The present invention relates generally to telecommunications equipment. More particularly, the present invention relates to telecommunications jacks that are configured to compensate for near end crosstalk.
In the field of data communications, communications networks typically utilize techniques designed to maintain or improve the integrity of signals being transmitted via the network (“transmission signals”). To protect signal integrity, the communications networks should, at a minimum, satisfy compliance standards that are established by standards committees, such as the Institute of Electrical and Electronics Engineers (IEEE). The compliance standards help network designers provide communications networks that achieve at least minimum levels of signal integrity as well as some standard of compatibility.
One prevalent type of communication system uses twisted pairs of wires to transmit signals. In twisted pair systems, information such as video, audio and data are transmitted in the form of balanced signals over a pair of wires. The transmitted signal is defined by the voltage difference between the wires.
Crosstalk can negatively affect signal integrity in twisted pair systems. Crosstalk is unbalanced noise caused by capacitive and/or inductive coupling between wires and a twisted pair system. The effects of crosstalk become more difficult to address with increased signal frequency ranges.
The effects of crosstalk also increase when transmission signals are positioned closer to one another. Consequently, communications networks include areas that are especially susceptible to crosstalk because of the proximity of the transmission signals. In particular, communications networks include connectors that bring transmission signals in close proximity to one another. For example, the contacts of traditional connectors (e.g., jacks and plugs) used to provide interconnections in twisted pair telecommunications systems are particularly susceptible to crosstalk interference.
To promote circuit density, the contacts of the jacks and the plugs are required to be positioned in fairly close proximity to one another. Thus, the contact regions of the jacks and plugs are particularly susceptible to crosstalk. Furthermore, certain pairs of contacts are more susceptible to crosstalk than others. For example, the first and third pairs of contacts in the plugs and jacks are typically most susceptible to crosstalk.
To address the problems of crosstalk, jacks have been designed with contact spring configurations adapted to reduce the capacitive coupling generated between the contact springs so that crosstalk is minimized. An alternative approach involves intentionally generating crosstalk having a magnitude and phase designed to compensate for or correct crosstalk caused at the plug or jack. Typically, crosstalk compensation can be provided by manipulating the positioning of the contacts or leads of the jack or can be provided on a circuit board used to electrically connect the contact springs of the jack to insulation displacement connectors of the jack.
The telecommunications industry is constantly striving toward larger signal frequency ranges. As transmission frequency ranges widen, crosstalk becomes more problematic. Thus, there is a need for further development relating to crosstalk remediation.
One aspect of the present disclosure relates to circuit board layering configurations adapted for supporting the effective compensation of crosstalk in a telecommunications jack.
Another aspect of the present disclosure relates to the use of high impedance lines to compensate for return loss caused by crosstalk compensation arrangements.
Still another aspect of the present disclosure relates to the use of capacitive couplings to overcome return loss issues caused by crosstalk compensation arrangements.
Still another aspect of the present disclosure relates to crosstalk compensation arrangements and methods for designing crosstalk compensation arrangements.
A variety of additional inventive aspects will be set forth in the description that follows. The inventive aspects can relate to individual features and to combinations of features. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the broad inventive concepts upon which the embodiments disclosed herein are based.
In use, wires are electrically connected to the contact springs CS1-CS8 by inserting the wires between pairs of the insulation displacement connector blades IDC1-IDC8. When the wires are inserted between pairs of the insulation displacement connector blades IDC1-IDC8, the blades cut through the insulation of the wires and make electrical contact with the center conductors of the wires. In this way, the insulation displacement connector blades IDC1-IDC8, which are electrically connected to the contact springs Cs1-CS8 by the tracks on the circuit board, provide an efficient means for electrically connecting a twisted pair of wires to the contact springs CS1-CS8 of the jack 120.
The contact springs CS1-CS8 are shown more clearly in
The circuit board 132 of the jack 120 is preferably a multiple layer circuit board. For example,
The circuit board 132 preferably includes structures for compensating for near end crosstalk that occurs at the jack/plug interface. In certain embodiments, the structures for compensating for near end crosstalk include capacitive couplings provided between the first and second conductive layers 140, 142. In preferred embodiments, the capacitive couplings are provided by sets of opposing, generally parallel capacitive plates located at the first and second conductive layers 140, 142. To increase the magnitude of the capacitive coupling provided between the capacitive plates of the first and second conductive layers 140, 142, it is desirable for the first dielectric layer 146 to be relatively thin. For example, in certain embodiments the first dielectric layer 146 can have a thickness t1 less than about 0.01 inches, or less than about 0.0075 inches, or less than about 0.005 inches, or less than 0.003 inches. In other embodiments, the thickness t1 can be in the range of 0.001 inches to 0.003 inches or in the range of 0.001 inches to 0.005 inches. In a preferred embodiment, the thickness t1 is about 0.002 inches.
In certain embodiments, the first dielectric layer 146 can be made of a material having a relatively low dielectric constant. As used herein, dielectric constants are dielectric constants relative to air. In certain embodiments, the dielectric constant of the first dielectric layer 146 can be equal to or less than about 5. In other embodiments, the dielectric constant of the first dielectric layer 146 can be less than or equal to about 4 or less than or equal to about 3. An example material for manufacturing the first dielectric layer 146 is a flame resistant 4 (FR-4) circuit board material. FR-4 circuit board material is a composite of a resin epoxy reinforced with a woven fiberglass mat.
The second dielectric layer 148 is preferably configured to isolate the third conductive layer 144 from the first and second conductive layers 140, 142. The second dielectric layer 148 can have a different thickness t2 than the thickness t1 of the first dielectric layer 146. In certain embodiments, the second dielectric layer 148 is at least 2.5 times thicker than the first dielectric layer 146 or at least five times thicker than the first dielectric layer 146. In still other embodiments, the second dielectric layer 148 is at least 10 times or at least 20 times thicker than the first dielectric layer 146. In one example embodiment, the thickness t2 of the second dielectric layer 148 is in the range of 0.050 inches to 0.055 inches. In another example embodiment, the thickness t2 of the second dielectric layer 148 is in the range of 0.040 inches to 0.050 inches.
The second dielectric layer 148 can also be manufactured of a different material as compared to the first dielectric layer 146. In certain embodiments, the second dielectric layer can have different dielectric properties as compared to the first dielectric layer 146. For example, in certain embodiments the first dielectric layer 146 can have a dielectric constant that is greater (e.g., at least 1.5 times or at least 2 times greater) than the dielectric constant of the second dielectric layer 148. In one example, the second dielectric layer 148 can be manufactured of a material such as FR-4. Of course, it will be appreciated that other materials could also be used.
The circuit board 132 includes a number of capacitive couplings having magnitudes and locations adapted to compensate for near end crosstalk. Near end crosstalk is most problematic between the 4-5 and 3-6 pairs. To compensate for near end crosstalk between the 4-5 and 3-6 pairs, three interdependent zones of compensation are used between tracks T4-5 and tracks T3-6. As shown at
In designing the compensation scheme of
To minimize the effect of phase shift in the compensation arrangement, it is preferred for the second vector 102 to be positioned as close as possible to the first vector 100. In
To maintain forward and reverse symmetry, it is preferred for the time delay between the third vector 104 and the fourth vector 106 to be approximately the same as the time delay between the first vector 100 and the second vector 102. As shown in
The time delay y between the second vector 102 and the third vector 104 is preferably selected to optimize the overall compensation effect of the compensation scheme over a relatively wide range of frequencies. By varying the time delay y between the second vector 102 and the third vector 104, the phase angles of the first and second compensation zones are varied thereby altering the amount of compensation provided at different frequencies. In one example embodiment, to design the time delay y, the time delay y is initially set with a value generally equal to x (i.e., the time delay between the first vector 102 and the second vector 104). The system is then tested or simulated to determine if an acceptable level of compensation is provided across the entire signal frequency range intended to be used. If the system meets the crosstalk requirements with the value y set equal to x, then no further adjustment of the value y is needed. If the compensation scheme fails the crosstalk requirements at higher frequencies, the time delay y can be shortened to improve performance at higher frequencies. If the compensation scheme fails the crosstalk requirements at lower frequencies, the time delay y can be increased to improve crosstalk performance for lower frequencies. It will be appreciated that the time delay y can be varied without altering forward and reverse symmetry.
It has been determined that when magnitudes of the second and third vectors 102, 104 are respectively −3M and 3M, the distance y is preferably greater than the distance x to provide optimized crosstalk compensation. However, if the magnitudes of the vectors 102, 104 are reduced below −3M and 3M (e.g., to −2.7M and 2.7M), the distance y is preferably less than the distance x to provide optimized crosstalk compensation.
Crosstalk can also be an issue between the 1-2 and 3-6 pairs. Particularly, substantial crosstalk can be generated between track T2 and track T3. As shown at
A two-zone compensation arrangement can be also be used to provide crosstalk compensation between the 4-5 and 7-8 pairs. For example,
In addition to the multiple zone compensation arrangements described above, a number of single zone compensations can also be used. For example, zone ZD1 is a single zone compensation including a capacitive coupling C12 provided between track T2 and track T5. Another single zone compensation ZE1 is provided by a capacitive coupling C13 formed between track T6 and track T8. Another capacitive coupling C14 between track T5 and track T6 compensates for unintended crosstalk generated within the board itself.
To address the crosstalk issue between the 4-5 and 3-6 pairs, a relatively large amount of capacitance is used. This large amount of capacitance can cause the jack to have unacceptable levels of return loss. A number of methods can be used to improve return loss performance. For example, return loss performance can be improved by increasing the impedance of tracks T3, T4, T5 and T6 of the board. The impedance of the tracks is preferably increased through the first, second and third zones of compensation, and also after the first, second, and third zones of compensation. The impedance can be increased by minimizing the transverse cross sectional area of tracks T3, T4, T5 and T6. An example transverse cross-sectional area of the tracks is in the range of 13 to 16 square mils (1 mil=0.001 inches). The impedance can also increase by routing the tracks so as to maintain a relatively large spacing between tracks T3 and T4 and between tracks T5 and T6. In one embodiment, the impedance of the tracks T3-T6 is greater than 100 Ohms. In another embodiment, the impedance is equal to or greater than 120 Ohms. In still another embodiment, the impedance of the tracks T3-T6 is equal to or greater than 150 Ohms. In still a further embodiment, the impedance of the tracks T3-T6 is equal to or greater than 175 Ohms. In a further embodiment, the impedance of the tracks T3-T6 is equal to or greater than 200 Ohms.
The impedance of tracks T3-T6 can also be increased by increasing the lengths of the tracks T3-T6 provided between the springs CS3-CS6 and the insulation displacement connectors IDC3-IDC6. In certain embodiments, this increased length can be provided by using serpentine or loop back routing configurations for the tracks T3-T6. In lengthening the tracks T3-T6 provided between contact springs CS3-CS6 and their corresponding insulation displacement connector blades IDC3-IDC6, in certain embodiments, the tracks T3-T6 can be lengthened to be at least one and a half times or at least two times as long as the straight line distance between the springs CS3-CS6 and their corresponding insulation displacement connector blades IDC3-IDC6. In other embodiments, the tracks T3-T6 can be at least three or four times as long as the straight line distances between the contact springs CS3-CS6 and their corresponding insulation displacement connector blades IDC3-IDC6.
The impedance of the tracks T3-T6 can also be increased by increasing/maximizing the spacing between track T4 and track T5, and between track T3 and track T6. In one embodiment, the tracks T4 and T5 diverge from one another as the tracks T4 and T5 extend away from the contact springs CS4 and CS5, and then converge again as the tracks T4 and T5 approach the insulation displacement connector blades IDC4 and IDC5. Thus, mid regions of the tracks T4 and T5 are spaced relatively far away from one another. In one embodiment, a spacing of at least 0.1 inches, measured in a direction parallel to a width W of the circuit board, is defined between portions of the tracks T4 and T5. In certain embodiments, this spacing represents at least ¼ of the width of the circuit board. It will be appreciated that similar spacings can be used between the track T3 and the track T6 to increase impedance.
Referring still to
Referring to
The capacitive coupling C7 of the first compensation zone ZB1 is provided by opposing capacitor plates C71 and C73 that are respectively provided at layers 140 and 142 of the circuit board. The capacitive coupling C8 of the first compensation zone ZB1 is provided by opposing capacitor plates C82 and C86 that are respectively provided at the layers 140 and 142 of the circuit board. The capacitive coupling C9 of the second zone of compensation ZB2 is provided by inter-digitated capacitor fingers C91 and C96 that are provided at layer 140 of the circuit board.
The capacitive coupling C10 of the first compensation zone ZC1 is provided by opposing capacitor plates C105 and C108 that are respectively provided at layers 140 and 142 of the circuit board. The capacitive coupling C11 of the second compensation zone ZC2 is provided by inter-digitated capacitor fingers C114 and C118 that are provided at layer 144 of the circuit board.
The capacitive coupling C12 of the zone of compensation ZC1 is provided by inter-digitated capacitor fingers C122 and C125 provided at layer 140 of the circuit board. The capacitive coupling C13 of the zone of compensation ZE1 is provided by parallel capacitor fingers C138 and C136 provided at layer 144 of the circuit board. The capacitive coupling C14 is provided by inter-digitated capacitor fingers C145 and C146 that are provided at layer 144 of the circuit board. The capacitive coupling C15 is provided by opposing capacitor plates C153 and C156 that are respectively provided at layers 140 and 142 of the circuit board. The capacitive couplings C16 is provided by opposing capacitor plates C164 and C165 that are respectively provided at layers 140 and 142 of the circuit board.
Referring still to
Referring still to
The circuit board is also provided with structures adapted for promoting manufacturing efficiency. For example, each set of opposing plate capacitors has a first plate that is larger than the corresponding second plate so that portions of the first plate extend outwardly beyond the boundaries of the second plate. This facilitates manufacturing efficiency because the exact registration between the plates is not required. Additionally, some of the plates are provided with stubs 910 that can be laser trimmed to exactly tune the capacitance so that the jack satisfies the relevant crosstalk requirements. The capacitance can also be tuned by using a combination of capacitor plates and parallel capacitor fingers at one zone of compensation. Furthermore, some of the tracks are provided with stubs 912 that can be used during design of the circuit board to manually vary the lengths of the tracks. In this way, the effect of varying certain track lengths can be empirically assessed.
The above specification provides examples of how certain inventive aspects may be put into practice. It will be appreciated that the inventive aspects can be practiced in other ways than those specifically shown and described herein without departing from the spirit and scope of the inventive aspects.
This application is a continuation of application Ser. No. 12/152,600, filed May 14, 2008, which is a divisional of application Ser. No. 11/402,544, filed Apr. 11, 2006, now U.S. Pat. No. 7,381,098, which applications are incorporated herein by reference, in their entirety.
Number | Name | Date | Kind |
---|---|---|---|
4766402 | Crane | Aug 1988 | A |
5663682 | Meline et al. | Sep 1997 | A |
5730622 | Olson | Mar 1998 | A |
5864089 | Rainal | Jan 1999 | A |
5963843 | Sit et al. | Oct 1999 | A |
5966648 | Ortberg et al. | Oct 1999 | A |
5997358 | Adriaenssens et al. | Dec 1999 | A |
6107578 | Hashim | Aug 2000 | A |
6120330 | Gwiazdowski | Sep 2000 | A |
6139371 | Troutman et al. | Oct 2000 | A |
6165018 | Arnett et al. | Dec 2000 | A |
6168474 | German et al. | Jan 2001 | B1 |
6231397 | de la Borbolla et al. | May 2001 | B1 |
6371793 | Doorhy et al. | Apr 2002 | B1 |
6379157 | Curry et al. | Apr 2002 | B1 |
6428362 | Phommachanh | Aug 2002 | B1 |
6441318 | Kiersh et al. | Aug 2002 | B1 |
6443777 | McCurdy et al. | Sep 2002 | B1 |
6449768 | Oftedahl | Sep 2002 | B1 |
6464541 | Hashim et al. | Oct 2002 | B1 |
6617947 | Stansbury | Sep 2003 | B1 |
6635821 | Loeffelholz et al. | Oct 2003 | B2 |
RE38519 | Doorhy et al. | May 2004 | E |
6736681 | Arnett | May 2004 | B2 |
D492292 | Ogren | Jun 2004 | S |
D495321 | Ogren | Aug 2004 | S |
6799989 | Doorhy et al. | Oct 2004 | B2 |
6830488 | Bush et al. | Dec 2004 | B2 |
6831527 | Loeffelholz et al. | Dec 2004 | B2 |
6840816 | Aekins | Jan 2005 | B2 |
6842348 | Lee | Jan 2005 | B2 |
D503399 | Ogren | Mar 2005 | S |
6866548 | Hashim | Mar 2005 | B2 |
6923673 | Doorhy et al. | Aug 2005 | B2 |
7043236 | Lee | May 2006 | B2 |
D526645 | Ogren | Aug 2006 | S |
7142414 | Lee et al. | Nov 2006 | B2 |
7186149 | Hashim | Mar 2007 | B2 |
7190594 | Hashim et al. | Mar 2007 | B2 |
7197294 | Anderson et al. | Mar 2007 | B2 |
7230192 | Loeffelholz et al. | Jun 2007 | B2 |
D547307 | Ogren | Jul 2007 | S |
7265300 | Adriaenssens et al. | Sep 2007 | B2 |
7381098 | Hammond, Jr. et al. | Jun 2008 | B2 |
7841909 | Murray et al. | Nov 2010 | B2 |
8550850 | Caveney et al. | Oct 2013 | B2 |
20030119372 | Aekins | Jun 2003 | A1 |
20030168235 | Loeffelholz et al. | Sep 2003 | A1 |
20040067693 | Arnett | Apr 2004 | A1 |
20040082227 | Hashim | Apr 2004 | A1 |
20040184247 | Adriaenssens et al. | Sep 2004 | A1 |
20050106946 | Doorhy et al. | May 2005 | A1 |
20050253662 | Seefried | Nov 2005 | A1 |
20050254223 | Hashim et al. | Nov 2005 | A1 |
20060014410 | Caveney | Jan 2006 | A1 |
20070195492 | Tamminen et al. | Aug 2007 | A1 |
20100167589 | Hammond, Jr. et al. | Jul 2010 | A1 |
Number | Date | Country |
---|---|---|
0 901 201 | Mar 1999 | EP |
Entry |
---|
U.S. Appl. No. 11/402,250, filed Apr. 11, 2006 entitled “Telecommunications Jack With Crosstalk Compensation Provided On A Multi-Layer Circuit Board,” 36 pages. |
U.S. Appl. No. 11/402,300, filed Apr. 11, 2006 entitled “Telecommunications Jack With Crosstalk Compensation And Arrangements For Reducing Return Loss,” 36 pages. |
European Search Report mailed Jul. 19, 2010. |
International Search Report mailed Oct. 26, 2007. |
Number | Date | Country | |
---|---|---|---|
20110318970 A1 | Dec 2011 | US |
Number | Date | Country | |
---|---|---|---|
Parent | 11402544 | Apr 2006 | US |
Child | 12152600 | US |
Number | Date | Country | |
---|---|---|---|
Parent | 12152600 | May 2008 | US |
Child | 13222788 | US |