US1548597A - Signaling system - Google Patents

Description

Aug. 4, 1925.

J. J. GILBERT SIGNALING SYSTEM Filed Nov. 14. 1921 I H. Tc

Patented Aug. 4, 1925.

' 'UNITED STATES PATET OFFICE.

JOHN J. GILBERT, OF PORT WASHINGTON, NEW YORK, ASSIGNOR TO WESTERN ELEC- TRIC COMPANY, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

SIGNALING SYSTEM.

Application filed November 14, 1921. Serial No. 514,845.

To all whom it may concern:

Be it known that I, JOHN J; GILBERT, a citizen of the United States, residing at Port Vashington, in the county of Nassau,

State of New York, have invented certain new and useful Improvements in Signaling Systems, of which the following is a full,

clear, concise, and exact description.

This invention relates to telegraph systems and more particularly to submarine cable telegraph systems. v p

In duplex telegraph systems where current impulses are transmitted over a single conductor in opposite directions simultaneously,

it is impossible to secure and maintain a perfect balance between the real and artificial lines; Consequently considerable difficulty isexperienced 'owingzto disturbances caused by theinitial surge of current'due'to a change ofpolarity applied to the signaling conductor, whichjtends to effect distortion of the incoming signals,and which may-haven harmful'effec't upon the subsequent'action of the apparatus used in correcting and amplifying the received signals. j

The principal object of this invention is the minimizing of the effects of such disturbances. i In carrying out this object there is preferably provided means associated with the signaling system utilizing duplex equipment whereby the receiving instrument may be alternately operatively connected with, and disconnected from, the real and artificial lines. p

Other objects of the invention will hereinafter appear. y v

In the drawing, Fig. 1 isa digrammatic ilhistration of a duplex cable system embodying the invention; Fig. 2 shows a curve use ful in describing the operation thereof; and Fig. 3 shows a special application of the invention to high speed signaling systems employing transmittingand receiving distributors.

Referrin-gfirst to Fig.2, a typical case of unbalance is illustrated, the curve A, B, C. D representing the current in the receiving instrument atone end of the line due tovoltage applied to the duplex network by the transmitter at the same end of the'line during the interval AE. Theportion A, B, C usually occupies only a small fraction of this interval, but on account of its large amplitude, it may interfere seriously with the incoming signals. The remainder of the un balance C, D is of comparatively small ambridge is represented by an artificial balanc-' ing network 7 comprising suitable resistances'and condensers connected to ground in the usual manner, the usual condensers 8 and 9 being provided in .the twoother arms of the bridge. In the bridge is an amplifier or shaping and correcting network 10 connected to the windings of a polarized relay 11 which, in turn, controls a local circuit including a source of current 12 and a recording instrument or sounder 13. The transmitter may include a rotatable drum let, a perforated tape 15 and associated brushes i6, 17 and 18. Associated with the transmitting drum members are neutral relays 19 and 20 and energizing batteries 21 and 22 for controlling a battery 23, in the manner well understood in the art, to impress currents ofeither polarity upon the line It is common practice in systems of duplex and multiplex telegraphy to connect the amplifying network 10 and receiving relay 11 directly across the arms 6 and 7 of the bridge, the accuracy of the systems depending upon the artificial network 7 which should have exactly the same electrical resistance and capacity as the real line 6. In ac cordance with the present invention, however, only one terminal of the receiving ap paratus is permanently connected in the bridge, as'at 2t,fthe other end being connected in such a way that it may alternately be connected to and disconnected from the bridge. This is accomplished in the present case bymeans of a brush 25 in circuit with the artificial network 7 and a brush 26 in circuit with the amplifying network 10, these brushes being adapted for alternate engagement with conducting segments 27 and the non-conducting surface of the distributor frame 28. When the brushes 25 and 26 rest upon conducting segments 27, as shown in the drawing, the receiving relay 11 is connected through the amplifying network 10 to the artificial balancing network 7, and when these brushes rest on the non-conducting surface 28, the receiving apparatus is in sulated from the duplex DQtWOIK. The dis- 65 is connected, it would simply be necessary eflfifa e lestns oil a e m n 2 a d t e tribut oij preferablypositioncd on the rotatable transmitting druiiii 14. The uniform conducting segments 27 aresliorter" thaii the tape" perforations in the transmit" tingtape 15' and are so oriented with respect to the perforations that the transmitting brush 17 or 18 will enter upon the' conducting surface of the drum 14: in advance of the entrance of the brushes" 25 and 26 1116611 arseg nent Q'Y. flhus, asthe drum l4 isrotated past the stationary brushesn the receivli s nem m i tl 'b in let from t e network atgthe beginning of each impulse ..dnring thetirne AC, at whiolitime the dis? turbance :c lueto unoalance; would ber eceived.

receiving 11 connected in operative:

r am wi h. t efjdur r ret re-: d s? sramhe. i@sem,- nd m y'beltj i l-t Referr ng no w to the modificat on shown nangemen't shown in Fig. is employed, but

nn eee ifh ape, t ansmi and c v- 25 ts soun r, Le, eyneli e qe d s u i employed ate e 1 en it e e' Hov in 91 's e gmen fifirnt he istr n e i i us d e transm t ing?si n s; the ee i i this.

1 asher-1e iim fe mlee e A secondrins eiz eeme i ll is: p vided e P13 19 rame: 23 has ed. fib rs," yr i t 9f:

. c .7 t n rele i lt S..a 'B -t yn nsu at -f refi l d eennee ed t9 t it ba- 'ane ia netw r 7 h rd in Oi rec v n se me t '12 is a p o i e ea h; gm nt brine e e ica y s eet ii Wit tan re ie fomagi et of t n i 3 .,.13h.et relfiren m i.7 dap e .17

impresses ur entsp e t e pe l r fyfiwm a-s i a-b-l sour :upentheliner qeim terl with" he; tra tt ng s gm n s t e usua ma nerith-Ah? tra isn tt inei. nts th brush 3 m gm nts 3.0, and eb i fi ed fro-m operative relation with the filllf plex' network during the very first part of each, "gna' 'ling impulse, or at the time when due to unbalance the greatest disturbance would ordinarily be received.

1 At all other times, however, the receiving' instrument 1s connected to theeleo trical'network and signals froin the distant endmay be received; In order that any desired portions of the'received signal will a r rive at a time when the receiving instrument The bru 3. ie-l e j i i e r 01 nit receivihlgl or transmitting rings on the distant distributor to be oriented properly with respect to the segments of the transmitting or receiving distributor at the near end. By. mutual arrangement "both receiving instruments may be freed from the efict of unbalance.

What. is claimed is 1. The method of eliminating disturbances due to duplex unbalance in cable telege raphy whioln comprises" automatically dis connect ngv the receiving apparatus from operative relation with tliedupl'ex network; during the time' when the iiiii jo'r' portion of" the disturbance is received, and at" all other times automatically maintaining tlie receiving instrument in o erative relation with the d h plex'network. l l

21' he method of eliminating distiiibano es diie to duplx' unb lance in 05 516 telegrapl y which comprises reinovingfthe receivmg apparatus from operative relation-:

ship withthe duplex network at or sli%htl y before the instant mar; large unba potential to the artificial line by'the trans} balancegcurrent" flowing, and at al other times durmg'the transmission of signals current is produced by the application of maintaining the receiving inflame-newer:

wa Qeeeete w t th de f 3. 1e combination with a telegraph line of a. duplex network at:each terminalconi prising an artificial nae; means at each terminal for applying signaling potential to said line,rreceiving apparatus at each terminal; means fo'r stopping reception at each terminal during-a portion at least. of the time sendin'g'l from that, terminal occurs whereby the effect of imperfect aapiex bridge balance is! decreased, and meai'isffor J maintaining synchronisni between said stop pingmeans at the two terminals.

4. Ina telegraphsy'stem,' an'iaii'i line, an artificial line, means for applyinj signaling potential to said main and arti 'cial lines, receiving a p aratus, and means for auto matically removing said receiving apparatus froni'operative relationship with said mificial. line at orslightly before the instant that large unbalance current ispro'duced by the application of saidsignaling'potential to the artificial line and for maintaining said receiving apparatus in operative relationship with said artificial line lat all other times during the transmission of signals. V v s p 5'. I nza telegraph system, a main li e, an artificial line, a bridge' connectinlg" the main and artificial lines; a receiving instruk equallength, and means for alternately and i regularly disconnecting said receiving instrument from, and connecting it to, said bridge, each period of disconnection beginning at or slightly before the instant of application to said bridge of each signaling potential impulse.

6. In a telegraph system, a main line, an artificial line, a bridge connecting the main and artificial lines, a receiving instrument in said bridge, a distributor for impressing signaling potentials upon said bridge and for alternately and operatively inserting said receiving instrument in and removing it from said bridge synchronously With the impression of signaling potentials upon said bridge.

7 In a telegraph system, a main line, an

JOHN J. GILBERT.

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