US3821465A

US3821465A - Telecommunication cable particularly paired cable with improved relative crosstalk properties for certain pairs

Info

Publication number: US3821465A
Application number: US00334137A
Authority: US
Inventors: S Karlstedt
Original assignee: Telefonaktiebolaget LM Ericsson AB
Current assignee: Telefonaktiebolaget LM Ericsson AB
Priority date: 1972-03-02
Filing date: 1973-02-20
Publication date: 1974-06-28
Anticipated expiration: 1991-06-28
Also published as: SE360944B; CA987756A

Abstract

A paired or quadded telecommunication cable have conductors arranged in groups. One pair or quad within each group does not change place and is shielded by the other pairs or quads within the group resulting in a high relative freedom of crosstalk.

Description

United States Patent [191 Karlstedt June 28, 1974 TELECOMMUNICATION CABLE,

PARTICULARLY PAIRED CABLE WITH IMPROVED RELATIVE CROSSTALK PROPERTIES FOR CERTAIN PAIRS [75] Inventor: Sten Lennart Karlstedt, Stockholm,

Sweden [73] Assignee: Telefonaktieboiaget L M Ericsson,

Stockholm, Sweden [22] Filed: Feb. 20, 1973 [21] Appl. No: 334,137

[30] Foreign Application Priority Data Mar. 2, 1972 Sweden 2654/72 [52] US. Cl. 174/113 R, 174/34, 174/35 [51] Int. Cl. H0lb 11/10 [58] Field of Search 174/34, 33, 35 R, 113 R,

[56] References Cited UNITED STATES PATENTS 2,014,214 9/1935 Smith 174/34 2,845,473 7/1958 Doherty 174/33 X 3,105,108 9/1963 Brazee 174/113 R 3,433,890 3/1969 Gabriel 174/113 R Primary Examiner-E. A. Goldberg Attorney, Agent, or Firm-Harte, Baxley and Spiccens [57] ABSTRACT A paired or quadded telecommunication cable have conductors arranged in groups. One pair or quad within each group does not change place and is shielded by the other pairs or quads within the group resulting in a high relative freedom of crosstalk.

1 Claim, 1 Drawing Figure 1 TELECOMMUNICATION CABLE, PARTICULARLY PAIRED CABLE WITH I IMPROVED RELATIVE CROSSTALK PROPERTIES FOR CERTAIN PAIRS The present invention relates to a telecommunication cable, particularly a paired or a quadded cable, for transmission of telecommunication signals, comprising a number of insulated conductors arranged as pairs or quads in groups or sub groups, wherein the pairs or quads changing their relative positions systematically or at random.

Cables of the kind under discussion are manufactured for reducing and compensating the crosstalk between conductor pairs or quads. Very good results have been achieved with cables of this kind and the crosstalk between arbitrarily chosen pair or quad combinations have been reduced to an acceptable level, as far as speech transmission is concerned. However, conductors intended for telephone calls are to an increasingly larger extent being used for transmission of other kinds of signals, e.g. signals for picture telephone, PCM- systems and data communication. In such connections the requirements for freedom of relative crosstalk are particularly high.

BRIEF DESCRIPTION OF THE DRAWING The FIGURE represents the cable in cross section.

The present invention relates to a cable in which a number of pairs or quads have a very high relative freedom of crosstalk which is achieved by practing the invention as defined by the appended claim.

An embodiment of the invention will be more fully described accompanying with, reference to the drawing, which in cross section, shows a telecommunication cable ll comprising ten groups 2, of which each one in turn comprises ten conductor pairs 3. In known embodiments these ten conductor pairs change places systematically or at random in such a way that the crosstalk between an arbitrarily chosen conductor pair and each one of the other conductor pairs is almost constant. In the shown embodiment there are eight conductor pairs in the periphery of the group, while two conductor pairs form the core of the group. According to the invention one or several pairs 4 in a number of groups are excepted from the relative changing of places and maintain their places along the whole length of thecable. For achieving the best possible'relative crosstalk freedom between the pairs 4 they are placed in the centre of the respective group. The other com ductor pairs then form a shield around the chosen pairs; and shield also protects these pairs from external disturbances. This is particularly advantageous in connection with aerial cables in which the surface layers are more exposed to external disturbances than the inner layers.

I claim:

1. A telecommunication cable comprising a plurality of telecommunication signal conductors wherein each of said telecommunication signal conductors comprises at least two insulated wires, said plurality being arranged into at least two groups, within each group the telecommunication signal conductors thereof being arranged to surround at least one of the telecommunication signal conductors while changing relative positions with respect to each other except for said one telecommunication signal conductor whose position remains constant along the length of the cable.