EP2697803A1

EP2697803A1 - Star-quad cable having a shield

Info

Publication number: EP2697803A1
Application number: EP12703976.6A
Authority: EP
Inventors: Gunnar Armbrecht; Helmut Reiter
Original assignee: Rosenberger Hochfrequenztechnik GmbH and Co KG
Current assignee: Rosenberger Hochfrequenztechnik GmbH and Co KG
Priority date: 2011-04-14
Filing date: 2012-02-06
Publication date: 2014-02-19
Anticipated expiration: 2032-02-06
Also published as: CA2826211C; JP2014511016A; WO2012139679A1; DE202011005272U1; KR101756254B1; HK1191726A1; US9214262B2; KR20140027268A; CA2826211A1; EP2697803B1; CN103443874A; US20140014392A1; TWM436214U; CN103443874B; JP5863943B2

Abstract

The invention relates to a star-quad cable for transmitting electrical signals, having at least two pairs of electrical conductors (10, 12, 14, 16), wherein each conductor (10, 12, 14, 16) comprises one wire (18) made of an electrically conductive material and a conductor sheath (20) radially enclosing the wire (18) and made of an electrically insulating material, wherein the conductors (10, 12, 14, 16) are arranged on the corners of a square in a cross-section of the star-quad cable, wherein the conductors (10, 12, 14, 16) of a pair are arranged on diagonally opposite corners of the square, wherein four conductors (10, 12, 14, 16) are twisted with each other at a predetermined stranding factor according to a star-quad arrangement, wherein a shield (22) made of an electrically conductive material and enclosing the two pairs of conductors (10, 12, 14, 16) is arranged radially on the outside, wherein the shield (22) is constructed from a weave of individual shield wires (23). According to the invention, at least one shield wire (23) or at least one shield wire bundle is stranded in a manner radially enclosing the conductors (10, 12, 14, 16) such that at least one of the stranded shield wires (23) or a shield wire bundle runs in the axial direction substantially parallel to a wire (18) of a conductor (10, 12, 14, 16).

Description

Star quad cable with screen

The present invention relates to a star quad cable for transmitting electrical signals with at least two pairs of electrical conductors, wherein each conductor comprises a core of an electrically conductive material and a conductor surrounding the wire conductor shell of an electrically insulating material, wherein the conductors in a Cross section of the star quad cable are arranged at the corners of a square, wherein the conductors of a pair are arranged at diagonally opposite corners of the square, wherein four conductors are twisted together according to a star quad array with a predetermined stranding factor, wherein one of the two pairs of Conductors radially outwardly surrounding screen is disposed of an electrically conductive material, wherein the screen is constructed of a mesh of individual shield wires, according to the preamble of claim 1. A so-called "star quad" is a stranding element for conductors with, for example, copper wires. Four conductors of pairs of conductors are twisted together to form two cross-shaped stranded double conductors. Two opposing conductors form a pair, each transmitting an electrical signal on a pair. In other words, the four conductors in the cross section of the star quad are arranged at the corners of a square, wherein the conductors of a pair are arranged at diagonally opposite corners. By thus perpendicular to each other pairs of conductors results in a desired high crosstalk attenuation from one pair to the other pair.

The quad-core cable is one of the balanced cables. In this cable four conductors are stranded with each other in a cross shape. This means that the opposite conductors each form a conductor pair. Due to the mutually perpendicular conductor pairs only very low crosstalk occurs. Another advantage of the star quad stranding is, in addition to the mechanical stabilization of the arrangement of the conductors relative to one another, the higher packing density than in a pair stranding. The stranding makes the conductors or individual wires longer than the cable itself.

The so-called. Stranding factor specifies the ratio of single-conductor length to cable length.

The stranding factor for telecommunications cables, for example, about 1, 02 bis

1, 04. The stranding factor correlates with a pitch

Pitch resulting from the helical arrangement of the stranded conductors. The pitch or slope or pitch indicates a thread at an axial distance of two thread notches.

The invention is based on the object, a star quad cable og. To improve the type of electrical properties for the transmission of electrical signals.

This object is achieved by a star quad cable og. Art solved with the features characterized in claim 1. Advantageous embodiments of the invention are described in the further claims.

In the case of a star quad cable of the aforementioned type, it is provided according to the invention that at least one shield core or at least one shield core bundle is so radial the conductor is stranded surrounding that at least one of the stranded shield wires or one of the shield wire bundles in the axial direction in each case runs parallel to a wire (18) of a conductor. This has the advantage that an improvement in the conduction of electrical shielding currents with corresponding improvement in the electrical properties of the quad-core cable is achieved.

A further improvement of the electrical properties or the transmission characteristic of the four-wire cable is achieved by stranding at least four shield wires or at least four shielding wires radially surrounding the conductors such that at least one of the stranded shielding wires or one of the shielding wire bundles is in each case in the axial direction runs parallel to a wire of a conductor.

A particularly secure guidance of the shield wires or shielding wire bundles in parallel along a respective wire of a conductor even at bending and torsional loads of the four-wire cable is achieved in that the screen core or shield wires or the / the shield core bundles is / are stranded with a stranding factor, which corresponds to a stranding factor of the ladder.

A particularly good conduction of shield currents assigned to one core each is achieved in that a respective shield core or a shield core on the one hand and a core on the other hand extend parallel to one another in the axial direction such that the shield core or the shield core bundle and the core are cross-sectioned at each point of the cable lie on the same diagonal of the square and the screen core or the shield wire bundle is arranged on a side facing away from the square side of the wire. Good electrical conductivity coupled with low manufacturing costs is achieved by making the wires from copper. A reduction of shielding currents with corresponding improvement of the transmission characteristics of the star quad cable and maintaining the transmission characteristics of the star quad cable even with bending and torsional loads that affect the screen mechanically, obtained by the fact that between the conductors and the screen an additional insulator jacket is arranged from an electrically insulating material. Settling phenomena in the quad-core cable are avoided and stripping of the quad-core cable is simplified since there is a reduced risk of damaging the wires when cutting an outer insulation jacket. In addition, the additional insulator jacket generates a radial bias on the conductor sheaths of the cores, whereby a mechanical stability of the star quad assembly is increased in bending and torsional loads.

A further improvement of the transmission characteristic of the star quad cable by enabling additional electrical compensation currents on the screen is achieved by the fact that radially outward on the screen, a second screen is arranged, which is electrically conductively connected to the screen. These equalizing currents make it possible to compensate for manufacturing tolerances which possibly lead to shielding wires and associated line not running exactly parallel to one another.

A particularly large-scale conduction of equalizing currents across the second screen is achieved in that the second screen is formed as a sheath or foil of an electrically conductive material.

A particularly good preservation of the flexibility of the star quad cable despite the second screen is achieved in that the second screen is constructed from a network of individual second shield wires. A high number of electrical contact points between the second screen cores of the second screen and the screen cores of the radially inner screen are achieved by the fact that the second shield cores in opposite directions to the Shielding cores of the screen, in particular with a stranding factor, which corresponds to the stranding factor of the shield wires of the screen are stranded.

The invention will be explained in more detail below with reference to the drawing. This shows in:

1 shows an exemplary embodiment of a star quad cable according to the invention in perspective view, FIG. 2 shows the star quad cable according to FIG. 1 in a schematic sectional view,

Fig. 3 is a schematic sectional view of a conventional star quad cable with a graphical representation of the distribution of an electric field, a schematic sectional view of a star quad cable according to the invention with a graphical representation of the distribution of an electric field, a graph of transmission of an electrical signal in dependence a frequency for the conventional star quad cable according to FIG. 3, a graphic representation of a transmission of an electrical signal as a function of a frequency for the star quad cable according to the invention according to FIG. 4 and FIG

Fig. 7 is a simplified schematic representation of stranded together

Ladders and a shield wire of the exemplary embodiment of the star quad cable according to FIGS. 1 and 2.

The illustrated in Figs. 1 and 2, preferred embodiment of a star quad cable according to the invention comprises four conductors 10, 12, 14, 16, each a core 18 made of an electrically conductive material and a conductor shell 20 made of an electrically insulating material. The conductors 10, 12, 14, 16 are twisted together to form a star quad array, ie at each point in the cross section of the four-wire cable are the conductors 10, 12, 14, 16 at a corner of a square 17. Each on a diagonal 19 of the square 17 opposite conductors 10, 12 and 14, 16 form a pair, ie, the conductors 10, 12 form a first pair of conductors or a first conductor pair 12, 14 and the conductors 14, 16 form a second pair of conductors or a second pair of conductors 14, 16 from. The twist of the conductors 10, 12, 14, 16 is carried out with a predetermined stranding factor, which requires a corresponding pitch or pitch s. The lay length s is in this case the axial distance at which a conductor 10, 12, 14, 16 once helically winds completely around a longitudinal axis of the four-star cable. FIG. 2 shows a coordinate system with an x-axis 40 and a y-axis 42. The coordinate system 40, 42 is arranged such that the origin 44 of the coordinate system 40, 42 lies exactly on the longitudinal axis of the star quad cable, so that this longitudinal axis forms a z-direction in space for the coordinate system 40, 42.

In the signal transmission, a first signal is transmitted to the first pair of conductors 10, 12, and a second signal is transmitted to the second pair of conductors 14, 16. By a corresponding phase shift between the first and second signal and the previously described spatial arrangement of the conductors 10, 12, 14, 16 relative to each other in a star quad array is in a known manner, a high crosstalk attenuation between the two conductor pairs 10, 12 and 14, 16 achieved. In a so-called differential mode, the signals on the conductor pairs 10, 12 and 14, 16 have a phase shift of 180 °.

The stranded conductors 10, 12, 14, 16 surrounding radially outside a screen 22 is arranged, which is composed of discrete or individual shield wires 23. A jacket 25 made of an electrically insulating material surrounds radially outside the entire structure of conductors 10, 12, 14, 16 and screen 22. Between the stranded conductor pairs 10, 12 and 14, 16 on the one hand and the screen 22 on the other hand is a additional insulating jacket 24 disposed of an electrically insulating material. This creates an additional spatial distance in the radial direction between the wires 18 of the conductors 10, 12, 14, 16 on the one hand and the screen 22 on the other. The resulting effect will be explained below with reference to FIGS. 3 and 4.

In Fig. 3 is a schematic sectional view of a conventional star quad cable with conductors 10, 12, 14, 16 with respective wires 18 and conductor shrouds 20 and a screen 22 is shown. The screen 22 is radially outward directly on the conductor shrouds 20 of the conductors 10, 12, 14, 16, so that there is a minimum radial distance between the wires 18 and the screen 22. Arrows show the distribution of an electric field when transmitting corresponding electrical signals via the conductors 10, 12, 14, 16, the greater the electric field, the larger the respective arrow is shown. It can be seen from Fig. 3 that forms a strong electric field between the wires 18 of the second pair of conductors 14, 16 and the screen 22. This indicates correspondingly high electrical currents along the screen 22, which are referred to below as "screen currents". High shield currents lead to all the effects that affect the screen 22, a high degree of influence on the electrical characteristics or the transmission characteristics of the four-star cable result. For example, bending and torsional stresses of the star quad cable, which result in mechanical deformation or even damage to the screen 22, lead to a severe deterioration of the electrical characteristics of the four-wire cable, although the cores of the star quad Cable may not be affected by mechanical changes or damage. Furthermore, the screen 22 is usually formed as a mesh of individual shield wires 23 and shield currents must, for example, to follow a wire 18 at contact points of shield wires 23 from a shield wire 23 to another switch. If, over time, these contact points age, there is a meaningful impediment to the current flow of the shield currents and thereby to a corresponding deterioration in the transmission of electrical signals the entire quad-core cable, although no age-related mechanical degradation has occurred in the wires 18 themselves.

FIG. 4 shows, in an analogous view as in FIG. 3, the distribution of the electric field for a star quad cable designed according to the invention with the additional insulator jacket 24. In this case, the screen 22 has a greater radial distance from the cores 18 than the conventional embodiment of a star quad cable according to FIG. 3 through the additional insulating jacket 24 arranged between the conductors 10, 12, 14, 16 on the one hand and the screen 22 on the other hand. It can be seen from Fig. 4 that the electric field is now concentrated between the conductors 10, 12, 14, 16. This means that with a star quad cable according to the invention significantly less screen currents result in the signal transmission. As a result, the effects described above with respect to FIG. 3, due to a deterioration of the screen 22 in the star quad cable according to the invention, accordingly have a smaller influence on the electrical properties of the star quad cable with regard to signal transmission. For example, degradation is an increase in attenuation for a useful signal in the quad-core cable. Even if the screen 22 is damaged or aged, the transmission characteristics of the star quad cable are significantly less adversely affected. In other words, the star quad cable designed according to the invention is considerably more resistant to damage or aging of the screen 22 with regard to the transmission characteristics for electrical signals.

In FIGS. 5 and 6, a frequency in [GHz] is plotted on a horizontal axis 26, and a transmission in [dB] on a vertical axis 28 for electrical signals. A first graph 30 in FIG. 5 illustrates the transmission 28 as a function of the frequency 26 in a common mode signal transmission (without phase shift between the signals on the conductor pairs 10, 12 and 14, 16) and a second graph 32 5 illustrates the transmission 28 as a function of the frequency 26 in a differential mode signal (with phase shift between signals on the conductor pairs 10, 12 and 14, 16) each for a A third graph 34 in Fig. 6 illustrates the transmission 28 as a function of the frequency 26 in a common mode signal transmission - without phase shift between the signals on the conductor pairs 10, 12 and 14, 16) and a fourth graph 36 in FIG. 6 illustrates the transmission 28 as a function of the frequency 26 in a differential mode signal transmission (with phase shift between the signals on the conductor pairs 10, 12 and 14, 16). The graphs 30, 32, 34 and 36 are each obtained from simulations for the arrangement according to FIGS. 3 and 4.

As can be seen from FIG. 5, second graph 32, in the case of a conventional star quad cable, a transmission breakdown occurs in a push-pull at approximately 2.9 GHz. This burglary is no longer present in a star quad cable according to the invention, as shown in Fig. 6, fourth graph 26 can be seen. This simulation result impressively shows the resounding and unexpected improvement in the electrical properties of the star quad cable according to the invention in the transmission of electrical signals. This improvement is already given here before damage or aging of the screen.

A significant improvement in the electrical properties or the transmission properties of the quad-core cable for electrical signals is achieved in that, according to the invention, at least individual shield wires 23 each follow one of the conductors 10, 12, 14, 16 in parallel. In other words, at least individual shield conductors 23 are stranded with the same lay length s or the same stranding factor as the conductors 10, 12, 14, 16. This is illustrated by way of example for a shield core 23a in FIG. In Fig. 7, the lay length s 46 is illustrated. The shield core 23a helically winds around the conductors 10, 12, 14, 16 through the stranding such that the shield core 23a extends parallel to the conductor 14. The exact relative arrangement between the shield wire 23a and the conductor 14 can be seen in FIG. The shield core 23a winds around the conductors 10, 12, 14, 16 at any point in the cross-section of the quad-core cable the conductor 14 and the shield wire 23a are on a common diagonal 19 and the shield wire 23a is disposed on a side of the conductor 14 facing away from the square 17. By virtue of this arrangement of the shield core 23a, a shield current assigned to the conductor 14 can follow the conductor 14 without transition to another shield core 23. By avoiding transitions of the shielding current from one shielding core 23 to another, the electrical conduction of the shielding current across the shield 22 improves and overall the electrical properties and / or the transfer characteristic of the four-core cable for the transmission of electrical signals is improved. In particular, for example, results in a low attenuation for the electrical useful signal transmitted by the star quad cable according to the invention.

The square 17 has, for example, a side length a 48 of 0.83 mm. These side length a corresponding to the distance of the center points of two adjacent conductors 10, 12, 14, 16. A position vector r _{vein l} in the coordinate system 40, 42 with the longitudinal axis of the star quad cable as a z-direction for the n-th wire to n = [1 ... 4] is then given with a free parameter t = [0 ... 1] for the z-direction and over a strike length s

A corresponding position vector f _nschirm in the coordinate system 40, 42 with the longitudinal axis of the star quad cable as a z-direction for a nsc irm-th shade of cores 23 and 23a is then reacted with a free parameter t = [0 ... 1] for the z-direction and over a stroke length s

^• COS [(2TT * t) + (n _screen -1) * Αφ]

^• sin [(27r · t) + {n _screen - 1) · Αφ]

s · t wherein dschirm a diameter 50 of a shield wire 23, 23a, _Sc n irm = [1 .. - N _SC ld], wherein Nschnm is a total number of screen wires, and Δφ = ττ - ^ - an angle 52

"Umbrella

between the diagonal 19 of the associated conductor, in the illustrated example of the conductor 14, and a straight line 60 through the origin 44 on which the respective shield wire 23 lies. For the shield core 23a, for example, Δφ = 0 °. Inserted with Δφ = " ^2π results

^N screen ^aa

nSchirm Although the shield core 23a is preferred for guiding the shield current associated with the conductor 14, this shield current of the conductor 14 may also be guided by one of the two shield conductors 23 adjacent to the shield core 23a. Thus, should the shield core 23a be damaged due to bending or torsional loading, the shield current may still flow substantially parallel to the conductor 14 across the shield 22 along the shield conductors 23a without having to make a change to another shield core 23.

A lay length s 46 is for example 40 mm. A radius 54 of the screen 22 is, for example, screen = 1.5 mm. A diameter 56 of a wire 18 is, for example, d _A = 0.48 mm. A diameter 58 of a conductor shell 20 is for example d _A deriso = a = 0.83 mm. The diameter 50 of a shield core 23, 23a is, for example, d _SC hirm = 0.1 mm.

Optionally, a second screen (not shown) made of an electrically conductive material is additionally arranged radially on the outside of the screen 22. This second screen is thereby electrically conductively connected to the screen 22 on its radially inner side, so that electrical compensation currents can flow over the second screen. As a result, by means of the compensation currents If necessary, manufacturing tolerances are compensated, which, for example, result in that the shield core 23a does not run exactly parallel to the associated conductor 14 (FIG. 2). By means of the equalizing currents over the second screen, aging phenomena or damage to the screen 22 can be compensated accordingly.

Claims

claims:

A star quad cable for transmitting electrical signals having at least two pairs of electrical conductors (10, 12, 14, 16), each conductor (10, 12, 14, 16) comprising a conductor (18) of electrically conductive material and a conductor sheath (20) radially surrounding the core (18) made of an electrically insulating material, wherein the conductors (10, 12, 14, 16) are arranged in a cross section of the star quad cable at the corners of a square, wherein the conductors ( 10, 12, 14, 16) of a pair are disposed at diagonally opposite corners of the square, each having four conductors (10, 12, 14, 16) twisted together according to a star quad array having a predetermined stranding factor, one of the two pairs of conductors (10, 12, 14, 16) radially outwardly surrounding screen (22) is arranged made of an electrically conductive material, wherein the screen (22) is constructed from a network of individual shield wires, characterized

at least one shield core or at least one shield core bundle is stranded radially surrounding the conductors (10, 12, 14, 16) in such a way that at least one of the stranded shield wires or one of the shield core bundles is substantially parallel to a core (18) of one Ladder (10, 12, 14, 16) runs.

2. star quad cable according to claim 1, characterized in that at least four shielding wires or at least four shielding wire bundles are radially surrounding the conductors (10, 12, 14, 16) surrounding, that in each case at least one of the stranded stranded wires or one of the shielding wire bundles in axial direction in each case parallel to a wire (18) of a conductor (10, 12, 14, 16).

3. star quad cable according to claim 1 or 2, characterized in that the shield core / shield wires or the / the shield core (s) is / are stranded with a stranding factor, which corresponds to a stranding factor of the conductors (10, 12, 14, 16).

4. star quad cable according to at least one of the preceding claims, characterized in that in each case a Schirmader or a Schirmaderbündel on the one hand and a wire (18) on the other hand in the axial direction parallel to each other so that the Schirmader or the Schirmaderbündel and the Core (18) lie at any point in the cross section of the star quad cable on the same diagonal of the square and the shield wire or the Schirmaderbündel on a side facing away from the square side of the wire (18) is arranged.

5. star quad cable according to at least one of the preceding claims, characterized in that the wires (18) are made of copper.

6. star quad cable according to at least one of the preceding claims, characterized in that between the conductors (10, 12, 14, 16) and the screen (22) an additional insulator jacket (24) is arranged made of an electrically insulating material.

7. star quad cable according to at least one of the preceding claims, characterized in that radially on the outside of the screen (22) a second screen is arranged, which is electrically conductive with the screen

(22) is connected.

8. star quad cable according to claim 7, characterized in that the second screen is formed as a sheath or foil of an electrically conductive material.

9. star quad cable according to claim 7, characterized in that the second screen is constructed of a network of individual second shield wires.

10. A quad-core cable according to claim 9, characterized in that the second shield wires are stranded in opposite directions to the shield wires of the shield (22).

11. A quad-core cable according to claim 10, characterized in that the second shield wires are stranded with a stranding factor which corresponds to the stranding factor of the shield wires of the screen.