US1537283A - Repeater for multiplex systems - Google Patents

Description

H. A. AFFEL REPEATER FQR MULTIPLEX SYSTEMS May 12, 1925.

Filed Sept. 30, 1919 EJJ Z Um ATTORNEY Patented May 12, 1925.

HERMAN A. AFFEL, or

BROOKLYN, NEW YORK, ASSIGNOR TO AMERICAN TELEPHONE AND TELEGRAPH COMPANY, A CORPORATION OF NEW YORK.

REPEATER FOR MULTIPLEX SYSTEMS.

Application filed September 30, 1919. Serial No. 327,457.

State of New York,

concern I, HERMAN A.

Arrnn, n the county of have inventin Repeaters for which the following to multiplex sigparticularly to resuch systems.

the invention rcsides in the provision of a repeater arrange;

ment for a multiplex carrier which separate amplifiers carrier frequency.

amplifying each system in are provided for Another feature of the invention resides in the provision of for a multiplex carrier plurality 'sions may simultaneously pcat'ei' arrangement being a. repeater arrangement system in which a of oppositely directed transmistake place, the reso organized that separate amplifiers will he provided for each carrier frcqucncy in each direction.

Another feature of the invention resides iii the provision of a repeater arrangement of the character described in the paragraph, in which pro separate oppositely into the proper group of preceding vision is made to directed transmissions amplifiers and to furthcr separate the diflcrent frequencies of the group of one-way transmissions, in order that they may be applied to the proper amplifiers for amplificati Still another feature of the invention resides in so arranging the transmitting channels associated with one outgoing line and the receiving channels associated with another incoming line at an intermediate station that the transniitti channels may be intci-con amplifiers.associated with ng and receiving nected so that the the channels may constitute one-way repeaters for amplifying through carrier transmissions.

These features are realized in the organization set forth in the following description and illustrated in the accompanying drawing, the figure of which constitutes a circuit diagram of one embodiment of the invention.

In the drawing, ML a two carrier transmission nd ML designate lines entering an intermediate station, which may be either a terminal station forsignaling in opposite directions, or a through repeater station for amplifying signals transmitted from one line to the other. A common transmitting circuit TL and a common receiving circuit RL are associated with the main line ML through a balanced transformer 10 and these circuits are rendered substantially conjugate by the provision of a balancing network MN, for balancing the main line ML. Similarly a common transmitting circuit TL and a common receiving circuit R-L are associated with the main line ML through a balanced transformer 10', an artificial line MN being provided for balancing the main line ML.

' A plurality of transmitting channels may be associated .with the common transmitting circuit TL through filters such as Tl? and TF These filters may be of any desired character, such as tuned circuits resonant to the carrier frequency which it is desired to transmit. Similarly a plurality of receiving channels may be associated with the common receiving circuit R-L throu h filters or tuned circuits such as RF and F the tuned circuits being resonant to the carrier frequency which it is desired to receive in a particularchannel. In a. like manner the transmitting circuit TL is associated with transmitting channels through tuned circuits TF and TF while the receiving circuit BL is associated with receivin channels throughtuned circuits such as RT, and RF In order tosupplement the separation between oppositely directed channels, which results from rendering-the oominon trans=- n'iitting and receiving circuits conjugate by means of the balancing artificial line, it may be desirable that the frequencies used for transmission in opposite directions should be different. The filters TF, and TF are therefore indicated. as being resonant at frequencies f, and f res ectively while the corresponding filters F and RF, in the receiving channels are indicated as being resonant at frequencies f, and f The filters TF, and TF associated with the transmitting channels of the main line ML, may have assigned to them the same frequencies as filters RF and RF so also frequencies f, and 7, corresponding to the frequencies to which the filters TF and TF are resonant may be assigned to the filters RF and RF associated with the receiving channels of the line ML.

The transmitting channel related to the filter TF includes a vacuum tube oscillator G1 of well-known type, the circuit of which is controlled by a transmitting relay TR, so

that telegraph signals may be translated into successions of trains of oscillations generated by the oscillator G The frequency of this oscillator, of course, the frequency of the filter TF An'amplifier TA is also included in the channel, for amplifying the carrier frequencies to be transmitted. This amplifier may be of any wellknown type, but is illustrated as a vac uum tube amplifier.

The receiving channel associated with the filter RF includes vacuum tube amplifiers RA and R A for amplifyingreceived carrier frequencies and a detector 'D for translating the received frequencies into telegraph signals. The detector may be of any well-known type, but is illustrated as a vacuum tube detector having in its output circuit receiving relay RR for repeating the received telegr. phic signals into a local receiving circuit. I

Similarly the channel associated with the filter TF includes an oscillator G con trolled by a transmitting relay TR and an amplifier TA While the receiving channel associated with the filter RF, includes vacuum tube amplifiers RA R A as well as a detector D, having in its output circuit a relay RR. The circuits of the various vacuum tube arrangements shown are all well known in the art and need not be further described. It will be understood that similar--apparatus will be associated with each of the other channels.

By means of the apparatus above described multiplex transmission may take place in either direction between the station illustrated and a distant station, over the line ML, and likewise two-way multiplex transmission may take place over the line tween the station illustrated and another distant st atioli. In order that the apparatus illustrated may be used for through repeating in connection with multiplex transmission taking place between the two distant stations over the lines ML and ML in tandem, means are provided for interconnecting oorresponding transmittin and receiving channels of the two lines, has a connection 21 may be provided between the output circuit of the amplifier R A of the receivin channel associated with the filter RF an the input circuit of the amplifier TA, of the transmitting channel associated will correspond to" with the filter TF This connection may be closed by means of a switch 8,. It will be noted that this connection does not disable the detector D,, but merely diverts some of the output energy from the amplifier R A to the amplifier TA The detector, therefore, still functions to record at the intermediate station the low frequency signals, while the high frequency carrier currents may be amplified by the amplifiers RA R A TA, and transmit-ted from the line ML to the line ML. When thus operated on a repeater basis, the generator (Sr should be inoperative. Since the generator does not oscillate except when the transmitting relay TR is actuated, by merelyleaving the circuit of the transmitting relay TR open the generator-will be, in effect, disabled.

A similar connection 21 tween the amplifier B A, fier TA,, for repeating in rection, said connection including a switch S,. It will be understood, of course, that similar connections may be made between other transmitting and receiving channels which have assigned to them the same frequency.

Where the system is to be operated on a germinal basis, the switches such as S and will be open. By operating the transmitting relay TR, successive groups of carrier oscillations will be generated by the generator G amplified by the amplifier TA, and transmitted through the filter TF to the common transmitting circuit TL. Similarly carrier frequencies from the other transmitting channels may be simultais provided he and the amplineously imposed upon the circuit TL and the several carrier frequencies transmitted over the line ML to the distant station. In coming carrier frequencies transmitted from the distant station will pass through the transformer 10' to the common receiving circuit RL and the frequcncieswill then be separated into the proper receiving channels by the filters such as RF, and RF The frequency passed through the filter RF" is amplified by the amplifiers RA, and RA, and is then detected or translated into low frequency signaling impulses by means of the detector D,, so that the receiving relay RR in the output circuit of the detector responds to the resultant direct current impulse and repeats said impulse to the local receiving circuit. Similarlyoutgoing transmissions may take place from the common transmitting circuit TL and over. the main line ML to a distant terminal station, while incoming transmissions from such station will be received by the common receiving circuit RL. As these operations will be similar to those already described, no further description is necessary.

When it is desired to operate the appathe opposite dimaintained open, so

ratus at the station illustrated, upon a through repeater basis, the switches such as S and S, will be closed. Referring to the circuit 21, it will be seen that a high frequency connection extends from the plate of the amplifier 11 A over the conductor-21 to the input or grid of the amplifier TA,. The return circuit is through the ground, as the filaments of both tubes are connected to ground. This connection acts as a shunt about the detector D,.. The circuit of the transmitting relay 'TR, should now be that the generator G, is inactive.

Vith the circuit in this condition, high frequency carrier currents incoming from the line ML are transmitted through the transformer 10 to the common receiving circuit RL and the various frequencies are selected by, means of the filters RF RF etc. into the proper channels. The frequency passed through he filter RF, is amplified by the amplifiers RA and B A, and part of the high frequency energy is then transmitted over the path 21 to the amplifier TA said energy being further amplified by said amplifier TA, and transmitted through the filter TF and over the circuit TL to the main line ML. Some of the high frequency energy from the output circuit of the tube T,A is also impressed upon the detector D and is thereby translated into low frequency signals to actuatethe-receiving relay RR, so that the signals which are imposed upon the repeated carrier transmission may be recorded at the repeater station. This provides a simple method of monitoring the action of the repeaters.

The action of the channels interconnected through the switch 5,, as well as the remaining channels which are not illustrated, will be similar to that already described and need not be further referred to.

It will be obvious thatthe general principles-herein disclosed may be embodied in many other organizations widely different from those illustrated, without departing from the spirit of the invention as defined in the following claims:

What is claimed is: h r

1. Ina signaling system, .a transmission line. means for simultaneously transmitting in one direction over said line a plurality of signals by means of carrier currents of a plurality of different frequencies, means for simultaneously transmitting in the opposite direction over said linea plurality of signals by means of carrier currents of a plurality of different frequencies, a one-way repeater in said line at an intermediate point for each carrier frequency transmitted in one direction, selective means on'the input side of each repeater for selecting thereto the carrier frequency to be amplified thereby, and selective means on, the output side of said on the input side of each repeater repeater for preventing carrier frequencies transmitted in the opposite direction from being lay-passed into said repeater, a oneway repeater in said line at an intern'iediatc oint for each carrier frequency transmitted 1n the opposite direction, a selective means for selecting the carrier frequency to be amplified thereby, and a selective device on the output side of each repeater for preventing carrier currents transmitted in said first mentioned direction from being by-passed into said repeater.

2. In a signaling system, a transmission circuit over which a plurality of carrier frequencies may be transmitted, means for impressing signals on each carrier frequency, a one-way amplifier corresponding to'each carrierfrequency associated with said transmitting circuit at an intermediate point, se lective means associated with the input side of each amplifier for selecting thereto the carrier frequency to be amplified, and selective means on the output side of each amplifier to prevent energy of other carrier frequencies from being by-passed into said repeater.

3. In a signaling system, a transmission circuit over which a plurality of alternating carrier currents may be simultaneously transmitted in opposite directions. means for impressing signals on each carrier current, a one-Way amplifier for each carrier frequency transmitted, said amplifier being associated with said transmission circuit at an intermediate point, a selective circuit associated with the input side of each amplifier for selecting thereto a single carrier frequency transmitted in its direction of trans iss'ion, and selective devices associated with tie output side of each amplifier for preventing carriercurrcnts of otherfrequencies from being by-passed into the output of the amplifier.

4. In asignaling system. a; transmission circuit overwvl'iich a plurality of carrier frequencies may be simi'iltaneously trans emitted in the opposite direction; a group of repeaters in said circuit at an intermediate point for amplifying the carrier frequencies transmitted in one direction, a second group of repeaters for amplifying the various carrier frequenciestransmitted in the opposite directions. means to separate the oppositely directed transmissions and apply them to the proper group of repeaters, and selective means to separate the various carrier frequencies and apply them to the proper amplifier of the group. i

t 5. In a signaling system, a pair of transmission lines over which a plurality of carrier currents may be transmitted, an intermediatestation at which said lines terminate, a plurality of channels for: superposing a'plurality of signals from said inter- Ill) mediate station upon one of said lines for transmission to a distant station, a plural ity of channels for receiving at said intermediate station a plurality of carrier frequencies transmitted over the other of said ines from another distant station, means associated with each of said first mentioned channels for translating low frequency signals into carrier frequencies, and means as sociated with said first mentioned channels for. amplifying, the carrier frequencies, means associated with said second mentioned channels for amplifying received carrier frequencies, means associated with said channels for translating the carrier frequencies into low frequency signaling currents, and means whereby the two sets of channels may be directly connected independently of said translating means, whereby the interconnected channels constitute through amplifiers for amplifying carrier currents transmitted from a distant station through said intermediate station to another distant station.

6. In a signaling system, an intermediate station, a pair of transmission lines extending in opposite directions to distant stations, a plurality of transmitting channels associated at said intermediate station with one of said lines, a plurality of receiving channels associated at said intermediate station with the other of said lines, means associated with each transmitting channel for translating low frequencyssignals into carrier currents, detecting means associated with each receiving channel, amplifying means associated with at least one of said sets of channels and means for directly interconnecting the transmitting and receiving channels independently of said translating and detecting-means, whereby the interconnected channels with their associated amplifiers constitute through repeaters for carrier frequencies transmitted from one distant station, through said intermediate station, to another distant station.

7. In a signaling system, an intermediate station, a pair of transmission lines extendin; in opposite directions to distant stations, a plurality of transmitting channels associated at said intermediate station with one of said lines, a plurality of receiving channels associated at said intermediate station with the other of said lines, means associated with each transmitting channel for translating low frequency signals into carrier currents, detecting means associated with each receiving eha nnel, amplifying means associated with at least one of said sets of channels, and means for directly interconnecting the transmitting and receiving channels independently of said translating and detecting means, without disabling said detectors, whereby said interconnected channels with the associated amplifiers constitute througl'r repeaters for amplifying carrier currents transmitted from one distant station, through said intermediate station, to another distant station, while said detectors record the signals at the intermediate station.

8. In a signaling system, an intermediate station, a pair of transmission lines extending in opposite directions to distant stations, means for transmitting a plurality of alternating carrier currents over said lines between said distant stations, each carrier current being transmitted from one distant station to the other at the same frequency throughout, means to impress signals upon each carrier current at one of said distant stations for transmission to the other, and means at said intermediatestation for impressing signals upon said carrier currents at said intermediate station for transmission to said distant stations.

9. In a signaling system, an intermediate station, a pair of transmission lines extending in opposite directions to distant stations, a plurality of alternating carrier current channels for signaling over said lines between said distant stations, each channel employing a carrier of the same frequency throughout the entire path from one distant station to the other, and means at said intermediate station for impressing signals upon each of said carrier currents at said intermediate station for transmission over said carrier channels to said distant stations.

10. In a signaling system, an intermediate station, a pair of transmission lines extending in opposite directions to distant stations, a plurality of alternating carrier current channels for signaling over said lines between said distant stations, each, of said channels employing alternating carrier currents of the same frequency throughout the entire path from one distant station to the other, and means at said intermediate station for impressing signals upon said carrier currents at said intermediate station for transmission in either direction to the distant terminal stations over each of said carrier channels.

11. In a signaling system, an intermediate station, a pair of transmission lines extending in opposite directions to distant stations, means whereby a plurality of alternating carrier currents may be transmitted between said distant stations over said trans mission lines, each alternating carrier current being transmitted at the same frequency from one distant station to the other, an amplifying repeater. for said alternating carrier currents at said intermediate sta tion, said repeater amplifying each of said alternating carrier currents without change in frequency, and means at said intermediate station for impressing signals upon said carrier channels through "said repeater.

12. In a signaling system, an intermediate station, a pair of transmission lines extending in opposite directions to distant stations, a plurality of alternating carrier current channels superposed on said transmission lines. for multiplex communication between said distant stations, each channel transmitting the same carrier frequency throughout the entire path from one distant station to for impressing signals upon said carrier channels through said repeater.

In testimony whereof, I name to this specification HERMAN A. AFFEL September, 1919.

have signed my 15 this 29th day of

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