US1672977A - Repeating coil - Google Patents

Description

F. E. FIELD RBPEATING 0011.

June' 12.11923,-

Filed July 26. 1922 Fra Patented June 12, 1928.

- N D- TATES PATIENT OFFICE. f

115mm: E. FIELD, or SOMERVILLE, NEW, JERSEY, VASSIGNOR 'ro WESTERN ELECTRIC v HCOMPANY, mconrona'rnn, on NEW YORK, 11. Y., A CORPORATION 01' NEW YORK.

REPEATING c011,.

Application filed July 26,

This invention relates to balanced translating circuits and pertains, especially to means for preventing unbalance and distortion in a speech transmission circuit in which i 6 transformers are employed for connecting a tween the cores and the casing are practi cally negligible whereas the capacities between the adjacent layers of the superposed coils have considerably larger values which cannot be neglected.

It isan object of'this invention to materially reduce 'in transformers of the above and similar types, the effect ofthe capacities between-the primary and secondary windin 1 A nother object of the invention is to substantially eliminate the effect of the capacities between the prima'rv and secondary 25 windingsof the input transformer;-

These objects are attained in general. by connecting the grids of the associated vac uum tubes to the layers of the secondary sections of the input'transformer which are non-adjacent to the primary sections of the transformer and by connecting the'cathodes of the tubes to the layers of the-secondary sections which'are adjacent the primary. The anodes of the tubes are connected to the non-adjacent layers of the primary sections of the output transformer and the cathodes to the adjacent lavers of the primary through a battery. The outer layers of the primary of theinputtransformer are connected so as to be in the-electrical center of the primary, and are therefore maintained at a substantially constant potential with'respectto ground when the winding is connected to-a' balanced circuit such as an 45 open wire'line The cathodes are grounded The etfect' of this arrangement thus is to short-circuit the interlayer capacities through ground. j I

Referring now to the accompanying drawings, Fig; '1 discloses the winding of the transformers and their connections to the repeaters, and Fig. 2 is a diagrammatic represent-ation thereof. r

i The circuit of this invention comprises a transformer B, the primary of which is con-' 1922. Serial No. 577,522.

nected to an incoming line A which is balanced with respect'to ground and the secondary of which is included. in the input circuit of a balanced vacuum tube repeater circuit C, the output'circuit of which includes the primary of a transformer D, the secondary of which is connected to an outgoing line E.

The input transformer may comprise a substantially rectangular frame 1 around the ends 2 and 3 of which are wound multilayer primary coils 4'and 5. Surrounding the coils 4 and 5 and having their inner layers adjacent the outer layers of said coils are multi-layer secondary coils 6 and 7 which cooperate with the coils 4 and 5 to formthe primary and secondary of the transformer.- Bindingposts 8,9, 10 and 11 are provided for the inner and outer layers of the primary coils 4 and 5. For the inner and outer layers ofthe secondary coils 6 and 7 are provided the binding posts 12, 13, 14 and 15. The binding posts 9 and 10 are connected to the incoming line and a conductor 16 con nects the binding posts 8 and 11. The con ductor 16 by virtue of its symmetrical po- 8 sition with respect to the incoming line of the circuit is maintained at effective ground potential becauseof the capacities to ground of the two members of-the incoming line. The binding posts 13 and 14 ofthesecondary coils are connected bya conductor 17 and the binding posts 12 and are connected, respectively. with the grids 18 and 19 of the repeater tubes 20 and 21. The cathodes 22 and '23 of the tubes 20'and 21 are in circuit with the battery24 which supplies heating current to the cathode I and are grounded at 25. The conductor 17 is connected to the negative pole of the battery 28. The output"transformer for this circuit may comprise a substantially rectangular frame 31 around the ends 32 and83 of which are wound multtlayer secondary coils 34 and 35; Surrounding the coils 84 and 35 and having their inner layers adjacent the outer layers of said coils are multi-layer primary coils 36 and 37' which cooperate with the coils'34 and 35 to'form the primary and secondary of a step down transformer. Bindingposts 38, 39, 40 and 41 are provided for the inner and outer layers of the primary coils 36 and 37.v For the inner and outer layers of the secondary coils 34 and 35 are provided the binding posts 42, 43, 44 and 4-5. The binding posts 39 and 40 are con nected by the conductor 46' to: the cathodes 22 and 23 through a low impedance battery 47 of relatively small voltage. The binding.

posts 38 and 41 are connected, respectively,

to the anodes 26 and 27 of the tubes and.

21. The binding posts 43 andist are connected to the outgoing line and the binding posts 42 and 45 are connected by conductor 48 which, because of its symmetrical: position with respect to the outgoing line of the circuit, is maintained at effective ground potential by virtue of the capacities to ground of the two members oi 'the outgoing line.

Fig. 2 discloses, diagrammatically, the effect of this method of connection upon the capacities between the adjacent layers of the primary and secondary coils of the input and: output transformers. Those portions of the: coils adjacent the binding posts 8 1 1, I2 and 1 5 represent-the outer layers of coils 4, 5,6 and 7,. respectively, and those portions adjacent the'binding posts 9, 10. 13 and 14 represent the inner layers of said coils 4, 5,

6 and 7 respectively. The capacities F and F are therefore conveniently represented as being between the outer ends of coils 4 and5 and the inner ends of coils 6 and 7,.respec tively. Since the terminals 8 and 13, and 11 and 14 of the capacities F and F are connected to'the ground potential member 16 and to ground 25, respectively, theeffect of these capacities is nullified to such. an extent that they h'avecno effect upon the transmission' of speech waves.

In the output transformer, those portions of the coils adjacent the binding posts 38. 41,- 42 .and 45 represent the outer layers of the coils 34, 35. 36 and 37, respectively, and those portions adjacent the binding posts 39, 40,- 43 and 44: represent the inner layers of said coils 34, 35, 36 and 37, respectively. The

capacities G and G are therefore conveniently represented as being between the innor end of coil 34 and the outer end of coil 36, and between the inner end of coil and the outer end of coil 37, respectively. Since the terminals 4-2-and 45 are connected to the I ground potential member lS and the terminals 39,.and 40 are maintained at a potential iii) .in excess of ground equal only to the potenfor keeping the adjacent layers of the priprising a multi-layer primary coil and a mary coils of each section at a fixed potential with respect to ground.

2. In a transmission'circuit, a transformer having a pair of sections, each section commulti-layer secondary coil surrounding said primary coil, a connectionbetween the outer layers of the primary coils, connections from thei nnerlayers of the primary coils to a line the two sides of which have like capacities to groundwhereby said first mentioned connection is at a fixed potential with respectto ground, a pair of vacuum tubes, each having a cathode and a grid, connections -be-' tween the outer layers of the secondary coils and the grids of said tubes, and connections between the inner layers of the secondary coils and-the cathodes of said tubes,said last named connections being grounded.

In a'transmission circuit, a transformer comprising coaxial multi-layer primary andsecondary windings-insane including connections from said windings to a line having like capacities between its two sldes and ground for maintaining the layer of the said connections at fixed potentials with respect to ground, said means lncludingaconductive path between one of said connections and ground. and electrical paths .from'the coils joined by the other. connection to line having its two sides similarly capacitatively related to ground.

5. In a transmission circuit, a transformer comprising a pair of multi-layer primary coils in series, means tor'keeping the ter- -minals of the outer layers of each'ot said coils at substantially ground potential, said means includingconnectionsfrom the inner layers of said primary coils to a line having like capacities between its two sides and ground, a pair of multielayer secondary coils surrounding said primary coils respectively, and connections between the terminals of the inner layers thereof and ground.

6. In a signaling circuit, a balancedtrans, mission line, a transformer comprising a pair of multi-layer primary coils connected in series and a pair of multi-layer second ry coils coaxial with and surrounding said primary coils, said'secondary coils being connected in series, connections from the inner to said transmission line and connections from the inner layer of each section of the secondary to an electrical device. said last named connections being grounded.

7. In a transmission circuit, a transformer comprising a pair of sections, each section comprising a primary and secondary coil arranged with the outer layer of one adjacent the inner layer of the other, a connection between the layers of said primary coils adjacent said secondary coils, means for maintaining said connection at substantially ground potential. said means including connections from the inner layers of said primary coils to a line having like capacities between its two sides and ground, a pair of vacuum tubes, each having a cathode and a grid, connections between the gridsof said tubes and the non-adjacent layers of said vsecondary coils, and connections between the cathodes of said tubes and the layers of said secondary coils adjacent said primary coils, said last named connection being grounded. 8. In a transmission circuit. a line having terminals substantially balanced with re spect to ground, a transformer comprising a pair of multi-layer primary coils, said coils having the terminals of their inner layers connected to theterminals of said line, a connection between the terminals of their outer layers, said last named connection bcing at a fixed potential with respect to ground, and a pair of secondary coils superposed on said primary coils. the inner layers of said secondary coils being connected to ground through a path of low impedance.

9. In a transmissioncircuit. in combination, an' incoming line. a't-ranstormcr com- ,prisng a plurality of primary windings symmetrically. arranged across the incoming line, connections between the outer layers of said primary windings. means including said line for maintaining said connections at sub- ,stantially ground potential, a multi..-layer secondary comprising a plurality of windings surrounding said primary windings, a plu rality of vacuum tubes. each having a cathode and a grid, connections between the outer layers of said secondary windings and the grids of said vacuum tubes. and connections between the inner layers of said secondary windings and the cathodes of said tubes, said last named conncctionsbeing grounded.

10. In a transmission circuit, a trans former having a plurality of sections, each tween its two sides and ground whereby saidconnection is maintained at substantially ground potential, a pair of vacuum. tubes, each having a cathode and a grid, connections from the layers of the secondary coils non-adjacent said primary coils to the grids of said tubes, and connections from the layers of the sections of said secondary adjacent said primary coils to the cathodes of said tubes, said last named connections being grounded.

11. In a balanced transmission circuit, an outgoing line, a transformer comprising a pair of multi-layer secondary coils, the terminals of the outer layers of said secondary coils being connected together, connections between the terminals of the inner layers of said secondary coils and said outgoing line, a pair of multi-la-yer primary coils surrounding said secondary coils, a pair of vac uum tubes, each having a cathode and an anode, connections between the terminals of the inner layers of said primary coils and the cathodes of said tubes, connections between the terminals of the outer layers of said primary coils and the anodes of said tubes and connections between the cathodes of said tubes and ground.

12. In a balanced transmission circuit, a pair of vacuum tubes, each having a cathode and an anode, an output transformer comprising a pair of Inulti-layer primary sections and a pair of multi-layer secondary sections, connections between the anodes of the tubes and the terminals of the layers of the primary sections non-adjacent the sec .ondary sections, connections between the FRANK E. FIELD.

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