Patent Application
20060131055
The present invention relates to an electrical cable that reduces alien crosstalk between cables. More specifically, a filler element disposed in the electrical cable reduces alien crosstalk between adjacent cables.
Interference between electrical cables bundled together in a cabling system decreases the efficiency of data transmission by the cabling system. Alien near-end crosstalk (ANEXT) and alien far-end crosstalk (AFEXT) noise is caused by the electrical unbalance between the twisted pairs of insulated conductors of adjacent cables. ANEXT and AFEXT are transmission noises that can increase the signal to noise ratio (SNR) and bit error rate (BER) in a cable transmission system, such as for a local area network.
Specifically, ANEXT and AFEXT occur when some of the signal current in a twisted pair of one cable couples with another twisted pair of another cable external to the signal path and along the path of a circuit between the two pairs. That noise corrupts the signal in the twisted pair external to the original signal path. When the circuit between the noise emitting and receiving twisted pairs egresses one cable boundary and crosses another cable boundary, the noise becomes alien crosstalk.
According to the present invention, there is provided an electrical cable that includes a cable jacket defining a central longitudinal axis and a plurality of twisted pairs of insulated conductors oriented longitudinally within the cable jacket. Each of the twisted pairs of insulated conductors has a width. A filler element is disposed in the cable jacket and is located adjacent to at least one of the twisted pairs of insulated conductors. The filler element defines a width that is substantially larger than the width of each the twisted pairs of insulated conductors. The filler element has a central axis laterally offset from the central longitudinal axis of the cable jacket. The filler element reduces alien crosstalk from an adjacent cable.
The present invention also provides an electrical cable that includes a cable jacket that defines a central longitudinal axis and a substantially non-circular outer perimeter. A plurality of twisted pairs of insulated conductors are oriented longitudinally within the cable jacket. Each of the twisted pairs of insulated conductors has a width. A filler element is disposed in the cable jacket and located adjacent to at least one of the twisted pairs of insulated conductors. The filler element has a central axis laterally offset from the central longitudinal axis of the cable jacket. The filler element is substantially circular in section transverse to the central axis and defines a diameter that is substantially larger than the width of each the twisted pairs of insulated conductors. The filler element reduces alien crosstalk from an adjacent cable.
Advantages and salient features of the invention will become apparent from the following detailed description, which, taken in conjunction with the annexed drawings, discloses preferred embodiments of the present invention.
A more complete appreciation of the invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:
Referring to
As seen in
Each twisted pair of insulated conductors 208, 210, 212, and 214 defines a width 216 and is supported in a first region 218 of the cablejacket 202. The cable jacket 202 defines a generally central longitudinal axis 220. The cable 100 can be twisted about the central longitudinal axis 220, as seen in
The width 228 of the first region 218 is substantially larger than the width 230 of the second region 222, thereby creating an uneven or lopsided outer perimeter 232 of the cable jacket 202, such that the shape of the electrical connector 100 in section transverse to the longitudinal axis 220 is substantially non-circular, as seen in
As seen in
The raised areas 106 and the cable jacket 104 are preferably formed as a unitary one-piece member. Alternatively, the raised areas 106 can be formed separately from the cable jacket 104 and attached to the cable jacket 104. The cable jacket 104 and the raised areas 106 can be formed of a dielectric material, such as PVC or polyolefin low smoke zero halogen.
Although it is preferable to include more than one raised area 106 with the cable jacket 104, a single raised area or more than two raised areas can be employed. Also, the thickness of the entire cable jacket 104 can be increased to reduce alien crosstalk.
Referring to
Referring to
Like the cables 100 and 300 of the first and second embodiments, the cross-sectional shape of the cable 400 is non-circular, such as an elliptical shape. The non-circular shape of the cable 400 defines an even outer perimeter 432 of the cable jacket 406. The non-circular cross-sectional shape of the cable jacket 406 increases the diameter of the cable 400 along one axis 406 of the cable 400. A central axis 426 of the filler element 404 is offset from the central longitudinal axis 420 of the cable 400. Since the width or diameter 424 of the filler element 404 is about twice the width 216 of each twisted pair of insulated conductors 208, 210, 212, and 214, the pairs 208, 210, 212, and 214 are prevented from encircling the filler element 404, so that the filler element 404 remains offset from the central longitudinal axis 420 of the cable 400. Similar to the first and second embodiments, by fashioning the cable 400 in this manner, the distance between twisted pairs of insulated conductors of adjacent cables is increased, thereby reducing alien crosstalk.
While particular embodiments have been chosen to illustrate the invention, it will be understood by those skilled in the art that various changes and modifications can be made therein without departing from the scope of the invention as defined in the appended claims. For example, any number of filler elements can be employed with the cable including one, two, or more than two filler elements.
