EP1130604A2 - Data or control cable and method for optimizing of such a cable - Google Patents

Abstract

The cable has at least one forward conductor and at least one return conductor. At least one conductor (1) is asymmetrical in geometric shape relative to its cross-sectional center of mass axis. The forward and return conductors are formed mirror symmetrically relative to each other. At least one conductor has a triangular, trapezoidal, semicircular or circular segment-shaped cross-section. Independent claims are also included for the following: a method for optimizing a data or control cable.

Description

The invention relates to a data or control cable with at least a forward and a return conductor. The invention also relates to a Method for optimizing such a control cable. In In this context, the term describes data or Control cable any cable arrangement that is suitable for data or Control signals at frequencies above 1 MHz, especially above 50 MHz or over 100 MHz, preferably in digital form.

There are many attempts, with data or control cables, their Operating frequency is over 1 MHz, crosstalk too Reduce. This is done, for example, by selected ones Stranding techniques or an elaborate insulation or a Shielding such conductors.

It is an object of the present invention to provide a data or control cable to be provided, which also go to a Crosstalk is optimized. Accordingly, it is a task present invention, an optimization method for such Specify cables.

As a solution, the invention proposes on the one hand a data or Control cable with at least one forward and one return conductor, at which has at least one conductor in its geometric shape with respect to a cross-sectional center of gravity of the conductor is rotationally symmetrical. In this regard, the Term "cross-sectional center of gravity" a line through a Leaders, who focus on the respective focus, especially the geometrical focal points, each one next to each other Cross-section is formed.

With such an arrangement, one can move between the back and forth field formed in a desired area for the return conductor focus. This concentration means that the field in the remaining areas is reduced, so in these remaining areas the risk of cross-talk is reduced.

In the present context, the term "field" is in the essentially directed to an electric field, which is at a signal transmission through the data or control cable. However, it goes without saying that, depending on the frequency or Application also magnetic fields or electromagnetic fields can be influenced accordingly advantageously. In particular does the term "field" also apply to a pair of data or control cable propagating shaft, which by the Operating frequency excited carries a signal.

In contrast to previous practice, the invention thus provides for the first time a generic data or control cable is ready at its single cores in cross-section from a round basic geometry is deviated.

The forward and return conductors are preferably mutually exclusive opposite mirror-symmetrical. Regarding one Data or control cable, which carries exactly two wires in this regard in particular a mirror symmetry with respect to a plane of symmetry arranged between the two conductors advantageous. It is understood that such an arrangement Field evenly in the desired area, preferably between the two leaders.

At least a first conductor can cross-section on its other side facing the conductor is flatter than the middle Radius of curvature of the first conductor. To this The surface portion of this conductor surface can be which faces the other leader. There As is well known, a current routing of conductors mainly in the one closest to the opposite conductor Surface area becomes larger in this way Area provided for power supply. To this Thus, the damping or the ohmic resistance of a such data or control cables reduced. It goes without saying that such a design also from the other, characteristic Features of the present invention independently advantageous solves this task.

In particular, at least one conductor can have a triangular, trapezoidal, semicircular or circular segment-shaped or a rectangular, preferably have a square cross section. Furthermore At least one conductor can have two corners, each through convex circumferential lines, by concave circumferential lines or by a convex and a concave circumferential line connected to each other are. These arrangements allow, with a suitable choice of Radii of curvature and the geometric arrangement of the conductors with each other, the side facing the other conductor flatter than to form the mean radius of curvature of the conductor. Depending on However, these instructions can also follow specific requirements other specifications are used.

As a further solution, the invention proposes a data or Control cable with at least one forward and one return conductor, at which the conductors are designed such that the second Location of a field between these conductors along the shortest connection between these conductors is smaller than that second location derivation of a round pair of conductors, each with identical Cross sectional area.

The invention also suggests a data or control cable at least one forward and one return conductor, in which the Conductors are designed such that the second location derivative of a Field between these conductors along the surface line at least one conductor has more than two zero points.

In addition, the invention proposes a data or control cable at least one forward and one return conductor, in which the Conductors are designed such that the second location derivative of a Field between these conductors along a perpendicular to the shortest connection between these conductors by a Center of this shortest connection in the area of The amount of the center is smaller than the second location derivative of a round pair of conductors, each with an identical cross-sectional area in exactly this area.

Here the functional mathematical is derived from a location Differentiation of the field according to a corresponding spatial direction Roger that.

Such a field course can be, for example, by Optimization method in the manner according to the invention provide that of a given conductor cross section one Conductor pair starting from a field density around the conductor pair determined and then the surface shape of at least one Conductor is varied such that the field density between the and the return conductor is enlarged.

Such a field can also be created using an optimization method are provided, which of a given conductor cross section determined the field density around the pair of conductors and then the surface shape of at least one conductor varies that the field density is reduced at a desired location.

Such a procedure is with known field calculation methods, especially with numerical field calculation methods, easily possible.

The present invention relates in particular to data or control cables which are operated under boundary conditions in which the equivalent conductive layer thickness is less than 100 μm , preferably less than 70 μm . The equivalent conductive layer thickness results from the skin effect, according to which a current flows more and more on the outer circumference of a conductor with increasing frequencies, and describes the depth of the surface area resulting from this consideration, which corresponds to the corresponding behavior of the respective conductor explained under the occurring frequencies.

In addition, the invention relates in particular to data or Control cables, which consist of solid conductors, because with these the claimed surface formations can be realized more precisely can, as is the case with strands or cables. On the other hand it is quite conceivable to use conductors according to the invention also from strands or Shaping cables, as long as the resulting structures in the Surfaces are mastered or are sufficiently small.

A particularly compact structure of the data or control cable follows when the pair of conductors from a common Isolation is surrounded, whose outer curvature in cross section has only one direction of curvature. In particular, this can common insulation a circular outer cross-section exhibit. With such a configuration, it presents itself The cable is extremely elegant on the outside. In addition, the Isolation in the areas next to the greatest field strength relatively strong between the circuit diagram. Since the isolation with their relatively large dielectric constant ε a field counteracts, such a structure requires that the field still is pushed further into the area between the pair of conductors. It it goes without saying that insulation designed in this way also regardless of the other features of the present invention is advantageous.

The insulation preferably encloses both conductors of the cable independently. This requires a particularly compact structure and also ensures that there is a distance between the two Ladders are observed very precisely. Such isolation " a cast "is also independent of the other features accordingly advantageous.

In addition, between the outgoing and the return conductor in one Propagation area for a wave running between the conductors a waveguide, preferably with an ε <1.5. In this way, the damping of a data or control cable can be further reduced. In this context the term "waveguide" designates any constructive Refinement that is made between the heads to a Spread a wave traveling between these conductors facilitate.

In particular, it is possible to use a waveguide To form white space. Such an empty space usually has one very low dielectric constant and thus favors one Spread a wave. Such an empty space can be particularly useful just deploy when the waveguide and the back and forth Return conductors are surrounded by a common insulation. In in this case, a corresponding one can simply be used in the insulation Empty space should be provided. In addition, such Empty space - as required - evacuated or with a gas or air be filled.

It is understood that the presence of such Waveguide also independent of the other characteristics of the present invention is advantageous to spreading a wave between the forward and the return conductor of a data or Promote control cables.

Because signals transmitted over a line, especially if the Transmission takes place digitally, consisting of many frequency components Compose (spectrum) is the specified Frequency preferably the center of gravity frequency, which - not too confuse with a carrier frequency from telecommunications - the Frequency with the greatest power amplitude. The Center of gravity is usually used for physical Dimensioning of the transmission channels used and can, depending on used transmission method significantly lower than that Data transfer rate are. In this respect, the present Invention in particular on data or control cables for the Transmission of bit streams can be used.

Such transmission methods, in the Anglo-Saxon literature often called coding, refer to those used here Methods. Important requirements for the procedures are one No DC voltage, the bandwidth requirement and the possibility a clock recovery. Here the differ different transmission methods usually in that the Bitstream to be transmitted in the level of the pulses to be coded, in their phase position, the duration or the flanks changes experiences. These can be clearly identified on the receiving side Bitstream detection and thus also used for clock recovery become.

Depending on the type of transmission, baseband transmission methods are used and broadband transmission methods. The former are unmodulated, while the latter with a modulation frequency are highlighted. The most famous broadband transmission methods include the various pulse modulation methods (for example PAM, PCM, PWM) and shift keying methods (e.g. PSK, FSK, ASK, DPSK). The main baseband transmission methods are Single current, double current, ternary or pseudo ternary methods (e.g. MLT coding, 8B / 6T coding, CAP coding, AMI coding). This also includes Manchester coding, Bipolar method (HDB coding) and coded diphase method. In the baseband transmission method, the frequency spectrum is of the transmission signal and the bandwidth it occupies directly depending on the transmission speed, but can vary depending on used transmission method vary widely. The digital Signals are fed into the cable in the form of pulses and occupy the entire bandwidth of the cable - or part of it, the other part usually no longer being used for other services is usable. Baseband transmission methods only offer one Channel that accordingly to the different needs needs to be tailored.

Figur 1

ein erstes erfindungsgemäßes Leiterpaar in schematischer Schnittdarstellung,

Figur 2

ein zweites erfindungsgemäßes Leiterpaar in schematischer Schnittdarstellung,

Figur 3

ein drittes erfindungsgemäßes Leiterpaar in schematischer Schnittdarstellung,

Figur 4

ein viertes erfindungsgemäßes Leiterpaar in schematischer Schnittdarstellung,

Figur 5

ein fünftes erfindungsgemäßes Leiterpaar mit einer gemeinsamen Isolation und einem Wellenleiter in schematischer Schnittdarstellung und

Figur 6

ein sechstes erfindungsgemäßes Leiterpaar mit einer gemeinsamen Isolation und einem Wellenleiter in schematischer Schnittdarstellung.

Further advantages, goals and properties of the present invention are explained with reference to the following description of the attached drawing, in which various data or control cables according to the invention are shown by way of example. The drawing shows:

Figure 1

a first conductor pair according to the invention in a schematic sectional view,

Figure 2

a second conductor pair according to the invention in a schematic sectional view,

Figure 3

a third pair of conductors according to the invention in a schematic sectional view,

Figure 4

a fourth conductor pair according to the invention in a schematic sectional view,

Figure 5

a fifth pair of conductors according to the invention with a common insulation and a waveguide in a schematic sectional view and

Figure 6

a sixth pair of conductors according to the invention with a common insulation and a waveguide in a schematic sectional view.

The data or control cable shown schematically in FIG. 1 comprises a pair of conductors 1 consisting of a forward and a return conductor, which is surrounded by a schematically indicated field 2.

As can be seen immediately, the conductors 1 are in relation to them Cross-sectional center of gravity formed asymmetrically. Here the side facing the other conductor 1 is flatter than that medium radius of curvature selected.

With such an arrangement, the field in the immediate Area compressed between the pair of conductors 1, which is the Field in the rest of the space reduced and thus a crosstalk is reduced.

As can be seen immediately, the conductors 1 are relative to one Level of symmetry 3 designed mirror-symmetrical.

Because the conductor 1 on your opposite Head facing side a relatively large Having a radius of curvature stands for the current supply relatively large ladder area available. This area is in particular larger than this for conductors with a round cross-section and comparable cross-sectional area would be the case.

The field formed by this ladder shape is on the gap compressed between the conductors 1. Along a shortest Connection 4 between the conductors 1 is the field opposite one Field with conductors which have a round conductor cross section, thus higher in terms of field strength. Along this shortest Connection 4, however, is the variation of the field strength reduced. This leads directly to the second derivative this field along the shortest connection 4 between them Conductors is smaller than the second derivative of a round pair of conductors with identical cross-sectional area.

When looking at the field along the plane of symmetry 3, which in the Cross section of a perpendicular 3 to the shortest connection 4 between these conductors 1 through a midpoint of these shortest Compound 4 corresponds, it follows that the second derivative of the Field in the area of the center is smaller than that second derivative of a round pair of conductors, each with an identical one Cross-sectional area in exactly this area. Here is the area around the center in its magnitude to the maximum Expansion of the conductor cross-sectional area limited.

If a conductor, for example from the intersection of line 4 with the Leaving the conductor surface, edged, the field strength varies non-uniform on the surface. This means that There are turning points in the field strength that correspond to the Make zero crossings in the second derivative.

Further advantageous conductor shapes are shown in FIGS. 2 to 4 the conductor pairs 5, 6 and 7 shown. Here the form is in Depending on the desired field effects as well as in Dependence on that for a corresponding ladder shape necessary manufacturing costs chosen.

It is understood that in the present context the type of conductor plays a subordinate meaning. The present invention is especially applicable to solid conductors and stranded conductors. Is conceivable however also an application to conductor arrangements in which a Conductor encloses a second conductor.

It goes without saying that the field and Conductor optimization when using data or Control cables with more than two conductors in their concrete Embodiments can be chosen differently. Nevertheless are the procedures to optimize the fields and especially to the field strength at the position of a conductor, which if possible should be left unaffected, reduce, identical.

The exemplary embodiments shown in FIGS. 5 and 6 have each have a pair of conductors 8 and 9, which are from a common Isolation 10 or 11 is surrounded. In these embodiments is the outer cross section of the common insulation 10 or 11 chosen round. It goes without saying that oval or Egyptian Shapes are conceivable.

The common insulation 10 and 11 enclose in both Embodiments each have a waveguide 12 or 13. This Waveguide is arranged in the area in which the greatest field strength is formed and in which thus one moving wave between conductors 8 and 9 respectively.

In the present exemplary embodiments, the waveguides are 12 or 13 formed by an empty space in the insulation 10 or 11. In addition to air, this empty space can also be used with another gas be filled or evacuated.

While in the embodiment shown in Figure 5 certain area of the conductor 8 points openly into the empty space 12, encloses the insulation 11 in that shown in Figure 6 Embodiment of the ladder 9 in its entirety.

Claims (19)

Data or control cable with at least one forward and one return conductor, characterized in that at least one conductor (1, 5, 6, 7, 8, 9) has a geometrical shape with respect to a cross-sectional center of gravity of the conductor (1, 5, 6, 7, 8, 9) is asymmetrical. Data or control cable according to claim 1, characterized in that the forward and return conductors (1, 5, 6, 7, 8, 9) are formed mirror-symmetrically opposite one another. Data or control cable according to claim 1 or 2, characterized in that at least one first conductor (1, 5, 6, 7, 8, 9) in cross section on its other conductor (1, 5, 6, 7, 8, 9) facing side is flatter than the average radius of curvature of the first conductor (1, 5, 6, 7, 8, 9). Data or control cable according to one of claims 1 to 3, characterized in that at least one conductor has a triangular, trapezoidal, semicircular or circular segment-shaped cross section. Data or control cable according to one of claims 1 to 3, characterized in that at least one conductor has two corners in cross section, which are connected by concave circumferential lines. Data or control cable according to one of claims 1 to 3, characterized in that at least one conductor has two corners in cross section, which are connected by convex circumferential lines. Data or control cable according to one of claims 1 to 3, characterized in that at least one conductor has two corners in cross section, which are connected by a convex circumferential line and by a concave circumferential line. Data or control cable according to one of claims 1 to 2, characterized in that at least one conductor has a rectangular, preferably square, cross section. Data or control cable with at least one forward and one return conductor, characterized in that the conductors (1, 5, 6, 7, 8, 9) are designed such that the second derivative of a field between these conductors (1, 5 , 6, 7, 8, 9) along the shortest connection (4) between these conductors (1, 5, 6, 7, 8, 9) is smaller than the second derivative of a round pair of conductors, each with an identical cross-sectional area. Data or control cable with at least one forward and one return conductor, characterized in that the conductors (1, 5, 6, 7, 8, 9) are designed in such a way that the second derivative of a field between these conductors at least along the surface line a conductor (1, 5, 6, 7, 8, 9) has more than two zero points. Data or control cable with at least one forward and one return conductor, characterized in that the conductors (1, 5, 6, 7, 8, 9) are designed such that the second derivative of a field between these conductors (1, 5 , 6, 7, 8, 9) along a perpendicular (3) to the shortest connection (4) between these conductors (1, 5, 6, 7, 8, 9) through a center point of this shortest connection (4) in the area of In terms of magnitude, the center point is smaller than the second derivative of a round pair of conductors, each with an identical cross-sectional area, in precisely this area. Data or control cable according to one of the preceding claims, characterized by at least one solid conductor. Data or control cable according to one of the preceding claims, characterized by a common insulation (10, 11) for the outgoing and return conductor (1, 5, 6, 7, 8, 9), the outer curvature of which in cross section is only one direction of curvature having. Data or control cable according to claim 13, characterized in that the common insulation (10, 11) has a circular outer cross section. Data or control cable according to one of the preceding claims, characterized in that between the outgoing and the return conductor (1, 5, 6, 7, 8, 9) in a propagation area, a waveguide (12, 13), preferably with an ε <1.5, is arranged. Data or control cable according to claim 15, characterized in that the waveguide (12, 13) is formed by an empty space. Data or control cable according to claim 16, characterized in that the waveguide (10, 11) and the outgoing and return conductors (1, 5, 6, 7, 8, 9) are enclosed by a common insulation (10, 11) are. Method for optimizing a data or control cable with at least one forward and one return conductor, characterized in that, starting from a given conductor cross-section, a field density around the conductor pair is determined and then the surface shape of at least one conductor (1, 5, 6, 7, 8, 9) is varied such that the field density between the forward and the return conductor (1, 5, 6, 7, 8, 9) is increased. Method for optimizing a data or control cable with at least one forward and one return conductor, characterized in that, starting from a given conductor cross-section, a field density around the conductor pair is determined and then the surface shape of at least one conductor (1, 5, 6, 7, 8, 9) is varied such that the field density is reduced at a desired location.

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