US1746960A - Carrier communicating system - Google Patents

Description

Feb. 11, 1930. H. w. NICHOLS CARRIER COMMUNICATING SYSTEM Original Filed Jan. 16, 1924 ra/d W M'c/la/s. y M

Patented Feb. 11, 1930 UNITED STATES PATEN'IO'FFICE HAROLD W. NICHOLS, OF MAPLEWOOD, NEW JERSEY, ASSIGNOR T0 WESTERN ELEC- TRIC COMPANY, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION" OF YORK CARRIER COMHUNICATING SYSTEM Original application filed .lanuary 16, 1924, Serial No. 686,472. Patent No. 1,696,249, dated December 25, 1928. Divided and this application filed October 5, 1925. Serial No. 60,446.

This invention relates to carrier signaling and more particularly to a method of and means for associating systems using-carrier waves guided by line conductors and unguided carrier waves so that the frequencies used for communication between stations of the unguided wave system are controlled by a'frequency supplied by the wire system.

This invention provides an arrangement in which a carrier line system may-be associated with a radio system, including a plurality of stations any one or more of which may be adapted to maintain one or more simultaneous two-way communications with one or more distant stations, the frequencies used at the different radio stations being controlled by a wave supplied by the carrier line system. It

therefore contemplates a communicating system comprising carrier line and radio sections in which the frequencies of the carrier waves used in the radio sections are definitely fixed relatively to each other and to one line carrier frequency.

In accordance with this invention the line system is associated with one or more radio systems so that one of the line carrier frequencies is used as astandard or control frequency from which is derived all of the frequencies used for radio communications.

At a terminal radio station, the selected line carrier frequency is supplied to an antenna for radiation to the remote stations. Also at the terminal station, and at the remote stachannel of the line system. One standard carrier frequency would be continuously radiated over the whole area affected, so that there could never be any disagreement in frequency between any two points in the radio network. The difiiculties attendant upon maintaining individual oscillators supplying oscillations of desired frequencies at the different radio stations would be avoided, and the frequency spacing between all of the channels of the radio system could be accurately fixed.

With a system of the type described above it would be possible to obtain the well-known advantages occurring from the transmission of one carrier side frequency for each message, whereby the amplifiers used for communication purposes could be operated at maximum efliciency so that the number of amplifiers required in the system would be re- .relatively fixed with respect to a frequency of the line system.

A feature of the invention is the provision of means for obtaining a control frequency for a radio system from a carrier line system, whereby the frequency relation at any two points of the radio network may be constant.

This application is a division of an application of H. W. Nichols, Serial No. 686,472, filed January 16, 1924, which issued as Patent 1,696,249, December 25, 1928.

For a complete understanding of the present invention, reference should be made to the following description read in conjunction with the attached drawing which showsone arrangement whereby the invention may be carried into effect.

Referring to the drawing there is shown a communication system comprising a 'carrier line 1, coupled to a terminal station TS for multiplex operation by means of which a plurality of simultaneous two-way communicar tions may be held with a plurality of remote stations RS and RS The system will be described as applied to radio telephony.

The arrangement illustrated comprises a terminal station TS including a carrier line, a control frequency radiating unit, an antenna system for three transmitting channels, complete-apparatus for one transmitting channel, means for coupling the terminal apparatus of two additional transmitting channels to the antenna system, and two complete stations RS and RS which may be used at points remote from the terminal station TS. At

the remote stations, the transmitting terminal apparatuses are shown schematically. It is to be understood that the transmitting apparatus for the two additional channels at station TS and those used at the remote stations will be similar to that included in the channel completely illustrated at-station TS. However, it is to be understood that the station TS will be provided with a receiving apparatus for each channel which is similar to the receiving apparatus, per se, used at each of the remote stations.

At station TS the line carrier wave of desired f1 equency C after being amplified by the device 2 will be supplied to an antenna 3 and also to a harmonic generator 4. The frequency C is the control frequency for the radio network. It is received at the remote stations on antennae 2-0 and is then translated into harmonic frequencies. At each remote station, one or more of the harmonics are used to transmit signal modulated waves, while others are used to combine with incoming signal modulated waves and reduced frequency signal modulated waves, derived from the incoming waves, 1n the detecting process to reproduce the signal modulations. The generator 4 may be any Well known arrangement for producing, from a current of one frequency, a number of current components of harmonically related frequencies. A typicalexample of a generator'whi ch may be used for this purpose is disclosed in Kendall U. SJPatent No. 1,446,? 52, February 27 1923.

The output circuit of the generator 4 is provided with a plurality of selective circuits, one of which 5 is shown as adapted to select one of the harmonic current components, for example the sixteenth harmonic, which is supplied to the coil 6 included in the circuit of the modulator 7. P

Associated with the modulator 7 is a speech current supply circuit, including a transmitter 8, battery 9 and coil 100 which is inductively related to the coil 6. It is to be understood that the local speech current circuit is intended to represent any type of telephone system over which a subscriber may be connected to the radio apparatus.

With this arrangement a carrier wave of frequency 160 and speech currents are sup- 1,74e,eco

plied to the modulator 7 to produce in its output circuit a speech modulated carrier wave.

Any well known system for producing the modulated carrier wave may be used including any well known form of modulator. However, since at the receiving station detection is effected by supplying oscillations to combine with the incoming modulated wave, transmission of the carrier-component is not essential to the operation of the system, and hence any well known type of balanced modulator, such as, for example, that shown in Carson Patent No. 1,343,307, June 15, 1920 may be useda Included in the outputc'ircuit of the-modulator 7 is a band filter BF, which is adapted to pass substantially without attenuation one side frequency component of the modulated wave. The output side of the band filter is coupled by a transformer 101 to the ante. ma

circuit including the radiating element 10 connected through the inductance 11, and condenser 12 to a ground system at 13.

Apparatus similar to that described above, is provided to supply a single side band modulated carrier Wave of different frequency to each of the antenna elements 14 and 15. In each case the carrier wave will be supplied by the harmonic generator 4. The seventeenth harmonic 'may be supplied to the modulating apparatus associated .with, the antenna element 14 and the eighteenth harmonic to the modulator associated with the antenna element 15.

vAssuming that) S represents the essential frequencies of the speech band, and the u per side band is transmitted in each case, t ere will be radiated from the antenna element 10 I'll tem should be designed to have an impedance minimum for each frequency band assigned to the different channels, and that the resonance conditions or points of minimum impedance for each band should be independently con-- trollable.

- A system which meets these requirements and which is simple and economical to construct is shown at the terminal station TS.

In this system the antenna sections 10, 14 and 15. which are electrically or reactively unequal, are suspended from masts or towers 16 by supporting cable 17 The antenna system is connected to acommon round system When 18 through separate down eads. hoisted into position, the antenna sections constitute the sides of an equilateral triangle having the towers at its vertices.

With this construction it has been found '13 that, by'making the towers of the proper heights, spacing them a sufficient distance apart and using supporting cables of the proper lengths, the antenna sections were so situated relatively to each other that three different signal modulated carrier waves could besimultaneously radiated without interference.

It has also been found that, under certain conditions, three different carrier modulated" waves can be simultaneously supplied through a single down lead to the antenna system and radiated therefrom without causing interference. One condition under which this can be done is to provide antenna sections which are electrically or reactively unequal.

For the purpose of disclosing one practical embodiment of this feature of the invention, the antenna system used with the three channel terminal station is described below. The antenna system was supported on towers 130 feet high, the sides of the equilateral triangle were 160 feet long and the supporting cables between each tower and the adjacent ends of the antenna was feet. The carrier frequencies used in the three channels were respectively 775,000 cycles, 750,000 cycles and 725,000 cycles.

In a second triangular system the towers were 165 feet high, 500 feet apart and the supporting cables were 200 feet long from the tower to the adjacent end of the antenna. The carrier frequencies used in the different channels were 700,000 cycles, 730,000 cycles and 7 60,000 cycles.

With both of these systems, reaction between the antenna sections was practically negligible.

The antenna system for a three channel station has been described above, but the principles of this feature of the invention may be I applied to a system having any number of provided.

antenna sections. In all cases the sections would be arranged in the form of a polygon, i. e.-a four, five, etc. sided figure, with the towers at its angles and should be so supported that the reactions between the antenna sections do not exceed a definite value.

The control frequency C will be continuously radiated from the antenna 3.

The-different stations of the system are each provided with a receiving antenna 19 adapted to selectively receive one of the mcoming carrier modulated waves radiated from the terminalstation.

For the purpose of disclosing the principles of the invention let it be assumed that RS and RS are distant stations adapted to cooperate with the terminal station described above, that the antenna 19 of RS is tuned to receive the signal wave 16 (H- S, the antenna ,19 of RS is selective of the signalwave-l8 C+S, and a third station having a receiving antenna tuned to the frequency 17 C+S 1s Each of these stations is also equipped with an auxiliary arrangement for receiving the control frequency. The auxiliary receiver comprises an antenna 20 connected to a harmonic generator 21. The output of the generator is coupled to a circuit 22 including a plurality of circuits tuned to certain of the harmonics of the control frequency.

Since the receivers operate in the same manner, though the frequencies dealt with in each case are different, the following description of the receiving apparatus at RS will serve to illustrate the method of operation of all the receivers used in the system.

The incoming carrier modulated wave 16 C-l-S is received by the antenna 19 and im-- pressed upon the circuit including the input terminals of the detector 23, herein shown by way of example, as a three-element space discharge device.

The circuit 22, coupled to the harmonic generator 21, includes a circuit 24 tuned to the fourteenth harmonic of the control frequency and a circuit 25 tuned to the second harmonic of the control frequency. The tuned circuit 24., adapted to supply a frequency of 14C is coupled by a circuit 26 to the input circuit of the detector 23.

The signal wave of frequency 16 C+ S and the wave of frequency 140 are combined in the detector 23 to produce in its output circuit an auxiliary carrier modulated wave of inaudible frequency 2 C+S, which is selected by device 27 and is sup lied to a circuit including the input terminals of a second detector 28.-

. Q Oscillations of the frequency 2Care sup-- plied through the coupling circuit 29 to the input terminals of the detector 28 in whichthey .are combined with the auxiliary carrier 2 C+S to produce the speech currents. Speech currents traversingthe output circuit of the detector 28 are transferred bythe coupling coil or transformer 30, selected by the device 31 which may consist of a tuned circuit or filter, and supplied to the re= ceiver 32. 1

Circuit 22- coupled to the harmonic generator includes a third tuned circuit 33 which is selective of. a frequency component suit able for transmission such as, for example, the 19th harmonic. The circuit 33 is coupled by a transformer 34 to a modulator 35, having associated with it a circuit 36 for sup plying speech currents. Speech modulated carrier waves, produced in the output circuit of the modulator 35 and having the carrier component" as well as one side band component suppressed, are supplied through a transformeror repeating coil 37 to a transmitting antenna.

-the proper harmonic components at these stations to cooperate with the incoming Wave to produce an'intermediate modulated wave of frequency 2 C+S, two-way communications may be established between the station RS1 and RS2.

Since RS and RS are typical, of the complete arrangements used at any of the stations of the system described, they may represent the apparatus of two channels of the terminal station of which the transmitter TS is the transmitting terminal. In this case, the transmitting apparatus of each channel is coupled to either the antenna section 10, 14 or 15, and generator at supplies to the input circuit of the detector 23 harmonic components, of the proper frequency to produce an intermediate modulated carrier of 2 0+5.

While a radio system'embodying a single multichannel terminal station has been described it will be apparent that the carrier line could be connected to any number of similar stations adapted for single or multichannel operation and that apparatus for 0011- tinuously radiating the control frequency may be used at any one or more of the termi-' nal stations.

From the preceding description it will be apparent" thatthis invention provides a 'carrier communicating system comprising line and radio sections having the frequency relation and the frequency spacing between the radio channels definitely fixed. With this system very close co-operation between the wire an power may be conserved and eflicient operation of the different sections of the system may be secured, while the charges for personnel and maintenance may be reduced to a minimum.

Although certain circuit arran ements and specific details have been descri ed for the purpose of completely and clearly dis closin the invention, it is to be understood t'hat t is invention is not limited to the specific features described, but only by the scopeb of theattached claims.

What is claimed is:

1. In a carrier communicating system comprising line systems and radio systems having any number of communicating channels, the method of controlling the frequency relation between the systems and between different channels of the radio systems which comprises supplying to the radio systems from the line system a line'carrier wave for rad1o sections may be obtained,

2. A carrier communicating system com- I prising line and radio systems and means for supplying from said line system a line carrier wave for use as a control wave for said.

rier wave for use as a control wave for said radio systems, a plurality of stations for said radio systems, means for radiating said control wave from a station local to said line system, and means at the different stations of said radio systems, for translating said control frequency wave into other waves of different frequencies which are used as carrier waves for outgoing signals and also as oscillations to be combmed with the incominc signal waves to effect detection.

n witness whereof, I hereunto subscribe my name this 1st day of October, A, D. 1925.

. HAROLD-W. NICHOLS.

use as acontrol wave for theradio systems,

radiating said control wave for frequency translation at remote points of the radio systems and eflz'ectin'g frequencytranslations of said control wave for signal radiation at a point local to said line and radio systems.

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