US1595118A - Telephone line with one-way repeater - Google Patents

Description

Patented Aug. 10, 1926.

I UNITED STATES lremerci* OFFICE..

WILHELM OHNEVSORGE, 0F DORTMUND, GEBHNY, ASSIG'NOR T0 SIEMENS mm AKTIENGESELLSCHAFT, DI' SIEMENSSTADT, NEAR BERLIN, GERMANY, A COB- roraarron or unaniem?.V

TELEPHONE LINE 'WITH ONE-WAY BEPEATEB.

Application filed' August 23, 1,921, Serial No. 494,569, and in Germany December 16, 1915.

(crumb 'annex'. rm: rnovrsrons or m or or innen s, 1921, 41 sur. L., 131s.)

For improving the transmission of speech and extending the range of telephonie communications repeaters are generally used which are inserted into the line for amplify- 5 ing the speakingcurrents. The methods of i inserting; the repeaters in the line are commoniliT based upon the differential or bridge circuit principle, which has however the inconvenience that the effect of the repeater is 10 considerably reduced on account of the subdivision of the output current.l For pre--` venting singing the two sections of the line must have approximately the same electrical characteristics. The electrical character l5 istics vary however continuously in each section of the line so that singing frequently occurs. But before the singing begins the speech maybe already distorted or become unintelligible on account of the interference 2U by natural. oscillations.

f For preventing these troubles two two wire-circuits hare already been used withl one way repeaters in cach circuit so that in each line only the current flowing in one 25 direction is amplified. But this system has the inconvenience that the connection of such a four wire circuit with the ends of a two wire line is not possible. Without this con-4 nection the four Wire system has however no 3U practical value. as all the'telephonic installations actually in use are designed for two wire circuits.

The present invention consists'in a method 'for obriating these difficulties and allowing 55- the connection of such a four wire circuit to the end of a two wire line'of usual design. An arrangement according to the invention F is shown on the drawing.

The accompanying drawingr represents a l diagram `of a four wire circuit arranged ac-y cardiner to my invention. B v the four wire circuit which consists of two wire circuits V and lll. talking" in both directions is possible. Through the two wire circuit V speech cur- 5 vente are transmittedA from the left to ,the right hand in the drawing and through the two wire circuits W in the opposite direction, Two wire circuits a and b are/ connect'cd to the two long distance wire circuits w 4V and W by means of a` `W'heatstone bridge and in the long distance circuits Vandl W arel inserted repeaters R, and 1L. respectively. 1

Tolhe opposite points/g, h; k, i r

tively i'mn; 0, Z of two Wheatstone bri ges' 55 l A andB are connected the ends of the long clistarice twowirc lines V1 W forming togethera fhr wire line. Two of the branches of cach'Wheatstone bridge contain each a transformer winding! c, d; e, f, the other M branches contain each the half of a coil p, q. The winding I of the transformer d is connccted to the ends of the` two wire line b (distance or subscribers line).y while the windingr I of the transformer r; is connected n with an iertificial balancing line w. llf the subscribcrs line and the artificial line4 are well balanced the talking current transmitted by the line V to the pointez', 'k of 'the bridge is subdivided in such a manner that 'm no current passes to the line W connected to the points g, l, of the bridge. The current circuit of the bridge is closed without attenuation over the two other branches of the coil q of the bridge. The coil q consists'of two 'la halves marked q. qu in the right hand portion of the figure and is bifilarly wound upon itel iron core in such manner that when the cui-y rent flows in parallel through the two halves-i. e. from the point i towards the su two outer ends g and u-only ohrnic resistance is offered to the current, because in that: case the currents flow' in opposite direction from the center towards the outer ends and thus their inductive effects neutralize each filli- 'other. By the transformer d the talking currents are transmitted inductively to the subscribers line b. If the speech is to be transmitted from the subecribers line to the four wire circuit the current induced in the un winding II by lthe winding I of the transformer d ilows principally through the winding II of the coil c of the balancing" line :c and the long distance line W, as the4 coil g of the bridge interposes in this case a W This has been confirmed practical experiments. F or compensating.,r the losses and furthermore obtainingr any desired amplifiration repeaters niay be inserted at the ends of 'the line Y and W. lthe effect of which may be adapted in a known manner to the two wire line by adjustable resistances. A niutual reaction between the repeaters arranged at the ends and in the. middle of the four wire circuit cannot occur as on account of the bridge no or onlia very Sinall current is flowing' from the line Y into the line lV. By means of this method in connection with the lone' distance four wire line provided with one way repeaters at convenient points langes of communication ot any distance :5000 kin. and more) are obtainable..

llavinfr now particularly `described and ascertained the nature of my .said invention and in what manner the saine is to be per formed, l declare that what l claiin is:-

1. A telephone s t'steni havingr in combination a tour wire circuit consistiirgr of a separate two wire long distance circuit for each directionl` a one way repeater in each of Said loner distance lines. an artificial balance line` a lVheatstone bridge at the ends of said long distance lines to opposite points of which are connected the ends ot' the loner distance lines, a transformer for each of two adjacent branches of each bridge, said transformers having one of their windings in circuit with their pertaining branch and having the other windings connected respectively to a two wire line and to said artificial balance line.

2i A telephone system havin);Y in combination a fonr wire circuit consisting of separate tno wire long distance lines fon each talkin;r direction. a one way repeater in each of said longr distance lines. an artificial bal ance line` a Wheatstone bridge at the ends of said lone distance lines to opposite points ot which are conne -ted the ends of the lon; r distance lines. a transformer `for each ot' two adjacent branches of each bridge. said transformers having one of their windings in circuit with their pertaining branch and having: the other \\indinfs connected rcspcctively to a two wire line and to said artificial balance line` an indnetance interposed in cach of thc two other adjacent. branches of the aid 'heatst'one bridges and allowing the transfer of the telephonie currents. front the connected two wire cir cuit. into one ot' the lon;r distance lilies while preventing the transfer to the other loner distance line.

ln testimonv wlicrcotl l affix in)- signature.

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