances L’ L2 are
`so adjusted that each primary is in close reso- l
`of the source S, two different electrical vi-
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`ments or circuits, as S’ and S2, since a suc-
`brations being emitted simultaneously or in
`rapid succession, as may be desired, at each
`cession of waves or impulses of different char-
`acteristics may be produced by an instrument
`closure of the circuit. The two receiving-
`circuits at the distant station, each tuned to
`having but one such circuit. A few of the
`respond to the vibrations produced by one of
`many ways which will readily suggest them-
`the elements of the transmitter, affect the
`selves to the expert who applies my invention
`sensitive devices a’ and co” and cause the re-
`are illustrated in Figs. 3, 4, and 5.
`In Fig. 3
`lays R’ and R3 to be operated and contacts
`a transmitting system e 33 d3 is partly shunt-
`of and 0” to be closed, thus actuating the re-
`ed by a rotating wheel or disk -D3, which may
`ceiver or relay R3, which in turn establishes
`be similar to that illustrated in Fig. 1 and
`a contact 03 and brings into action a device
`which cuts out periodically a portion of the
`a3 by means of a battery d4, included in a
`coil or conductor 53, or, if desired, bridges it by
`local circuit, as shown. But evidently if
`an adjustable condenser 03, thus altering the
`through any extraneous disturbance only one
`vibration of the system c 33 d3 at suitable in-
`of the circuits at the receiving-station is af-
`tervals and causing two distinct kinds or
`fected the relay R3 will fail to respond.
`In
`classes of impulses to be emitted in rapid suc-
`this way a communication may be carried on
`cession by the sender.
`In Fig. 4 a similar re-
`with greatly-increased safety against inter-
`suit is produced in the system e 34 d4 by pe-
`ference and privacy of the messages may be
`riodically short—circuiting, through an induc-
`secured. The receiving-station shown in Fig.
`tion-coil L3 and a rotating disk D4 with insu-
`2 is supposed to be one requiring no return
`lating and conducting segments, a. circuit 19"
`message; but if the use of the system is such
`in inductive relation to said system. Again,
`that this is necessary then the two-stations
`in Fig. 5 three distinct vibrations are caused
`will be similarly equipped, and any well-
`to be emitted by a system c 35 d5, this result
`known means, which it is not thought neces-
`being produced by inserting periodically a
`number of turns of an induction-coil L4 in se-
`sary to illustrate here, may be resorted to for
`enabling the apparatus at each station to
`ries with the oscillating system by means of
`be used in turn as transmitter and receiver.
`a rotating disk B5 witl1 two projections 195195
`In like manner the operation of a receiver,
`and three rods or brushes 725, placed at an an-
`as R3, may be made dependent instead of
`gle of one hundred and twenty degrees rela-
`upon two upon more than two such trans-
`tively to each other. The three transmitting
`mitting systems or circuits, and thus any de-
`systems or circuits thus produced may be en-
`sired degree of exclusiveness or privacy and
`ergized in the same manneras those of Fig. 1
`safety against extraneous disturbances may
`or in anyother convenient way. Correspond-
`be attained. The apparatus as illustrated in
`ing to each of these cases the receiving-sta-
`Figs. 1 and 2 permits, however, special re-
`tion may be provided with two or three cir-
`sults to be secured by the adjustment of the
`.cuits in an analogous manner to that illus-
`order of succession of the discharges of the
`trated in Fig. 2, it-being understood, ofcourse,
`that the different vibrations or disturbances
`primary circuits P’ and P2 or of the time in-
`tervals between such discharges. To illus-
`emitted by the sender follow in such rapid
`trate: The action of the relays R’ R2 may be
`succession upon each other that they are prac-
`regulated either by adjusting the weights
`tically simultaneous so far as the operation of
`of the levers Z’ 7.3, or the strength of the bat-
`such. relays as R’ and R2 is concerned. Evi-
`teries b’ 69, or the resistances 1" 7'2, or in other
`dently, however, it is not necessary to em ploy
`well-known ways, so that when a certain order
`two or more receiving-circuits, but a single
`of succession or time interval between the dis-
`circuit may be used also at the receiving-sta-
`charges of the primary circuits P’ and P2 ex-
`tion constructed and arranged like the trans-
`ists at the sending-station the levers Z’ and Z2 mitting-circuits orsystemsillustratedin Figs.
`will close the contacts 0’ and c2 at the same
`3, 4, and 5, in which case the corresponding
`instant, and thus operate the relay R3, but
`disks, as D3 D4 D", at the sending will be
`driven in synchonism with those at the receiv-
`will fail to produce this result when the order
`of succession of or the time interval between
`ing stations as far as may be necessary to se- .
`the discharges in the primary circuits is an-
`cure the desired result; but whatever the na-
`other one. By these or similar means addi-
`ture of the specific devices employed it will
`tional safety against disturbances from other
`be seen that the fundamental idea in my in-
`sources may be attained and, on the other
`vention is the operation of a receiver by the
`conjoint or resultant efiect of two’ or more
`hand, the possibility afforded of effecting the
`operation of signaling by varying theorder
`circuits each tuned to respond exclusively to
`waves, impulses, or vibrations of a certain
`of succession of the discharges of the two cir-
`cuits.
`Instead of closing and opening the cir-
`kind or class produced either simultaneously
`or successively by a suitable transmitter.
`cuit of the source S’, as before indicated, for
`It will be seen from a consideration of the
`the purpose of sending distinct signals it may
`nature of the method hereinbefore described
`be convenient to merely alter the period of
`either of the transmitting-circuits arbitrarily,
`that the invention is applicable not only in
`the special manner described, in which the
`as by varyingthe inductance of the primaries.
`Obviously there is no necessity for using
`transmission of
`the impulses
`is effected
`transmitters with two or more distinct ele-
`through natural media, but forthe transmis-
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`723,188
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`sion of energy for any purpose and Whatever
`the medium through which the impulses are
`conveyed.
`'
`What I claim is-
`re-
`1. The method of operating distant
`ceivers which consists in producing and trans-
`mitting a plurality of kinds or classes of elec-
`trical impulses or disturbances, actuating by
`the impulses or disturbances of each kind or
`class one of a plurality of circuits tuned to
`respond to impulses of such kind or class and
`operating or controlling the operation of a
`receiver by the conjoint action of two or more
`of said circuits, as set forth.
`2. The method of signaling, which consists
`in producing and transmitting a plurality of
`kinds or classes of electrical impulses ordis-
`turbances, developing by theimpulses of each
`class a currentin one of aplurality of receiv-
`ing-circuits tuned to respond exclusively
`thereto and controlling by means of the con-
`joint action of such circuits a local circuit,
`as set forth.
`3. The method of signaling which consists
`in producing a plurality of series of impulses
`or disturbances difiering from each other in
`character and order of succession, exciting
`by the impulses of each series one of a plu-
`rality of receiving-circuits tuned to respond
`exclusively thereto and controlling by the
`conjoint action of such circuits a local cir-
`cuit, as set forth.
`4. The method of signaling which consists
`in producing a plurality of series of electrical
`impulses of different character, varying the
`time interval between the emission of such
`impulses, exciting by the impulses of each se—-
`ries one of a plurality of receiving-circuits
`tuned to respond exclusively thereto and con-
`trolling by the conjoint action of such cir-
`cuits a local circuit, as set forth.
`5. The method of transmitting electrical en-
`ergy for conveying intelligible signals which
`consists in producing a plurality of electrical
`impulses ofdi “e rent character, developingby
`the impulses of each kind a current in one
`of a plurality of receiving-circuits tuned to
`respond exclusively thereto, controlling the
`action or effect of the transmitted impulses
`upon the receiving-circuits by varyingthe
`character of said impulses, and operating or
`controlling the operation of a receiver by the
`conjoint action of two or more of said receiv-
`ing-circuits, as set forth.
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`r
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`6. The method of transmitting electrical en— 55
`ergy which consists in producing a plurality
`of electrical waves or impulses of different
`periodicities, varying the order of tra_ns1nis-
`sion of the waves or impulses forming ele-
`ments of the signal sent, according as one or
`another receiving-station is to be communi-
`cated with where (proper circuit-closing mech-
`anism being provided at each receiving-sta-
`tion) the transmitted signal will be intelligi-
`ble at and only at the intended receiving-
`station.
`7. The method of transmitting intelligence,
`which consists in selecting and associating to-
`gether in predetermined order of succession
`two or more electrically-generated impulses
`of different periodicity, forming elements of
`signals to be sent, and transmitting such se-
`lected impulses with reference to the conjoint
`action of both or all in the production of a
`signal at a distant point, substantially as set
`forth.
`8. In asystem of telegraphy,wherein signals
`or messages aresent by the use of a plurality
`of electricalimpulses of different periodicities
`and in a predetermined order of succession,
`the method of ascertaining at any particular
`station the particular signal sent to that sta-
`tion, which consists in the selection, to form
`a signal, of certain transmitted impulses of
`different periodicities and of a predetermined
`order of succession to the exclusion of all oth-
`ers, as set forth.
`9. The improvement in the art of transmit-
`ting electrical energy which consists in oper-
`ating or controlling a receiving mechanism
`by a series or group of electrical impulses of
`different periodicities and of a predetermined
`order of sucession.
`10. In a system for the transmission of elec-
`trical energy, for sending signals or messages
`to any one of two or more receiving-stations,
`the method of transmitting the message with
`reference to the intelligible receipt thereof
`at the desired station, which consists in the
`transmission of electrical waves or impulses
`of different periodicities in varying order of
`transmittal by a separate order or grouping
`of transmittal for each receiving-station.
`NIKOLA TESLA.
`
`Witnesses:
`M. LAVVSON DYER,
`BENJAMIN MILLER.
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