US1480216A - Transmission system - Google Patents

Description

Jan. 8 1924. 1,480,216

J. MILLS TRANSMISSION SYSTEM Filed 001;. 11, 1916 T I T /m/en for.

l I Jalm Mil/s.

Affy.

Patented Jan. 8, 1924.

UNITED STATES 1,480,216 PATIENT OFFICE.

JOHN MILLS, OF WYOMING, NEW JERSEY, ASSIGNOR '10 WESTERN ELECTRIC COM- PANY, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF'NEW YORK.

TRANSMISSION VSYSTEM.

Application filed October 11, 1916. Serial No. 124,958.

will be understood from the hereinafter contained description of one embodiment thereof comprising a wireless system in which each of a plurality of terminal stations comprises a wireless telephone transmitting and receiving system and a wire telephone system associated therewith.

It is an object of the invention to prevent a circulation of power between the local transmitting and receiving system or to insure that the signals received by a wireless receiving system will be transmitted along the line wire in such manner as to not thereby effect the transmission of the same signal from the local wireless transmitting system.

The invention provides for generating at a transmitting station a control tone ofla definite frequency outside of the usual talking range, preferably below, which shall be superimposed upon the original talking current impressed on the modulator of the wireless transmitter. The carrier wave transmitted is accordingly modulated by both the talking and the control tone currents. Thetransmitted wave is received at a distant station Where it is detected. The detected signal currents are sent over the line wire and the simultaneously detected control currents operate a relay to render inoperative the local wireless transmitting apparatus by disconnecting the latter from the line wire. The local wireless transmitting apparatus is automaticall rendered operative by being connectedv to t e line wire upon the cessation of the detected control oscillations. Means are also provided to prevent the transmission of energy from the sending conductor or antenna while energy is being received by the receiving antenna at the local Station.

, A local circulation of power. or singing,

is thereby prevented as the signal currents are confined to the line wire and cannot effeet a transmisson of energy from the local transmitting apparatus.

Another object of the invention is to provide method and means for generating the control tone by means of talking currents.

This is done by supplying talking cur-- rents of suitable intensity to a tuned circuit, the natural period of vibration of which is the control frequency. Along with the control currents thus generated will be transmitted some of the impressed talking currents. The latter are suppressed by means of a filter which selectively transmits only the control currents.

A further object is to provide novel means for and methods of transmitting and utilizing control currents.

, Another object is to provide means for and methods of simultaneously efi'ectin a change in the condition of a distant station and translating message currents at that station.

For further particulars of the invention, reference may be made to the drawing, in

which, Fig. 1 indicates diagrammatically a are associated with a wired telephone s stem comprising a line wire 3. The hne,

3 represents any conductive system, either long or short, through which signal currents may be transmitted.

transmitted from the antenna 4 of the wireless transniitting system to a distant station, and si als from the distant station are adapte to be received by the antenna 5 of the wireless receiving-system, the received signals being transferred to the line wire 3. Talking currents originating in the line wire 3 are transferred bymeans of the transformers 6 and 7 .to the circuit 8 which includes a double pole switch 9, normally closed by means of the spring 46. By means of the switch 9, the talking currents are supplied to a circuit including the coils 10, 11 and 12. The coil 12 is inductively related with the coil 13in the input circuit of the Signals orig mating in the line wire 3 are adapted to be amplifier 14, the output circuit of the latter being adapted to supply amplified talking currents to the circuit 15. f

Inductively related with the coils 10 and 11 is the coil 16 which supplies telephonic currents to the input circuit of amplifier 17 The output circuit of'amplifier 17 is adapted to supply amplified signal currents to a circuit including inductance 18 and, condenser 19 tuned to a frequency beyond the usual talking range and called the, control frequeicy. The oscillations of the control frequency are vibrations of the natural period I of the tuned circuit including elements 18,

currents as will hereinafter be more fully set forth. The amplifier 21 is then adapted to supply amplified control currents to the circuit 23. I

The vamplifiers 14 and 21; are essentially unidirectionally conducting so that a local circulation of power in the circuit including amplifiers 14, 17 and 21 is prevented. Each conductor in the circuits 15 and 23 is provided with condensers 48, 49, and 51 as shown, whereby the direct currents, in the output circuits of amplifiers 14 and 21, are

confined to their respective output circuits. The circuits 15 and 23 are connected in parallel and are adapted to supply amplified talking and control currents to the resistance 24 connected in the input circuit of modulator 25. The utility of and principles of operation of the thermionic amplifier as a modulator have been heretofore discovered by others. Briefly, its operation, when 0011- nected in circuit as herein indicated, depends I rent is one in which the amplitude,

upon the fact that when the device is adjusted to work upon a suitable curved part ofthe grid potential-plate current characteristic and a given high frequency and one or more low frequency waves are impressed upon the input or grid circuit thereof, a'component ofthe output or plate current is a current having the given high frequency, but varying in "amplitude in accordance with the one or more low frequencies. Sucha current of variable amplitude is known as a modulated current. In a broader aspect, however, a modulated high frequency cfurroquency, wave form, or other characteristic is varied in accordance with a current wave former 32, the secondary of whic of lower frequency. The generator 26 of carrier oscillations is inductively associated with-the inputcircuit of modulator 25 by means of the transformer 27. The resist- Y ance 24 serves as a source of amplified signal and control currents, and since it is serially connected with the generator 26, the output circuit of modulator 25 is adapted to supply carrier oscillations modulated in accordance with both the signal and control currents. The modulated oscillations supplied by modulator 25 may be amplified by means'of one or more amplifiers 28. Amplified modulated oscillations are supplied to the sending antenna 4 by means of the transformer 29.

The carrier oscillations modulated in accordance with both signal and control current transmitted from a distant station are adapted to be received by the antenna 5. This antenna is inductively-connected to a suitable detector 30 by means of the transformer 31. The outputtcircuit of detector 30 includes the primary windin of a transis adapted to supply detected control and signal current to the circuit 33. The circuit 33 is connected through the filter 34 with the line wire 3, the filter 34 being adapted to su press currents of filter 34 forms a bridge connection with the line wire 3, the latter including the artificial line 47. The artificial line 47 tends to prevent the transmission of speech frequency signaling current tothe circuit 8'. However, no artificial line is perfect unless it is an exact hence additional means are provided to open circuit 8, and positively prevent the loss of the energy of received signals therein, as well as reventing their action upon the transmitting apparatus, or the circuit 18,

19. In advance of the filter 34 is connected the relay 35 which is responsive tothe control currents. When relay 35 is energized, it attracts its normally open armature 36 to complete a circuit from battery 37 to the relay 38 controlling switch 9. This opens the switch 9 and renders the transmitting system 1 inoperative by disconnecting the latter from the line wire3. When signals are no longer received by antenna 5 and relay 35 is deenergized, the spring 46 returns switch 9 to its normally closedposition. The relay 35 typifies any suitable means which will be selectively operated by control currents from the remote station. Selectivity of control currents may be effected by making use of difierences in frequency or other wave characteristic. In order to prevent any radiation of energy from the antenna 4, an armature 52- of relay 35 controls, through the connecting conductor 53, the circuit of the generator 1130 When relay 35 is energized the generator the control frequency. T e

circuit is opened. The means for opening the circuit 8 and the means for controlling the circuit of generator 26 may be used together or separately and are typical of many possible-equivalent arrangements for controlling the transmitting apparatus.

The terminal station A in Fig. 2 is identical with. the station just described, shown in Fig. 1. The terminal station B is similar to the station A except as to the adjustments of its filters and its control current generator whereby the station B is adapted to transmit carrier oscillations modulated in accordance with control currents of a frequency different from those transmitted from station A, and-the-carrier wave enerated at one station is of a frequency di erent from that of the carrier wave supplied at the other station. Each receiving system is tuned to the carrier frequency. supplied by the distant station. Furthermore, the modulated wave transmitted from. station B is adapted to be received by antenna 5 of station A, and the modulated wave transmitted from antenna 4 of station A is adapted to bereceived by the antenna 39 of station B. For simplicity, the'block 40 in Fig. 2 has been used to designate all of the connections'between switch 9 and transformer 29 in Fig. 1. The block 41 represents'the filter 34 in Fi 1, and all of the connections between this filter and the transformer 31 in Fig. 1 are represented by the block 42. The blocks 43, 44

and 45 at terminal station E represent circuits which are similar to the blocks 40, 41 and 42. respectively, at station A except for the adjustment of the various elements whereby each station'is adapted to generate and transmit both control and carrier currents of a frequency different from those generated and transmitted by the other station as explained above.

"Signal currents originating in line wire 3 will generate control currents of a freuency beyond the usual talking range, and t ese control and signal currents will be transmitted from antenna 4 as modulations of a carrier wave. This modulated wave will be received by antenna 39 at station B where the detected control currents will be effective to render the local transmitting apparatus inoperative by disconnecting the same from its associated line wire. The filter represented by block 44 at station B insures that only the signal currents will be transmitted to the line wire to which it is connected. The transmitting apparatus at station B becomes inoperative when carrier waves modulated by signal and control currents are being received by the antenna 39.

The presence of the control currents effectuates this result. During such times the transmitting antenna at station B will not transmit any energy, and therefore does not affect the receiving antenna; 5 or 39. In a similar manner, signals originating in the line wire at station B will generate control currents and effect the transmission of a carrier wave which is modulated in accordance with both the signal and the control currents. This modulated wave will be received by antenna 5 at station A where the signal currents will be transmitted along line wire '3 and the local transmitting. apparatus at station A will be rendered inoperative as long as the signal and control currents are received. As soon as talking ceases at either one of. the terminal stations, the relay at the other stag tion will be deenergiz'ed and the spring 46 will be effective to restore the connection of the transmitting apparatus to its associated line wire.

The .term telephonic currents as used herein is not limited to speechcurrentsg but may include other currents which may be transmitted by telephone apparatus such as those used to reproduce music. obvious that the invention maybe util'zed in connection with carrier current'or 0%her wire or cable signaling systems by substi uting conductive lines for the antennas. While one method only of producing control oscillations is disclosed herein, certain aspects of the invention involve pr nci les of broad novelty which are not dependent on any particular method of or means for producing the control oscillations. One .such important feature comprises transmitting signals and control energy as energy variations of the same frequency. Control currents.

may be defined as currents or impulses of, such characteristic Or characterlst cs as Wlll cause a useful and desired effect other than the mere reproduction of a message or part of a message at a' cooperating station. How-- ever, the use of control currents as defined herein is not intended to cover the case where waves of a third frequency are introduced and combined with a carrier wave modulated in accordance with a si nal for the purpose of securing greater l selectivity in reception of the signal. However, vthe possible useful applications of control currents according to the principles of the herein described invention are very extensive. Certain other features of the invention are of very general application and may be variously utilized.

What is claimed is:

1. The method of producing oscillationsof substantial amplitude of a frequency beyond the usual talking range which consists in impressing telephonic currents on an otherwise non-oscillatory' circuit tuned to a fre- (pjency beyond the usual talking range, t ereby producin oscillations of the free natural eriod 0 said circuit, separating said osci ations from other oscillations, and

amplifying them.

2. A stem for producing oscillations without t e speech frequency range, comprising a space discharge repeater, a source of It wil be ectrical telephone currents connected to the input" range which consists in ilmpressing telephonic currents on a circuit tuned to a frequency beyond the usual talking range, and

in suppressing oscillations of a frequency different from that of the natural oscillations of said circuit.

4. A enerator of relatively low frequency oscillations comprising a source of telephonic curren'ts,-,a circuit tuned to a frequency beyond the usual talking range, means connecting said circuit and said source whereby said clrcuit is caused by said source to carry oscillatory currents of its natural frequency, and means for separating said oscillations'from other oscillations.

5.111 a signaling system, the combination of a source of telephonic currents, a circuit tuned to a frequency beyond the usual talking range, meansfor supplying said currents to said circuit whereby currents of said frequency beyond the usual talking range are generated, and means associated with said circuit for suppressing oscillations of; a frequenciy within the usual talking range.

6; n. a signaling system, the combination of a source of telephonic currents, a circuit tuned to a frequenc beyond the usual talking range, means or supplying said currents to said circuitwhereby currents of said frequency beyond the usual talking range are-generated, and a filterinductively associated with said circuit.

7. The combination of a line wire provid-- ing a source of telephonic currents, a circuit tuned to a frequenc beyond the usual talking range, means or. impressing said curs rents onsaid circuit whereby currents of said frequency beyond the usual talking range" are generated, and a transmission circuit associated with said tuned circuit, said trans mission circuit comprising means for suppressing oscillations-of a frequency within the usual talking range.

8. In a wireless system, the combination of sources of control, signal, and carrier oscillations, means for modulating said carrier oscillations in accordance with both said control and signal oscillations, means for transmitting said modulated oscillations, means at a distant station for detecting said modulated oscillations, a signaling device for receiving the detected signal oscillations, and means responsive to the detected control oscillations.

9. In a wireless system, the combination income of a line wire comprising a source of telephonic currents, sources of control and-carrier oscillations, means for modulating said carrier oscillations in accordance with said telephonic currents and with said control osillations, a conductor adapted to transmit said modulated oscillations, a conductor adapted to receive said transmitted modu lated oscillations, means for detecting said telephonic currents and said control oscillations, at line wire adapted to transmit said detected telephonic currents,and means responsive to said detected control oscillations. v

10. In a high frequency signaling system, the combination of a source of telephonic currents,.a circuit tuned to a frequency beyond the usual talking range, means for supplying said currents to said circuit, a source of carrier oscillations, means for modulating said carrier oscillations in accordance with the natural oscillations of said tuned circuit, and a sending conductor adapted to transmit said modulated oscillations.

11. In a high frequency signaling system, the combination of a source of telephonic currents, a circuit tunedto a frequency beyond the usual -talking range, means for supplying said currents to said circuit, a filter adapted to suppress oscillations ofa frequency within the usual talking range and adapted to transmit the natural oscillations of said tuned circuit, a

- source of carrier oscillations, means for modulating said carrier oscillations in accordance with said natural oscillations, and a sending conductor associated withsaid modulating means. I,

12,111 a telephonesystem, the combination of a source of telephonicjcurrents, a cir' cuit tuned ton frequency beyond the usual talking range, means for supplying said currents to said.. c'ircuit wheneby currents of said frequency beyond -the.;usual talking range are generated. a filterfladapted to suppress oscillations of a frequency within theusual talking range and adapted'to transmit the natural oscillations of said tuned circuit, and

a circuit comprising means for combining said telephonic currents and said natural oscillations. v

. 13. In a telephone system, the -combina-. tion of a source of telephonic currents, a circuit tuned to a frequency beyondthe usual talking range, means for supplying. said currents to said circuit, a filter adaptedto supe press oscillations of a fre uency within the usual talking range and a apted to transmit the natural oscillations of said tuned circuit, a generator of carrier oscillations, means for modulating said carrier oscillations in accordance with said telephonic currents and natural oscillations, and means for transmitting said modulated oscillations 14:. The combination of an asymmetrically ice conducting circuit adapted to transmit telephonic currents, a second asymmetrically conducting circuit comprising means for tuning the same to a control frequency, a source of telephonic currents for supplying said circuits, and a circuit supplied by said asymmetrically conducting circuits whereby said telephonic currents and control currents are superimposed.

15. In a telephone system, the combination of a circuit adapted to transmit telephonic currents, said circuit comprising a thermionic amplifier, a second circuit comprising means for tuning the same tov a control frequency and a thermionic amplifier, a source of telephonic currents adapted to supply said circuits, and a sending circuit associated with the output side of said amplifiers whereby amplified telephonic and control currents are combined in said sending-circuit.

16. The combination'of an asymmetrically conducting circuitadapted to transmit telephonic currents, a second asymmetrically conducting circuit adapted to transmit control currents, said second circuit comprising means for tuning the same to a control he quency and means for suppressing telephonic currents, a source of telephonic currents for supplylng said circuits, and a sending circuit connected tobe supplied by said asy-mmetrically conducting circuits, said asymmetrical circuits being so connected as to preof a line wire, a sen v ce vmg antenna assoclated with said line vent a local circulation of currents therethrou h.

17. n a signaling system, a terminal station comprising a telephone transmitting and receiving system, and means responsive to an energization of said receiving system for rendering said transmitting system inoperative, but leaving said receiving-system I operative.

18. In a high frequency signaling system, a terminal station comprising a radio telephone transmitting and receiving system, a Wire telephone system associated with said radio telephone system, and means automatically operating by virtue of energy received by said. receiving 3 stem for control ling the transmission 0 signaling waves from said wire' telephone system to said transmitting system. i g

19. In a telephone system, the combination of a line wire, a receiving conductor adapted to receive modulated carrier waves and to transmit signals to said line wire and a sending conductor adapted to transmit signals from said line wire as modulated'carrier waves, and means automatically operating when signals are received by said receiving conductor for controlling the operative connection of said sending conductor to said line wire.'

- 20. In a telephone system, the combination ing antenna and a rewire, and means comprising a relay for automatlcally preventmg the transmlsslon of energy from. said sending antenna-while enu energy wire telephone system associate with said radio system, said transmitting system comprising a modulator and an'antenna and said receiving system comprising an antenna anda detector, and meansv responsive an energization of said receiving system to pre vent the transmission of energy from said I sendin system;

23. n a high frequency signaling system, I

the combination of. a line wire, a sendin conductor and a receiving conductor associated with said line wire, a distant source of control oscillations and of signal oscillations, and means responsve to the reception of control oscillations from said source by said receiving conductor for preventing the transmission of en conductor.

24.- In a high frequency signaling system, the combination of a line wire, a sending conductor and a receiving conductor associated with said line wire, a distant source of control oscillations and of signal oscillations, and a movable member r onsive to, the reception of control oscillatlons from said source by said receiving conductor for preventing the transmission of energy from said sending conductor.

25. In a high frequency signalin a terminal station comprising a ine wire rgy from said sending system,

adapted to transmit signal oscillations and y a te ephone transmitting and receiving system; said transmitting system compris ng a generator of control osc1llations,'a generator of carrier oscillations, means for modulatmg said carrier oscillations in accordance withfsaid signal and control oscillations and a conductor adapted to transmit said modulated oscillations; said receiving system comprising a conductor adapted to receive modulated signal and control oscillations, the frequency of the'latter being different from that of aid generated control oscillations; and means responsive to said received control oscillations for preventing the transmission of oscillations from said sending conductor. a

26. In a highfrequency signaling system, a terminal station comprising a me wire adapted to transmit signal oscillations and s nesoa'ie oscillations; means for preventing the transmission of the received control oscillations to 7 said line wire; and means responsive to said received control oscillations for preventing the transmission of oscillations from said sendin conductor.

27. n a high frequency signaling system, a terminal station comprising a line wire adapted to transmit signal oscillations and a telephone transmitting and receiving system; said transmitting system comprising a generator of control oscillations, a gen= erator of carrier oscillations, means for modulating said carrier oscillations I in accordance with said signal and control oscillations and a conductor adapted to transmit said modulated. oscillations; said receiving system comprising a conductor adapted to receive modulated signal and control-oscillations, the frequency of the latter being different from that of said generated control oscillations; and a movable member responsive to said received control oscillations to render said transmitting system inoperative.

28. In a wireless signaling system, the combination of a line wire, a telephone transmitting and receiving system, a receivcombinationof' a line wire, a telephone I ing: conductor, anda sending conductor assoclated w th said line wire, a distant source of control and signal oscillations adapted to supply said receiving conductor, and meansresponsive tothe reception of control OSCil. lations from said source by said receiving conductor for preventing the transmission of energy from said sending conductor.

29. In a wireless signaling system, the

transmitting and receiving system, a receivinn conductor, and a sending conductor associated with said'lin'e wire, a distant source of control and signal oscillations adapted to simultaneously supply said receiving con .ductor, and means rnsive to the reception of control oscillations from said source by said receiving conductor for preventing the transmission ofienergy from said sendmg conductor.

30. In a wlreless signaling. system. the combination of a line wire, a telephone transmitting and receiving system associated with said line wire, a distant source of control and signal oscillations apted to supply said receiving conductor, and means responprising a line wire,

sive to the reception of control oscillations by said receiving conductor for preventing the transmission of energy from said sending conductor, and means for transmission of the receive iations to said llne wire.

( ipreventing the control oscil- 31. In a high frequency signaling system,

a plurality of terminal stations each comprising a wireless telephone transmitting and receiving systemand a wire telephone system adapted to transmit telephonic currents associated with said wireless system; one of said terminal stations comprising a source of control oscillations, a generator of carrier oscillations, means for modulating said carrier oscillations in accordance with said telephonic currents and control oscillations, a conductor adapted to transmit said modulated oscillations; the receiving s stem at another of saidstations being a apted to said stations responsive to oscillations'received from another of said stations to renand der the local transmitting system inoperative. I i

33. In a high frequency signaling system, a pluralit of communicating terminal stations eac comprising a radio telephone transmitting and receiving systemv and a wire telephone s stem associated with said radio system, an means at each of said stations for automatically controlling the operative connection 'of the wire system to the local transmitting system when energy is received from another of said'stations.

34:. In a telephone system, a plurality of communicating terminal stations each coma sending antenna and a receiving antenna associated with said line wire, and means comprising a movable memher at each of said stations for automatically preventing the transmission of energy from a sending antenna while the local receiving antenna is receiving energy from I another station.

said receiving system comprising av conductor for receiving detecting the received oscillations, and

means responsive to the detected control oscillations for acting upon the local transmitting system, the control currents supplied by the source at one of said stations being of a frequency difierent from that of the control currents supplied at the relations, means for modulatin said carrier oscillations in accordance with said telephonic and control currents and means for transmitting said modulated oscillations; said receiving system comprising a con ductor for receiving the modulated oscillations transmitted from another station,

means for detecting the received oscillations, and means responsive tot-he detected control oscillations for preventing the transmission of oscillations from the cal transmitting system; the control currents supplied by the source at one of said stations being of a frequency different from that of the control currents supplied at the remainder of said stations.

35 terminal stations each comprising a line wire adapted to transmittelephonic our- 37. In a signaling system, a plurality of rents, a telephone transmitting and receiving system associated with said line Wire; said transmitting system comprising a source of control currents, a generator of carrier oscillations, means for modulating said carrier 0scillations in accordance with said'telep'honic and control currents and means for transmitting said modulated oscillations; said receiving system comprising a conductor for receiving the modulated oscillations transmitted from another station, means for detecting the received oscillations; means for preventing the transmission of said control oscillations to said line wire and a movable memberresponsive to the detected control oscillations for preventing the transmission of oscillations from the local transmitting system while modulated oscillations are being received; the source at each of said stations supplying control currents of a fre-' quency dlfi'erent from that supplied at the remaining stations.

38. In a signaling system, a plurality of terminal stations each comprising a line wire adapted to transmit telephonic currents,

a telephone transmitting and receiving system associated with said line wire; said transmitting system comprislng a source of modulated oscillations" transmitted from another station, meanstor .c'ont'rol currents, a generator of carrier oscillations, means 'for modulating said carrier oscillations in accordance with said telephonic and control currents and means for transmittin said modulated oscillations; said receiv ng system 7 comprising a conductor for receiving the modulated oscillae tions transmitted from another station, means for detecting the received oscillations, and a relay responsive to the detected control oscillations for disconnecting the local transmitting system from its associated line wire; the source at each of said terminal stations supplying control currents of a frequency different from thatsupplied by the others.

3 9. In a high frequency signaling system, a terminal station comprising a Wireless telephone transmitting and receivingfsystem, and means automatically operating under the influence of energy received by said receiving system for controlling theoperation of said transmitting system.

40. The method of signaling which comprises supplying impulses, a telephone signal and carrier waves and in causing the telephone signal to produce modulation of the carrier waves by the impulses.

41. The method of signaling which comprises supplying sustalned oscillations, a telephone signal and carrier waves and in causing the telephone signal to produce modulation of the carrier waves both by the signal and by the impulses during the continuanceof said si a1.

42. The method of signaling which comprises supplying sustained oscillations, a telephone signal and carrier waves, deriving said oscillations from said telephone signal and in modulating said waves in accordance with said oscillations.

43. A signal transmission system comprising the combination at the transmitting station of means for supplying a carrier wave, means for modulating said carrier Wave in accordance with both a message and with control impulses, means for impressing the resulting energy upon a transmitting medium, and means at a cooperating receiv-- in station controlled by the control impu se energy for-varying the receiving condition for the energy representing the message.

44. A signaling system comprising a modulator, means for supplying high frequency waves to said modulator, a plurality quency waves to said, modulator, and a pluparallel connected -with said of sources of modulating waves, a plu- 4 1' rality of paths in parallel connected to said modulator for leading modulating waves first named current mitting energy each of said paths being unsymand another path for from said thereto, metrically conducting, leading high frequency Waves means to said modulator.

4:6. A signaling system comprising a modulator, meansfor' supplying high frequency wavestov said modulator, a plurality of paths connected in parallel for supplying modulating. impulses to said modulator, a vacuum tube repeater 'in each of said paths, and unlike sources of modulating impulses connected to each of said paths. 1

47. The method which comprises producing at a transmitting station current of a characteristic which will operate receiving apparatus at a distant station, causin said current to generate other current whic will not operate said receiving apparatus, transfrom which similar currents can be derived at a distant station, deriving said currents at said station, utilizing said to eperate-receiving apparatus, and utilizing said other'current to control apparatus other than said receiving apparatus at said distant station.

48. In a signaling system, a plurality oi stations, each of said stations comprising a source of signaling current, means at each of said stations actuated by said source for generating control oscillations, and means at each station responsive to the generation of control oscillations at another of said stationsto prevent the operation of the local means for generating control oscillations.

49. in a carrier current system, a pair of stations, means at one of said stations-for producing carrier oscillations and control oscillations, means for modulating the carrier oscillationsin accordance with the con" troloscillations, energy transmitting means at the other or said stations, means for de-' riving control oscillations from said modulated oscillations, and means operative under the influence of said derived oscillations for controlling the transmission of signals from said other station to said one station by said energy transmitting means...

50. Themethod of signaling which comprises simultaneously varying the amplitude of the oscillations of a continuous alternat ing current in accordance with both signals and control impulses and preventing the production of control impulses when signals are not being sent.

51. The method of signaling which com prises simultaneously and concurrently varying the amplitude of the'oscillations of a continuous alternating current in accordance with both signal and control energy and separating and cooperatively utilizing the signal and control energy at a receiving station.

52. The method of carrier wave signal ing which comprises producing signals and control energy and transmitting the signals inseam and the control energy concurrently and not separately as variations of the carrier Wave.

53. The method of carrier Wave signaling which comprises producing and transmitting through a common medium sign'als and control energy simultaneously as variations of thecarrier wave, and separating and separately but cooperatively utilizingvthe signal' tion of means for supp ying a carrier wave,

means-for causing energy variations of said carrier Wave in accordance w th signals,

means for causingenergy variations of said carrier wave in accordance with control oscillations of a difi'erent frequency than the signals for affecting a cooperating receiving station, meansfor separating the control oscillation energy from ener of signaling frequency at a receiving station, and causing"these energies to produce difterent results contributing to the reception ofthe message represented by the energy of signaling frequency. i

56 In a signaling system, the combination of means at a transmitter for supplying a current ofa iven frequency, means at the transmitter or varying the energy content of said current for transmitting signals, and means at the transmitter controlled by said second-mentioned means for causing variations of ener y content of said current in accordance with control variations.

5?. lln a transmitting system, the combi nation of means for supplying a carrier wave, means for modulating the carrier wave in accordance with a wave to be transmitted,

and means for simultaneously modulating the carrier wave in accordance with control impulses for maintaining a cooperating receiving station in a condition adapted for receiving.

58. In a signaling system, the combina tion of means for supplying acurrent of a given frequency, means for concurrently varying the energy content of said current for transmitting signals, and means for causing variations of energy content of said current in accordance with control variations for maintaining a cooperating receiving station in a suitable condition for re ceivin 59. tion of means for supplying a. current of a given frequency, means for varying the energy content of said current in'accordance li; a signaling system, the combina-' with message currents, means for 'varying the energy content of said current in accordance with control impulse energy, a cooperating, station adapted to receive the message represented by said message currents, said station including means operated by the reception of said control energy for Y waves impressed upon one of said low fre- 7 quency lines to the other thereof, and devices responsive to the transmission of signaling waves in one direction through one of saidchannels for rendering and maintaining the other of said channels incapable of transmission.

61. A system comprising two low frequency lines, a high frequency system connecting said lines normally operative for the two-way transmission of signals between said lines, and devices responsive to the transmission of signaling waves in one direction through the system for rendering the high frequency system inoperative for transmitting in the other direction.

62. A telephone system comprising two speech-frequency circuits, two-way transmission apparatus normally conditioned for reproducing in either of sad circuits speechfrequency waves corresponding to those" in the other thereof by transmitting between said circuits waves modulated in accordance with speech-frequency currents existing in the circuit at the transmitting terminal, and devices controlled by and responsive to transmission in one direction for establishing and maintaining a condition unsuitable for transmission in the opposite direction.

63. A signaling system comprising twocircuits adapted to carry currents of comparatively low frequency, two-way transmission apparatus normallyconditioned for reproducing ineither of said circuits signals corresponding to those impressed upon the other thereof by transmitting higher frequency waves varied .in accordance with the low frequency waves impressed upon the circuit at the transmitting station, and circuit-varying devices responsive to transmission in one direction for disestablishing the normal condition for transmissionjin the opposite direction.

64. A radiant energy system comprising two stations each normally adapted to transmit radiant energy signals and to receive radiant energv signals transmitted from the other thereof, and means at one of said stations responsive to the reception of signals from the other of said stations for rendering and maintaining the receiving station inoperative for transmission.

65. A telephone iysteni .comprising "two stations each norma y adapted to transmit modulated high frequency waves and to receive and. translate into speech-frequency currents modulated high frequency waves transmitted from the other of said stations, and devices at one of said stations responsive to the reception of waves from the other thereof to change said station from the normally operative to an inoperative condition for transmitting.

66. A system comprising two communicating stations, means at one of said stations for transmitting carrier frequency waves, means operable under the influence of sound waves to vary said waves in accordance with a wave having a form characteristically different from said sound waves, and means at the other of saidstations operable under the influence of said varied waves to effectuate a result other than the reproduction of sound. v

67. A system comprising two stations,

.means at one of said stationsfor producing signaling frequency waves and carrier waves, means-operable under the influence of said signaling waves to cause non-signaling variations'in said carrier waves, a relay at the other of said stations, and means selectively operable by the reception of said waves having non-signaling variations. to actuate said relay. 68. A system comprising means for .producing voice currents or waves, means responsive to the production of voice currents for pr ucing, varying in accordance with said voice currents and other currents, and radiating high frequency waves, a circuit. at a receiving station, means responsive to the production of voice waves at said transmittings'tation to reproduce said waves, and means for reproducing said other currents and separatelv utilizing the energy thereof to vary the condition of said circuit.

69. The method of receiving modulated high frequency waves which'comprises deriving speech waves and otherwaves from the modulated waves, utilizing the speech waves to reproduce speech, and utilizing the other waves to maintain the receiving sta- 'tion in a more effective receivlng condltion than during the absence of said other waves.

70. The method of signaling which comprises producing a carrier wave and a signal wave and causing the si al to produce a plurality of sets of variatlons in the carrier wave, one of said sets being capable of reproducing the signal at a receiving station,

so 'I ceiving station operative by and responsive characteristics other than voice currents,

said source being operable under the influence of voice currents to produce such other currents, a third source of i currents, and means for combining the voice and other currents with currents from said' third source.

74. in a telephone system, a source of voice current, transmission devices, and means operable under the influence of voice waves produced by said source to-cause said transmission devices to transmit a current or wave from which a control current having characteristics other than a voice currentv may be derived at a distant intercommunh eating station.

75. in a signaling system, a source of electrical waves, a modulator, a plurality of paths between said sourceand said modulator, and means whereby said source causes waves of difierent characteristics to be trans mitted through said paths to said modulator. v

76. Thecombination of a source of waves, another source of waves of a frequency difierent from said first mentioned source operative under the influence of the production of waves by said first mentioned source and a third source of waves with a combining device and cans for impressing waves from-said sources upon said combining device.v

77. In atransmitting system, a carrier wave source and a source of voice waves in combination with means operative under the influence ofwaves from said second mentioned source to cause modulation of the carinseam rier waves in accordance with waves other than voice Waves.

means operable by and during the transmission of energy of a definite characteristic from another ofsaid stations for rendering the transmitting circuit of said one station inoperative.

80'. in combination, a telephone line, a radio transmitting means including a radiation system, a radio receiving means including an absorption system separate from said radiation system, means for normally connecting said line simultaneously to said radio transmitting and receiving means to permit radio telephony in either direction, and means other than a balancing circuit in said connecting means to prevent signals received by said receiving means frombeing transmitted to said transmitting means over said connecting means.

81. The method of signaling by electromagnetic waves which comprises radiating signaling waves from one station and thereby rendering inoperative another transmitting station during the continuance of signal radiation from the first-named station.

82. The method of signaling by electromagnetic waves which comprises radiating carrier waves from one station, intermittently modifying the carrier waves by means of signals, and maintaining another transmitting station inoperative during the time the transmitted waves are modified but not during the time unmodified waves are transmitted.

In witness whereof, it hereunto subscribe my name this 9th day of @ctober, A. 'D., 1916; l

' JOHN Mints.

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