No. 723,188.

PATENTED MAR. 17,1903. N. TESLA. METHOD OF SIGNALING. APPLIOATION FILED JUNE 14, 1901.

NO MODEL, OJ

WITNESSES:

.

11. . A

~~~

~~ TIlE NORRIS PETERS

BV

A

INVENTOR.

,rW~.:L i'....t.a..£c.t......

/~'~A~ co.

PHOTO.UTHO .. W"'S)-IINClTON,

o.

C

,UNITED STATESP ATENT OFFICE. NIKOLA TESLA, OF NEW YORK, N. Y.

METHOD OF SIGNALING. SPECIFICATION forming part of Letters Patent No. 723,188, dated March 17, 1903. Original application filed July 16,1900, 3erial No, 23,847, Divided and this application filed June 14,1901. Serial No, 64,522, eNo model.)

.

To (ill wh01n it 711>ay concern: " 1 are us~d little advantage in this respect is to Be it known that I, NIKOLA TESLA, a cit·i- he derived from tuuing the circuits. It be,zen of the United States, residing in the bor-I ing an impf\rative I'eqnirement in most pracough of Manhattan, in the city, county, aud tical applications of such systems of Rignal- 55 5 State of New York, have invented certain ing or intelligence transmission that the signew and useful Improvements in Methods of nals 01' messages shollld be exclusive or priSignaling, of which the following is a speci- vate, it is highly deRil'able to do away with fication, reference being had to the drawings the above limitations, especially in view of accompanying and forming a part of tbe the fact which I have observed that tbe in- 60 ro same, flnence of powerful electrical dist,nrbancos In certain systems for transmitting intelli- upon Rensit.ive receh'el's extends eve~l on gible messages or governing the movementR land to distances of many hundreds of miles, and operations of distant automata electrical and consequently, in accordance with theory, impulses or disturbanceR pl'oduced by suit- Ilt.ill fart,her on sea. To ovel'come t,hese draw- 65 {5 able apparatus are con veyed through the nat- backs and to enable a g'l'eat num bel' of transural media to a receiving-circuit capable of mitting and receiving stations to be operated responding to the impUlses, and thereby ef- selectively and exclusively and without any fecting the control of other appliances. Gen- danger of the signals or messages being diserally a special device, highly sensitive, il:l tUl'bed, intercepted, or interfered with in any 70 20 connected to the receiving-circuit, which in way is the object of my present iuvention. order to render it 8t,ill more sllsceptible and Broadly I:ltafed, this invention consists in to reduce the liability of its being affected generating two or more kinds or classes of by extraneous disturbances is carefully ad- disturbances or impulses of distinctive charjllstec1 so as to be in tune with the transmit- acter with respect to their effect upon are- 75 25 tel'. Bya scientific design of the sending ceiving-cil'cllit and operating thereby a disand receiving cil'cuits and other apparatus tant receiver which comprises two or more and skilful adjustment of the same these .circuits, each of which is tuned to respond objects may be in a measUl'e attained; but exclusively to the disturbances or impulses in long experience I have found that not- .of one kind 01' class and so arranged that the 80 30 withstanding all constructiYe ad vantages and operation of the receiver is dependent upon experimental resources t.his method is in their conjoint 01' resultant action. many cases inadequate. Thus while I have By employing only two kinds of distllrhsUClceeded in so operating selectively under ances or series of impulses instead of one, as certain favorable conditions more than one has heretofore been done, to opeeate a re- 85 35 hundred receivers in most cases it is prac- ceiver of this kind I have found that safety ticable to work successfully but a few, the against the disturbing influences of othel' number rapidly diminishing as, either owing sources hI increased to such an extent that I to gl'eat distance or other causes, the energy believe this number to be amply sufficient in available in the tuned circuits becomes most cases for rendering the exchange of sig- 90 40 smaller and the receivers necessarily more nals or messages reliable and exclusive; but delicate. Evidently a circuit however well in exceptional instances a greatel' number constructed and adjusted to respond exclu- may be used and a degree of safety against sively to vibrations of one period is apt to mutual and extmneous interference attained, be affected by higher harmonics and still I snch as is comparable to that afforded by a 95 45 more so by lower ones. vVhen the oscilla- combiuation-lock. The liability of a receiver tions are of a very high frequency, the llum- being affected by distnrbances emanating bel' of the effective harmonics may be large from other sources, as well as that of the sigand the receiver consequently easily dis- nals or messages being received by instrlltm'bed by extraneous influences to such an ments for which they are not intended, may, 100 50 extent that when very short waves, such as however, be reduced not only by an increased those produced byHertzian spark apparatus, I number of the cooperative c1isturbances or

2

723,188

seriesofimpulsesj but also by judicious choice of the same and order in which they are made to act, upon the re~eivel" Evidently there are a great many ways of 5 generating impulses or disturbances at any wave length, wave form, number or order of succession, or of any special ch~.racter, such as will be capable of fulfilling the requirements above stated, and there are also many 10 ways in which such impulses or disturbances may be made to coopemte and to cause the receiver'to be actuated, and inasmuch as the skill and practical knowledge in these novel fields can only beacqllired by long experience T5 the degree of safety and perfection attained will necessarily depend upon the ability and resource of the expert who applies my invention; but in order to enable the sam'e to he successfully practiced by any person pos20 sessed only of the more general knowledge and experience in these branches I shall describe the simplest plan of carrying it out which is at present known to me. POI' a better understanding of the subject 25 reference is now made to the accompanying dmwings, in whichFigures 1 and 2 represent diagmmmatically an apparatus and circuit connections employed at the sending and receiving stations, 30 respectively, for the practice of my in ven t10n; nnd Figs. 3, 4, and 5, modified means which may be employed ill the practical application of the invention. , In Fig. 1, S' S2 are two spirally-wound coils ;~i or conductors connected with their inner ends to preferably elevateu terlllinals D' and D2, respectively, and with theil' outer ends to an earth-plate E. These two coils, conductors, or systems D'S' E and D2 S2 E have different