Data cable

Abstract

Cable (1) for transmitting data, comprising at least two conductors (2), each conductor (2) - a conductor (3) extending in a longitudinal direction (12), - an insulating layer (4) surrounding the conductor (3) as well as - comprising a conductor screen (5) enclosing the insulating layer (4), characterized in that an electrically insulating spacer (9) arranged between the conductor screens (5) of the conductors (2) is designed such that a minimum distance (11) of 20 µm is maintained between the conductor screens (5) of the conductors (2) along the longitudinal direction (12).

Description

AREA OF INVENTION

[0001] The invention relates to a cable for transmitting data, comprising two conductors, each conductor comprising a conductor extending in a longitudinal direction, an insulating layer enclosing the conductor and a conductor shield enclosing the insulating layer. STATE OF THE ART

[0002] To transmit data using electrical conductors, this data is encoded as an electrical signal sequence, which is transmitted from a transmitter to a receiver as a time-dependent voltage and / or current signal via a conductor extending in a longitudinal direction.

[0003] Along the longitudinal direction of the conductor, the signal sequence can be exposed to interference from the conductor's environment, particularly electric and magnetic fields. To minimize the influence of such interference on the transmitted data and to prevent disruption or damage to the transmitted data caused by electrical interference fields, measures for shielding the data or the conductor through which the data is transmitted are necessary.

[0004] Shielded cables for transmitting data encoded as electrical signal sequences are known in the art. The simplest form of such a cable is a coaxial cable, which essentially comprises a central conductor and a shield electrically insulated from this central conductor. The shield itself is electrically conductive and is, for example, made of metal foil or wire braid. An electrically non-conductive insulating layer is arranged between the conductor and the shield, thus providing galvanic isolation between the conductor and the shield, as well as electrostatic shielding of the conductor by the shield, which acts like a Faraday cage. A conductor shielded in this way, with the conductor and shield separated by an electrically non-conductive insulating layer, is called a core.

[0005] Interference signals are shielded from the conductor by the aforementioned conductor shield. However, such interference signals can cause charge displacements within the conductor shield, which in turn lead to unwanted currents in the conductor shield, which in turn generate electrical and magnetic interference signals.

[0006] Such interference signals can alter the signal transmitted by the conductor and thus disrupt it. Put simply, the electric and magnetic fields corresponding to the signal are superimposed with the electric and magnetic fields of the interfering signal, causing the signal's characteristics, such as amplitude, frequency, and / or phase, to change, at least temporarily. This results in the information encoded by the signal being altered, and consequently, faulty information reaching the receiver.

[0007] To prevent or mitigate the effects of interference signals on the transmitted data described above, the conductor carrying the voltage signal corresponding to the transmitted data is shielded. Various types of conductor shields are known for this purpose.

[0008] The primary function of a conductor shield is electrostatic shielding, based on the principle of a Faraday cage. This prevents electrical interference from affecting the conductor being shielded, or the signal it transmits. To function as an electrostatic shield, the conductor shield itself must be conductive, but it must not touch the conductor being shielded.

[0009] Electrostatic shielding should be distinguished from galvanic shielding. Galvanic shielding, also called galvanic isolation or insulation, refers to the separation of the conductor from other electrically conductive components of the cable by an insulating layer, i.e., by an electrically non-conductive medium. Galvanic shielding prevents electric current from flowing from the conductor to the other electrically conductive component.

[0010] In addition to conductors, the conductor shields of the conductors themselves can also be considered as current-carrying or shielding media, since currents such as eddy currents can be induced in the conductor shield acting as a current-carrying medium by the interference signals shielded by the conductor shield, which in turn generate a magnetic interference signal.

[0011] Another source of interference is other current- or voltage-carrying elements located in the vicinity of the conductor, especially other conductors. This also applies if these other conductors are themselves used for data transmission – data transmitted in these other conductors located in the vicinity of the conductor acts as interference for the data transmitted by the conductor.

[0012] The aforementioned current- or voltage-carrying elements can generate magnetic fields, which can subsequently induce unwanted currents in the conductor shield or the conductor itself. Since magnetic interference fields are fundamentally not shielded by electrostatic shielding, measures other than simply enclosing the conductor in a shield are required to shield against magnetic fields.

[0013] Problems related to electrical and / or magnetic interference occur particularly frequently with multi-core cables, i.e., cables that contain more than one conductor or more than one core. Any unwanted currents that can be generated in the conductor shields as described above can, in principle, propagate across multiple conductor shields in multi-core cables. TASK OF INVENTION

[0014] It is therefore the object of the invention to overcome the disadvantages of the prior art and to propose a cable which achieves both galvanic and simultaneous magnetic isolation of the shields of the individual conductors from each other. PRESENTATION OF THE INVENTION

[0015] This problem is solved with a cable according to the invention for transmitting data, comprising at least two conductors, wherein each conductor comprises a conductor extending in a longitudinal direction, an insulating layer enclosing the conductor and a conductor shield enclosing the insulating layer, in that an electrically insulating spacer arranged between the conductor shields of the conductors is designed such that a minimum distance of 20 µm is obtained between the conductor shields of the conductors along the longitudinal direction.

[0016] In this context, "data" refers to an electrical signal sequence, i.e., electrically encoded information. The data is therefore present as a time-dependent voltage or current signal. The term "data" as used in the invention described herein encompasses both analog and digital data or signals. Furthermore, unless otherwise specified, the term "signal" within the scope of this invention means the same as the term "data," namely the time-dependent voltage or current signal transmitted by the conductor.

[0017] As an electrical signal sequence, transmitted data is subject to general electrostatic and electrodynamic principles. Therefore, it can be influenced or altered, in particular by external electrical or magnetic interference fields or signals acting on the cable from outside, which is undesirable.

[0018] Interference signals, in this context, are all electric or magnetic fields that are not generated by the time-dependent voltage signal corresponding to the transmitted data itself. Interference signals can originate, for example, from power lines that generate an alternating field with a frequency of 50 or 60 Hz, depending on the region. In the high-frequency range, signals from radio, telecommunications, or mobile communications technology are conceivable examples of interference signals.

[0019] To protect the signal transmitted by the conductor from the influence of these interference signals, various types of shielding of the conductor are provided.

[0020] The insulating layer, made of a non-conductive material, preferably plastic, forms a galvanic shield for the conductor.

[0021] The conductor shield, made of a conductive material, preferably metal, particularly preferably copper, steel or aluminium, is provided as an electrostatic shield for the conductor and limits, preferably prevents, the influence of electrical interference signals on the conductor.

[0022] Since magnetic interference signals can, on the one hand, penetrate the conductor shield and directly affect the conductor, and on the other hand, indirectly affect the conductor by inducing further electrical and / or magnetic interference signals in the conductor shield, a simultaneous magnetic shield is provided according to the invention in addition to the galvanic shielding and the electrostatic shielding.

[0023] Such magnetic shielding weakens the effect of magnetic interference signals on the conductor and the conductor shield as described above.

[0024] Magnetic shielding is achieved by providing a spacer, which, due to its electrically insulating properties, simultaneously forms a galvanic isolation between the conductor shield and the conductor shield of at least one other conductor, in order to prevent the propagation of unwanted induced currents, which, as previously described, can generate further interference signals, from one conductor shield to the other.

[0025] The spacer creates a minimum distance of 20 µm between the conductor shields of the conductors, which, due to the distance dependence of the field strength of any magnetic interference field of a current induced in the other conductor shield, creates magnetic insulation between the conductor shields.

[0026] A minimum distance of 20 µm means that between the conductor shields of the at least two conductors or, if more than two conductors are provided, in pairs between any two conductors, a distance of at least 20 µm perpendicular to the longitudinal direction is provided along the entire longitudinal direction of the cable according to the invention.

[0027] Due to the minimum spacing of 20 µm, it is possible to arrange the conductors in the cable in a very space-saving manner while simultaneously providing magnetic and galvanic shielding, resulting in a high proportion of the conductor's cross-section to the total cross-section of the cable.

[0028] The spacer is electrically insulating. This means that the spacer comprises at least one electrically non-conductive layer that extends completely along a closed surface around all but at most one of the conductor shields. In other words, the spacer is designed such that no electrical current can flow from any conductor shield to the at least one other conductor shield.

[0029] Provided the above-mentioned condition is met, it is not excluded that the spacer may also include electrically conductive components. For example, the spacer may comprise a metal foil, preferably a metal foil made of ferromagnetic material, particularly preferably of iron, which is coated with an electrically non-conductive material such as insulating varnish.

[0030] The form of the spacer can be arbitrary in principle. It can be, for example, a foil encasing the conductor shields, spacer elements such as block elements or an electrically non-conductive granulate that surround the conductor shields section by section and ensure the minimum distance, or even a gas, such as air, or a combination of these elements.

[0031] The spacer is designed to shield the conductor screens from each other both galvanically and magnetically, or to form a galvanic shield and a magnetic shield between the conductor screens.

[0032] The spacer encloses the conductor shield of at least one conductor, at least partially.

[0033] Because the spacer is electrically insulating, galvanic isolation is achieved between the conductor shields in addition to magnetic isolation. This prevents the propagation of an interference signal generated in one conductor shield by induction or influence to the other conductor shield.

[0034] In other words, a “cross-talking” effect is prevented or reduced in this way with regard to both electrical and magnetic interference signals.

[0035] The simultaneous galvanic and magnetic shielding of the conductor shields from each other enables the transmission of high-frequency signals up to the range of 20 GHz and above.

[0036] According to a particular embodiment of the invention, it is provided that each insulating layer has an insulating layer thickness of at least 0.1 mm.

[0037] The specific insulation layer thickness can be chosen according to the desired impedance of the conductor in question and / or according to the dielectric constant of the material from which the insulation layer is formed, whereby the ratio of the insulation layer thickness to the impedance can be described at least approximately by the mathematical-analytical model of a cylindrical capacitor.

[0038] The insulation layer thickness does not have to be constant; both a constant and a non-constant insulation layer thickness can have advantages.

[0039] A constant insulation layer thickness makes the insulation layer particularly easy to manufacture, as it can then be produced, for example, as a tube with a uniform wall thickness or extruded onto the conductor.

[0040] In contrast, a non-constant insulation layer thickness, preferably one that does not repeat periodically along the longitudinal direction, has the advantage that any interference signal induced by the signal transmitted in the corresponding conductor is modulated aperiodically in the conductor shield, making it easier to filter out in the frequency domain.

[0041] According to a particular embodiment of the invention, the insulation layer of the first conductor has a different insulation layer thickness than the insulation layer of the second conductor.

[0042] This allows the interference signals in the respective conductor shields to have different amplitudes and be modulated differently, preferably aperiodically. This makes it easier to suppress noise using electronic filters.

[0043] According to a particular embodiment of the invention, the minimum distance is not constant.

[0044] This can result in an asymmetrical cross-section of the spacer, but the varying minimum distance can also be compensated for, for example, by correspondingly symmetrical variation of the insulation layer thickness.

[0045] The asymmetrical cross-section of the spacer creates an asymmetrical pairing of conductors or wires, which improves the aperiodic modulation of any interference signal in the conductor shields, allowing it to be filtered out even more effectively in the frequency domain.

[0046] According to a particular embodiment of the invention, the spacer means comprise two films made of dielectric material, wherein the first film encloses the conductor screen of the first conductor and the second film encloses the conductor screen of the second conductor at least partially.

[0047] The wrapping of the conductor shields by the foils can be done section by section, for example spirally with a corresponding spiral gap, or without gaps, or overlapping or in multiple layers.

[0048] A tubular version of the films is also conceivable.

[0049] A multi-layered sheathing of the conductor shields results in particularly robust galvanic shielding. A spiral sheathing, especially one with a spiral gap, has the advantage that the conductor is particularly flexible and especially easy to bend.

[0050] According to a particular embodiment of the invention, each foil is designed as a strip, which strip is wound spirally around the conductor screen, with a gap between two adjacent turns of the strip.

[0051] The foil encases the conductor shield. If the foil is designed as a tape wound spirally around the conductor shield, this encasement is achieved by wrapping the tape around the—essentially cylindrical—conductor shield. This creates turns, with a turn being defined as the section of the tape that corresponds to a full rotation of the cylinder on the essentially cylindrical surface of the conductor shield. In other words, a turn begins at the point on the tape where, viewed longitudinally, the tape is adjacent to the point where the turn originated.

[0052] This gap makes the conductor particularly flexible. Furthermore, when the cable, and thus the individual conductors, are bent, the spirally wound band can shift, narrowing the gap. This prevents the band from overlapping itself, thus avoiding an increase in the diameter of the conductors and therefore the cable. This allows for particularly tight bending radii of the conductors and the cable.

[0053] According to a particular embodiment of the invention, it is provided that each strip has a strip width of at most 1 mm and each gap has a gap width of at most 0.5 mm.

[0054] The permissible bending radius of the cable, which results from how tightly a cable can be bent without damaging it, is usually at least on the order of the total diameter of the cable, but regularly several times the total diameter.

[0055] With a strip width of at least 1 mm and a gap width of 0.5 mm, the bending radius is larger than the gap width, which prevents contact between two adjacent conductor shields.

[0056] Furthermore, the gap width is then so small that the conductor shields are stiff enough that they cannot penetrate the gap.

[0057] To avoid resonance, the gap width must be less than half the wavelength of the signal transmitted by the respective conductor. A combination of a wavelength of 1 mm and a gap width of 0.5 mm is particularly advantageous. This ensures effective decoupling between adjacent conductors to minimize electromagnetic interference and crosstalk.

[0058] The geometry described above supports both the transmission of pulsed signals and the transmission of periodic, especially sinusoidal, signals, which requires a correspondingly precise matching of the wavelength of the signal and the gap width.

[0059] A 1mm strip width offers a stable conductor area that can be used both as an inner conductor in coaxial constructions and as a signal carrier in a differential pair configuration. A 1mm strip width is particularly advantageous for impedance control in high-frequency signals and for effective current carrying capacity when current is conducted through the conductor or shield.

[0060] According to a particular embodiment of the invention, it is provided that, viewed in the direction of view along the minimum distance to the respective conductors, the turns of the wound tape on one conductor overlap the gaps arranged on the other conductor between two adjacent turns of the wound tape.

[0061] This arrangement of the tapes ensures that, while each conductor has its own spirally wound tape as a foil or spacer, the relative arrangement of the tapes of two different conductors to each other guarantees particularly reliable galvanic isolation between the conductor shields. At those points on one of the two conductors where its conductor shield is exposed—these are the areas of the gaps between two adjacent turns of the tape—the tape of the other conductor is positioned, so that along the entire longitudinal direction between the conductor shields of the two conductors, at least one tape, namely either the tape of one conductor or the tape of the other, or both tapes, are present. In this way, contact between the conductor shields of the conductors is prevented along the entire longitudinal direction.

[0062] According to a particular embodiment of the invention, the cable for transmitting pulsed signals is provided with a spatial half-value width in the conductor of 5 mm to 30 mm and the half-value width is greater than the sum of a channel height formed from strip width and gap width.

[0063] The full width at half maximum (FWHM) is specifically defined as the spatial width of the signal pulse at half the pulse height. This width is calculated based on the average propagation speed of 0.7c (70 percent of the speed of light) of the signal transmitted by the conductor and the pulse duration. The term "full width of half maximum" (FWHM) is also commonly used in measurement technology.

[0064] The propagation speed of the signal depends on the conductor material and is therefore a material constant. A value of 0.7c is a guideline for common metallic conductor materials such as copper, copper alloys, or aluminum.

[0065] A spatial half-width of 5 to 30 mm corresponds to a maximum pulse frequency of approximately 50 to 500 GHz.

[0066] The fact that the spatial half-width of the signal is greater than the pitch avoids disturbances such as resonances (so-called suck-outs) or peaks in the high-frequency characteristics of the respective conductor.

[0067] When the foil presses against the conductor screen according to this embodiment, marks are created. These marks affect the signal in such a way that they can cause reflections, which can also constructively superimpose themselves on any resonances described above.

[0068] The foil not only acts as a spacer but also has a signal-dependent effect directly linked to the signal's half-power width. The pitch of the foil, implemented as a strip, only affects the electromagnetic properties of the corresponding conductor without interference if the half-power width is greater than the pitch. The strip also contributes to the galvanic isolation of the conductors from each other.

[0069] According to a particular embodiment of the invention, the spacer means comprises magnetizable material.

[0070] Suitable magnetizable materials include iron foil, iron oxide, iron nanoparticles, µ-materials, generally ferromagnetic materials or metamaterials, or a combination of these materials.

[0071] The inclusion of magnetizable material in the spacer represents another possibility for creating magnetic shielding.

[0072] When an electrically conductive, magnetizable material is used as magnetic shielding, it includes, for example, an electrically non-conductive coating on its surface or an electrically non-conductive film surrounding the magnetizable material in order to ensure simultaneous galvanic shielding.

[0073] By incorporating magnetizable material into the spacer, even more effective magnetic shielding is achieved than by the minimum distance of 20 µm provided by the spacer alone.

[0074] The foil does not necessarily consist entirely of magnetizable material, but can be made of an insulating material such as plastic, into which magnetizable particles are embedded, so that the foil is magnetizable overall but simultaneously non-conductive. In this way, the foil provides magnetic shielding while maintaining its galvanic shielding function. It is also conceivable that the foil comprises a layer of magnetizable material and another layer of an insulating material, as is the case, for example, with an iron foil coated with insulating varnish.

[0075] According to a particular embodiment of the invention, it is provided that at least one of the foils comprises magnetizable material.

[0076] This provides the magnetizable material in a form that is particularly easy to manufacture.

[0077] If an electrically conductive magnetizable material is used, the films include an electrically insulating layer to achieve simultaneous galvanic isolation.

[0078] According to a particular embodiment of the invention, it is provided that the magnetizable material is arranged in at least one gap.

[0079] To achieve magnetic shielding, in the case of a foil designed as a tape, it can also be provided that magnetizable material, which creates a magnetic shield, is arranged or embedded in the gaps between two adjacent turns of the tape.

[0080] To ensure galvanic isolation, the magnetizable material is electrically insulating overall. Electrically insulating overall means that no electric current can flow through the magnetizable material as a whole. This is achieved, for example, by having the magnetizable material enclose an insulating layer or, if the magnetizable material is particulate, by encasing the particles in an insulating material.

[0081] The fact that the magnetizable material is arranged in at least one gap means that the magnetizable material can be arranged in at least one gap between two turns of the tape of one, the other or both of two adjacent conductors.

[0082] Since the gaps represent an enclosed space that is only open at the ends of the cable, the magnetizable material can, for example, also be in powder form, although other forms of the magnetizable material, such as another strip, are not excluded.

[0083] Magnetizable material in powder form or as a bulk material has the advantage that it easily deforms when the wires or cable are bent, making the wires or cable particularly flexible.

[0084] According to a particular embodiment of the invention, it is provided that the conductors of the respective wires have different diameters.

[0085] The different diameters allow for different values ​​of the conductor's ohmic resistance. The conductor's diameter thus represents one degree of freedom regarding the adjustability of the cable's impedance.

[0086] According to this embodiment, the diameters of the other cable components can also vary in accordance with the varying diameter of the conductors. This is particularly the case when the cable diameter is constant in the longitudinal direction.

[0087] The other components of the cable, in particular the insulation layers and the foils of the individual conductors, as well as the minimum distance between the conductors, can also vary. This allows, for example, the strength, i.e., the degree of ability to shield magnetic or electric fields, of the magnetic and / or galvanic and / or electrostatic shielding to be varied.

[0088] The varying diameters of the conductors can also be compensated for by correspondingly varying diameters or thicknesses of other components, in particular the insulation layer thickness of the insulation layers, so that overall the cable has a constant diameter in the longitudinal direction.

[0089] According to a particular embodiment of the invention, the cable comprises at least three conductors, wherein two conductors are designed as a differential pair and the third conductor is designed as a coaxial conductor or as a conductor for power supply.

[0090] The magnetic, galvanic and electrostatic shielding of the individual conductors of the cable described above works regardless of which electric current flows in the conductors.

[0091] The aforementioned shielding also works, for example, if the corresponding conductor is used for power supply instead of signal transmission.

[0092] Since the currents carried by supply lines are regularly many times higher than the currents of signal transmission lines, supply lines regularly emit a comparatively strong magnetic interference field.

[0093] The above also applies analogously to electrical interference fields emanating from supply lines, since the voltages carried by supply lines are regularly higher than the voltages carried by signal transmission lines.

[0094] The use of a single conductor for power supply therefore has the advantage that power supply and signal transmission can be provided with just one cable, which, for example, reduces the number of cables required for an electronic device and makes this device easier to handle, while at the same time preventing unwanted interference from the power supply on the signal transmission.

[0095] According to a particular embodiment of the invention, an even number of wires are provided and the wires are twisted together in pairs.

[0096] Such a twisted pair arrangement of the wires is also called "twisted pair" and additionally contributes to making the cable as noise-free as possible.

[0097] According to a particular embodiment of the invention, it is provided that an overall shield is provided which at least partially encloses the conductors and the spacer means and which contacts the conductor shield of at least one of the conductors.

[0098] Such an overall shield establishes a further shielding effect in addition to the magnetic, galvanic and electrostatic shielding provided by the conductors.

[0099] The overall shield is made of an electrically conductive material, preferably a metallic material, and particularly preferably a magnetizable material. The overall shield therefore acts as an electrostatic and galvanic shield, or, if made of a magnetizable material, also as a magnetic shield, and in turn shields against electric and, if applicable, magnetic fields acting on the entire cable, thereby further reinforcing the shielding of the individual conductors.

[0100] Through contact between the overall shield and the conductor shield of at least one of the conductors, the potential of the overall shield and the potential of the conductor shield of this at least one conductor are equalized, preventing current from flowing between the overall shield and the conductor shield of the at least one conductor.

[0101] The conductors are galvanically and magnetically isolated because the overall shield is soft enough to penetrate any gap that may be present. In this case, the conductor shields are locally contacted. However, these local contact points through the overall shield have a very high ohmic contact resistance, so galvanic isolation is maintained in this sense. Current flow between the conductor shields is therefore possible, but the contacting described above and the controlled galvanic isolation prevent this current flow from becoming disruptive. BRIEF DESCRIPTION OF THE FIGURES

[0102] The invention will now be explained in more detail using exemplary embodiments. The drawings are exemplary and are intended to illustrate the inventive concept, but in no way to restrict or even exhaustively represent it.

[0103] This shows: Fig. 1 a schematic cross-sectional view through two adjacent conductors of a data cable according to the invention, Fig. 2 An embodiment of the data cable with a spirally wound band in a schematic axonometric view, Fig. 3 a vein with a spirally wound band and schematic representation of a signal pulse in a schematic axonometric view, Fig. 4 a schematic cross-sectional view of a data cable comprising four wires, Fig. 5 an exemplary, measured frequency characteristic of the data cable for longitudinal conversion transfer loss (LCTL) and Fig. 6 a schematic damping diagram. WAYS TO IMPLEMENT THE INVENTION

[0104] Fig. Figure 1 shows a cross-section through two conductors 2 of a cable 1 according to the invention, comprising a conductor 3 for data transmission. For clarity, the individual components of the conductor 2 are only shown on the conductor 2 depicted on the right.

[0105] The conductor 3 is designed to ensure the transmission of the data itself and is therefore made of an electrically conductive material such as a metal, preferably copper or a copper alloy. In other words, an electrical signal sequence encoding the data is transmitted through the conductor 3 from a transmitter in a longitudinal direction 12 to a receiver.

[0106] To protect conductor 3 from the influence of electrical and magnetic interference signals, conductor 3 must be shielded in various ways. For this purpose, different layers, arranged essentially concentrically around conductor 3, are provided.

[0107] The first layer surrounding conductor 3 is an insulating layer 4, which has an insulating layer thickness of 10 and is made of an electrically non-conductive material, or in other words, an insulating material. This galvanically isolates conductor 3 from the environment of conductor 2.

[0108] The insulation layer 4 can, for example, comprise or consist of plastics such as polyethylene (PE), polypropylene (PP) or polyvinyl chloride (PVC).

[0109] The insulation layer 4 can also include a foil screen (not shown), for example comprising an Al-PETP foil. The insulating layer 4 is itself enclosed by a conductor shield 5. The conductor shield 5 is made of an electrically conductive material. Suitable materials for the conductor shield 5 include, for example, metal foils or wire mesh.

[0110] A particularly preferred embodiment of such a wire mesh corresponds to an optical coverage by the wire mesh of at least 85 percent.

[0111] In principle, a closed conductive pipe or a conductive hose through which the conductor 3 together with the insulating layer 4 is guided could also be conceivable as a conductor shield 5.

[0112] The insulating layer 4 surrounds the conductor 3 and is therefore, in the illustrated embodiment, shaped like a tube, with the conductor 3 extending in the inner cavity of this tube and the conductor shield 5 extending along the outer surface of this tube.

[0113] Because the conductor shield 5 is made of an electrically conductive material and encloses the conductor 3, the conductor shield 5 acts as a Faraday cage and therefore provides electrostatic shielding. This electrostatic shielding prevents an electric field present in the space around the conductor 2 from penetrating the conductor shield 5.

[0114] The conductor shield 5 is itself enclosed by a foil 6. The foil 6 is electrically non-conductive and therefore provides galvanic shielding of the conductor shield 5 to prevent current flow from the conductor shield 5 to the conductor shield 5 of at least one other conductor 2.

[0115] The foil 6 is part of the spacer 9, which creates a minimum distance 11 of at least 20 µm in order to form magnetic insulation between the conductor shields 5 of the two conductors 2.

[0116] The cable 1 comprises at least two conductors 2, each of which in turn comprises a conductor 3, each an insulating layer 4, which insulating layers 4 do not necessarily have to have the same insulating layer thickness 10, each a conductor shield 5 and each a foil 6.

[0117] The foil 6 prevents the conductor shield 5 of one of these two conductors 2 from touching the conductor shield 5 of the other of at least two conductors. In other words, the foil 6 prevents an electrically conductive contact between the conductors 2.

[0118] The film 6 is enclosed by a spacer 9, whereby the spacer 9 can also consist of the film 6. In this case, which is not in Fig. However, the embodiment shown in 1 is as follows: Fig. 4 corresponds to the foils 6 of the corresponding adjacent conductors 2 touching. The in Fig. In contrast, the spacer shown in Figure 1 comprises not only the foils 6 of the conductors 2 but also air. In other words, the conductors 2 are spaced apart from each other while maintaining a minimum distance 11 of 20 µm, such that a gap is formed between the foils 6 of the respective conductors 2.

[0119] The spacer 9 creates a minimum distance 11 between the conductor shields 5 of the conductors 2. This minimum distance 11 between the conductor shields 5 provides magnetic shielding between them, since a magnetic field emanating from one conductor shield 5, which can be generated, for example, by unwanted currents induced in the other of the at least two conductor shields 5, becomes smaller as the distance between the conductor shields 5 increases. The minimum distance 11 thus establishes a minimum level of magnetic shielding.

[0120] To create stronger magnetic shielding, the foil 6 can, for example, comprise magnetizable material, without affecting the foil 6's non-conductive property. One embodiment of such a non-conductive foil 6 comprising a magnetic material would be a foil 6 made of plastic in which iron particles are embedded.

[0121] Fig. Figure 2 shows a cable 1 in a schematic axonometric view transverse to the longitudinal direction 12, wherein the individual layers described above are cut open at different locations in the longitudinal direction 12, so that the conductor 3, the insulating layer 4, the conductor shield 5 and the spacer 9 designed as a foil 6 are visible.

[0122] The foil 6 is designed as a band 14 wound spirally around the conductor screen 5.

[0123] A cable 1 comprising three wires 2 is shown.

[0124] According to the illustrated embodiment, the three conductors 2 are enclosed by a total shield 7. This total shield 7, like the conductor shields 5, is made of an electrically conductive material and therefore forms an additional electrostatic shield, since the total shield 7 itself acts as a Faraday cage.

[0125] In order to additionally galvanically insulate the cable 1 and also to protect it from mechanical influences, a cable sheath 19 is also provided according to the embodiment shown.

[0126] Fig. Figure 4 shows cable 1 as it is in Fig. 2 is shown, however with a total of four veins 2 and also in a schematic sectional view.

[0127] According to the in Fig. In the embodiment shown in Figure 4, the spacer means 9 consists only of the foils 6 of the respective adjacent conductors 2, which accordingly also touch each other.

[0128] Fig. Figure 3 shows a single conductor 2 in a schematic axonometric view transverse to the longitudinal direction 12 comprising the conductor 3, the insulating layer 4, the conductor screen 5 and the spacer 9 designed as a foil 6, wherein the foil 6 is designed as a band 14 wound spirally around the conductor screen 5.

[0129] The spiral arrangement of the band 14 creates turns 13 and, corresponding to the turns 13, columns 15.

[0130] The columns 15 have a gap width of 17. The band 14 itself has a strip width of 16. The strip width 16 and the gap width 17 together result in a pitch of 8 of the turn 13.

[0131] As previously described, the signal is carried in conductor 3. According to the illustrated embodiment, this signal is a pulsed signal, wherein the pulse has a spatial half-width 18.

[0132] The half-width 18 is greater than the pitch 8.

[0133] Fig. Figure 5 shows measurement data of a cable according to the invention, specifically the longitudinal conversion transfer loss (LCTL) as a function of the signal frequency.

[0134] Fig. Figure 5 shows that the longitudinal conversion transmission loss of a cable 1, 23 according to the invention is in the range of less than -35dB, while for the longitudinal conversion transmission loss of a cable according to the state of the art 24 only a value of about -20dB is achieved.

[0135] Fig.Figure 6 shows the attenuation dip 22 (see attenuation curve 21) occurring in a cable known from the prior art, which is caused by internal reflections in a certain frequency range. This attenuation dip 22 is also prevented in the cable 1 according to the invention by the conductor shield 5 and the foil 6 (see attenuation curve 20), so that the transmission characteristics are also significantly improved in this frequency range. REFERENCE MARK LIST 1 cable 2 wires 3 conductors 4 Insulation layer 5 conductor shield Slide 6 7 Total screen 8 gear height 9 Spacers 10 Insulation layer thickness 11 Minimum distance 12 Longitudinal direction 13 turns Volume 14 15 columns 16 strip width 17 gap width 18 Half-width 19 Cable sheath 20 Attenuation curve of cable 1 21 Attenuation curve of a cable according to the state of the art 22 Damping drop 23 Longitudinal conversion transmission loss of the cable according to the invention 1 24 Longitudinal conversion transmission loss of a cable according to the state of the art

Claims

[1] Cable (1) for transmitting data, comprising at least two conductors (2), each conductor (2) - a conductor (3) extending in a longitudinal direction (12), - an insulating layer (4) surrounding the conductor (3) as well as - comprises a conductor shield (5) enclosing the insulating layer (4), characterized by , that an electrically insulating spacer (9) arranged between the conductor shields (5) of the conductors (2) is designed such that a minimum distance (11) of 20 µm is maintained between the conductor shields (5) of the conductors (2) along the longitudinal direction (12). [2] Cable (1) according to claim 1, characterized by , that each insulation layer (4) has an insulation layer thickness (10) of at least 0.1 mm. [3] Cable (1) according to one of claims 1 to 2, characterized by , that the insulation layer (4) of the first conductor (2) has a different insulation layer thickness (10) than the insulation layer (4) of the second conductor (2). [4] Cable (1) according to any one of claims 1 to 3, characterized by , that the minimum distance (11) is not constant. [5] Cable (1) according to any one of claims 1 to 4, characterized by , that the spacer means (9) comprise two foils (6) of dielectric material, wherein the first foil (6) encloses the conductor screen (5) of the first conductor (2) and the second foil (6) encloses the conductor screen (5) of the second conductor (5) at least section by section. [6] Cable (1) according to claim 5, characterized by , that each foil (6) is designed as a strip (14) which strip (14) is wound spirally around the conductor screen (5) wherein there is a gap (15) between two adjacent turns (13) of the strip (14). [7] Cable (1) according to claim 6, characterized by , that each strip (14) has a strip width (16) of at most 1 mm and each gap (15) has a gap width (17) of at most 0.5 mm. [8] Cable (1) according to one of claims 6 to 7, characterized by, that, viewed in the direction of view along the minimum distance (11) to the respective conductors (2), the turns (14) of the wound band (13) on one conductor (2) overlap the gaps (15) arranged on the other conductor (2) between two adjacent turns of the wound band (13). [9] Cable (1) according to any one of claims 6 to 8, characterized by , that the cable (1) is designed for the transmission of pulsed signals with a spatial half-value width (18) in the conductor (3) of 5 mm to 30 mm and the half-value width (18) is greater than the sum of a pitch height (8) formed from strip width (16) and gap width (17). [10] Cable (1) according to any of the preceding claims, characterized by , that the spacer (9) comprises magnetizable material. [11] Cable (1) according to claim 10 and according to any one of claims 5 to 9, characterized by , that at least one of the foils (6) comprises magnetizable material. [12] Cable (1) according to claim 10 and according to any one of claims 6 to 9, characterized by , that magnetizable material is arranged in at least one gap (14). [13] Cable (1) according to any one of claims 1 to 12, characterized by , that the conductors (3) of the respective wires (2) have different diameters. [14] Cable (1) according to any one of claims 1 to 13, characterized by , that the cable (1) comprises at least three conductors (2), wherein two conductors (2) are configured as a differential pair and the third conductor (2) is configured as a coaxial conductor or as a power supply conductor. [15] Cable (1) according to claim 14, characterized by , that an even number of wires (2) are provided and the wires (2) are twisted together in pairs. [16] Cable (1) according to any one of claims 1 to 15, characterized by, that a total shield (7) is provided which at least partially encloses the conductors (2) and the spacer means (9) and which contacts the conductor shield (5) of at least one of the conductors (2).

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