Periodic filtering of transmission line cables.

Abstract

A differential transmission line cable includes a notch filter that manages common-mode energy. The cable includes a narrow section having two adjacent conductors, each having a narrow cross-sectional area and spaced closely together. The cable also includes a wide section longitudinally adjacent to the narrow section. The wide section includes two adjacent conductors, each having a wider cross-sectional area greater than the narrow cross-sectional area and spaced more widely apart than the narrow spacing. The wide and narrow cross-sectional areas and the wide and narrow spacings are specified so that the differential mode impedance of the differential transmission line cable is constant throughout both the narrow and wide sections, and the difference in common-mode impedance of the narrow and wide sections creates a notch filter that manages common-mode energy in the differential transmission line cable.

Description

[Technical field]

[0001] The present invention relates generally to electronic transmission lines and, more particularly, to transmission lines configured to manage common mode energy in electronic systems. [Background technology]

[0002] A transmission line is a specialized cable or other structure designed to carry radio frequency alternating current (i.e., electrical current at such a high frequency that the wave nature of the current must be taken into account). Transmission lines can be used for such purposes as connecting computer data transmitters and receivers for computer network connections and high-speed computer data buses.

[0003] An integrated circuit (IC), also known as a "microchip", silicon or computer "chip", is a specially manufactured piece of semiconductor material such as silicon into which complex electronic circuits are inscribed using photolithographic processes. Types of ICs can include computer processors, memory, analog, and customizable devices. Because ICs can be relatively fragile, they are often mounted and / or surrounded by a protective, supportive ceramic or plastic package. Electrical connections to the chip may be provided by metal contacts, which may include pins or solder balls located on the outside of the chip package. Summary of the Invention

[0004] An embodiment may be directed to a differential transmission line cable including a notch filter configured to manage common mode energy. The differential transmission line cable may include a narrow portion. The narrow portion may include a first conductor having a first cross-sectional area and a second conductor disposed adjacent to the first conductor at a first spacing. The second conductor may have a cross-sectional area that matches the first cross-sectional area. The differential transmission line cable may also include a wide portion longitudinally adjacent to the narrow portion. The wide portion may include the first conductor having a second cross-sectional area larger than the first cross-sectional area. The wide portion may also include a second conductor disposed adjacent to the first conductor at a second spacing larger than the first spacing. The second conductor may have a cross-sectional area that matches the second cross-sectional area. The first cross-sectional area, the first spacing, the second cross-sectional area, and the second spacing may be specified such that the differential mode impedance of the differential transmission line cable is constant throughout both the narrow portion and the wide portion. The first cross-sectional area, the first spacing, the second cross-sectional area, and the second spacing may also be specified to create a notch filter that uses the difference in common mode impedance of the narrow and wide portions to manage common mode energy in the differential transmission line cable.

[0005] Embodiments may also be directed to a method of manufacturing a differential transmission-line cable including a notch filter configured to manage common-mode energy. The method may include forming a wide portion of a first conductor of the differential transmission-line cable, the wide portion having a first cross-sectional area. The method may also include forming a narrow portion of the first conductor longitudinally adjacent the wide portion, the narrow portion having a second cross-sectional area smaller than the first cross-sectional area. The method may also include forming a wide portion of a second conductor of the differential transmission-line cable, the wide portion having a cross-sectional area that matches the first cross-sectional area. The method may also include forming a narrow portion of the second conductor, the narrow portion having a cross-sectional area that matches the second cross-sectional area.

[0006] The embodiments may also be directed to an electronic system. The electronic system may include a differential transmission line cable including a first conductor and a second conductor, each having a narrow portion and a wide portion. The narrow portion may have a first cross-sectional area, and the wide portion may have a second cross-sectional area larger than the first cross-sectional area. The narrow portions may be adjacent to each other with a first spacing, and the wide portions may be adjacent to each other with a second spacing larger than the first spacing. The electronic system may also include a differential driver circuit having output terminals electrically coupled to the first conductor and the second conductor at a first end of the differential transmission line cable. The electronic system may also include a differential receiver circuit having output terminals electrically coupled to the first conductor and the second conductor at a second end of the differential transmission line cable.

[0007] The above summary is not intended to describe each illustrated embodiment or every implementation of the present invention. [Brief description of the drawings]

[0008] The drawings contained herein are incorporated in and form a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. The drawings are only illustrative of particular embodiments and are not intended to limit the invention.

[0009] [Figure 1] 1 illustrates an electronic system using a differential transmission line cable in accordance with an embodiment of the present invention.

[0010] [Diagram 2] 1 includes views illustrating differential transmission line cables and differential transmission line cable arrangements according to embodiments consistent with this figure.

[0011] [Diagram 3] FIG. 1 is a flow diagram illustrating a method for manufacturing a differential transmission line cable according to an embodiment consistent with this figure.

[0012] [Figure 4] 1 illustrates a wire extrusion and machining process according to an embodiment consistent with this figure.

[0013] [Diagram 5] 1 illustrates a wire extrusion and narrowing process according to an embodiment consistent with this figure.

[0014] [Figure 6] 1 illustrates a wire extrusion and narrowing process according to an embodiment consistent with this figure.

[0015] [Figure 7] 1 illustrates a wire coating process according to an embodiment consistent with this figure.

[0016] [Figure 8] 1 illustrates the marking, insulation, and placement of a differential transmission line cable according to an embodiment consistent with this figure.

[0017] [Figure 9] 1 includes graphs and schematic diagrams illustrating common mode insertion loss as a function of frequency for a differential transmission line cable functioning as a notch filter, according to embodiments consistent with this figure.

[0018] While the invention is susceptible to various modifications and alternative forms, specifics thereof have been shown by way of example in the drawings and will be described in detail. It should be understood, however, that the intention is not to limit the invention to the particular embodiments described. On the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the scope of the invention.

[0019] In these drawings and the Detailed Description, like numbers generally refer to like components, parts, steps and operations. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] Certain embodiments of the present invention may be understood in the context of providing common mode energy management for differential transmission line cables for electronic devices, such as servers, that may be used to provide data over a network to clients connected to the servers. Such servers may include, but are not limited to, web servers, application servers, mail servers, and virtual servers. Although not necessarily limited thereto, the embodiments discussed in this context may facilitate an understanding of various aspects of the present invention. Certain embodiments may also be directed to other devices and related applications, such as providing common mode energy management for differential transmission line cables for electronic devices, such as computing systems, that may be used in a wide variety of computational and data processing applications. Such computing systems may include, but are not limited to, supercomputers, high performance computing (HPC) systems, and other types of special purpose computers. Embodiments may also be directed to providing common mode energy management for cables in consumer and small office / home office (SOHO) electronic devices, such as personal computers, laptops, and mobile network server devices.

[0021] Electromagnetic compatibility (EMC) is understood to be the ability of electrical equipment and / or systems to function acceptably in their electromagnetic environment. This acceptable functioning may be achieved by suppressing the unintended generation, propagation, and reception of electromagnetic energy by electrical equipment and / or systems. Such electromagnetic energy may cause undesirable effects such as electromagnetic interference (EMI) or possibly physical damage to electronic equipment in operation. The goal of EMC is the correct operation of equipment in a common electromagnetic environment.

[0022] Differential signaling can be used to electronically transmit information using two complementary signals that are sent over two corresponding conductors in a pair, also called a "differential pair." The information sent over the pair of conductors is represented by the voltage difference between the two complementary signals. The alternating current (AC) common-mode voltage of the differential pair can be caused by many electrical characteristics that can make it very difficult, if not impossible, to completely design out of the data transmitter circuitry. These characteristics can include, for example, skew and mismatch between the rise / fall times of the complementary signals. The AC common-mode voltage present in the differential pair can then generate electromagnetic interference that can radiate out of the cable that contains the paired conductors.

[0023] In some applications, such cables, e.g., High Speed ​​Serial Interface (HSSI) cables, may include differential pairs used to transmit signals within an electronics enclosure (e.g., a server cabinet). In some applications, such cables may also include those used to transmit signals externally between electronics enclosures. EMI radiating from cables either inside or outside an electronics enclosure may be received by other nearby electronic equipment and cause malfunctions there. It is desirable to manage and / or eliminate EMI radiation from data transmission cables to both increase the reliability of nearby electronic devices and systems, and also to meet EMC compliance regulations and guidelines.

[0024] Certain types of electronic hardware can be used to filter out or otherwise mitigate the multi-GHz common-mode EMI frequencies radiating from data transmission cables, but each has significant drawbacks.

[0025] As an example, a printed circuit board (PCB) based structure called a "transmission line grid" (TLG) can be used to filter common mode EMI frequencies. Such a TLG structure can be designed and manufactured into a PCB and function by providing one or more notch filters at desired frequencies that match the EMI frequency or frequencies to be filtered / managed. TLG structures, also known as "electromagnetic band gap" structures, are limited in that they function only in PCB structures and cannot be accommodated in electronic cables. Electromagnetic band gap structures can use a lot of PCB area, introduce gaps in a solid plane, have a narrow frequency band, and are sensitive to the dielectric constant variations of the PCB. The net length of the TLG structure on the PCB also imposes a limit on the number of TLG cells that can be implemented, which in turn limits the filter depth and / or the number of frequencies that can be filtered.

[0026] Spread spectrum IC clocking can also be used to mitigate common-mode EMI radiation problems. However, such clocking schemes can be costly and can significantly complicate on-chip clocking devices and clock tree implementations, increasing clock jitter and design complexity for IC high-speed serial (HSS) interfaces. EMI absorbing materials can be used, but such materials are costly and may only be applicable in limited scenarios, and are generally impractical for most electronic cabling solutions. Common-mode chokes can also be used, but they generally have a very limited frequency range, consume excessive PCB area, and require the filtered signal to be transferred to an outer PCB layer. Thus, a need remains for a solution that effectively filters common-mode EMI frequencies from electronic cabling.

[0027] According to the embodiment, the TLG method implemented on the data transmission cable can filter a wider range of frequencies with a larger filter depth than the TLG implementation on the PCB. The cable-based filter implementation may also allow the filtering characteristics to be changed by modifying the cable, for example, a special cable may be used only when filtering is required to pass EMC testing, and no modification is required to the PCB, including the TLG implementation.

[0028] According to an embodiment, a differential transmission line cable with a common mode notch filter includes adjacently arranged and repeating differential transmission line pair cells. Each of these cells has a physical length equal to half the electrical wavelength of the center frequency of the common mode electromagnetic waves to be suppressed during transmission of an electrical signal over the differential transmission line. Each cell includes a pair of conductors separated from each other by a close spacing along half the cell length and a wide spacing along the other half of the cell length. The diameter of each conductor and the spacing between the conductors of each cell vary with the length of the cell according to a repeating pattern. The diameter and spacing can be selected such that the differential mode impedance of the differential transmission line is the same at every point along the length of each cell. The common mode impedance of the differential transmission line varies periodically according to the diameter and spacing of each portion of each cell.

[0029] Engineered common-mode impedance variations through wire diameter and spacing dimensions are used to create notch filter "cells" that can be effective in filtering out specified frequencies of common-mode EMI emissions from the cable. Such filtering solutions are cost-effective, easy to implement, and may not require PCB modifications to change frequency characteristics.

[0030] Various aspects of the present invention may help manage and reduce EMI broadcasts from cables used to interconnect PCBs in electronic systems. These embodiments can provide cost-effective EMI management without using PCB area or requiring invasive modifications to existing electronic systems. Embodiments may include multi-stage implementations of notch filters that can provide deep filter characteristics for efficient and effective EMI filtering. Embodiments can provide wideband EMI filtering.

[0031] Embodiments of the present invention can utilize existing proven cable, insulation, and manufacturing techniques to provide a cost-effective cooling device for use with electronic systems. Aspects of the various embodiments may be used for secure protocol transfer and / or specific cryptographic applications.

[0032] Certain embodiments relate to transmission lines configured to manage common-mode energy in an electronic system. FIG. 1 illustrates an electronic system 100 using a differential transmission-line cable 114 according to an embodiment of the present invention. FIG. 1 specifically illustrates and may help provide an understanding of an electronic system including a differential driver circuit 102 and a differential receiver circuit 108 electrically interconnected through a differential transmission-line cable 114. Under certain conditions, the differential transmission-line cable 114 may radiate EMI inside or outside the electronic system. It should be understood that the view included in FIG. 1 is provided for illustrative purposes only and may not accurately represent physical characteristics of elements such as ICs, IC packages, PCBs, and differential transmission-line cables 114, such as component types, IC package types, physical dimensions, and size.

[0033] The electronic system 100 includes a PCB 116A on which an IC 110A is mounted with an IC package 112A, and a PCB 116B on which an IC 110B is mounted with an IC package 112B. The IC 110A includes a differential driver circuit 102, and the IC 110B includes a differential receiver circuit 108. The differential driver circuit 102 has an output terminal 104 electrically coupled to conductors 118A and 118B at a cable end 120A of the differential transmission line cable 114. The differential receiver circuit 108 has an input terminal 106 electrically coupled to conductors 118A and 118B at a cable end 120B of the differential transmission line cable 114. The differential transmission line cable 114, the PCB 116A, the PCB 116B, the IC packages 112A, and 112B are configured to electrically couple the differential driver circuit 102 to the differential receiver circuit 108.

[0034] For ease of illustration, ICs 110A and 110B are illustrated, but ICs 110A and 110B may represent other types of electronic components, such as electronic modules, discrete, or active devices or components. In some applications, the differential signals carried on conductors 118A, 118B may result in common-mode AC voltages on these conductors. These common-mode AC voltages may then cause EMI radiation from differential transmission line cable 114 into or outside the electronic system, as discussed above.

[0035] FIG. 2 includes a view 200 illustrating a differential transmission line cable and a view 250 illustrating a differential transmission line cable arrangement according to an embodiment consistent with this figure. View 200 illustrates a differential transmission line cable 114 consistent with FIG. 1, which includes two conductors 118A and 118B, each having a narrow portion 224 and a wide portion 226. View 200 can be particularly useful for illustrating the dimensions, spacing, and arrangement of the conductors 118A, 118B, particularly in relation to a cell length equal to half a particular wavelength (λ / 2). Each cell 230 includes a narrow portion 224 adjacent to a wide portion 226 in a longitudinal direction. The differential transmission line 114 includes a common mode notch filter cell 230 formed from the narrow portion 224 and the wide portion 226 of the conductors 118A and 118B.

[0036] In an embodiment, the length L2 of the wide portion 226 is consistent with the length L1 of the narrow portion 224, with both L1 and L2 being consistent with a quarter of a wavelength (λ / 4) corresponding to the center frequency of the common mode electromagnetic wave to be suppressed during the transmission of the differential signal through the differential transmission line cable 114. For ease of illustration, FIG. 2 shows only one complete narrow portion 224 and one complete wide portion 226 for each of the conductors 118A and 118B, but implementations of the present invention may include a potentially greater number of portions 224 and 226 that are adjacent to each other in the longitudinal direction of the conductors 118A and 118B. In general, a greater number of cells 230 provides improved suppression of the common mode signal and its higher harmonics. The notch filter formed by one or more cells 230 may be configured to effectively manage the common mode energy. The notch filter characteristics are further detailed in FIG. 9 and the associated description.

[0037] Narrow portions 224 of conductors 118A and 118B have a cross-sectional area 222B, and wide portions 226 of conductors 118A and 118B have a cross-sectional area 222A that is greater than cross-sectional area 222B. Narrow portions 224 are adjacent to each other with a distance D1 between them, and wide portions 226 are adjacent to each other with a distance D2 greater than or equal to distance D1.

[0038] According to an embodiment, the cross-sectional areas 222A, 222B and distances D1, D2 of the conductors 118A and 118B in each cell 230 are specified such that the differential mode impedance of the differential transmission line cable 114 is constant throughout both the narrow portion 224 and the wide portion 226 of the cell 230. In an embodiment, the difference in common mode impedance between the narrow portion 224 and the wide portion 226 is used to create a notch filter (e.g., 950 in FIG. 9) to manage the common mode energy of the differential transmission line cable 114. The cross-sectional areas 222A, 222B and distances D1, D2 may be determined using electronic design automation (EDA) software (e.g., similar electronic design software such as an electromagnetic field analysis tool). Each cell 230 has a length equal to half the electrical wavelength of the center frequency of the common mode electromagnetic waves to be suppressed during transmission of the electrical signal through the differential transmission line.

[0039] In an embodiment, an electrically insulating coating (see 770 in FIG. 7) generally surrounds the conductors 118A, 118B. However, for ease of illustration, the electrically insulating coating is not shown in FIG. 2 and the reader is referred to FIG. 7 for explanation and details.

[0040] View 250 illustrates differential transmission-line cable 214B adjacent to additional differential transmission-line cables 214A and 214C. Cables 214A, 214B, and 214C correspond to differential transmission-line cable 114 illustrated in view 200 of FIGS. 1 and 2. Narrow portion 224 of differential transmission-line cable 214B is adjacent to wide portion 226 of differential transmission-line cable 214A. This arrangement may facilitate interlocking packing of differential pairs within the cable assembly. Such an interlocking arrangement may help increase the density of differential pairs within a defined volume of the cable assembly without increasing crosstalk between the pairs.

[0041] 3 is a flow diagram 300 illustrating a method of manufacturing a differential transmission-line cable 114 including a notch filter (950 of FIG. 9) configured to manage common mode energy, according to an embodiment consistent with this figure. A differential transmission-line cable formed by these process operations may correspond to the differential transmission-line cable 114 of FIG. 1 and may have common mode filtering / suppression properties that provide to significantly reduce EMI from the cable. In some applications, such a transmission-line cable may be configured to transmit data signals over a differential pair, as discussed in connection with FIG. 1.

[0042] Performing method 300 may result in a transmission line cable (e.g., differential transmission line cable 114 of FIG. 1) with enhanced EMI management and suppression capabilities. Electronic systems manufactured in accordance with embodiments may also reduce EMI. Embodiments of the present invention are generally consistent with existing ICs, electronic packages, PCBs, cables, and electronic systems, as well as existing design methodologies and techniques and methods for manufacturing electronic systems.

[0043] The progression described corresponding to operations 304-318 begins with a billet of conductor material (e.g., 442 in FIG. 4) and ends with differential transmission line cable 114 in FIG. 2. These process operations can be completed using processes and materials currently used in electronic systems manufacturing, such as drilling, alignment, placement, insertion, and soldering processes, and solder paste 330.

[0044] It should be understood that the operations described in response to Figure 3 may be performed in processes further illustrated in Figures 4-7 and described in the associated text. It should be noted that the examples illustrated and described in connection with Figures 4-7 are provided for illustration only, and not for limitation, and other process operations not illustrated or described may be used within the scope of the present invention. For ease of explanation, it should be understood that, unless otherwise noted, the figure reference numbers in the description of Figure 3 below are generally found in view 200 of Figure 2.

[0045] From start 302, method 300 moves to operation 304. Operation 304 generally refers to forming a wide portion of a first conductor of a differential transmission line cable. According to an embodiment, a wide portion 226 of conductor 118A having a cross-sectional area 222A is formed from a billet of material such as copper, copper alloy, tin, nickel, niobium, or titanium (see FIG. 4 for details). This forming may include an extrusion operation 404 as illustrated in FIG. 4 and described in the associated text. This extrusion operation 404 may include use of a die (e.g., 436 in FIG. 4) having a diameter 446 in FIG. 4 and a die opening 436A that matches the cross-sectional area 222A of conductor 118A in FIG. 2. Once the wide portion is formed, method 300 moves to operation 306.

[0046] Operation 306 generally refers to forming a narrow portion longitudinally adjacent to the wider portion of the first conductor. According to an embodiment, narrow portion 224 is formed from existing conductor 118A having existing diameter 446 in FIG. 4 corresponding to cross-sectional area 222A. Formation of narrow portion 224 can be completed by any one of post-extrusion machining operation 402 in FIG. 4, post-extrusion narrowing operation 504B in FIG. 5, or post-extrusion narrowing / stamping operation 625 in FIG. 6. Formed narrow portion 224 has cross-sectional area 222B smaller than cross-sectional area 222A and corresponding to diameter 448 in FIG. 4. After operation 306, narrow portion 224 is longitudinally adjacent to wider portion 226. Once the narrow portion is formed, method 300 moves to operation 308.

[0047] Operation 308 generally refers to forming a wide portion of the second conductor of the differential transmission line cable. According to an embodiment, the wide portion 226 of the conductor 118B is formed using an operation substantially similar to operation 304, as described above. In some embodiments, operation 308 may be performed simultaneously with operation 304. Once the wide portion is formed, method 300 moves to operation 310.

[0048] Operation 310 generally refers to forming a narrow portion of the second conductor. According to an embodiment, narrow portion 224 is formed from existing conductor 118B using an operation substantially similar to operation 306, as described above. In some embodiments, operation 310 may be performed simultaneously with operation 306. After operation 310, narrow portion 224 is longitudinally adjacent to wide portion 226. Once the narrow portion is formed, method 300 moves to operation 312.

[0049] Operation 312 generally refers to forming additional wide portions of the first and second conductors. According to an embodiment, additional wide portions 226 are formed in the existing conductors 118A, 118B using an operation substantially similar to operation 304, as described above. In some embodiments, operation 312 may be performed simultaneously on both the first conductor 118A and the second conductor 118B. After operation 312, the additional wide portions 226 are longitudinally adjacent to the narrow portions 224 of the conductors 118A, 118B. Once the additional wide portions are formed, method 300 moves to operation 314.

[0050] Operation 314 generally refers to forming additional narrow portions 224 of the first and second conductors. According to an embodiment, the additional narrow portions 224 are formed in the existing conductors 118A, 118B using an operation substantially similar to operation 306, as described above. In some embodiments, operation 314 may be performed simultaneously on both the first conductor 118A and the second conductor 118B. After operation 314, the additional narrow portions 224 are longitudinally adjacent to the wider portions 226 of the conductors 118A, 118B. Once the additional narrow portions are formed, method 300 moves to operation 316.

[0051] Optional operation 316 generally refers to applying an electrically insulating coating to the first and second conductors. According to an embodiment, an electrically insulating coating 770, FIG. 7, is applied to the existing conductors 118A, 118B using a wire coating die 702, as shown in FIG. 7 and described in the associated text. The electrically insulating coating 770, FIG. 7, may specifically help prevent shorts between the conductors 118A, 118B, and may be applied using a continuous coating process. In some embodiments, operation 316 may also include a marking operation, as shown in FIG. 8 and described in the associated text. Such a marking operation may result in markings (e.g., 870, 872, FIG. 8) being applied to the narrow and wide portions 224, 226 of the conductors 118A and 118B, FIG. 2. Once the electrically insulating coating is applied, method 300 moves to operation 318.

[0052] Optional operation 318 generally refers to providing a narrow portion of a first conductor adjacent to a narrow portion of a second conductor. The location of such conductors is important for establishing both common mode and differential impedances, as discussed above, so that the differential transmission line cable 114 functions properly in filtering and reducing EMI during data transmission. The markings applied to the differential transmission line cable 114 in operation 316 may be used to properly align the conductors 118A and 118B. Once the narrow portion of the first conductor is provided adjacent to the narrow portion of the second conductor, the method 300 may end at block 320.

[0053] Figures 4-7 are provided to illustrate various process operations that may be used to form conductors from an electrically conductive material and to form an electrically insulating coating on the formed conductor. It should be understood that Figures 4-7 are not limiting and that other processes and operations may be utilized to form and insulate the conductors within the scope of the present invention. It should be understood that the flow of material in Figures 4-6 is from right to left according to the arrows provided in Figures 4-6 and the flow of material in Figure 7 is from left to right.

[0054] 4 illustrates a wire extrusion and machining process 400 according to an embodiment consistent with this figure, which includes an extrusion operation 404 followed by a post-extrusion machining operation 402. The extrusion operation 404 is useful in illustrating or providing a visual understanding of the process of material conversion of a "bulk" or raw material of a billet 442 into a conductor 118 consistent with the conductors 118A, 118B of FIG. 2. According to an embodiment, the billet 442 may include materials such as copper, copper alloy, tin, nickel, niobium, or titanium.

[0055] During extrusion operation 404, such material may be compressed by a leftward force applied to ram 438 of die machine 439, which in turn is applied to dummy block 440. This compressive force causes the material in billet 442 to be extruded through die opening 436A of die 436, which is connected to container 444. During extrusion operation 404, billet 442 may be heated and / or melted to hasten extrusion. The resulting extrusion (wire) 434 has a diameter 446 as determined by die opening 436A of die 436 and travels leftward as illustrated in FIG. 4.

[0056] After extrusion operation 404 and possibly a cooling stage, a post-extrusion machining operation 402 is used to selectively create one or more narrowed portions 224 in conductor 118. Continuing to the left, conductor 118 is selectively machined with machining head 432, which includes a concave cutting surface as shown in machining head 432 (side view). Machining head 432 is used to selectively remove material from conductor 118, resulting in a reduction in diameter 446 to a smaller diameter 448. Diameter 446 corresponds to cross-sectional area 222A in FIG. 2, and diameter 448 corresponds to cross-sectional area 222B in FIG. 2.

[0057] The cutting head 432 may be moved toward or away from the conductor 118 by automated machinery and / or control systems (not shown) to section the conductor 118 into alternating wide and narrow portions 226 and 224. Those skilled in the art of wire manufacturing will appreciate that such automated machinery and / or control systems are well understood and commercially feasible.

[0058] To create narrow portion 224 of conductor 118, having smaller diameter 448, cutting head 432 may move toward conductor 118 a distance "d" equal to half the difference between diameter 446 and diameter 448. Once conductor 118 has progressed leftward and narrow portion 224 of length L1 has been created, cutting head 432 may be moved away from conductor 118 by the automation and / or control system the distance d. Cutting head 432 may remain away from conductor 118 until length L2 of conductor 118 has been moved leftward, after which cutting head 432 may re-engage with conductor 118.

[0059] Thus, alternating motion of cutting head 432 toward and away from conductor 118 may specifically serve to create corresponding alternating narrow and wide portions 224 and 226, respectively. It should be appreciated that extrusion operation 404 and subsequent post-extrusion cutting operation 402 are processes that may be performed continuously and consistent with conventional wire production and feed rates. As such, each of the described portions of conductor 118 may be created without having to remove conductor 118 from the extruder or cutting machine.

[0060] 5 illustrates a wire extrusion and narrowing process 500 according to an embodiment consistent with this figure, which includes an extrusion operation 504A followed by a post-extrusion narrowing operation 504B. The extrusion operation 504A, die set 539, and billet 442 materials are substantially similar to those described in connection with operation 404 of FIG.

[0061] After extrusion operation 504B and possibly a cooling stage, a post-extrusion narrowing operation 504B is used to selectively create one or more narrowed portions 224 in conductor 118. As conductor 118 travels leftward, it is selectively narrowed by passing through die opening 437A of die 437, which is secured within die assembly 439A. According to an embodiment, conductor 118 may be drawn or "pulled" through one or both of die assemblies 539 and 539A. Die 437 is used to selectively narrow conductor 118, thereby reducing diameter 446 to smaller diameter 448. Diameter 446 corresponds to cross-sectional area 222A in FIG. 2, and diameter 448 corresponds to cross-sectional area 222B in FIG. 2.

[0062] The machining die openings 437A of the die 437 can be made larger or smaller by automated machinery and / or control systems (not shown) to section the conductor 118 into alternating wide and narrow portions 226 and 224. Those skilled in the art of wire manufacturing will appreciate that such automated machinery and / or control systems are well understood and commercially feasible.

[0063] To create narrow portion 224 of conductor 118 having smaller diameter 448, die opening 437A may be decreased by a distance of [2×d] around conductor 118, where “d” is equal to half the difference between diameter 446 and diameter 448. As conductor 118 progresses leftward and creation of narrow portion 224 of length L1 is completed, die opening 437A may be increased by an automation and / or control system by a distance of [2×d] around conductor 118. Die opening 437A may remain enlarged until length L2 of conductor 118 has been moved leftward, after which it may be decreased again around conductor 118.

[0064] Thus, the described alternating expansion and contraction of die opening 437A around conductor 118 may specifically serve to create corresponding alternating narrow and wide portions 224 and 226, respectively. It should be appreciated that extrusion operation 404 and subsequent post-extrusion narrowing operation 504B are processes that may be performed continuously and consistent with conventional wire production and feed rates. As such, each of the described portions of conductor 118 may be made without having to remove conductor 118 from the extruder or wire narrowing / die machine.

[0065] 6 illustrates a wire extrusion and narrowing process 600, according to an embodiment consistent with this figure, including an extrusion operation 604 and a post-extrusion narrowing / stamping operation 625. The extrusion operation 604A, die set 439, and billet 442 materials are substantially similar to those described in connection with operation 404 of FIG.

[0066] After extrusion operation 604 and possibly a cooling stage, a post-extrusion narrowing / stamping operation 625 is used to selectively create one or more narrowed portions 224 in conductor 118. As conductor 118 travels leftward, it is selectively narrowed by being stamped / compressed by stamp 652 of stamp machine 639. According to an embodiment, conductor 118 may be drawn or "pulled" through one or both of die machine 439 and stamp machine 639. Stamp machine 639 is used to selectively narrow conductor 118, thereby reducing diameter 446 to a smaller diameter 448. Diameter 446 corresponds to cross-sectional area 222A in FIG. 2 and diameter 448 corresponds to cross-sectional area 222B in FIG. 2.

[0067] Each portion of the conductor 118 may be stamped with a stamp 652 in a stamping machine 639 to separate the conductor 118 into alternating wide and narrow portions 226, 224. The stamping machine 639 may include automated machinery and / or a control system (not shown). Those skilled in the art of wire manufacturing will appreciate that such automated machinery and / or control systems are well understood and commercially feasible.

[0068] An appropriate force can be applied by stamp 652 of stamping machine 639 to create narrow portion 224 of conductor 118 having smaller diameter 448. Stamp 652 can include a "stop" or tolerance to control the amount of compression of conductor 118 from diameter 446 to smaller diameter 448. Proceeding leftward, conductor 118 can be stamped by stamping machine 639 at intervals of length equal to L2 to create an array of consecutive alternating narrow portions 224 and wide portions 226. Thus, a control system of stamping machine 639 can specifically serve to sense the length of conductor 118 that has passed under stamp 652 and alternately stamp and release conductor 118 accordingly.

[0069] It should be appreciated that the extrusion operation 604 and subsequent post-extrusion narrowing / stamping operation 625 are processes that can be performed continuously and consistent with conventional wire production and feed rates. Thus, each of the described portions of conductor 118 may be made without having to remove conductor 118 from the extruder or narrowing / stamping and die machines. According to an embodiment, the characteristics of stamp 652 may be varied to accommodate multiple desired conductor 118 characteristics.

[0070] FIG. 7 illustrates a wire coating process 700 according to an embodiment consistent with this figure. FIG. 7 illustrates a die for coating a wire 702, which may be useful to provide a visual understanding of machines and associated processes for coating bare wires / conductors with an electrically insulating coating. Such machines and processes may be particularly useful for coating wires, such as conductors 118 / 118A / 118B, and are consistent with operation 316 of FIG.

[0071] The die for coating the wire 702 includes a vertical extruder barrel 752 through which molten insulating material, such as a polymer melt 756, flows downwardly in a direction indicated by melt flow direction 748. The polymer melt 756 flows through a screen pack 746 and a breaker plate 754, which can aid in improving mixing and filtering of the polymer melt 756.

[0072] A bare wire matching the conductor 118 is received in the bare wire insert 762 and moves from left to right as shown in Figure 7. A vacuum seal 766 helps maintain the proper vacuum between the conductor / wire 118 and the core tube 758 through which the wire passes. A small partial vacuum 768 is pulled between the wire 118 and the polymer within the core tube 758 to promote adhesion of the polymer coating to the wire 118.

[0073] Moving to the right, wire 118 emerges from core tube 758 and mold section 760 as coated wire 764 having an electrically insulating coating 770 applied thereto. Electrically insulating coating 770 may specifically help protect conductor 118 and prevent undesired electrical contact between adjacent conductors, for example, when assembled into a differential pair.

[0074] According to an embodiment, the coating process described above may be accomplished after the final stage of the conductor 118. This process may occur as the wire is pulled through the die at high speeds (e.g., up to 50 m / s (10,000 ft / min)), consistent with similar existing wire coating processes. The conductor 118 may provide rigidity during a post-coating cooling process, which may be aided in conductor stiffness by passing the coated wire through a water-cooled section. After the cooling process, the finished insulated wire may be wound onto a spool.

[0075] 8 illustrates the marking, insulation, and placement of differential transmission-line cables, including three differential transmission-line cables 814A, 814B, and 814C, according to an embodiment consistent with this figure. FIG 8 illustrates the marking, insulation, and placement of differential transmission-line cables 814A, 814B, 814C, consistent with operations 316 and 318 of FIG 3 and FIG 7.

[0076] After a wire coating process (e.g., 700) and subsequent cooling, the conductors 118A, 118B have an electrically insulating coating 770 on their outer surfaces. Markings (e.g., marking 872 and marking 870) may be applied to the electrically insulating coating 770 to mark various portions of the conductors 118A, 118B, for example, at the center of the wide portion 226 and the narrow portion 224, respectively. These markings may then be used to align the differential transmission line cables (e.g., 814A, 814B, and 814C).

[0077] Alignment of the differential transmission line cables (e.g., 814A, 814B, and 814C) can be useful for efficient packaging within a cable assembly, or for reasons of optimizing or tuning the electrical performance of the differential transmission line cables, or both.

[0078] Various methods of marking the conductors 118A, 118B may include stamping the conductors with a die (see, for example, FIG. 6) or marking the conductors with various types of inks or paints, or both. Methods of marking the conductors may also include applying thermochromic liquid crystals used in microcapsules to allow color identification of features related to changes in the conductor shape. X-ray techniques may also be used for subsequent alignment of the differential pairs.

[0079] 9 includes a graph 900 illustrating common mode insertion loss as a function of frequency, according to an embodiment consistent with this figure, and a schematic diagram 950 of a differential transmission line cable functioning as a notch filter. Graph 900, in particular, can be useful in expressing and providing a visual understanding of the effect that including various numbers of cells (see 230 in FIG. 2) has on the depth of the filter notch characteristic.

[0080] The y-axis of graph 900 corresponds to the common mode insertion loss generated by an electrical circuit simulation of a transmission notch filter consistent with this figure, in accordance with an embodiment of the present invention. The x-axis of graph 900 corresponds to the operating frequency (GHz) of the notch filter. Curve 982 represents the common mode insertion loss of a filter consistent with the structure of differential transmission line cable 114, including four cells arranged in series. Similarly, curves 984 and 986 represent the common mode insertion loss characteristics of filters including six and eight cells, respectively.

[0081] It is noted that the graph 900 clearly shows that increasing the number of cells in the notch filter can provide effective and efficient filtering characteristics for the differential transmission line cable functioning as a notch filter, according to an embodiment. The more cells in the cable, the more effective the common mode signal suppression provided to the cable. An electronic system designer can adjust the number of specific cells 230 in FIG. 2 included in the differential transmission line cable to produce the desired filtering characteristics that effectively reduce the common mode EMI in the cable. Thus, different cables can be manufactured with different amounts of EMI suppression (e.g., 5, 10, 15, 20 dB).

[0082] The notch filter schematic 950 helps illustrate the electrical circuit representation of the narrow and wide portions 224, 226 of the differential transmission line cable 114. The narrow and wide portions 224, 226 each include the conductors 118A and 118B, corresponding ground lines, and various electrical elements that represent the properties of the conductors. The electrical elements shown include line resistances Ra(1), Ra(2), Rb(1), and Rb(2), conductances Ga(1), Ga(2), Gb(1), and Gb(2), capacitances Ca(1), Ca(2), Cb(1), and Cb(2), line inductances La(1), La(2), Lb(1), and Lb(2), mutual capacitances Cm(1) and Cm(2), and mutual inductances K1 and K2.

[0083] Electrical circuit designers can utilize electrical circuit modeling and simulation tools to simulate the effect of different wire geometries that may result in changes to these parameters, which can then be used to tune common mode and differential impedance values. The specification, modification, and simulation of these impedance values ​​can provide valuable insight to embodiments of the present invention when designing wire sections (i.e., narrow and wide sections, shapes, and spacing).

[0084] The description of various embodiments of the present invention is presented for illustrative purposes, but is not intended to be exhaustive or limited to the disclosed embodiments. Many modifications and variations that do not depart from the scope of the described embodiments will be apparent to those skilled in the art. The terminology used in this specification has been selected to explain the principles of the embodiments, practical applications, or technical improvements to the art found in the market, or to enable those skilled in the art to understand the embodiments disclosed herein.

[0085] In a preferred embodiment of the invention described herein, there is provided an electronic system comprising: a differential transmission line cable including first and second conductors each having a narrow portion and a wide portion, the narrow portion having a first cross-sectional area and the wide portion having a second cross-sectional area larger than the first cross-sectional area, the narrow portions being adjacent to each other with a first spacing between them and the wide portions being adjacent to each other with a second spacing between them that is larger than the first spacing; a differential driver circuit having output terminals electrically coupled to the first and second conductors at a first end of the differential transmission line cable; and a differential receiver circuit having output terminals electrically coupled to the first and second conductors at a second end of the differential transmission line cable. Preferably, the electronic system further comprises a first integrated circuit (IC) including a differential driver circuit, a second IC including a differential receiver circuit, a first printed circuit board (PCB) on which the first IC is mounted, and a second PCB on which the second IC is mounted, wherein the differential transmission line cable, the first PCB, and the second PCB are configured to electrically couple the differential driver circuit to the differential receiver circuit. According to this specification, the following items are also disclosed. [Item 1] 1. A differential transmission line cable including a notch filter configured to manage common mode energy, the differential transmission line cable comprising: A narrow portion, a first conductor having a first cross-sectional area; and a second conductor disposed adjacent to the first conductor at a first distance, the second conductor having a cross-sectional area matching the first cross-sectional area; A narrow portion including a wide portion longitudinally adjacent to the narrow portion, the first conductor having a second cross-sectional area greater than the first cross-sectional area; and a second conductor disposed adjacent to the first conductor at a second spacing greater than the first spacing, the second conductor having a cross-sectional area matching the second cross-sectional area; Including the wide part and Equipped with the first cross-sectional area, the first spacing, the second cross-sectional area, and the second spacing are: The differential mode impedance of the differential transmission line cable is constant throughout both the narrow portion and the wide portion; and A difference in common mode impedance between the narrow section and the wide section is used to create a notch filter that manages common mode energy in the differential transmission line cable. Specified, differential transmission line cable. [Item 2] an additional narrow portion coincident with the narrow portion and longitudinally adjacent the wide portion; an additional wide portion coincident with the wide portion and longitudinally adjacent the additional narrow portion; Item 2. The differential transmission line cable of item 1, further comprising: [Item 3] 3. The differential transmission line cable according to item 1 or 2, wherein a length of the wide portion is equal to a length of the narrow portion. [Item 4] 4. The differential transmission line cable according to any one of claims 1 to 3, wherein the first conductor is separated from the second conductor by an electrically insulating coating. [Item 5] 5. The differential transmission line cable according to any one of items 1 to 4, wherein a length of the wide portion and a length of the narrow portion each correspond to a quarter of a wavelength corresponding to a center frequency of a common-mode electromagnetic wave to be suppressed during transmission of a differential signal through the differential transmission line cable. [Item 6] 6. The differential transmission line cable according to any one of claims 1 to 5, wherein the differential transmission line cable is provided adjacent to an additional differential transmission line cable that matches the differential transmission line cable. [Item 7] 7. The differential transmission line cable according to item 6, wherein the narrow portion of the differential transmission line cable is provided adjacent to the wide portion of the additional differential transmission line cable. [Item 8] 1. A method of manufacturing a differential transmission line cable including a notch filter configured to manage common mode energy, the method comprising: forming a widened portion of a first conductor of the differential transmission line cable, the widened portion having a first cross-sectional area; forming a narrow portion of the first conductor longitudinally adjacent to the wide portion, the narrow portion having a second cross-sectional area smaller than the first cross-sectional area; forming a widened portion of a second conductor of the differential transmission line cable, the widened portion having a cross-sectional area that matches the first cross-sectional area; forming a narrowed portion of the second conductor, the narrowed portion having a cross-sectional area that matches the second cross-sectional area; A method comprising: [Item 9] forming an additional narrow portion longitudinally adjacent said wide portion; forming an additional wider portion longitudinally adjacent to the additional narrower portion; 9. The method of claim 8, further comprising: [Item 10] 10. The method of claim 8 or 9, further comprising providing an electrically insulating coating on each of the first conductor and the second conductor. [Item 11] 11. The method of any one of claims 8 to 10, further comprising providing the narrowed portion of the first conductor adjacent to the narrowed portion of the second conductor. [Item 12] 12. The method of any one of claims 8 to 11, further comprising providing the differential transmission line cable adjacent to an additional differential transmission line cable that matches the differential transmission line cable. [Item 13] Item 13. The method of item 12, further comprising providing the narrow portion of the differential transmission line cable adjacent to the wide portion of the additional differential transmission line cable. [Item 14] Item 14. The method of any one of items 8 to 13, wherein forming the narrow portions of the first conductor and the second conductor comprises removing material from the wide portions of the first conductor and the second conductor in a machining operation. [Item 15] 15. The method of any one of claims 8 to 14, wherein forming the wide portions of the first conductor and the second conductor comprises passing the first conductor and the second conductor through a die machine having a die opening that matches the first cross-sectional area. [Item 16] 16. The method of any one of claims 8 to 15, wherein forming narrow portions of the first conductor and the second conductor comprises passing the first conductor and the second conductor through a die machine having a die opening that matches the second cross-sectional area. [Item 17] Item 17. The method of any one of items 8 to 16, wherein forming the narrow portions of the first conductor and the second conductor comprises a stamping operation configured to match the cross-sectional area of ​​the narrow portions of the first conductor and the second conductor to the second cross-sectional area. [Item 18] Item 18. The method of any one of items 8 to 17, further comprising applying markings to each of the first conductor and the second conductor indicating the positions of the narrow and wide portions of the first conductor and the second conductor, respectively.

Claims

1. 1. A differential transmission line cable including a notch filter configured to manage common mode energy, the differential transmission line cable comprising: A narrow portion, a first conductor having a first cross-sectional area; and a second conductor disposed adjacent to the first conductor at a first distance, the second conductor having a cross-sectional area matching the first cross-sectional area; A narrow portion including a wide portion longitudinally adjacent to the narrow portion, the first conductor having a second cross-sectional area greater than the first cross-sectional area; and a second conductor disposed adjacent to the first conductor at a second spacing greater than the first spacing, the second conductor having a cross-sectional area matching the second cross-sectional area; Including the wide part and Equipped with the first cross-sectional area, the first spacing, the second cross-sectional area, and the second spacing being: The differential mode impedance of the differential transmission line cable is constant throughout both the narrow portion and the wide portion; and The difference in common mode impedance between the narrow section and the wide section is used to create a notch filter that manages common mode energy in the differential transmission line cable. Specified, The differential transmission line cable is provided adjacent to an additional differential transmission line cable that matches the differential transmission line cable.

2. an additional narrow portion coincident with the narrow portion and longitudinally adjacent the wide portion; an additional wide portion coincident with the wide portion and longitudinally adjacent the additional narrow portion; The differential transmission line cable of claim 1 , further comprising:

3. 3. The differential transmission line cable according to claim 1, wherein a length of the wide portion is equal to a length of the narrow portion.

4. 4. The differential transmission line cable of claim 1, wherein the first conductor is separated from the second conductor by an electrically insulating coating.

5. 5. The differential transmission line cable according to claim 1, wherein a length of the wide portion and a length of the narrow portion each correspond to a quarter of a wavelength corresponding to a center frequency of a common-mode electromagnetic wave to be suppressed during transmission of a differential signal through the differential transmission line cable.

6. 2. The differential transmission-line cable of claim 1, wherein the narrow portion of the differential transmission-line cable is disposed adjacent to the wide portion of the additional differential transmission-line cable.

7. 1. A method of manufacturing a differential transmission line cable including a notch filter configured to manage common mode energy, the method comprising: forming a widened portion of a first conductor of the differential transmission line cable, the widened portion having a first cross-sectional area; forming a narrow portion of the first conductor longitudinally adjacent to the wide portion, the narrow portion having a second cross-sectional area smaller than the first cross-sectional area; forming a widened portion of the second conductor of the differential transmission line cable, the widened portion having a cross-sectional area that matches the first cross-sectional area; forming a narrowed portion of the second conductor, the narrowed portion having a cross-sectional area that matches the second cross-sectional area; Equipped with The method further comprising providing the differential transmission-line cable adjacent to an additional differential transmission-line cable that is matched to the differential transmission-line cable.

8. forming an additional narrow portion longitudinally adjacent said wide portion; forming an additional wider portion longitudinally adjacent to the additional narrower portion; The method of claim 7 further comprising:

9. 9. The method of claim 7 or 8, further comprising the step of providing an electrically insulating coating on each of the first conductor and the second conductor.

10. 10. The method of claim 7, further comprising providing the narrow portion of the first conductor adjacent to the narrow portion of the second conductor.

11. 8. The method of claim 7, further comprising providing the narrow portion of the differential transmission-line cable adjacent to a wider portion of the additional differential transmission-line cable.

12. 12. The method of claim 7, wherein forming narrow portions of the first and second conductors comprises removing material from the wide portions of the first and second conductors in a machining operation.

13. 13. The method of claim 7, wherein forming the widened portions of the first and second conductors comprises passing the first and second conductors through a die machine having a die opening that matches the first cross-sectional area.

14. 14. The method of claim 7, wherein forming narrow portions of the first and second conductors comprises passing the first and second conductors through a die machine having a die opening that matches the second cross-sectional area.

15. 15. The method of claim 7, wherein forming the narrow portions of the first and second conductors comprises a stamping operation configured to match the cross-sectional area of ​​the narrow portions of the first and second conductors with the second cross-sectional area.

16. 16. The method of claim 7, further comprising providing each of the first and second conductors with markings indicating the locations of the narrow and wide portions of the first and second conductors, respectively.

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