The present invention relates to a high-speed data cable.
Typical cables for these transmissions are, on the one hand, more or less stiff coaxial cables where an inner conductor is surrounded by a cylindrical outer conductor, and on the other hand, more flexible differential (balanced) cables where positive and negative cores run parallel to one another. The cores can be a solid single conductor or strands of several conductors. The cores are separated from one another by an insulating material. Within one strand, the conductors can be loosely adjoined or can be twisted. The differential pair can form a cable itself (with cladding) or can form a cable with several other differential pairs within a bundle.
Problems occur in particular at high data rates, such as due to higher ohmic conduction losses at higher frequencies and runtime differences (of the signals in the time domain) between the conductors of a core (multipath propagation). The same lead to reduced signal quality and, consequently to poorer transmission efficiency, i.e. lower data rate, lower range, higher necessitated transmitting power or the same.
According to a first embodiment, a high-speed data cable may have: at least one core pair, wherein a conductive shielding surrounds the cores; an insulating cable cladding encloses the conductive shielding; and each of the cores includes at least three electric conductors, wherein the conductors are arranged in a twisted manner equidistantly to a longitudinal center axis of the respective core; and each conductor abuts, on its outer surface, on at least one insulating material through which the conductors of the respective core run separately from one another.
Another embodiment may have the usage of an inventive high-speed data cable for balanced signal transmission.
According to another embodiment, a system may have: an inventive high-speed data cable, wherein the system is implemented to transmit a balanced signal via the high-speed data cable.
The core idea of the present invention is the finding that it is possible to enable high-frequency data transmission in a high-speed data cable in a more efficient manner, wherein in particular at high-frequencies a lower attenuation results. The high-speed data cable includes at least one core pair, wherein a conductive shielding surrounds the cores. The conductive shielding results in increased interference immunity of the cable, which allows, among others, faster data transmission. An insulating cable cladding encloses the conductive shielding and protects the cable, among others, from mechanical loads and corrosion. Each of the cores includes at least three electric conductors insulated from each other, wherein the conductors are arranged in a twisted manner equidistantly to a longitudinal center axis of the respective core. Due to the equidistant arrangement of the conductors to a longitudinal center axis, all conductors of a respective core have the same length. Due to the twisting, each conductor passes a possible interference source with a specific periodicity, or an alignment of the electric characteristics or environment of the individual conductors within the core is given due to the alternation of the positions of the conductors within the core. Thus, signal run time differences within each core of the cable are prevented due to conductors having different lengths. Different paths in this multipath propagation are electrically equal. Each of the conductors abuts on at least one insulating material on its outer surface. In the respective core, the conductors run separately from another. Due to the electric insulation of the conductors between one another a greater surface results, with the same amount of material of the electric conductors, and hence a greater effective cross-sectional area of the core at high frequencies, since in the same the current is guided primarily close to the surface (skin effect). The skin effect describes the confinement of the signal current to an ever smaller space (close to or at the conductor surface) at higher frequencies. Thus, the conductor cross-section available for current transport is effectively reduced, or the ohmic resistance increases with increasing frequencies. Thus, in particular at high frequencies, the skin effect results in high signal attenuation.
Embodiments of the present invention will be detailed subsequently referring to the appended drawings, in which:
A conductive shielding 108 surrounds the cores 104a, 104b in longitudinal direction and forms a Faraday cage around the cores 104a, 104b. The cores 104a, 104b can each be surrounded in pairs by a common conductive shielding 108. Alternatively, an individual shielding per core or a plurality of cores together would be possible. By the Faraday cage, the cores 104a, 104b are protected against outer electromagnetic alternating fields. This means that capacitive or inductive couplings of interferences on the cable 100 are prevented or at least reduced. Additionally, the Faraday cage of the shielding 108 prevents the cores 104a, 104b from emitting electromagnetic alternating fields, whereby further cores 104a, 104b of the cable 100 as well as the environment of the cable 100 are protected from electromagnetic emissions.
The conductive shield 108 can be produced of any conductive material, for example, the conductive shielding 108 is formed from metal-clad plastic foil or non-insulated metal wires. Further, the conductive shielding 108 can surround one core pair 102 each in any form, for example, wound or braided. Advantageously, the conductive shielding 108 is a wire mesh where individual metal wires not insulated with respect to one another are placed on top of one another, or a plastic clad metal foil that is wound around the cores 104a, 104b. The conductive shielding 108 is produced in dependence on the desired mechanic flexibility or stiffness and/or the necessitated electric shielding characteristic of the cable 100. The conductive shielding 108 can be produced as closed/solid cladding or as a combination of the above described elements.
The cores 104a, 104b can be twisted with one another or stranded, i.e. the cores 104a, 104b are twisted around a common axis in a longitudinal direction. Twisting the cores 104a, 104b supports the balanced characteristics of the cable 100. Interferences acting, for example, on the cores 104a, 104b from a specific direction are identically imprinted on both cores 104a, 104b of the core pair 102. In several core pairs 102, the individual core pairs 102 in the cable 100 can be twisted to a different extent. This reduces coupling-in of interferences of the core pairs 102 between the same.
An insulating cable cladding 106 encloses the conducting shielding 108 and forms the surface of the cable 100. The insulating cable cladding 106 can consist, for example, of polyvinylchloride (PVC), polypropylene (PP), polyethylene (PE) or another insulating material. The insulating cable cladding 106 encloses the conductive shielding 108 completely and prevents an electric connection between the conductive shielding 108 and the environment of the cable 100. Additionally, the insulating cable cladding 106 protects the cable 100 from chemical or mechanical influences which can result in damages of the cable 100. The insulating cable cladding 106, for example, can be extruded on the conductive shielding 108.
The conductors 110 are arranged equdistantly (at the same distance) to a longitudinal center axis 118 of the respective core 104a, 104b. Thus, when considering the core cross-section, a circular arrangement of the conductors 110 around a center of the core 104a, 104b results, or the centers of the conductors 110 are arranged on a circle around the longitudinal center axis 118. In each core 104a, 104b, the conductors 110 are arranged in a twisted or warped manner around the longitudinal axis 118. Twisting of the conductors 110 increases the flexibility of the core 104a, 104b, i.e. the more the conductors 110 are twisted in the core 104a, 104b, the more flexible the core 104a, 104b can be bent, whereby small bending radii with the core 104a, 104b are possible without breaking the conductors 110 in the core 104a, 104b. Additionally, the same electrical (environmental) conditions are obtained for all conductors. However, stronger twisting also results in a greater effective conductor length with the same outer length of the cable. The individual conductors 110 of a core are each short-circuited at the ends of the cable. This can be performed, for example by soldering or crimping.
In further implementations of the core 104a, 104b, a plurality of conductors can be equidistantly arranged within the core 104a, 104b. Advantageously, one core includes 3 to 18 conductors 110.
At its outer surface, each conductor 110 abuts on at least one insulating material in which the conductors 110 of the respective core 104a, 104b run separately. The insulating material encloses the conductor 110 and prevents electric currents between the conductors 110. The insulating material between the conductors 110 reduces the influence of the skin effect. The skin effect occurs when a higher-frequency alternating current flows through an electric conductor. Here, the current density within the conductor is lower than at its surface. The displacement of the current to the surface increases with increasing frequency. This results in undesired attenuations of an electric cable. By the insulation of the individual conductors with respect to one another, the effective surface is increased with constant cross-section. Instead of a single conductor, several small electric conductors are available, which results in a greater surface. This results in an effectively higher conductor cross-section at high frequencies. This results in a lower attenuation in the respective core 104a, 104b.
As shown in
In the embodiment of
The insulating cover 212 can, for example, be a resist layer or a plastic as used, for example, for the core or cable cladding. The advantage of a resist layer is that a thin-walled and inexpensive insulating cover 212 is possible, wherein the wall strength of the insulating cover 212 can be in a range of less than 10 μm to 80 μm. The ratio between wall strength of the insulating cover 212 and the radius of the conductor 210 is in the range 0.015 to 0.42. Since the voltage potentials between the conductors 210 of the core 202 are small, thin-walled insulation is sufficient. The breakdown strength of the resist layer insulation is, for example, in the range of 2 kV/mm. Thereby, 10 μm thin resist layers can be used, wherein the potential difference may be 40V. All conductors 210 of a core 202 carry the same signal, such that the potential differences remain very small, for example by local run time differences. The thin-walled insulation results in lower volume and weight of the conductors 210.
The conductors 210 having the insulating cover 212 are enclosed by the core cladding 216.
Further, the core 204 shown in
In the arrangement shown in
The isolator core 214 (non-conductive core) and the planar coverage of the isolator core surface (core surface) with conductor 210 with insulating cover 212 ensures that all conductors 210 have the same length and, hence, run time differences of the useful signal are prevented.
Additionally, the isolator core 214 (non-conductor) inside the core 204 (arrangement) and the insulating cover 212 reduce the proximity effect. In electrical engineering, proximity effect relates to effect of current constriction or current displacement between two closely adjacent conductors under the influence of alternating currents due to the magnetic leakage between the same, caused by rectified currents in the conductors 210. Similar to the skin effect, the rectified current in the adjacent conductor has the urge to prevent current flow at the surface. The current is forced into a smaller cross-section. By keeping the adjacent conductor apart, its influence can be reduced.
The isolator core 214 is advantageously made of an insulating material which, hence, does not conduct electric current. Suitable materials for the isolator core 214 are, for example, plastics or rubber. In particular, the isolator core 214 is made of polypropylene, polyamide or polyethylene. Here, the material can be processed, for example, in a massive manner, in a formed manner or also as monofil.
Compared to known cables where the inside of the core also consists of a metallic conductor, apart from increasing the data rate, the weight of the cable is also reduced by replacing conductors 210 with non-conductors as isolator core 214.
The insulating cover 212 shown in
A stabilizing foil 309 surrounds the two core pairs 302a, 302b and keeps the same in their position. The stabilizing foil 309 can be made, for example, of elastic material which is applied closely to the cores or can be implemented as a shrink sleeve which is shrunk onto the cores 304. The stabilizing foil 309 can also have electrically conductive characteristics and, hence, form a conductive shielding 309 as described above, for example a metal-clad plastic foil.
A conductive shielding 308 can be arranged around the stabilizing foil 309, which is, for example, implemented as wire mesh. Further, the conductive shielding 308 can be surrounded by a cable cladding.
The individual electric conductors of one of the cores 304 are graphically illustrated as a surface due to the low resolution of
As shown in the embodiment, the cores 304 can consist of six electrical conductors 310 each, which comprise an insulating cover 312 at their outer surfaces and are embedded in a core cladding 316. The conductors 310 are twisted around the isolator core 314 running along the longitudinal center axis 118, such that each individual conductor 310 runs, across the length of the cable 300, through the same relative positions with respect to the further other cores 304 and the conductive shielding 308. Only in this way equal electric ratios and hence the same electric parameters (in particular signal run times) of each conductor 310 are given.
Embodiments of the high-speed data cable 100, 300, 500, 600 can be used in any application with high data rates. Among others, these are all cables of the Ethernet Standard, LVDS cables, HDMI cables, TV transmission cables and also USB cables. Further fields of usage are possible. In high-frequency technology transmissions, it is generally necessitated to adapt the wave impedance of the cable 100, 300, 500, 600 to the source and terminating impedance of the transmission path. The wave impedance of the core pair 302a, 302b results from inductance per unit length and capacitance per unit length and is between 50Ω to 300Ω, advantageously, a wave impedance of the high-speed data cable 100, 300, 500, 600 is in the range between 75Ω to 160Ω (differential). However, the wave impedance can also be higher.
The isolator core 414 comprises recesses on its surface which are advantageously implemented according to the radius of the conductors 410. On the side facing away from the isolator core 414, the conductors 410 are molded or extruded into the core cladding 416. Thus, there is no electric connection between the conductors 410. By the embodiment shown in
The cores 504 have one isolator core 515 each, which is arranged along the longitudinal center axis 118 and around which ten conductors 510 with insulating cover 512 are arranged.
Due to the abutting conductors 510, the core cladding 516, as already shown in
Due to the low resolution of
The embodiments shown in the figures show the arrangement of electrically conductive and non-conductive elements in the cross-section of the core 604 of the cable 600. This new arrangement reduces the attenuation up to the GHz range and additionally reduces the weight of the cable 600. Both are obtained by further use of the materials that were conventionally used.
In other words, and by exemplarily using the reference numbers of
This disclosure describes a specific arrangement of the conductors 310 of a core 304 for reducing the attenuation with constant cross-section with a focus on high rate data transmission where signal run times are important. Further, the structure of the cable 300 for high rate data transmission using this core 304 is described. The objective is a cable 300 having a controlled wave resistance, low attenuation and small diameter.
In the core 304, advantageously, 3 to 18 resist-insulated massive conductors 310 are stranded around an isolator core 114 (non-conductive core).
The cable 300 allows reduced attenuation with constants diameter and materials (except the insulating cover 312 (additional resist layer) of the conductors 310 (single wires)). Also, “the top metal layer” of the conductors of a conventional core can be replaced by resist, i.e., the diameter of the conductor 310 can be reduced such that the previous outer diameter of the core 304 is maintained with the insulating cover 312. This reduces the weight per conductor. The overall outside diameter of the cable can stay the same. The cable 300 is particularly suitable for high rate data transmission in the gigahertz range where run time differences also have to be considered.
Embodiments of the high-speed data cable can be used for balanced signal transmission. Here, the high-speed data cable can be used, for example, in a system that is implemented to transmit a balanced signal via the high-speed data cable. Such a system comprising a high-speed data cable can be, for example, a network comprising a plurality of computers or a communication network, for example, for voice transmission. Here, in the broadest sense, computer means active network nodes, including at least a processer having a memory and to which also peripheral devices, such as sensors, control devices, monitors, cameras, etc. can be connected.
While some aspects have been described in the context of an apparatus, it is obvious that these aspects also represent a description of the respective method, such that a block or device of an apparatus can also be considered as respective method step or as a feature of a method step. Analogously, aspects that have been described in the context of or as a method step also represent a description of a respective block or detail or feature of a respective device. Some or all of the method steps can be performed by a hardware apparatus (or by using a hardware apparatus), such as a microprocessor, a programmable computer or an electronic circuit. In some embodiments, some or several of the most important method steps can be performed by such an apparatus.
While this invention has been described in terms of several advantageous embodiments, there are alterations, permutations, and equivalents which fall within the scope of this invention. It should also be noted that there are many alternative ways of implementing the methods and compositions of the present invention. It is therefore intended that the following appended claims be interpreted as including all such alterations, permutations, and equivalents as fall within the true spirit and scope of the present invention.
Number | Date | Country | Kind |
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102013207743.2 | Apr 2013 | DE | national |
102013223584.4 | Nov 2013 | DE | national |
This application is a continuation of copending International Application No. PCT/EP2014/057481, filed Apr. 14, 2014, which claims priority from German Application No. 10 2013 207 743.2, filed Apr. 26, 2013, and from German Application No. 10 2013 223 584.4, filed Nov. 19, 2013, which are each incorporated herein in its entirety by this reference thereto.
Number | Date | Country | |
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Parent | PCT/EP2014/057481 | Apr 2014 | US |
Child | 14923285 | US |