US1667792A - Radio signaling system - Google Patents

Description

May 1;192s. v 1,667,792

' DE LOSS K. MARTIN RADIO S IGNALING SYSTEM Filed Jan. 11, 1923 mame cal-re Plum INVENTQR Patented May l, 1928.

UNITED .STATES PATENT OFFICE.-

. DE Loss n MARTIN, or onANGa'NEW-Jnnsnx, AssieNon To .aMERicA'N TELEPHONE y AND TELEGRAPH COMPANY, A CORPORATION or NEW Yonx.

RADIO SIGNALING SYSTEM.

This invention .relates to radio signaling.

` Campbell, Serial No. 327,553, dated September 30, 1919. By the proper spacing of the separate antenna structures constituting such an array and by the proper phasing of the currntsimpressed upon or received by such antenna structures, the directional characteristic of'such structures for transmitting and receiving may be controlled. Bysuch control we may effect maximum radiation or reception in a single direction or in two directions, either diametrically o posite lor at a more acute angle toeach ot er, or we may eiect simultaneous vradiation in many directions. v These, however, are by no means the only ways in which radiation from an' antenna array may be controlled but are simply illustrative of the directional iiexibil-v ity of an antenna array.

My invention consists in the utilization of this inherent characteristic of' an antenna `oarray to effect the transmission of telegraph or telephone signals between two or more stationsfconstituting a system.

- This invention will be better understood from the following description when read in connection with the attached drawing, of

Y which Figure 1 shows schematically two sta.-

tions, each having an antenna array by means of which the method in which my invention is embodied may be carried out, Figs. 2 and 2 show directional characteristics of a stem in which my invention is embodied, ment for a station adapted to'transmit telegra h signals in accordance with the princip es of my invention and Fig. 4 shows the circuit arrangement for a station adapted to transmit telephone signals.

In Fig. 1, A represents .a transmitting station and B a receiving station, each havty of separatefa'ntenna structures, a at ig. 3 shows the circuit arrange- .B depen irigian antennaarray, represented by a plul shown the use of an antenna array at the receiving station, it should be understood that an antenna array is not necessary at the receiving station in order to carry out the invention since an type of receiving antenna may used. lllloreover, the invention .is not limited to an antenna arra. of a particular type but may be embodied in any type of an arrayin which the directional characteristic may be readily changed by varying the phase angle of the currents ap.- plied to the separate antenna structures whereby the direction of radiation ofthe entire array may be readily changed. For the purpose of describing the principle of my invention the characteristic of the array shown at the transmitting station A of Fig.

l is that represented by the solid line cli'arn acteristic of Fig. 2. 'This characteristic designated a shows maximum radiation toward the right, and the zone'of radiationV is rather narrow. There is also a certain amount lof radiation, but' a relatively small amount, which is represented by the otherv solid line Aloois which radiate from the If the axial point o this characteristic. transmitting station A vnormally transmits alongthe line 1, the array .connected with 'thev receiving station B will vbe aiected thereby tothe maximum degree, assuming,

ofcourse,`that the individual antenna structures at stationB are so located and the phase controllingapparatus connected with the individual antenna and with the common receiving circuit are likewise so ad-V of the radiated wave is along the line 2 or 3, the antenna arra at station B would be affected to a lesser egree than if the transmission had been along the line 1 and, by Y controlling the radiation characteristic, the

effect upon the station B may made substantial y nil. From the foregoing brief de.

scription, it will be seen that the degree of receptiviy of the antenna array at station s radiation o f the ener from station A.

I employ this principle for the transmission of telegraph signals b directing a high frequency `impulse along t line 1 to repreupon the direction of maximum v sent the transmission of a marking signal and I alter the direction of radiation, that is to say, I direct-it along the lines 2 or 3 to represent a spacing signal. The form of the radiation characteristic, and the direction of-propagation for the marking and the Thus, 'in Fig. 2a' the `characteristic of the marking signal. designated a is similar to that shown in Fig. 2. In order to send a spacing signal, the radiation characteristic is changed so as to eectively suppress radiation along the line 1, whereby substantially no energy reaches thedistant receiving station along this line. This is shown by the dotted line characteristic designated b which shows substantially equal radiation in four directions but in which the amount of radiation in any direction is Avery small.

Having in mind the basic principle under which signals may be transmitted to a distant receiving station either by changing the line t of direction of transmission of the antenna array as shown in Fig. 2 or by changing the directional characteristic of the array as shown in Fig. 2, I `will now proceed to describe two transmitting cirlcuits embodying the foregoing principles,

one of which, Fig. 3, shows the means for transmitting telegraph signals and the other of which, Fig. 4., shows means for transmitting telephone signals.

In Fig. 3, X1, X2, X3 and Xn represent a plurality of antennastructures spaced at a definitempuart of a wave Vlength apart and, taken together, constitutingthe antenna array. Connected with each of the said antennae is a power am liier designated A1, A2, Aa and' An. ile these power amplifiers may be of any well known type it would probably be desirable to use the Iyvell known thermionic vacuum tube ampliers.

f. amptlifier's through a plurality of phase shi ing devices, PS2, PS2, PS3 and PSn is a source of high frequency current O, which Connected with each of the said the condensers-has a definite impedance Z.;

at the frequency of the current generated by the source O. Each of the said phase shifting devices has associated therewith supplemental condensers designated C3 and C4', in connection with PS1,which normally are lnot connected effectively into the circuit of the network.

High frequency oscillations will be impressed by the conductors 3 and 4 upon the conductors 13 and Maand will be radiated by'the antenna X1; and in similar manner oscillations will be impressed upon the conductors l5 and 16, 17 and 18 and 19 and 20 and radiated by the antennae X2, X3 and `Xn. Assuming that-the key K is open, the phase angle which these oscillations will have when applied to the respective antennae will be'determinedby the impedance Z2 of the networks PS2, PS2, PS3 and PSD, individual to their respective antennae. Let it ybe assumed that these' oscillations are phased in suc-l1 a manner that the direction of radiation is represented by the dotted line charac'teristic b of Fig. 2'. This represents the transmission of aspacing signal to the distant receiving station, since theI amount of energy received there may be made practically nil by making the angle 9 suiiciently large. In order to transmit a' marking signal, the key K isclosed, which in turn operates the relays R1 and R2 of phase shifter PS1 by the iow of current from the battery B over conductors 2 'and 6, relays R1 and R2, conductors 5 and 1 and through the key K. 'In similar manner, other relays connected with the phase Shifters PS2, PS3

and PSu would be controlled by the current from the battery B. The operation of relays R1 and R2 effectively connects into the network of the phase shifter PS1 theV condensers C2 and C2', which changes the phase angle of the-current flowing from the source O to the antenna X1 because the impedance of the net work is changed from Z to Z. In hke manner, although not necessarily to the same degree, the phase angle of the current owing from the -same'source to the other antennae of the array would be changed so that the directional characteristic of the array would be represented by a of Fig. 2. 'Huis results, therefore, in the transmission of n marking signal to the distant receiving station.

In carrying outl the method of operating -llU r he direction of the of Fig. 2a, but,

this circuit in the Fig. 2, the amount of radiation in any direction is practically signal is being transmitted, while, on the ot er hand, the radiation is a maximum in receiving station when a marking signal is to be transmitted. This may be .effected in the arrangement shown in Fig. 3 by the proper adjustment of the networks'of the various phase Shifters to produce substantial neutralization of radiation whenthe key K is open as shown by b on the other hand, to effect maximum radiation along a predetermined line, as represented by a of Fig. 2, when amarking signal is to be transmitted.

The arrangement for transmitting telephone signals is showniin Fig. 4., in which the same reference numerals or letters as are of all of these devices,

used in Fig.. 3 represent similar parts. In

this figure, a type of antenna array similar to that shown in Fig. 3 is used. Each antenna of the array has connected therewith a power amplifier which is connected through a phase shifter with a. source of high frequency current O. The phase shifter differs structurally, at least, from that shown in Fig. 3. Y Phase shifter PS1, which is typical comprises a plurality ofiron core inductance coils, .of which certain of the windings are connected with the high frequency source and other windings are connected with the low frequencyncrophone M, having The high frequency L4 have,connected therewith condensers C1, C2, C, and C4,

which togetherv constitutea network having a deinite impedance Zo at the frequency of the source O, provided the permeability of theiron cores remains fixed. The phase anle of the current supplied to the antenna gil, for example, may be changed-by varying the ermeability of the iron cores. This may be one by actuating the microphone M,

which varies the ilow' of current from the battery B over a circuit comprising conductors` 1 and 5,' windings Le, L5, L9, L7 and L8 and conductors 6 and 2. It will be readily seen that the permeability of the iron-cores-upon which the various windings are placed will be varied in accordance with the voice currents resulting from the actuation of the mii ances which results inl substantially mmer crophone M. These variations of the permeability of these cores will result in changing the value of the high frequency induct diate changes in the.l phase angle ofthe high frequency currentsl applied to the 1 antenna X1. It will, -of course, be apparent that while these changes in the phase angle are occurring in the current applied to e antenna X1, similar changes occurl in the cur- -rents applied to the other antenna, by virtue of the operations of the phase Shifters PS2,

manner represented by nil when a spacingA voice Waves are imp ingi-ng upon the microa direct current source B connected therewith. windings L11, L2, L3 land circuit is shown in Fig. 12 of the said Aappli- PS3 and PSD. If the phase Shifters are sov adjusted that when no variations of theidirect Acurrent circuit are occurring, the phase cordance with the changes in the direct curi rent circuit resulting fromthe voice waves. It will be apparent, therefore, that at a distant receiving station such as B of Fig. 1, having an antenna array which is adjusted to give maximum receptivity along the linev 1, the' receptivity would vary in accordance with variations of the 'angle 0 representing the deviation of the radiation characteristic from this line, that is to say, the amount ofcurrent received at B would vary in accord- -ance with 'the voice waves impressed upon the microphone M. It will be accordingly seen that the radiation characteristic va. of

Fig. 2 which represents the normal radiation o the antenna array of Fig. 4, when no pl1one M, may be shifted in accordance with `the volce waves impressed upon the said'microphone so that the angle 0 which the longitudinal axis of the characteristic a makes with vthe line `joining the transmitting and the receiving stations line 1 of Fig. 1, will vary in accordance with variations of the voice waves.

lWhile no mention has been made'heretoy lfore of the arrangement of the receiving circuit of this system, it is to be understood that any well known type of receiving antenna may be used. If it be desired to use an an tenna array at the receiving station, such a cation of George A. Campbell, Serial No.` 327,533. It employs a plurality of antennee spaced a definite part of a wave length apart and having connected therewith and individual thereto a each havin and phase s ifting devices, which circuits are connected with a common receiving circuit` having a suitable local-source of high frequency oscillationsfor the4 detection of the 120 lowfrequency signals. While this invention has been `describe as embodied .in a paiticular form and arrangement of parts iris to'be understood i that it is capable of embodiment in other and 125 di'erent'form within the spirit and scope of the appended claims. Y f What is claimed is: l 1. In a vradio signaling system having a transmitting station comprising a transmit- 180 ico as, for example, the.4

plurality of circuits, the necessary filters, ampliiiers ting antenna array, Aa source of high frequency current, and signaling means for controlling the vdlrectional characteristic of the said array connected therewith, and a .re

i trolling the directional characteristic of the said. array connected therewith, and a receiving station having receiving apparatus connected therewith, the method of signaling which consists in varying the magnitude of radiation in a given direction only by and in accordance with the signals being. transmitted.

3. In a .radio signaling system havinga transmitting station comprising a. transmitting antenna array, a source of high frequency current, and signaling means for controlling the directional characteristic of the said array connected therewith, and a. receiving station having receiving apparatus connected therewith, the method of signaling which consists in producing maximum radiation in a given direction only to effect the transmission of one type of signal and to produce substantial suppression of radiation to effect the transmission of a different type of signal.

4. In a radio signaling system haying a transmitting station comprising a transmitting antenna. array, a source of high frequency current, and signaling means for controlling the directional characteristic of the said array connected therewith, and a receiving station having receiving apparatus connected therewith, the method 0f signalving which consists .in varying the phase of the high frequency currents by and in accordance with the signals being transmitted,

whereby the directional characteristic of the array maybe varied.

5. In a radio signaling system comprising a'transmittin station and a `receiving station', each having an antenna array arranged for unilateral transmission and reception therebetween, the degree of receptivity varying with the changes in the directional chari acteristic of the transmitting array, the method of signaling which consists in producing such a directional characteristic' of the transmitted-wave as to eii'ect maximum receptivity and varying the directional characteristic to vary the degree of receptivity by and in accordance with `the signals being tennae, means individual to each antenna to control the phase of the current supplied thereto by the said common source of current, and means to simultaneously change the phase of the current supplied to each antenna whereby the array is caused t0 have a different dlrectional characterlstic.

'7. In a radio signalingsystem, the combih nation with an antenna array comprising a` plurality of antennae substantially equally spaced apart, of a source of high frequency .currentcommon to the said antennae, a phase shifter individual to each antenna and connected between the said source and each antenna, a source of signalsalso common to said antenna, and switching means individual t0 each phase shifter and controlled by said source of signals to change the constants of the saidzphase shifter whereby the phase angleof the currents supplied to the .antennae is changed and the axis of the beam. of energy radiated by the said array is shifted.

In testimony whereof, I have signed my- Vname to this specification this 10th day of- January, 1923.

, IniLossicMARTIN.-l

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