US759216A - Wireless signaling apparatus. - Google Patents

Description

PATENTED MAY 3, 1904.

L. DE FOREST.

WIRELESS SIGNALING APPARATUS.

APPLICATION FILED MAR. 14, 1903.

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W/ TNE SSE S UNITED STATES Patented May 3, 1904.

PATENT OFFICE.

LEE DE FOREST, OF NEW YORK, N. Y., ASSIG-NOR TO THE GREATER NEW YORK SECURITY COMPANY, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

WIRELESS SIGNALING APPARATUS.

I SPECIFICATION forming part of Letters Patent N0. 759,216, dated May 3, 1904.

Original application filed May 14, 1902, Serial No. 107,273. Divided and this application filed March 1a, 1903. Serial To all whom, it may concern:

Be it known that 1, LEE DE Fonnsr, a citizen of the United States, and a resident of the city of New York, borough of Manhattan, in the county and State of New York, have invented certain new and useful Improvements in Wireless Signaling Apparatus, of which the following is a specification.

My invention relates to certain improvements in wireless signaling apparatus whereby the syntonizing thereof may be better secured and the effects of Waves non-syntonic therewith may be neutralized.

My invention consists of the novel parts and combinations thereof hereinafter described, and particularly pointed out in the claims.

This application is a division from my application for an improvement in wireless signaling devices, Serial No. 107,273, filed May 14, 1902. I

The drawings accompanying herewith show my invention embodied in forms now preferred by me and in sufficient variety to make clear the principles thereof and the manner of carrying them out.

Figures 1, 2, and 3 show forms of apparatus designed to respond to either one of two wavetrains differently periodic, but to be unresponsive to both simultaneously received and also to aperiodic wave-trains. Fig. 4 shows an apparatus designed to respond only to periodic wave-trains of one frequency, but to be unresponsive to all others. Fig. 5 shows a receiving apparatus designed like that of Fig. 4 to respond to periodic waves of one frequency, but to be unresponsive to all other wave-trains whether periodic or aperiodic. Figs. 6 and 7 show forms of sending or wave-train-producing devices adapted to work in harmony with 4 the forms of receiving apparatus herein shown. Figs. 8 and 9 are similar forms of apparatus designed to respond to wave-trains of either of two frequencies, but to be unresponsive to wave-trains of all other character, as well as to more than one simultaneously received.

One of the most serious troubles which has heretofore beset syntonic wireless signaling (N0 model.)

has been the inability to protect the syntonic receiving apparatus from the effects of aperiodic wave-trains, which by their power and 5 strength are able to force vibrations in any syntonic receiving apparatus. The effect of such an aperiodic wave-train is analogous to that of a blow given a tuning-fork, which causes it to vibrate irrespective-of any element 5 5 of time pertaining to the object delivering the blow. The same effect in a less degree is caused by a periodic wave-train if of any strength. By my present invention I am enabled to protect the indicating apparatus from the disturbing effect of such wave-trains and to make it responsive only to wave-trains of the desired frequency. I do not attempt to protect the wave-responsive device from the effect of such waves, but make such connec- 5 tions therefrom to the indicatingdevices that the effect thereon will be neutral except when the wave-trains are of the designed character. My present invention involves the use of two wave-responsive devices and a single sig- 7 nal-indicating device, with which the wave-responsive devices are connected in such a way as to oppose or neutralize each other. Each of these wave-responsive devices is connected with a wave-collector or antenna in any desired or usual manner, and said connection may be of a syntonic character for both or syntonic for one and non-syntomc or aperiodic for the other.

In Fig. 1 two antennae or wave-collectors A and B are shown, each connected with a system of Lecher conductors of different periods, whereby a difference in syntony is ob tained. The principle and action of these Lecher conductors are fully set forth in my 5 application Serial No. 97,239, liled March 8, 1902, and will not herein be repeated. 1n the apparatus shown in this figure the parallel conductors b and a, extending from the base of the antenna B to the wave-responsive de- 9 vice R, form one resonant syntonic system, while the conductors to and at, extending from the base of the antenna A to the wave-rcsponsive device-R, form another resonant syntonic system. In this case both systems employ a common length of conductor a, and the ground connection is made with this conductor.

A local indicating-circuit is provided for each wave-responsive device; but only a single indicating instrument is employed, the two local circuits being connected therewith in such manner as to oppose each other, so that if equal effects are simultaneously received from each circuit the result will be that each will neutralize the other and the instrument will not be caused to give a signal. This is true of the various forms of my invention herein shown.

In Fig. 1 both local circuits have a common section which contains the local battery Y. Choke-coils K K are also shown. The indicating instrument herein shown is a telephonereceiver F, having two oppositely-wound coils f and f one in each local circuit. With both of these equally energized no efiect will be produced in the diaphragm f, while if either be alone energized the usual telephonic effect will be produced in the diaphragm. An aperiodic wave-train will produce equal oscillations in both of the collecting systems, and consequently will not affect the indicating device. A periodic wave-train, if of the period for which either system is designed, will either affect that system to the exclusion of the other or will affect that system much more than the other and will therefore produce an unequal effect in the two coils f and f thus affecting the diaphragm to give a signal. Such an apparatus is thus responsive to a single wave-train of the frequency of either system and is unresponsive to periodic wave-trains of other periods or to aperiodic wave-trains. It would also be unresponsive to two simultaneously received periodic wave-trains corresponding in period, respectively, with the two systems.

The apparatus shown in Fig. 2 is like that of Fig. 1, eXcept'that the two systems are entirely distinct and separate. The antenna A has the Lecher conductors a a, while the antenna B has the conductors 6 b. The two 10- cal circuits are also entirely distinct.

The apparatus shown in Fig. 3 is like that shown in Fig. 1, except that the inductancecoils L and condensers G are employed to tune the systems. These may be employed in combination or separately. In fact, the method of securing the periodicity of the receiving systems is immaterial.

In Fig. f the antenna A is shown as connected with a periodic system consisting of Lecher conductors a c, the period being adjusted by condenser C. The antenna B is, however, directly connected with its waveresponsive device R, and this system is therefore aperiodic. An aperiodic wave train will, however, affect one system as readily as another, which is also true of a periodic wavetrain not agreeing with the periodic system. Neither will therefore be able to produce any effect upon the indicating device, while a Wave-train agreeing in period with the periodic receiving system will cause an unequal effect upon the coils of the indicating device and will thus produce a signal.

In such forms as have two ground connections, such as shown in Figs. 2, 3, and 4:, one of these ground connections should have a condenser G therein to prevent short-circuiting the local battery and yet permit free passage of the aerial waves.

Fig. 5 shows an apparatus like that shown in Fig. A, except that inductance-coils L are used to determine the period of the apparatus and a single antenna common to both systems is used.

Figs. 6 and 7 show forms of sending or wave-producing devices which may be used. It is of course evident that any form of periodicwave-producing apparatus may be used as a sending or transmitting device. If, however, an aperiodic wave-producer be combined with a periodic wave producer, any form of receiving apparatus not equipped with the protective feature of my invention would be affected by the aperiodic waves emitted. This would interfere with their receiving other messages, and if the emission of such aperiodic wave-trains be made to follow each other in an order having no relation to the order of the periodic wave-trains which convey the message such unprotected receiving apparatus would be hopelessly confused and unable to decipher the message, even if it were adjusted to the proper period.

Fig. 6 shows an antenna A connected with a syntonic system consisting of Lecher conductors c a. This is energized through a transformer T T from a spark-gap S, which is in a resonant circuit containing condensers C and a circuit containing a source of electromotive force, herein shown as consisting of an alternating generator P. This last circuit is provided with a key L, by which the duration and time of emitting the wave-trains may be controlled. The above apparatus constitutes a periodic wave-emitting system. The antenna B is connected directly with the circuit which contains the secondary T of the transformer, the primary T of which is in the circuit containing a source of electromotive force, herein shown as an alternating generator P. In this case no key or other means for intermitting the series of sparks is shown. Consequently a continuous series of sparks will be emitted. The apparatus of Fig. 7 is the same, except that one antenna only is used, it being connected with both sparking-cir cuits. Also both sparking-circuits are connected with the same source of electromotive force. The key is is, however, inonly one circuit. The single common antenna may be used in any of these devices in place of two antennae whenever desired.

Figs. 8 and 9 show forms of apparatus which are alike, except that Fig. 9 shows the threewire Lecher system and Fig. 8 the four-wire Lecher system. The indicating device. herein shown as a telephone-receiver, is placed in the central branch of a WVheatstone bridge. If the resistances U U are properly proportioned, a signal is given in the receiving in strument only when one of the wave-responsive devices R or R .is affected and not when both are affected.

It is evident that the principles of my invention may be applied to any syntonic receiving system and is not limited to use with the forms herein shown. The kind of waveresponsive and indicating devices employed is also immaterial. Any of the well known forms of such devices may be employed in carrylng out my invention.

Having thus descr1bed my mventlon, what I claim, and desire to secure by Letters Patcut, is

1. In a receiving apparatus for space-Sig naling, the combination with a syntonic and a non-syntonic receiving system, each containing a wave-responsive device, of an indicating device connected with both wave-responsive devices to be oppositely affected thereby.

2. In a receiving apparatus for space-signaling, the combination with a syntonic and a non-syntonic receiving system, each containing a wave-responsive device, of a local indi eating-circuit for each wave-rcsponsive device and an indicatingdevice common to both local circuits and oppositely affected by each.

In testimony whereof I have hereunto affixed my signature, this 25th day of February, 1903, in the presence of two witnesses.

LEE DE FOREST.

Vitnesses M. W. NOLAN, J. V. McMANUs.

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