US928371A - Signaling by electromagnetic waves. - Google Patents

Description

9. A. PBSSBNDBN. SIGNALING BY AELECTROMAGVNETIG WAVES. `APPLICATION FILED MAY 4, 1906.

PatenaJulyzo, 1909.

WITNESSE'S:

REGINALD A. FESSENDEN, OF WASHIGTON, DISTRIGTVOF COLUMBIA.

sIGNALrG BY ELECTROMAGNETIC wA'vEsL Specification. of Letters Pate-nt.

Patented July 2o, i909.

Application nled Hay 4,y 1966. Serial No. 315,266.

,To all whom fit may concern:

Be it known `that I, REGINALDfA. FEssEN- DEN, a citizen of the United States, residing at Washington, District of Columbia, have invented certain new and useful Impovements in Signaling by Electromagnetic Waves, of which the following is a specification. i

. M` invention herein relates generally to wire ess telegraphy, and more especially to provision for tuning the circuits in apparatus for this purpose, as hereinafter more fully described. I

In the accompanying drawing forming a art of this specification, Figures 1, 2 and 3 illustrate diagrammatically different combinations of elements of my improved apparatus, and Figs. 4 and 5 show in plan and section a variable transformer.

, In the practice of my invention, I provide a capacity and inductance in shunt to each other and in operative relation to the aerial, and a receiver in operative relation to the condenser and inductance circuit.

The aerial 1 isgroundedas at 2, and has a variable inductance 3 in series therewith. The aerialFig. 1 is also connected to inductances 4 and 6, in shunt to a condenser 5.

The inductance 4 is preferably variable and the inductance 6 forms lthe primary of a transformer. having a secondary 7. Both 6 and 7 are preferably constructed so as to be capableof yadjustment as illustrated in Fig. 4. A rcceiver'8, telephone 9, potentiometer -10, inductance 11 and condenser 12 are arranged in the circuit of the secondary 7. The condensers 5 and 12 are preferably adjustable, as is also the indutance 11. The aerial is preferably tuned to the frequency of oscillations which it is desired to receive, and also the shunt circuit 4, 5 and 6, either alone or in conjunction with the secondary circuit 7, 12, 8 and 11. The circuit 7, 12, 8 and 11 is also preferably tuned to the frequency which it is desired to receive.

In the construction shown in Fig. 2, the aerial 1, which is grounded as at 2, is connected in series with the inductance y14. The inductances 15 and 16, which are preferably adjustable, are shunted by the variable condenser 13. The receiver 19 is connected across the inductance 16. The ycircuit of the receiver 19 includes a variable inductance 18, an adjustable capacity 17', telephone 20, and

potentiometer 21,. 'Contact points c and b.

are adjustable.

The construction shown in Fig. 3 is especially applicable for use for the prevention of interference. The aerial 1 is grounded as at 2 and is connected tothe variable inductances 3, 24 and 25. The aerial is also connected to inductances 27 and 28, whichfare arranged in shunt to the capacities"l or condensers 23 and 26. The inductances 27 and 28 form primaries whose secondaries are shown at 29 'and 30. In the circuit with these secondaries are included the variable inductance 31, adjustable capacity 36, 'receiver 34, 'potentiometer 35 and telephone or other indicating instrument 33.` The transformers have preferably a variable .ratio of turns, the construction shown in Fig.

quency, and the circuit 1, 3, 25, 26, 28 and 2i to the other frequency.

The variable transformer shown in Figs.

v4 and 5 consists of two pairs of drums 37, 38,

and 39, 40,-of which the drums 37 and 40 are referably formed of metal'or other conductlng material, andy are mounted in suitable bearings so as to be capable of rot-ation, while Where, e

the drums 38 and 39 are formed of insulating p v material, the drum 39 being rotatable within the' drum 38 and adjustable in and out of the same by means of the threaded rod 41 passing through drum or cylinder 39. The drums 37 and 38 are made of the same diameter and are adapted to be driven simultaneously by suitable connection, as, for example, the sprocket chain 42;, shown. and ,40 are also of the same diameter and are connected by a s rocket chain 43 .or other suitable means. v

alsoy adjustable longitudinally by means of a screw 44. A. portion of a length .of wire is wound on the drum 37, and another portion on the drum 38, and by rotating these drums,y

The drums 39 he drum orcylinder 40 is v is wound artially on the drum 39 and )artially on t e drum 40, and by rotating t fese drumsthewire can be wound oli of one and on to the other. It will be observed that as the wire is wound off or on the drum 39, it is moved 'axially out of and into the drum 38,

'and that the coils on the drums 38 'and 39 will form the members of a transformer which canbe varied by rotating these drums in the manner stated.

I am aware that the use of a shunt resonant circuit for producing selectivity in electro-magnetic apparatus is old. VI am also aware that the use of a secondary operatively connected to an inductance` in parallel with a' condenser is old, where the short circuited coil of a short circuitcd dynamometer operates as a secondary. And I am also aware that this arrangement has been used in connection with an untuned aerial.

The interference,preventer may be used.

with four branch circuits, with a sending station emitting two frequencies in this case, two of the branches are rei'erably tuned to the two frequencies' whic it is desired to receive, and the other branches are used as balancing branches to cut out interfering signals.

I claim herein as my invention:

1. In a receiving system for Wireless teleg` raphy, an inductive connection with variab e primary, a condenser, a detectorior electroy'magnetic waves connected with the secondary of the inductive connection through said condenser, a condenser shunted with the low resistance for electric oscillations, an antenna, connections from said loop to the antenna and to the ground.

3. In asystem for wireless telegra hy an' inductive connection having a varia le primary, a detector for electromagnetic waves in circuit with the secondary of said inductive connection,an antenna in circuit with the primary of said inductive connection through a variable inductance, and a condenser shunted about the variable primary.

4. In a receiving system for wireless telegraphy a circuit including a condenser and 'a detector for electromagnetic waves, a circuit.

including an elevated conductor and a variable inductance, and an inductive connection between said circuits having a primary, variable as to the number of its turns, in series with the variable inductance and elevated conductor. y

5. In a receiving system for wireless telegraphy a circuit including a condenser and a detector for electromagnetic waves, a circuit l including an elevated conductor and a variable inductance andan inductive connection between said circuits havingv a primary in series with the variable inductance and elevated conductor and having a secondary variable as to the number of its turns in series with'the condenser and detector.

6. In a receiving system for wireless telegraphy an inductive connection having a primary and secondary variable as to the ratio of their turns, a detector for electromagnetic waves in circuit with the secondary, and an elevated conductor in circuit with the primary through a variable inductance.

In testimony whereof, Iliave hereunto` set my hand. v

REGINALD A. FESSENDEN.

l Witnesses:

LEONARD MORGAN, WILLiAM HELGEN.

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