Abstract
Two electromagnetic interference (EMI) controlling tape application methodologies for unshielded twisted pair (UTP) cable include Fixed Tape Control (FTC) and Oscillating Tape Control (OTC). In FTC, tape application angle and edge placement are controlled to maintain position of the tape edges over a base of nonconductive filler in the cable. In OTC, the tape application angle is continuously varied, resulting in crossing of the tape edges over all of the pairs of conductors with varying periodicity. In both implementations, the filler allows a cylindrical shape.
Claims
1. A cable, comprising: a first twisted pair of insulated conductors; a second twisted pair of insulated conductors; a filler separating the first twisted pair of insulated conductors from the second twisted pair of insulated conductors; and a multi-layer conductive barrier tape comprising a continuous conductive material contained between two layers of a dielectric material, the conductive material of the barrier tape extending to each lateral edge of the two layers of the dielectric material, the barrier tape surrounding the first twisted pair of insulated conductors, the second twisted pair of insulated conductors, and the filler.
2. The cable of claim 1, wherein the filler comprises a dielectric material.
3. The cable of claim 1, wherein the filler has a helical twist at a first angle.
4. The cable of claim 3, wherein the barrier tape has a helical twist at a second angle.
5. The cable of claim 4, wherein the second angle varies between the first angle and a third angle, distinct from the first angle.
6. The cable of claim 4, wherein the second angle varies between a first value, less than the first angle, and a second value, greater than the first angle.
7. The cable of claim 4, wherein the second angle is equal to the first angle.
8. The cable of claim 4, wherein the second angle varies along the length of the cable.
9. The cable of claim 3, wherein the first twisted pair of insulated conductors and the second twisted pair of insulated conductors have a helical twist around the filler at the first angle.
10. The cable of claim 1, wherein the filler comprises at least one arm.
11. The cable of claim 10, wherein a seam of the barrier tape is positioned above a terminal portion of an arm of the filler.
12. The cable of claim 10, wherein the filler comprises four arms in a cross shape.
13. The cable of claim 10, wherein each arm ends in a symmetrical terminal portion.
14. The cable of claim 10, wherein the terminal portion of each arm is wider than a middle portion of said arm.
15. The cable of claim 10, wherein the terminal portion of each arm has a trapezoidal profile.
16. The cable of claim 10, wherein a pair of arms of the filler forms a channel; and wherein the first twisted pair of insulated conductors is positioned within the channel.
17. The cable of claim 1, further comprising a jacket surrounding the conductive barrier tape.
18. A method of manufacture of a cable, comprising: providing a first twisted pair of insulated conductors and a second twisted pair of insulated conductors; positioning a filler between the first twisted pair of insulated conductors and the second twisted pair of insulated conductors; and wrapping the first twisted pair of insulated conductors, second twisted pair of insulated conductors, and filler with a conductive barrier tape comprising a conductive material contained between two layers of a dielectric material, the conductive material of the barrier tape extending to each lateral edge of the two layers of the dielectric material.
19. The method of claim 18, further comprising: helically twisting the filler at a first angle; and helically twisting the conductive barrier tape at the first angle.
20. The method of claim 18, further comprising: helically twisting the filler at a first angle; and helically twisting the conductive barrier tape at an angle varying between the first angle and a second angle.
Description
BRIEF DESCRIPTION OF THE FIGURES
(1) The patent or application file contains at least one drawing executed in color. Copies of this patent or patent application publication with color drawings will be provided by the Office upon request and payment of the necessary fee.
(2) FIG. 1 is a cross section of an embodiment of a UTP cable incorporating a filler;
(3) FIG. 2A is a cross section of an embodiment of the filler of FIG. 1;
(4) FIG. 2B is a cross section of another embodiment of a filler;
(5) FIG. 2C is a cross section of still another embodiment of a filler;
(6) FIG. 2D is a cross section of an embodiment of a UTP cable incorporating an embodiment of the filler of FIG. 2B;
(7) FIG. 2E is a cross section of an embodiment of a UTP cable incorporating an embodiment of the filler of FIG. 2C;
(8) FIG. 3A is a cross section of an embodiment of a barrier tape;
(9) FIG. 3B is a cross section of an embodiment of a barrier tape around the filler of FIG. 2A showing improper placement above a pair channel;
(10) FIG. 3C is a cross section of an embodiment of a barrier tape around the filler of FIG. 2A showing proper placement above filler terminal portions;
(11) FIG. 3D is a cross section of an embodiment of a barrier tape around the filler of FIG. 2B showing proper placement above filler terminal portions;
(12) FIG. 3E is a top view of an embodiment of fixed tape control installation of a barrier tape on a UTP cable incorporating a filler;
(13) FIGS. 3F and 3G are plan views of an embodiment of oscillating tape control application of a barrier tape on a UTP cable incorporating a filler, in a first application angle and second application angle, respectively;
(14) FIG. 3H is a diagram of an embodiment of a device for oscillating tape control application;
(15) FIGS. 4A and 4B are charts and tables of measured PSANEXT and PSAACRF, respectively, for an embodiment of a UTP cable with a longitudinally applied barrier tape;
(16) FIGS. 5A and 5B are charts and tables of measured PSANEXT and PSAACRF, respectively, for an embodiment of a UTP cable with a helically applied barrier tape;
(17) FIGS. 6A and 6B are charts and tables of measured PSANEXT and PSAACRF, respectively, for an embodiment of a UTP cable with a spirally applied barrier tape;
(18) FIGS. 7A and 7B are charts and tables of measured PSANEXT and PSAACRF, respectively, for an embodiment of a UTP cable with a FTC method applied barrier tape having improper placement of a tape edge;
(19) FIGS. 8A and 8B are charts and tables of measured PSANEXT and PSAACRF, respectively, for an embodiment of a UTP cable with a OTC method applied barrier tape; and
(20) FIGS. 9A-9C are tables of measured return loss for embodiments of UTP cables with a longitudinally applied barrier tape, a helically applied barrier tape, and an OTC method applied barrier tape, respectively.
(21) In the drawings, like reference numbers generally indicate identical, functionally similar, and/or structurally similar elements.
DETAILED DESCRIPTION
(22) The present disclosure addresses problems of cable to cable or alien crosstalk (ANEXT) and signal Return Loss (RL) in a cost effective manner, without the larger, stiffer, more expensive, and harder to consistently manufacture design tradeoffs of typical cables. In particular, the methods of manufacture and cables disclosed herein reduce internal cable RL and external cable ANEXT coupling noise, meeting American National Standards Institute (ANSI)/Telecommunications Industry Association (TIA) 568 Category 6A (Category 6 Augmented) specifications via two tape application design methodologies.
(23) First, in one embodiment, a Fixed Tape Control (FTC) process helically applies a barrier tape around a cable comprising pairs of unshielded twisted pair (UTP) conductors with a filler ensuring dimensional stability for improved internal cable electrical performance. The FTC process precisely controls the placement and angle of the barrier tape edge on a terminal portion of the filler, sometimes referred to as an anvil, T-top, or arm end, such that the tape edge has little variation from that location and does not fall on top of or periodically cross over the pairs. The consistency of the tape's edge improves RL, and the location of the tape edge manages ANEXT.
(24) Second, in another embodiment, an Oscillating Tape Control (OTC) process helically applies a barrier tape around the cable with a continuously varying angle. In this process, the barrier tape edge crosses all of the pairs of conductors of the cable with varying periodicity, with slightly increased RL compared to the FTC process as a compromise for less precise tooling, less cabling machine operator experience and expertise, less set up variation and risk, and consequently lower overall complexity and expense.
(25) Accordingly, these two tape application methods either vary the location of the tape edge such that coupling from the pairs to the tape edge is reduced as the tape edge doesn't periodically cross the pairs (as occurs with a typical longitudinal or spirally applied tape) resulting in increased RL, or a typical helically applied tape that follows the stranding lay of the cable where the tape edge can consistently be proximate a given pair in the cable, causing excessive coupling of signals of the given pair to the tape edge and resulting in unacceptable levels of ANEXT in the cable.
(26) In some embodiments, the barrier tape may comprise an electrically continuous electromagnetic interference (EMI) barrier tape, used to mitigate ground interference in the design. In one embodiment, the tape has three layers in a dielectric/conductive/dielectric configuration, such as polyester (PET)/Aluminum foil/polyester (PET). In some embodiments, the tape may not include a drain wire and may be left unterminated or not grounded during installation.
(27) The filler may have a cross-shaped cross section and be centrally located within the cable, with pairs of conductors in channels between each arm of the cross. At each end of the cross, in some embodiments, an enlarged terminal portion of the filler may provide structural support to the barrier tape and allow the FTC process to locate the tape edge above the filler, rather than a pair of conductors. The filler allows a cylindrical shape for optimized ground plane uniformity and stability for improved impedance/RL performance.
(28) Referring first to FIG. 1, illustrated is a cross section of an embodiment of a UTP cable 100 incorporating a filler 108. The cable includes a plurality of unshielded twisted pairs 102a-102d (referred to generally as pairs 102) of individual conductors 106 having insulation 104. Conductors 106 may be of any conductive material, such as copper or oxygen-free copper (i.e. having a level of oxygen of 0.001% or less) or any other suitable material, including Ohno Continuous Casting (OCC) copper or silver. Conductor insulation 104 may comprise any type or form of insulation, including fluorinated ethylene propylene (FEP) or polytetrafluoroethylene (PTFE) Teflon, high density polyethylene (HDPE), low density polyethylene (LDPE), polypropylene (PP), or any other type of low dielectric loss insulation. The insulation around each conductor 201 may have a low dielectric constant (e.g. 1-3) relative to air, reducing capacitance between conductors. The insulation may also have a high dielectric strength, such as 400-4000 V/mil, allowing thinner walls to reduce inductance by reducing the distance between the conductors. In some embodiments, each pair 102 may have a different degree of twist or lay (i.e. the distance required for the two conductors to make one 360-degree revolution of a twist), reducing coupling between pairs. In other embodiments, two pairs may have a longer lay (such as two opposite pairs 102a, 102c), while two other pairs have a shorter lay (such as two opposite pairs 102b, 102d). Each pair 102 may be placed within a channel between two arms of a filler 108, said channel sometimes referred to as a groove, void, region, or other similar identifier.
(29) In some embodiments, cable 100 may include a filler 108. Filler 108 may be of a non-conductive material such as flame retardant polyethylene (FRPE) or any other such low loss dielectric material. Referring ahead to FIG. 2A, illustrated is a cross section of an embodiment of the filler 108 of FIG. 1. As shown, filler 108 may have a cross-shaped cross section with arms 200 radiating from a central point and having a terminal portion 202 having end surfaces 204 and sides 206. Each terminal portion 202 may be anvil-shaped, rounded, square, T-shaped, or otherwise shaped. Each arm 200 and terminal portion 202 may surround a channel 208, separating pairs of conductors 102 and providing structural stability to cable 100. Filler 108 may be of any size, depending on the diameter of pairs 102. For example, in one embodiment of a cable with an outer diameter of approximately 0.275, the filler may have a terminal portion edge to edge measurement of approximately 0.235. Although shown symmetric, in some embodiments, the terminal portions 202 may have asymmetric profiles. Similarly, although shown flat, in some embodiments end surfaces 204 may be curved to match an inner surface of a circular jacket of cable 100.
(30) FIG. 2B is a cross-section of another embodiment of a filler 108. Terminal portions of each arm 200 need not be identical: in the embodiment shown, two arms end in blunt portions 203a similar in size and shape to the arm, with sides 206 and end surfaces 204, while two arms end in anvil shaped portions 202. As with the embodiment of FIG. 2A, each adjacent arm 200 and terminal portions 202, 203a surround a channel 208.
(31) FIG. 2C is a cross-section of another embodiment of a filer 108. In the embodiment illustrated, terminal portions 203b of each arm are T-shaped, with flat ends 204 and sides 206. In other embodiments, as discussed above, ends 204 may be curved to match an inner surface of a circular jacket of a cable. Each adjacent arm 200 and terminal portions 203b surround a channel 208.
(32) FIG. 2D is a cross section of an embodiment of a UTP cable 100 incorporating a filler 108 as shown in FIG. 2B. Similarly, FIG. 2E is a cross section of an embodiment of a UTP cable 100 incorporating a filler 108 as shown in FIG. 2C. Other portions of cables 100 and 100, such as conductors, barriers, and jackets may be identical to those described above in connection with FIG. 1.
(33) In another embodiment not illustrated, some arms may have a T-shaped terminal portion 203b, while other arms have a blunt portion 203a, an anvil shaped portion 202, or any other such shape. Although FIGS. 2A-2C are shown with fillers having four arms, in other embodiments, a filler may have other numbers of arms, including two arms, three arms, five arms, six arms, etc.
(34) Returning to FIG. 1, in some embodiments, cable 100 may include a conductive barrier tape 110 surrounding filler 108 and pairs 102. The conductive barrier tape 110 may comprise a continuously conductive tape, a discontinuously conductive tape, a foil, a dielectric material, a combination of a foil and dielectric material, or any other such materials. For example, and referring ahead briefly to FIG. 3A, illustrated is a cross section of an embodiment of a barrier tape 110 having a multi-layer configuration (the illustration may not be to scale, with the central portion narrower or thicker in various embodiments). In the embodiment illustrated, a conductive material 302, such as aluminum foil, is located or contained between two layers of a dielectric material 300, 304, such as polyester (PET). Intermediate adhesive layers (not illustrated) may be included. In some embodiments, a conductive carbon nanotube layer may be used for improved electrical performance and flame resistance with reduced size. Although shown edge to edge, in some embodiments, the conductive layer 302 may not extend to the edge of the tape 110. In such embodiments, the dielectric layers 300, 304 may completely encapsulate the conductive layer 302. In a similar embodiment, edges of the tape may include folds back over themselves.
(35) Returning to FIG. 1, the cable 100 may include a jacket 112 surrounding the barrier tape 110, filler 108, and/or pairs 102. Jacket 112 may comprise any type and form of jacketing material, such as polyvinyl chloride (PVC), fluorinated ethylene propylene (FEP) or polytetrafluoroethylene (PTFE) Teflon, high density polyethylene (HDPE), low density polyethylene (LDPE), or any other type of jacket material. In some embodiments, jacket 112 may be designed to produce a plenum- or riser-rated cable.
(36) Although shown for simplicity in FIG. 1 as a continuous ring, barrier tape 110 may comprise a flat tape material applied around filler 108 and pairs 102. Referring now to FIG. 3B, illustrated is a cross section of an embodiment of a barrier tape 110 around the filler 108 of FIG. 2A. The tape 110 has a first edge 306a and a second edge 306b, referred to generally as edge(s) 306 of the barrier tape 110. In the embodiment illustrated in FIG. 3B, the edges 306a and 306b lie above channels 208. Pairs 102 within said voids could electrically couple to the corresponding edge 306, resulting in increased ANEXT. By contrast, FIG. 3C is a cross section of an embodiment of a barrier tape 110 around the filler 108 of FIG. 2A showing proper placement above filler terminal portions 202. In this configuration, edges 306 of the tape 110 are as far as possible from any channel 208 and corresponding pair 102. As shown, in some embodiments, barrier tape 110 may have sufficient width such that a first edge 306a is above a first terminal portion 202 and a second edge 306b is above a second terminal portion 202. This allows for 90 degrees of overlap of the tape 110, preventing leakage, while placing both edges 306 above terminal portions 202. In other embodiments, barrier tape 110 may overlap by 180 degrees, 270 degrees, or any other value, including values such that one edge may land on a channel. FIG. 3D is another cross section of an embodiment of a barrier tape 110 around an embodiment of a filler 108, such as that shown in FIG. 2B. As shown, edges 306a, 306b of a barrier tape 110 may be positioned above a terminal portion 202, 203a of the filler 108.
(37) Referring now to FIG. 3E, illustrated is a plan view of an embodiment of fixed tape control (FTC) application of a barrier tape 110 on a UTP cable incorporating a filler. FIG. 3E is not shown to scale; in many embodiments, barrier tape 110 may have a significantly larger width than the cable, such that the barrier tape 110 may overlap itself as discussed above in connection with FIG. 3C. The cable in FIG. 3E is enlarged to show detailed positioning of end portions 204 of terminal portions 202 of filler 108 and pairs 102 visible in channels between each terminal portion. As shown, the cable may include a helical twist at an angle .sub.c 308 from an axis of the cable.
(38) In FTC application, barrier tape 110 may be applied at a corresponding angle .sub.t 310 with .sub.c=.sub.t. An edge of the tape 110, such as edge 306b, may be placed over an end portion 204 of a terminal portion 202. Accordingly, because angles 308, 310 are matched, the tape edge 306 will continue to follow the end portion 204 of the terminal portion without ever crossing above a channel or pair 102. This prevents electrical coupling of pairs 102 to conductive edges 306 of tape 110, and thus reduces leakage and ANEXT.
(39) The FTC application provides superior control over ANEXT with low RL due to the avoidance of crossing of pairs by the barrier tape. However, because the angle .sub.t 310 and placement of an edge 306 over a terminal portion 202 needs to be precisely controlled to prevent the edge from crossing beyond the end portion 204 of the terminal portion and over a channel, some manufacturing implementations may be expensive and/or require more experienced operators and machinists. In one extreme example, if angle .sub.t 310 is equal to .sub.c 308, but the tape placement is above a first pair of conductors 102, then the tape edge 306 will follow the pair of conductors around the cable continuously along their length, resulting in one pair of four having much higher ANEXT and RL. Similarly, with very long manufacturing runs of cable, even a minor difference in .sub.c 308 and .sub.t 310 will eventually result in the edge 306 being above a pair 102, resulting in lengths of cable that will fail to meet specification and must be discarded.
(40) Instead, an acceptable tradeoff may be found by continuously varying the tape application angle .sub.t 310, in an oscillating tape control (OTC) application method. FIGS. 3F and 3G are plan views of an embodiment of OTC application of a barrier tape on a UTP cable incorporating a filler, in a first application angle .sub.t 310 and second application angle .sub.t 310, respectively. As with FIG. 3E, FIGS. 3F and 3G are not shown to scale, but show the cable enlarged to show detailed positioning of end portions of the terminal portions and pairs visible in channels between each terminal portion. In the OTC application method, the tape angle .sub.t 310 is continuously varied from first angle .sub.t 310 to second angle .sub.t 310 and back. As a result of the difference between .sub.t 310 and .sub.c 308, over a length of the cable, an edge 306 of barrier tape 110 will cross over all pairs 102, eliminating the extreme situation discussed above where the edge follows a single pair of conductors within the cable. This may be particularly useful in embodiments utilizing fillers 108 having smaller terminal portions, such as blunt terminal portions 203a as discussed above in connection with FIG. 2B. Furthermore, because the difference between .sub.t 310 and .sub.c 308 is being continuously varied, edge 306 will not cross any particular pair at a simple periodic interval. Because any such constant periodic intervals will correspond to some integer multiple of wavelengths at some frequency, the impedance discontinuities will compound resulting in increased RL at that frequency, adversely affecting the performance of the cable. Such problems are avoided via the OTC application method. In some OTC application methods, a filler need not be used, as the tape edge already crosses over the conductor pairs, or a filler may be a single-armed or flat separator between the pairs or have multiple arms, each of which end in a blunt terminal portion.
(41) Referring briefly to FIG. 3H, illustrated is a diagram of an embodiment of a device for oscillating tape control installation. As with FIGS. 3E-3G, FIG. 3H is not shown to scale. In one embodiment of the device, a roller (or bar) 312 may be attached to a plate 314 which may be moved back and forth along a track of a predetermined length (illustrated by dashed line 316). Said roller or bar 312 may rotate with the barrier tape 110 during application to a cable, or may be fixed and have low friction such that barrier tape 110 may slide freely across the bar during application. Barrier tape 110 may extend from a feed source (not illustrated) and lay tangent to roller or bar 312 as shown, twisting as it leaves the roller or bar to helically wrap around the cable. As plate 314 and roller or bar 312 are moved back and forth along traverse 316, angle .sub.t 310 is continuously varied. Traverse 316 may be of any length, and plate 314 and roller or bar 312 may be moved along the traverse at any speed. For example, given a 3 lay of the cable, traverse 316 may be 8 inches, 5 inches, 3 inches, or any other such length. Similarly, given a cable linear speed of 100 feet per minute, the stroke speed across the traverse 316 may be of a similar 100 feet per minute, 50 feet per minute, 10 feet per minute, or any other such speed. For example, in some implementations, the traverse speed may be between 3 to 20 inches per minute. Although variation in tape application angle .sub.t 310 eliminates simple periodic relationships between pairs 102 and edges 306, the crossing will still be periodic at some extended length, as a factor of cable lay and advancement speed, plate/roller or bar stroke length, and plate/roller or bar stroke speed. Accordingly, certain combinations of length and speed may not have the desired levels of ANEXT and RL, depending on the required specification and frequency range.
(42) The FTC and OTC application methods result in significant improvements of ANEXT and RL compared to various tape application methodologies of barrier tapes used in typical cables. FIGS. 4A and 4B are charts and tables of measured power sum alien near end crosstalk (PSANEXT) and power sum alien attenuation to crosstalk ratio, far-end (PSAACRF), respectively, for an embodiment of a UTP cable with a longitudinal barrier tape. Unlike either the FTC or OTC implementations discussed above, edges of longitudinal barrier tape do not rotate around the cable, even as the pairs (and filler, in some implementations) rotate within the cable. Accordingly, tape edges frequently and periodically cross conductor pairs, resulting in the high levels of alien crosstalk shown. In the graphs and accompanying tables, frequencies are labeled in MHz; with alien crosstalk levels shown in decibels below nominal signal levels. Multiple tests were performed, with worst case and average results included. TIA specification levels are also shown and illustrated in the graphs in a solid red line.
(43) FIGS. 5A and 5B are charts and tables of measured PSANEXT and PSAACRF, respectively, for an embodiment of a UTP cable with a helically applied barrier tape with angle .sub.t equivalent to cable lay angle .sub.c, As discussed above, in such embodiments, a tape edge is positioned over one of the conductor pairs, resulting in increased ANEXT.
(44) FIGS. 6A and 6B are charts and tables of measured PSANEXT and PSAACRF, respectively, for an embodiment of a UTP cable with a spirally applied barrier tape with angle .sub.t different from cable lay angle .sub.c, but constant, as opposed to the OTC application discussed above. As discussed above, in such embodiments, a tape edge periodically crosses the pairs, resulting in increased ANEXT.
(45) FIGS. 7A and 7B are charts and tables of measured PSANEXT and PSAACRF, respectively, for an embodiment of a UTP cable with a FTC helically applied barrier tape having improper placement of a tape edge, similar to the example in FIGS. 5A and 5B. Because the tape edge lies over a pair of conductors in this embodiment, the pair generates more ANEXT. While other pairs may have acceptable performance, the cable as a whole may not meet the specification requirements.
(46) FIGS. 8A and 8B are charts and tables of measured PSANEXT and PSAACRF, respectively, for an embodiment of a UTP cable with an OTC helically applied barrier tape. As shown, ANEXT is significantly improved over the embodiments illustrated in FIGS. 4A-7B, while maintaining low manufacturing costs.
(47) FIGS. 9A-9C are tables of measured return loss for embodiments of UTP cables with a longitudinally applied barrier tape, a helically applied barrier tape, and an OTC helically applied barrier tape, respectively. Each return loss test was performed multiple times, according to the values in the count column, and a mean, average worst case margin from the specification limit, and standard deviation were calculated from the results. The table also includes a Cpk index that quantifies the capability of a product's design and manufacturing process. Cpk is calculated as the headroom, defined as the average worst case result, divided by three times the standard deviation. The Cpk index value is proportional to a % defect rate, with a Cpk of 0.00 equal to a 50% defect rate, a Cpk of 0.40 equal to an 11.507% defect rate, a Cpk of 1.00 equal to a 0.135% defect rate, etc. Lower Cpk values accordingly indicate a higher likelihood of failure.
(48) As shown, the return loss results for the OTC barrier tape cable were superior to the longitudinally applied barrier tape and helically applied barrier tape results, with no Cpk index value below 1.2, with the sole exception of one pair at the 550-625 MHz range, beyond the industry standard performance of 500 MHz
(49) Accordingly, the fixed and oscillating tape control cable application methods discussed herein and the geometry of the filler allow for significant reduction in ANEXT and return loss without increasing cost or cable diameter, and without requiring additional jacketing layers, complex tape design or wrapping systems, including discontinuous foil tapes, or additional steps during cable termination. Although discussed primarily in terms of Cat 6A UTP cable, fixed and oscillating tape application control may be used with other types of cable including any unshielded twisted pair, shielded twisted pair, or any other such types of cable incorporating any type of dielectric, semi-conductive, or conductive tape.
(50) The above description in conjunction with the above-reference drawings sets forth a variety of embodiments for exemplary purposes, which are in no way intended to limit the scope of the described methods or systems. Those having skill in the relevant art can modify the described methods and systems in various ways without departing from the broadest scope of the described methods and systems. Thus, the scope of the methods and systems described herein should not be limited by any of the exemplary embodiments and should be defined in accordance with the accompanying claims and their equivalents.
