Patent Application
20140060913
1. Field of the Invention
The present invention relates to a twisted pair cable for communication of high speed signals, such as a local area network (LAN) cable. More particularly, the present invention relates to a twisted pair cable having a separator tape between twisted pairs within the cable, which reduces or eliminates the likelihood of transmission errors because of internal or alien crosstalk, and hence allows for a relatively higher bit rate transmission.
2. Description of the Related Art
Along with the greatly increased use of computers for homes and offices, there has developed a need for a cable, which may be used to connect peripheral equipment to computers and to connect plural computers and peripheral equipment into a common network. Today's computers and peripherals operate at ever increasing data transmission rates. Therefore, there is a continuing need to develop a cable, which can operate substantially error-free at higher bit rates, by satisfying numerous elevated operational performance criteria, such as a reduction in internal and alien crosstalk when the cable is in a high cable density application. e.g. routed alongside other cables.
Each twisted wire pair A, B, C and D includes two insulated conductors. Specifically, the first twisted wire pair A includes a first insulated conductor 13 and a second insulated conductor 15. The second twisted wire pair B includes a third insulated conductor 17 and a fourth insulated conductor 19. The third twisted wire pair C includes a fifth insulated conductor 21 and a sixth insulated conductor 23. The fourth twisted wire pair D includes a seventh insulated conductor 25 and an eighth insulated conductor 27.
Each twisted wire pair A, B, C and D is formed by having its two insulated conductors continuously twisted around each other. For the first twisted wire pair A, the first conductor 13 and the second conductor 15 twist completely about each other, three hundred sixty degrees, at a first interval w along the length of the cable 1. For the second twisted wire pair B, the third conductor 17 and the fourth conductor 19 twist completely about each other, three hundred sixty degrees, at a second interval x along the length of the cable 1. For the third twisted wire pair C, the fifth conductor 21 and the sixth conductor 23 twist completely about each other, three hundred sixty degrees, at a third interval y along the length of the cable 1. For the fourth twisted wire pair D, the seventh conductor 25 and the eighth conductor 27 twist completely about each other, three hundred sixty degrees, at a fourth interval z along the length of the cable 1.
Each of the wire pairs A, B, C and D has a fixed twist interval w, x, y, z, respectively. Each of the twist intervals w, x, y, z is different from the twist interval of the other wire pairs. As is known in the art, such an arrangement assists in reducing crosstalk between the wire pairs within the cable 1, which is referred to as internal crosstalk. In one embodiment of the prior art, each of the twisted wire pairs A, B, C and D has a unique fixed twist interval of slightly more than, or less than, 0.500 inches. Table 1 below summarizes the twist interval ranges for the twisted pairs A, B, C and D.
A cable 1, as described above and depicted in
Applicants have appreciated that at higher data transmission rates, the internal and alien crosstalk are more problematic. The crosstalk transmitted from, and received by, the pairs with the longer twist lengths are the most problematic. Therefore, in the prior art, the dielectric separator 3 is placed so as to separate and distance the two twisted pairs C and D with the longest twist lengths y and z. However, this technique of employing the separator 3 may be insufficient when the data transmission rate is increased.
Hence, a new cable structure to reduce the influences of internal and alien crosstalk is needed in the art as the data transmission rates are increased.
Applicants have invented a twisted pair cable with new structural features, the object of which is to enhance one or more performance characteristics of a LAN cable, such as reducing internal and alien crosstalk, insertion loss, matching impedance, reducing propagation delay and/or balancing delay skew between twisted pairs, and/or to enhance one or more mechanical characteristics of a LAN cable, such as improving flexibility, reducing weight, reducing cable diameter and/or reducing smoke emitted in the event of a fire.
These and other objects are accomplished by a cable that includes a jacket surrounding a cable core. The cable core includes four twisted pairs. An S-shaped separator separates two of the twisted pairs from the other two twisted pairs. The S-Shaped separator may be formed with two layers or three layers, wherein at least one layer is conductive. In alternative embodiments, one or both ends of the S-shaped separator make electrical contact to mid-portions of the separator to create one or two shielding cambers within the cable.
In a first alternative or supplemental embodiment of the invention, a cable includes: a first conductor; a first insulating material surrounding said first conductor to form a first insulated conductor; a second conductor; and a second insulating material surrounding said second conductor to form a second insulated conductor, wherein said first and second insulated conductors are twisted about each other to form a first twisted pair; a third conductor; a third insulating material surrounding said third conductor to form a third insulated conductor; a fourth conductor; and a fourth insulating material surrounding said fourth conductor to form a fourth insulated conductor, wherein said third and fourth insulated conductors are twisted about each other to form a second twisted pair; a fifth conductor; a fifth insulating material surrounding said fifth conductor to form a fifth insulated conductor; a sixth conductor; and a sixth insulating material surrounding said sixth conductor to form a sixth insulated conductor, wherein said fifth and sixth insulated conductors are twisted about each other to form a third twisted pair; a seventh conductor; a seventh insulating material surrounding said seventh conductor to form a seventh insulated conductor; an eighth conductor; and an eighth insulating material surrounding said eighth conductor to form an eighth insulated conductor, wherein said seventh and eighth insulated conductors are twisted about each other to form a fourth twisted pair; a jacket surrounding said first, second, third and fourth twisted pairs, said first and third twisted pairs residing in approximately a first half of said cable, and said second and fourth twisted pairs residing in approximately a second half of said cable, wherein a region between said first and second halves of said cable defines a middle region; and a tape separator disposed within jacket, and separating said first and third twisted pairs from said second and fourth twisted pairs, said tape separator having a first edge and an opposite second edge, said first edge being disposed proximate said middle region, wherein said tape separator extends from said first edge partially around said second and fourth twisted pairs, through said middle region, partially around said first and third twisted pairs, and ends at said second edge, wherein said second edge is located proximate said middle region.
In a second alternative or supplemental embodiment of the invention, a cable includes: a first twisted pair; a second twisted pair; a third twisted pair; a fourth twisted pair; a jacket surrounding said first, second, third and fourth twisted pairs, said first and third twisted pairs residing in approximately a first half of said cable, and said second and fourth twisted pairs residing in approximately a second half of said cable, wherein a region between said first and second halves of said cable defines a middle region; and a conductive tape separator disposed within jacket, and separating said first and third twisted pairs from said second and fourth twisted pairs, said tape separator having a first edge, said first edge being disposed proximate said middle region, wherein said tape separator extends from said first edge partially around said second and fourth twisted pairs, and through said middle region.
In a third alternative or supplemental embodiment of the invention, a method of making a cabling includes: twisting a first insulated conductor and a second insulated conductor to form a first twisted pair; twisting a third insulated conductor and a fourth insulated conductor to form a second twisted pair; twisting a fifth insulated conductor and a sixth insulated conductor to form a third twisted pair; twisting a seventh insulated conductor and an eight insulated conductor to form a fourth twisted pair; inserting a tape separator amongst the first, second, third and fourth twisted pairs so as to separate the first and third twisted pairs from the second and fourth twisted pairs; and extruding a jacket around the first, second, third and fourth twisted pairs and tape separator to form the cable, wherein the first and third twisted pairs reside in approximately a first half of the cable, and the second and fourth twisted pairs residing in approximately a second half of the cable, wherein a region between the first and second halves of the cable defines a middle region, characterized by, the separator having a first edge and an opposite second edge, and said inserting proceeds so that the first edge is disposed proximate the middle region, wherein the tape separator extends from the first edge partially around the second and fourth twisted pairs, through the middle region, partially around the first and third twisted pairs, and ends at the second edge, wherein the second edge is located proximate the middle region.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.
The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus, are not limits of the present invention, and wherein:
The present invention now is described more fully hereinafter with reference to the accompanying drawings, in which embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.
Like numbers refer to like elements throughout. In the figures, the thickness of certain lines, layers, components, elements or features may be exaggerated for clarity. Broken lines illustrate optional features or operations unless specified otherwise.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the specification and relevant art and should not be interpreted in an idealized or overly formal sense unless expressly so defined herein. Well-known functions or constructions may not be described in detail for brevity and/or clarity.
As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. As used herein, phrases such as “between X and Y” and “between about X and Y” should be interpreted to include X and Y. As used herein, phrases such as “between about X and Y” mean “between about X and about Y.” As used herein, phrases such as “from about X to Y” mean “from about X to about Y.”
It will be understood that when an element is referred to as being “on”, “attached” to, “connected” to, “coupled” with, “contacting”, etc., another element, it can be directly on, attached to, connected to, coupled with or contacting the other element or intervening elements may also be present. In contrast, when an element is referred to as being, for example, “directly on”, “directly attached” to, “directly connected” to, “directly coupled” with or “directly contacting” another element, there are no intervening elements present. It will also be appreciated by those of skill in the art that references to a structure or feature that is disposed “adjacent” another feature may have portions that overlap or underlie the adjacent feature.
Spatially relative terms, such as “under”, “below”, “lower”, “over”, “upper”, “lateral”, “left”, “right” and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is inverted, elements described as “under” or “beneath” other elements or features would then be oriented “over” the other elements or features. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the descriptors of relative spatial relationships used herein interpreted accordingly.
The first twisted pair 33 includes a first insulated conductor 37 formed by a first insulating material 37A surrounding a first conductor 37B, and a second insulated conductor 38 formed by a second insulating material 38A surrounding a second conductor 38B, wherein said first and second insulated conductors 37 and 38 are twisted about each other to form the first twisted pair 33.
The second twisted pair 34 includes a third insulated conductor 39 formed by a third insulating material 39A surrounding a third conductor 39B, and a fourth insulated conductor 40 formed by a fourth insulating material 40A surrounding a fourth conductor 40B, wherein said third and fourth insulated conductors 39 and 40 are twisted about each other to form the second twisted pair 34.
The third twisted pair 35 includes a fifth insulated conductor 41 formed by a fifth insulating material 41A surrounding a fifth conductor 41B, and a sixth insulated conductor 42 formed by a sixth insulating material 42A surrounding a sixth conductor 42B, wherein said fifth and sixth insulated conductors 41 and 42 are twisted about each other to form the third twisted pair 35.
The fourth twisted pair 36 includes a seventh insulated conductor 43 formed by a seventh insulating material 43A surrounding a seventh conductor 43B, and an eighth insulated conductor 44 formed by an eighth insulating material 44A surrounding an eighth conductor 44B, wherein said seventh and eighth insulated conductors 43 and 44 are twisted about each other to form the fourth twisted pair 36.
The twist lengths w, x, y and z of the first, second, third and fourth twisted pairs 33, 34, 35 and 36 may be the same as listed in Table 1 for twisted pairs A, B, C and D, respectively. For example, a first twist length w of the first twisted pair 33 may be shorter than a third twist length y of the third twisted pair 35, and a second twist length x of the second twisted pair 34 may be shorter than a fourth twist length z of the fourth twisted pair 36. It should be noted that other twist lengths than those listed in Table 1 may be employed while practicing the benefits of the present invention.
The first through eighth insulating materials 37A-44A may be formed of a flexible plastic material having flame retardant and smoke suppressing properties, such as a polymer or foamed polymer, common to the cabling art, like fluorinated ethylene propylene (FEP), polyethylene (PE) or polypropylene (PP). A radial thickness of the first through eighth insulating materials 37A-44A would typically be greater than seven mils, such as about tens mils or about eleven mils. The first through eighth conductors 37B-44B may be solid or stranded, and may be formed of a conductive metal or alloy, such as copper. In one embodiment, the first through eighth conductors 37B-44B are each a solid, copper wire of about twenty three gauge size.
In one embodiment of the invention, the first and third twisted pairs 33 and 35 reside in approximately a first half of the cable 31A, and the second and fourth twisted pairs 34 and 36 reside in approximately a second half of the cable 31A. A region R between the first and second halves of the cable 31A defines a middle region.
A separator tape 51A is located within the jacket 32 and separates the first and third twisted pairs 33 and 35 from the second and fourth twisted pairs 34 and 36. The tape separator 51A has a first edge 53 and an opposite second edge 55. The first and second edges extend in a same direction as an extension length of the cable 31A. The first edge 53 is disposed proximate the middle region R and the fourth twisted pair 36. The tape separator 51A extends from the first edge 53 partially around the fourth twisted pair 36, then partially around the second twisted pair 34, through said middle region R, then partially around the first twisted pair 33, then partially around the third twisted pair 35, and ends at the second edge 55, wherein the second edge 55 is located proximate the middle region R and the third twisted pair 35. The resulting cross sectional shape of the separator tape 51A is S-shaped.
Of course, the S-shape shown in
As seen in
The nonconductive, first layer 57 provides strength, while the conductive, second layer 59 provides the s-shaped tape with its shielding qualities. Hence, the tape separator 51A has electrically conductive properties to shield the first and third twisted pairs 33 and 35 from the second and fourth twisted pairs 34 and 36. This arrangement greatly reduces the occurrence of internal crosstalk in the cable.
As illustrated in
As illustrated in
In the embodiments of
Such an arrangement offers several advantages. First, there are more design freedoms in the cable to tune the cable to a specific performance characteristic. When the cable required four different twist lengths, there was a minimum twist length w, a maximum twist length Z, and two different intermediate twist lengths x and y. The smaller twist length w was paired with the larger intermediate twist length y on one side of the separator 3, and the largest twist length z was paired with the smaller intermediate twist length x on the other side of the separator 3. This pairing was a compromise that allowed for a sufficient difference in the twist lengths for twisted pairs that were on a same side of the separator 3. The cable would have performed poorly if the smallest twist length w and the largest twist length z were deployed on one side of the separator 3, and the two intermediate twist lengths x and y were deployed on the other side of the separator 3 because the twist length difference between the two intermediate twist lengths x and y would have been insufficient to prevent internal crosstalk between the two twisted pairs 34 and 35 at high data speeds.
With the cables of the present invention, one could employ the smallest twist length w adjacent to the longest twist length z on one side of the separator 51. Because of the greater difference in twist lengths the internal crosstalk between the two grouped twisted pairs should be relatively improved as compared to the prior art situation where the smallest twist length w was paired with the larger intermediate twist length y. Since, the separator 51 completely isolates the first and third twisted pairs 33 and 35 from the second and fourth twisted pairs 34 and 36, the two twisted pairs on the other side of the separator 51 can also employ twist lengths of w and z, respectively.
A second advantage is that there are fewer “types” of twisted pairs used in the cable. In the prior art, a cable manufacturer needs to assemble and store twisted pairs having four different twist lengths, e.g., twist lengths of w, x, y and z. In the cable of the present invention, the cable manufacturer needs to only manufacture and store twisted pairs having two different twist lengths, e.g., w and z, or perhaps w and y.
The embodiments of
The embodiment of
In the embodiment of
Although a thin layer of insulation is shown on each of the conductors of the twisted pairs 73, 74, 75 and 76, it would be possible to use bare conductors (without an insulating layer and then wrap a thin layer of insulating material around each twisted pair along the dashed lines 73A, 74A, 75A and 76A. Although
The first separator tape 85 may be added if the internal crosstalk between the first and third twisted pairs 33 and 35 needs to be improved for a desired level of cable performance. The second separator tape 87 may be added if the internal crosstalk between the second and fourth twisted pairs 34 and 36 needs to be improved for a desired level of cable performance. Although
The separator tapes 85 and/or 87 may also be employed in the other embodiments of the present invention, such as in the cables depicted in
The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are to be included within the scope of the following claims.
