US1029724A - Telephone-repeater. - Google Patents

Description

F. J. SHUBERT. TELEPHONE REPEATEB.

APPLICATION FILED JAN. 21, 1011.

IAKHYE autumn WITNESSES: I EN R .fifiw' By A TTORNE Y FRANK JOSEPH SHUIBERT, 0F PORTLAND, OREGON.

TELEPHONE-REPEATER.

Application filed January 27, 1911., Serial No. 605,032.

the art, at an intermediate point between the sections of a line connecting two telephone stations; and the association of these relays with the line circuits in such way that the incoming and enfeebled voice currents from the transmitting station will be instrumental in the production of other voice currents similar in wave form but greatly strengthened in volume, which larger-voice currents will go forth from the intermediate or relay station to the receiving station.

It has been found in the practice of the telephone repeater art that a ditiiculty arises when the'attempt is made to make the repeater system transmit alternately in opposite directions, as is necessary in ordinary telephonic conversation. This ditliculty manifests itself as a result of mutual interference between the receiving and transmitting elements of the repeater system. The strengthened currents passing from the repeater station on the receiving section of the line will affect the receiving element of the relay associated with that line section, in the same way that incoming currents over that section would affect this receiving element; and this, in turn, through the action of the corresponding transmitting element of the relay, will affect the receiving ele ment of the relay of the. other line section. This again, through its associated transmitter element, will react'on the receiving element of the firstmientioned line section, producing an endless chain of disturbances, and resulting in a phenomenon which is sometimes called howling.

It is a particular object of my present invention to so arrange the circuits and parts of my repeater system as to eliminate this difficulty, and to this end I make such pro-' visionthat the respective receiving elements of the relays of each of the line sections at the repeater station will be affected only by the incoming voice currents of its corresponding line section, and will be wholly unresponsive to any outgoing or relayed currents over its section of the line. I accomplish this by employing at the repeating station a pair of artificial lines, each having approximately 1 the same electrical characteristics as the corresponding section of the telephone line: and so associating these artificial lines with the circuits and apparatus of the repeater system that incoming currents over one of the line sectionswill have complete inductive association with the electromagnetic element of the corresponding relay; but so that the relayed currents from the transmitting element of one of the telephone relays Wlll pass out over the proper line section and the corresponding artificial line in such way as to affect inductive neutrality with respect to the receiving element of the relay corresponding to that line section.

A further and important object of my invention is to afford ready means for balancing the electrical characteristics of the artificial line with those of the corresponding line section, this means comprising a suitable source of varying current for test purposes, together with a convenient arrangement of switches and test apparatus, as will be more fully described hereinafter.

The drawing which accompanies this specification contains but a single figure, which is a diagrammatic representation of the circuits and apparatus at the repeater station connecting the two sections of the telephone line. It is to be understood that the apparatus represented by this drawing is subject to wide variation, the drawing purporting to represent only the general types of apparatus to be employed rather than the specific details, after a manner that is well understood in circuit diagrams relating to the telephone art.

Referring to the drawing, the repeating station ends of the two sections of the line.

are indicated at 2 and 21. Associated with each of these line sections are two induction coils and 7 for-the line section 2, and 20 and 16 for the line section 21, the purposes of which I shall presently make clear.

The telephone relays employed in connection with my system may be of any of they well known types, consisting" of an electromagnetic receiving element and a variable resistance transmitting element, the latter Specificatibn of Letters Patent. Patented June 18, 1912,

being placed under the-influence of the former through the medium of a soft iron armaof a carbon transmitter button similar to that of the well known solid back transmitter. The stationary element of this button is indicated at 25. Similarly, the repeater relay associated with the line section 2 consists of an electromagnet 10 and the variable resistance element 11 12. The electromagnet 10 is adapted to receive impulses from the line section 2 through the inductive in fluence of the coil 4. The variable resistance element of this relay comprises the armature and movable electrode 11 and the stationary electrode 12. The production of these relays, which are indicated diagram matically merely as a telephone receiver associated-with a telephone transmitter, forms no art of my invention, and I desire it to be .oistinctly understood that my invention contemplates the use of any form of relay elements which are capable of receiving a small or feeble current, and through the action of this current, producing in another circuit a larger and stronger current of similar wave form.

In the lower portion of my drawing I show diagrammatically two artificial lines associated with the line sections 2 and 21, respectively. The artificial line associated with the line section 21, as shown at 22, consists of a variable noninductive resistance 28, a variable inductive resistance 40, and a variable capacity 30. The switching arrangements shown for varying any of these at will are obvious, and these maybe of any well known type. The artificial line 8, corresponding to the line section 2, consists of variable non-inductive resistance 27, a variable inductive resistance 41, and a variable capacity 29. These artificial lines shall have a possible range of resistance, inductance and capacity wide enough to cover the possible range of the corresponding characteristics of the line sections with which they are associated.

The receivers 33 and 34 are adapted to be associated ,with the secondary coils 9' and 23 of the induction. coils 4 and 20, by means of the switches 35 and 36, respectively; ,the operation of these switches serving at the same time to cut off the corresponding receiving elements 10 and 24 of the telephone relays. In like manner the switches 37 and 38 may be actuated to cut off the normal connection between the secondary windings .15 and 26 of the induction coils 16 and 7 from their corresponding relay transmitter elements, and, when so operated, to connect these secondary windings with the circuit 39, which is connected with a source of high frequency alternating current. capable of giving as close approximation as may be desired in frequency and volume to voice currents. These receivers 33 and 34 and switches 35, 36, 37 and 38 play no part in the ordinary normal operation of the repeating system, and it is'convenient. in securing an understanding ofthe normal operation of my system to ignore these two receivers and to remember that the inductioncoil windings 9 and 23 are connected directly to the terminals of the receiving magnets 10 and 24, and that the induction coil windings l5 and 26 are connected directly in the local circuits of .the transmitting relay elements 12 and 25.

these incoming currents will pass through the windings 31- and 3 of the induction coil 4 in series, and throu h the artificial line 8 as a path from one slde of the line to the other. In other words, if the flow be con-j sidered as from the upper to the lower side of the line 2, the currents will divide at the point 5, one portion flowing through :the secondary winding 6 ot the induction coil 7 and the other portion flowing through the winding 3 and the artificial line. The effects of these two components of the current flowing in the same direction through the coils 31 and 3 of the induction coil 4 Wlll be cumulative with respect to the secondary winding 9 of that coil, and the induced currents in that coil willflow through the receiving magnet 10 of the relay associated with the line 2. The varying flow of current through the receiving magnet 10 will cause corredepended upon to aflect the receiver at the distant end of the line 21. Since the secondary coil 17 taps the inductive center of the line winding of the coil 20, and since the artificial line '22 is assumed to present the winding 32 over the real line 21 to the dis tant instrument, and the other portion will fiow through the winding 19 over the artificial line'22. Since these two portions of the current are alike in volume, form and phase, and since they flow in opposite directions through the two similar coils l9 and 32, it follows that their inductive influence on the winding 23 will be ml, and therefore that they will produce no effect upon the receiving magnet 24 of the relay associated with the line 21. Since the entire arrangement is symmetrical with respect to the two lines, it follows that any currents received over the line 21 will produce similar but stronger currents in line 2 without any retroactive effect upon the receiving .magnet 10 of that line. 1 v

It will be seen that I accomplish the transmission through the repeater device in either direction in such manner that relayed or strengthened currents will not affect the receiving magnet of the relay associated with the receiving section of the line. I do this by causing a division of both incoming and outgoing currents, and so associating each relay receiving magnet with its section of the line, that the two parts or divisions of any incoming currents to the repeating' station over that section will act upon the relay receiving magnet cumula- I tively; whilethe two divisions of any outgoing current from. the repeating station over that section will be equal, and will act on the relay receiving magnet difierentially. In the particular arrangement which I show, this result is accomplished by connecting the coils 6 and 17 to the center point-s of the line windings of the coils 20 and 4, and as the coils 6 and 17 are the ones which receive the induced currents from the local circuits of the relays, it follows, owing to the fact that the characteristics of the artificial lines are the same as those of the real lines, that the relayed currents through the two halves of the line winding-of the coils 20 and 4, respectively, will be always equal and in opposite directions. It is clear, however, that the two windings 3 and 31 of the coil i, or 19 and 32 of the coil 20, need not necessarily be made equal, as any in equality between the two windings of one of these pairs may be compensated for by a proportional adjustment of the resistance and other characteristics of the corresponding artificial line with respect to its line section.

In order to provide for the convenient adjustment of the artificial lines to make them as nearly as possible bear the proper relations, in their electrical characteristics, to the'correspondiug real lines, I provide the keys 36, 37, 33, the receivers 33 and 34, and the high frequency alternating current circuit 39. The generator connected with this circuit 39 maybe-one of alternating currents having a frequenjcy approximating that of the average frequency of vibration of the human voice, or it may be a generator of voice currents, such as an ordinary telephone transmitter. Assuming that it is desired to adjust the artificial line 8 to be as nearly as possible like the real line 2, the key 35 should be operated, thus'disconnecting relay magnet 10 and connecting the receiver 33 in its place in the circuit of -the induction coil winding 9. At the same time the key 38 should be thrown, thus disconnecting the coil 26 from the local circuit which includes the variable resistance '25 42-, and at the same-time connecting this coil 26 with the generator circuit 39. Under these conditions current from the generator circuit 39 will pass through the winding 26 v and will cause induced currents .to pass through the corresponding winding 6. These currents will divide at the point 5 between the real line 2 and the artificial line 8. When the artificial line has been made in all electrical respects like the real line, the current flowing through thetwo will be equal, and as these pass in opposite direction through the windings 3 and 31, their combined eiiects upon the coil 9 will be Therefore, silence in the receiver 33 will indicate that the proper adjustment of the artificial line 8 has been attained for the existing conditions on the real line "2. The

sameexplanation with respect to the keys 36 22 with the, real line 21 may be determined or secured.

Having thus described my invention, what I claim as new and desire"to secure by United States Letters Patent is:

1. In a telephone repeater system, a telephone line divided into two sections; a telephone relay, an induction coil having one winding in one of said line sections and its other Winding in a localcircuit including the receiving magnet of said relay, whereby said relay may receive energy from said sectionof the line; an artificial line associated .With the other section of said line, and

means for passing therelayed currents from said relay into said other section and said artificial line in multiple.

multiple.

2. In a telephone repeater system, two sections of a telephone line extending from a relay-station; a telephone relay; an induction coil having one winding connected to the receiving magnet of said relay and its other windin in one of said line sections; an artificial fine associated with the other section of said line and having similar electriczil characteristics; and means for passing the relayed currents from said relay into said other section and said artificial line in 3. In a telephone repeater system, two sections of a tele hone line joined at a relay station; a te ephone relay; an induction coil associating said relay with one of said line sections; an artificial line associated with the other section of said line; means for passing the relayed currents from said relay into said other section and said artificial line in multiple; and a second relay havingits receiving coil associated with said other line section and said artificial line,

'whereby relayed currents from said first re-.

lay do not afi'ect the receiving element of saidsecond relay.

4. In a telephone repeater system, a telephone line divided into two sections; a telephone relay; an induction coil having one of its windings connected in the circuit of one of said line' sections and its other winding connected with the receiving magnet'of said relay; an artificial line associated with the other section of said line; a local circuit for the transmitting element of said relay; a source of current in said local circuit, and an induction coil having its primary in said local circuit and its secondary in a common path in said artificial line and said other section of said telephone line.

5. In a telephone repeater system, a telephone line divided into two sections; a telehone relay; an induction coil connected to inductively transmit energy from one of said line sections to the receiving magnet of said relay; an artificial line associated with the other section of said line; a local circuit for the transmitting element of said relay; a

J source of current in said local circuit; an in- 'duction coil having its primary in said local circuit and its secondary in a common path in said artificial line and said other section of said telephone line; and a second relay having its receiving coil-diiferentiall associated with said other line section an said artificial line, whereby relayed currents from said first relay do'not afiect the receiving element of said second relay.

6. In a telephone repeater system, a pair of line sections joined at a repeater station; a pair of tele hone relays, each capable of receiving fe b e currents from one line section and impressing augmented currents on the other line section; a pair of artificial lines, one for each line section; an induction coil for each line section, each having its primary in the local circuit of the relay corresponding to the other section and its secondary in a common path of its own line and the corresponding artificial line; and a second induction coil for each line section having one-half its'primary in its line section and one-half in the corresponding artificial line, and its secondary connected with the relay magnet of that line section.

7. In a telephone repeater system, a pair of line sections terminating in a relay station a pair of artificial lines; means for adjusting said artificial lines to possess similar electrical characteristics to their respective line sections; means for impressing a periodically varyin test current on one of said line sections an its corresponding artificial line in multiple; and a telephone receiver adapted to be inductively, differentially associated with said line section and saidartificial line for determining the roperadjustment of said artificial line with respect to said line section.

8. In a repeater system, a telephone linedivided into two sections; an' artificial line for each line section; a source of test current; means for impressing said test current on each line section and its corresponding artificial line; a test instrument adapted to be differentially associatedwith res ect to the test currents from said source owing through the line section and its artificial line; and means for adjusting the electrical characteristics of each artificial line to approximate those of its line section.

9. In a repeater system, a telephone line divided into two sections; an artificial line for each line section; a source of test current; means for impressing said test current on either of said line sections and its corresponding artificial line; a test instrument

Images