US1799188A - Cross-talk reduction - Google Patents

Cross-talk reduction Download PDF

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Publication number
US1799188A
US1799188A US315255A US31525528A US1799188A US 1799188 A US1799188 A US 1799188A US 315255 A US315255 A US 315255A US 31525528 A US31525528 A US 31525528A US 1799188 A US1799188 A US 1799188A
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United States
Prior art keywords
circuits
quad
circuit
quads
section
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Expired - Lifetime
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US315255A
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English (en)
Inventor
Myron A Weaver
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AT&T Inc
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American Telephone and Telegraph Co Inc
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Filing date
Publication date
Application filed by American Telephone and Telegraph Co Inc filed Critical American Telephone and Telegraph Co Inc
Priority to US315255A priority Critical patent/US1799188A/en
Priority to FR680485D priority patent/FR680485A/fr
Priority to DEI39652D priority patent/DE528281C/de
Application granted granted Critical
Publication of US1799188A publication Critical patent/US1799188A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B3/00—Line transmission systems
    • H04B3/02—Details
    • H04B3/32—Reducing cross-talk, e.g. by compensating
    • H04B3/34—Reducing cross-talk, e.g. by compensating by systematic interconnection of lengths of cable during laying; by addition of balancing components to cable during laying

Definitions

  • This invention relates to a method and means for reducing crosstalk between telephone circuits, particularly telephone circuits in cable.
  • thehconductors are arranged in groups of four called a squad. Each group offour conductors serves for carrying three ordinary telephone conversations, one pair of conductors forming one socalled side circuit, the other pair forming another so-called side circuit and the conductors of each pair when connected in parallel forming one side of a so-called phantom circuit. From'thestandpoint of crosstalk, it is desirable to reduce as far as practicable the number of sections, of cable between repeater points in which any two of these circuits are carried in the same cable quad.
  • first circuit will be relatively small from each of the other circuits with which it is re lated. While the total crosstalk may be as great as though the circuits were routed in the same relation throughout the entire system, it will be made up of a number of small components from a number of different circuits so that the resultant crosstalk is not in telligible but is in the nature of unintelligible noise.
  • I i q I ,Ifall of the circuits are treated in this manner any particular circuit will no longer receive crosstalk in a large number of re-, p'eater sections ,from any given circuit in the same quad with it, but will receive crosstalk from many circuits any one or which is in the same quad with it for only one repeater section.
  • the crosstalk overheard in each circuit will then consist of a multiplicity ofrelatively weak conversations, and the chance of understanding any one conversation taking place on another circuitrwill be much reduced.
  • the method of cross-connectin g the circuits in accordance with the present invention results in an approach to the desirable condition of equal and'very slnall crosstalk from all of the circuits in the cable into any one circuit.
  • Observations on circuits arranged in accordance with the present invention have shown that a condition is approached where there is practically no intelligent crosstalk but simply i. unintelligible noise.
  • the system has in addition to the advantages above outlined the further advantage that i the inter-connectionof the circuits at the repeater stations gives a considerable reduction in the ratio between maximum and average noise (including "crosstalk, efi'ects) In other words, consideringa group of circuits,
  • FIG. 1a and 16 show respectively the symbol representing the connection between a phantom and its two associated side circuits, and the symbol representing a two-wire repeater.
  • Fig. 1 of the drawing each pair of conductors constituting a side circuit is represented, for the sake of simplicity, by a single line instead of a pair of lines one for each conductor.
  • a cable extends between terminal points A and E through repeater points B, C and D.
  • This cable may include any desired number of quads, of which, for purposes of illustration, six quads, each involving two side circuits of two conductors each and a common phantom, are treated as a group.
  • the connections of each side circuit of a quad are shifted at each repeater point so that each side circuit will be connected to the conductors of other side circuits in different quads.
  • the connections are so shifted that the phantom, while in effect continuing straight through from section to section, is, due to the cross-connection of the side circuits, actually associated with a dilferent pair of side circuits in each successive repeater section.
  • the pairs corresponding to each side circuit are numbered in regular order, and in the case illustrated in Fig. 1 these numbers run from 1 to 12, inclusive, although the method is applicable independently of the number of quads to be treated and of the number of repeater stations in the system.
  • the phantom circuits as already stated, are so connected as to proceed straight through each repeater station.
  • the side circuits however, incoming from each preceding repeater (or terminal) are connected individually to the repeaters of the next lowerodd numbered side circuits, if they are normally connected to odd numbered side circuits, or to the repeaters of the next higher even numbered side circuits if they normally connect to even numbered side circuits.
  • the repeater that was normally connected to the highest odd numbered side circuit in the group (which in the case assumed. is 11) is connected to the lowest odd numbered side circuit (1), while the repeater that was normally connected to the lowest even numbered side circuit (in this instance 2) is connected to the highest even numbered side circuit (12) inthe group.
  • the even numbered side circuits in the group have their connections shifted or rotated in one direction and the odd numbered side circuits have their connections shifted or rotated in the opposite direction.
  • the transmission on the three units of a quad in four-wire circuits is always in the same direction, the energy levels on the three units are about the same, and crosstalk between the units is not amplified to the extent it is when the units may transmit in opposite directions as in two-wire circuits.
  • the condition does not arise, however, in which the sending end of a circuit is crosstalking into the receiving end of a circuit in the same quad and thereby competing in the latter with the attenuated currents transmitted fron'i the sending end thereof.
  • the cross-connections in accordance with the present invention need not be made as frequently as in the case of two-wire circuits.
  • a cable, system the conductorsof which are arranged in a plurality of quads, each quad comprising a pair of side circuits upon whicha phantom circuitis superimposed
  • the method o'freducing-the eiiect ot' crosstalk which consists in shifting the connectionsoi the conductors of the quads at each of more than two junction points between cable sections without shifting the phantom connections so that each side circuit of any given quad in one section will be routed through successively different quads in each of more than twosu'cceeding sections and the phantom will be superposed on different side circuits in different sections.
  • each quad comprising a pair of side circuits upon which a phantom circuit is superposed, and in which correspondingly numbered quads are grouped in each'succeeding section
  • the method of reducing the eiiect of crosstalk which consists in shifting the connections of the conductors of the quad at each of a plurality of junctions between sections so that one side circuit of each quad will be connected to the corresponding side circuit of a quad of a succeeding numerical order in one direction in the next cable section, and the other side circuit of each quad will be connected to the corresponding side circuit of a quad of a succeeding numerical order in the opposite direction.
  • each quad comprising a pair of side circuits upon which a phantom circuit is superposed, and in which correspondingly numbered quads are grouped in each succeeding section
  • the method of reducing the effect of crosstalk which consists in shifting the connections of the conductors of the quad ateach 01'' a plurality of junctions between sections so that one side circuit of each quad will be connected to the corresponding side circuit of a quad of a succeeding numerical order in one direction in the next cable section, and the other side circuit of each quad will be connected to the corresponding side circuit of a quad of a succeeding numerical orderin the opposite direction, and connecting the conductors of the phantom circuit of each quad of one section to the phantom conductors. of the corresponding quad oi the succeeding section at each junction point between sections.
  • a cable system comprising a plurality of cable sections each comprising a plurality of conductors arranged in quads, each quad comprising a pair of side circuits and a phantom circuit superposed on the pair of side circuits, the conductors of the side circuits and the phantom of each quad of each section being cross-connected to the conductors of the side circuits and phantoms of the quads of the succeeding section so as tosuperpose the phantom of each quad upon a diiierent pair of side circuits in each of a plurality of successive sections.
  • a cablesystem comprising a plurality of cable sections each comprising a plurality of conductors arranged in quads, each quad comprising a pair of sidecircuits andta phantom circuit superposed on the pair of side circuits-,the conductors of the side circuits ot'ea'ch quad to'each'section'heiug cross-connected to the conductors of the side circuits of the quads 01": the succeeding section Without shifting the phantom connections so that each side circuit of any given quad in one section will be successively routed over conductors of diiierent quads in each of more than two succeeding sections and the phantom will be superposed on diiierent side circuits in diiierent sections.
  • a cable system comprising a plurality of cable sections each comprising a plurality of conductors arranged in quads, each quad comprising a pair of side circuits and a phantom circuit superposed on the pair of side circuits, the conductors of the side circuits and the phantom of each quad of each section being cross-connected to the conductors of the side circuits and phantoms of the quads of the succeeding section so that each side circuit of any given quad in one section will be routed over conductors of diiierent quads in each of a plurality of succeeding sections, with the phantom of each quad of a given sec tion superposed upon a different pair of side circuits in each of a plurality of successive sections.
  • a cable system comprising a plurality of cable sections each comprising a plurality of conductors arranged in quads, each quad comprising a pair of side circuits and a phantom circuit superposed on the pair of side circuits, a corresponding number of quads of each section being grouped and numbered so that the quads in a group'in each section will be correspondingly numbered in the same successive order in each section, the conductors of the side circuits of each qua-d of a group in each of a plurality of cable sections being cross-connected to conductors of quads of the corresponding group of the next section so that one side circuit of each quad of the group will be connected to the corresponding side circuit of a quad of succeeding numerical order in one direction in the next cable section, and the other side cir cuit of each quad of the group will be connect-ed to the corresponding side circuit of quad of succeeding numerical order in the opposite direction.
  • a cable system comprising a plurality of cable sections each comprising a plurality of conductors arranged in quads, each quad comprising a pair of side circuits and a phantom circuit superposed on the pair of side circuits, a corresponding number of quads of each section being grouped and numbered so that the quads in a group in each section will be correspondingly numbered in the same successive order in each section, the con ductors of the side circuits of each quad of a group in each of a plurality of cable sections being cross-connected to conductors of quads of the corresponding group of the next section so that oneside circuit of each quad o'f'the group will be conne'cted to'the airesponding side circuit of a quad of succeeding numerical order 1n one direction in the next cable section, and the other s1de circult of each quad of the group will be connected to, the corresponding side circuit of a quad of succeeding numerical order in the opposite direction, and the conductors of the phantom of each
  • each quad comprising a pair of side circuits upon which a phantom circuit is superposed
  • the method of reducing the effect of crosstalk which consists in shifting in eifect the connections of the phantom circuits at each of a plurality of junction points between the cable sections so as to superimpose the phantom upon a different pair of side circuits in each of a plurality of successive sections.

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Cable Transmission Systems, Equalization Of Radio And Reduction Of Echo (AREA)
US315255A 1928-10-26 1928-10-26 Cross-talk reduction Expired - Lifetime US1799188A (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
US315255A US1799188A (en) 1928-10-26 1928-10-26 Cross-talk reduction
FR680485D FR680485A (fr) 1928-10-26 1929-08-19 Procédé et dispositifs pour réduire les phénomènes d'interférence dans les circuits électriques de signalisation
DEI39652D DE528281C (de) 1928-10-26 1929-10-25 Schaltungsanordnung zur Herabsetzung der stoerenden Wirkungen des Nebensprechens in Fernmeldekabeln mit Verstaerkern

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US315255A US1799188A (en) 1928-10-26 1928-10-26 Cross-talk reduction

Publications (1)

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US1799188A true US1799188A (en) 1931-04-07

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US315255A Expired - Lifetime US1799188A (en) 1928-10-26 1928-10-26 Cross-talk reduction

Country Status (3)

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US (1) US1799188A (fr)
DE (1) DE528281C (fr)
FR (1) FR680485A (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2696526A (en) * 1940-09-24 1954-12-07 Int Standard Electric Corp Balancing of carrier cables
US5435752A (en) * 1992-12-18 1995-07-25 The Siemon Company Electrically balanced connector assembly
US5459643A (en) * 1993-09-30 1995-10-17 The Siemon Company Electrically enhanced wiring block with break test capability

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2696526A (en) * 1940-09-24 1954-12-07 Int Standard Electric Corp Balancing of carrier cables
US5435752A (en) * 1992-12-18 1995-07-25 The Siemon Company Electrically balanced connector assembly
US5474474A (en) * 1992-12-18 1995-12-12 The Siemon Company Electrically balanced connector assembly
US5459643A (en) * 1993-09-30 1995-10-17 The Siemon Company Electrically enhanced wiring block with break test capability

Also Published As

Publication number Publication date
FR680485A (fr) 1930-05-01
DE528281C (de) 1931-06-27

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