US1141386A - Method of transmitting and receiving electrical energy. - Google Patents

Description

R. A. FESSENDEN.

METHOD OF TRANSMITTING AND RECEIVING ELECTRICAL ENERGY.

APPLICATION FILED NOV. 22' 1907. 1,141,386. I

Patented June 1, 1915 z/ i zwrmare rare rarnnir canton REGINALD A. FESSENDEN, OF BRANT I-IAIJSEY M. BARRETT,

ROCK, MASSACHUSETTS, ASSIGNOR, BY MESNE ASSIGNMENTS, TO SAMUEL IVI. KINTNEB, 0F PITTSBURGH,

PENNSYL VANIA, AND

OF BLOOMFIELD, NEW JERSEY, RECEIVERS.

METHOD OF TRANSMITTING AND RECEIVING ELECTRICAL ENERGY.

Specification of Letters Patent.

Patented'd'une l, 1915.

original application filed August 26, 1904, Serial No. 222,301. Divided and this application filed November 22, 1907. Serial No. 403,285.

To all whom it may concern:

Be it known that I, REGINALD A. Fn'ssnN- DEN, a citizen of the United States, residing at Brant Rock, in the county of Plymouth, State of'Massachusetts, have invented a certain new and useful Method of Transmitting and Receiving Electrical Energy, of which thefollowing is a specification.

My invention relates generally to the transmission and receipt ,of electrical energy, more particularly to telegraphy by means of oscillating currents, and still more especially to wireless telegraph) by means of electromagnetic Waves.

This application is a division of m 00- pending application No. '222,30l filed'Au "from the oscillations received, such difierof frequency being preferably slight and predetermined degree. Thus tor use I" d I may employ the apparatus shown Fig. 1, where 1 is an aerial groundat 2', 3 the primary of a transformer whose secondary 4t forms part of a circuit comprising a condenser 5, a coil 6 and with or without an additional inductance 66.

14 is a coil placed in inductive relation to the coil 6. The coil 6 may, if desired. have a magnetic core, as shown at 10 in Fig. 2, preferably consisting of extremely fine iron wire or sheet. The coil 14 is preferably fastened to a diaphragm or spring 7 and may be used directly as a telephone, or otherwise as shown in Fig. 2, it may move the contact or microphone 13 attached to it and connected with a battery 11 and indicating instrument 12.-

'17 is a source adapted to continuously maintain oscillations, preferably of a conthe interaction between voltages, or

stant strength cited by the source 17 in the coil 14. Alter-' the coil 6 may be attached to the diaphragm 7, and coil 14 natively, it is obvious that may be fixed. The interaction between the two fields produced by'the two coils causes the diaphragm 7 to move andproduce an indication, preferably by the efilcts of'the beats produced. A much stronger indication is produced by the interaction between the currents generated by the electromag netic waves and the locally generated magnetic field than would be produced by the currents dueto the electromagnetic waves alone, because the locally generated magnetic field may be made to have any strength desired.

It is characteristic of this invention that the locally generated alternating magnetic field is generated continuously and not intermittently as by a spark discharge. The duration of a single oscillation produced by a spark is in the millionth of a second. train oftwenty oscillations or twenty com plete waves, such as is commonly used in the art, this train of waves will last for approximately one ondhundred-thousandths of a second. Even if the train of waves should be prolonged to one hundred complete periods, the total duration of the train of waves would only be one twenty-thousandths of a second. The apparatus commonly used in the art for producing electrical discharges gives from five to" one hun-- dred and twenty sparks per second. Taking a figure near the higher number, say one 1 hundred sparks per second it will be seen neighborhood of one four- If we consider a I val between successive sparks the frequency of the locally and any practical coincidence could not be expected more than once in several seconds. It is also characteristic of my method that generated magnetic field should not be the same as that of the oscillations which it is desired to receive, for in this case. the chances are-even that the phase difierence should be such that no indication would be produced, there local frequency,

- tween difierent stations,

being no beats produced. It is also preferred 'that the difference in frequency should be small, because if the difference in frequency be large, the beats will occur at such rapid intervals as to produce an inaudible indication, where a telephone diaphragm is used, or a weak indication, through the inability of the diaphragm or spring 7 to respond quickly.

Itwill beevident that the number of beats per second will depend upon the difference between the transmitted frequency and the and as this may be varied, this affords a means of distinguishing beand where the receiving mechanism is made selective to the beat frequency, means of cutting out all stations except those with which it is desired to communicate.

Where the signals are produced by the in-- teraction of voltages instead of currents an appropriate corresponding type of receiver is used,-for example an electro-static telephone receiver.

This method may be used for simultaneously sending in Fig. 2; for a source of oscillating currents 25 may be operatively connected to the wireless conductor 1, 2 and so arranged as to generate oscillations in the aerial 1. This source 25 is also operatively connected as by the transformer 68, 69 out the use of the capacity 27, with the coil 14, in such a way that when the key 78 is depressed so as to cause oscillations to be generated in the wireless conductor, as by closing the circuit containing the field coil 76 and local exciting battery 7 7, oscillations of the same frequency and of the same duration are caused to occur in the coil 1%, and by adjusting condenser 22 the respective phases of the oscillations generated in the coils 6. 14, are arranged so as to be 90 de- Thus they produce no effect 7 or microphone 13, or at effect in one direction so grees apart. on diaphragm most a continuous and receiving, as shown with or with- I long as the oscillations persist. By this means the effect of the oscillations generated by 25 upon the receiver is neutralized or compensated and may be rendered entirely. inappreciable especially Where the receiver is tuned to respond to a given mechanical frequency. This allows sending without disturbing of the receiving apparatus. In Fig. 2 the condenser 27 may also be used for controlling the phase of the oscillations generated in the circuit 68, 27,25.

As alternative to 'the construction in Fig 6 and 14 bothv former, 4 is the secondary of the transformer,

and 16 is a stretched wire in the circuit of the secondary. The secondary 1S by the use of an inductance preferably tuned 71, the wire 16 being also 70 and capacity preferably frequency, 2'. e. the frequency of the'beats between the received and local oscillations. 10 is a magnetic core of finely laminated wire or sheet embracing the wire 16, and 14 is a coil operatively connected with the local source 17, which may be a high frequency dynamo as shown. In operation currents generated by the electro-magnetic waves in wire 16 in the field of core 10 will interact with the magnetic field generated by the source 17 in the magnet coil 14: and its core 10 and cause the wire to vibrate by such interaction, thereby producing an indication.

By the term alternating currents I intend to include oscillating currents, z. e. all currents varying periodically in intensity whether the sign of the oscillations be changed or not. Having thus described my invention and illustrated its use, what I claim as new and desire to secure by Letters Patent, is the following:

1. The method of. detecting the presence of alternating currents which comprises exciting a field at the station where such currents are received bysaid received currents, maintaining a supplementary field interacting with said first field, by means of a local source of energy, and meanwhile producing by said local source a compensating field which nullifies its signal producing effeet at the receiving station, while signals are being sent from said station.

2. The method of simultaneously sending and receiving wireless signals which comprises exciting a field by the received oscillations, exciting a second field by'oscillations locally produced and having a frequency 7 definitely differing from those received,

tuned to the desired mechanical time being sent,

menses causing the two fields to interacjt to produce a signal, and transmitting electric Waves of a frequency definitely diifering'from those being received, substantially as described.

' 3. The method of signa ing Which comprises exciting a field of force by oscillations received at a station, exciting a supplementary field by ,a local high frequency source and operating a receiving indicating instrument by the combined eflects of said two fields, generating oscillations for sending from the same station and neutralizing their effect on the receiving instrument by causing interaction in the field excited by received oscillations.

t. in. wireless telegraphy the method of receiving at a sending station which comprises exciting a field, of force by the reeeived oscillations and also by the oscillaannulling the effects of the letter on a receiving instrument operated by the influence of saidfield excited by the regeiyied oscillations by oscillations in a local iii wireless telegraphy the method of receiving at a sending station which comprises exciting a local field of force both by the sent and received oscillations and annulling the eliect of the former on a supple-- mentary local field excited by a local source and operating an indicating instrument by the combined effects of said field and the field excited by received oscillations:

6. The method of simultaneous sending and, receiving electric signals which comprises exciting a field of force by the received oscillations and also'by oscillations being sent, maintaining a supplemental locally excited field, producing signals by interaction of said two fields, and annulling the effect/of the oscillations being sent on the receiving field by oscillations of the same frequency simultaneously produced in said supplemental locally excited field.

In testimony whereof I have hereunder signed my name in' the presence of the subscribed witnesses.

REGINALD A. FESSENDEN.

Witnesses:

Jnssnn E. BENT, Annnnmn WOLENE.

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