US1006635A - Space telephony. - Google Patents

Description

L. DE PUREST.

SPACE TELEPHONY.

APPLICATION FILED JULY 8, 1907.

Patented Oct. 24, 1911.

T0 rek'om 'it may concern:

UNITED STATES PATENT OFFICE.

LEE nirormsr, or new YORK, N. Y., assmuoa r0 on roansr mmo summons 00., a a coaroaarxou or new: roux.

'sracn 'riinnrnoii'r.

Be. it known that I, LEE on FOREST, a citia zen of the United States, and a resident of New York, in the county of New York and State of New York, have invented a new and useful Improvement in Space Telephony I, of which the following is a specification. I y invention relates to certain novel 1mprovements and discoveries which I have made relating to the art of transmitting signals between two separated points without the use of artificial conductors and it' relates particularly to the wireless transmission of vocal or other sounds, including articulate speech.

My invention comprises certain features, parts and combinations thereof which will be hereinafter described and particularly pointed out in the claim.

The drawin s which accompany and form a part 0 this specification represent in diagram several arrangements of apparatus and circuits which have been employed, although it will be understood that I do not limit myself to the articular arrangements therein illustrate inasmuch as many modifications may be made in said apparatus and circuits without departing from the principle of my invention.

In the drawings, Figures 1, 2 and 3-represent space telephone transmitting systems constructed in accordance with the present invention.

In the figures, G is a nerator of unidirectional electromotive orce herein rep resented as a direct current dynamo.

G is a polyphase generator, herein shown as a three-phase generator.

R R are resistances.

'C is a condenser. g

S is a discharger herein shown as a gap in which an electric arc may be created between suitable electrodes;

S" is a discharger herein shown as a spark-gap.

S S are spark-gaps located in the transmitting antenna and herein shown in the earth connector thereof.

A is an antenna earthed at E.

M is a transformer of which the primary andlsecondary windings are I, and I respec: tive y.

T a transmitter herein shown as a microphone.

B is a battery.

. tor.

Specification or Letters l atent. Patented Oct. 24, 1911. Application ma July 8, 1907. serial No. semen.

D Dare electromagnets.

signaling each signal element, as a dot or a dash, is transmitted by a series of oscillations caused by a series of sin le sparks, the spark series representing di erent signal elements being separated by a period of time in which there are no sparks. Each of thesesparks represents a series of electrical oscillations of high frequency and of decreasing amplitude-that 18, the wave train sent out is damped and the rate of damping is greater or less depending on whether the oscillating system at the transmitter is a good radiator or a good resona- For long distance transmission it is desirable that the transmitting system should combine both qualitiesthat is, that it should have a very decided period of itsown and should still radiate outwardly from its upright wire a considerable amount of energy at every oscillation. In a strongly damped wave train the first few oscillations, while of considerable amplitude, are soon sore'duced in amplitude as to be of little value in exciting a receiving antenna or [circuit into response. Such wave train therefore has little cumulative excitin feet u on any receiving apparatus.

fore or the purpose of carrying out the .present lnvention I prefer to use an appav wave train, even if the maximum amplitude of the latter be much greater than that of the former. A receiving system whose natural period of electrical vibration coincides with that of the wave train will ultimately pick up and respond to a weak but persistent wave train'by reason of the cumulative efi'ect of said wave train thereon.

In my resent invention I make use of a substantia ly contlnuou's series of waves, or as near an approach to a continuous radiation of waves as is practicable and modify which are herein described and illustrated in the accompanying drawings.

potentials for radiatin It has been pointed outby Duddell, Peukert, Guthe, and Simon that if a circuit containing self-induction and capacity be put in shunt around a direct current are and the resistance of said are properly adjusted, the arc will give out a musica note, the pitch of which coincides with the frequency of the electrical oscillations in said shunt circuit. It has also been pointed out by I Tesla that if said are be created in an atmosphere containing hydro en, the -operation thereof is mademore e cient. It is also known that if a telephone transmitter and battery be suitably associated with the aforesaid are and its circuit, words spoken in the microphone transmitter will be reproduced and magnified in sound in the arcitself. In the case of a direct current are shunted by self-induction and capacity and ordinarily poken of as the singing-arc, there is an ternating or oscillating current in the shunt circuit which is continuously maintained b means of the direct current of the arc. Y T 's is the exact electrical analogue ofthe acoustic henomenon where a-continuous blast of air maintains a reed in rapid vibration, as in an organ pipe. Where a microphone transmitter is associated with said are or its circuit, the minute current fluctuations produced in the microphone circuit by the sonorous' vibrations of the air accompanying the sounds which afl'ect said microphone may be employed in various ways for varying the amplitude of the cur.- rents in said are or its circuit in accordance with said sounds. We ma also employ s ark-balls for the purpose 0 creati tlcally continuous trains of electrica oscillations, and in either case by using a source of direct current of sufliciently high voltage and by reducing the dimensions of the selfinduction and capacity in the shunt circuit, we may obtain for a proper length and resistance of ga the continuous generation of' electrical osci ations of suificiently high frequency to efiect the radiation of electromagnetic waves. Such an arrangement applied to wireless tel phy is shown in Figs. 1 and 2 in which e circuits S 0 I are sources of undam ed or practically continuous elec- .trical osc1 lations of high frequency. The oscillations in these circuits may be transmitted to the radiating antenna A in any suitable manner and asjshown herein the oscillation transformer M is employed for this purpose. By this arrangement the otential of the direct current source G need he only moderate because the desired high purposes may be obtained by said trans ormer in which the ratio of transformation may be as large as desired. The direct current potentials are in no case measures of the potentials ex'isting in the oscillation circuit since by the resonance eifects of the latter, a large increase in. electromotive force always 1s obtained. Where however it is desirable to obtain direct current potentials in excess of those conveniently obtainable from a direct current generator, the arrangement shown in Fig. 3 may be employed.

' n Fig. 3, the conductors of the threephase generator G are connected to the points 1, 2, 3, which may be inclosed in a suitable vessel 5, and to the star-point 0 of zero potential through the inductances L L L respectively. If from said starpoint a conductor be led to the plate 4, there will be obtained in said conductor a unidirectional current flowing in the direction of the arrow, said current being the resultant of the currents flowing through the vessel 5, which may contain any sultable atmosphere maintained at any desired ressure, from the points to the plate. Th1s resultant unidirectional current will be practically a constant current and of a volta practically equal to that of the alternating currents delivered by the generator G. As will be obvious a transformer may be interposed between the point-and-plate arrangement which constitutes a polyphase rectifier, an the generator G. 'I' do not limit myself to the particular form of lyphase rectifier shown in Fig.3 inasmuc as various other forms may be employed for securing from a high potential polyphase current a unidirectional currento any desired voltage. In the circuit which includes the point 0 and plate 4 a discharger S for the condenser C may be inserted and there will be .polyphase system may be connected hearth and the antenna A may be associated in any, suitable manner with the oscillation circuit,

the associating means being shown in the present instance as consisting ofthe autotransformer M.

If a continuous wave train produced by the transmitting systems shown in Figs. 1, 2 or 3 impinges upon a receiving antenna and if the amplitudes of said wave trains are varied in any arbitrary manner and at any rate within the limit of audibility or within the limit of response of the diaphragm of a telephone receiver, which is properly associated with an oscillation detector, sounds of corresponding intensities produce corresponding changes and rates of vibration will be produced by said telephone reeciver. It is therefore only necessar to alter the amplitudes of the waves 0 the continuous train of waves produced at the transmitting station to correspond with the amplitudes and rates of vibration of the acoustic waves to be trans: mitted, to bring about reproductions of such acoustic vibrations in the receiver, be these Current fluctuations produced in the cir cuit of the battery B and transmitter T in the strength of the magnetic field across the gap and such changes in strength of said magnetic field produce corresponding variw tions in the amplitude of the electrical oscillations created in the circuits of the ga s S or S. As shown in Fig. 1, the transmltting circuit with its magnets D D, may be associated with the source of practically continuous electrical oscillations, while as shown in Figs. 2 and 3, it may be associated with a gap S included in the antenna circuit, preferably in the earth connector thereof where the current is a maximum and where it serves as a resistance, without, however, interruptin the continuity of the oscillations surging ack and forth therethrough, the conductivity of such resistance being varied by varying the strength of the magnetic field in which it is placed.

It will be noted that the electrical waves which 'are depended upon for the transmission from one station to another are not the impulses which are directly produced bythe action of the sound waves or the currents in the circuit of the microphone. transmitter, but are waves which are produced in a circuit which is distinct from such microphone circuit and are not dependent for their production or primary intensity upon the action of said microphone. any necessary relationship between the period or the transmitting-impulses and the period of the sound waves. The periods of the sound waves correspond with the periods of the variations in intensity of the transmitted electroma etic waves. In other words, the rate of vlbration of the transmitted waves is wholly distinct from that of the sounds to be transmitted and the amplitude of said waves is varied in accordance with that of said sounds, and the rate of variation of the amplitude of said waves corresponds with the rate of vibration of said sounds.

I claim:

In a space tele" hone transmitting system, a transmitting antenna, means for developing electrical oscillations therein, spark-electrodes in said antenna, electro-magnets arranged in proximity thereto and a telephone .transmitter and source of electrical energy associated with saidelectromagnets.

In testimony whhreof, I have hereunto subscribed my name this 3d day of July, 1907.

1 LEE on FOREST. Witnesses:

Rosoon KENT, Tnoms I. GALLAGHER.

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