HK1134169B - Telecommunications jack with crosstalk compensation and arrangements for reducing return loss - Google Patents

Description

Telecommunications jack with crosstalk compensation and means for reducing return loss

RELATED APPLICATIONS

This application is a PCT international patent application filed on 10.4.2007, with american national companies ADC Telecommunications, inc. (ADC Telecommunications company) as the designated applicant in all countries except the united states, and with american national Bernard Hammond, jr. and british national David P Murray and Ian r.george as the designated applicant in the united states, and claiming priority from U.S. utility patent application serial No. 11/402, 300 filed on 11.4.2006.

Technical Field

The present invention relates generally to telecommunications equipment. More particularly, the present invention relates to a telecommunications jack for compensating for near-end crosstalk.

Background

In the field of data communications, communication networks typically utilize techniques for maintaining or improving the integrity of signals transmitted over the network ("transmission signals"). To protect the integrity of the signals, the communication network should at least meet a compliance standard established by a standards committee, such as the Institute of Electrical and Electronics Engineers (IEEE). The compliance standard helps network designers provide a communication network that achieves at least a minimum level of signal integrity and some compatible standards.

One popular type of communication system uses twisted pair electrical wires to transmit signals. In twisted pair systems, information such as video, audio, and data is transmitted in a balanced signal over a pair of wires. The transmission signal is defined by the voltage difference between the wires.

Crosstalk can adversely affect signal integrity in twisted pair systems. Crosstalk is unbalanced noise caused by capacitive and/or inductive coupling between wires and twisted pair systems. As the signal frequency range increases, the effects of crosstalk become more problematic.

The effect of crosstalk also increases as the transmission signals are closer to each other. Therefore, the communication network includes areas that are particularly sensitive to crosstalk due to the proximity of the transmission signals. In particular, the communication network includes connectors that bring transmission signals into proximity of each other. For example, contacts of conventional connectors (e.g., jacks and plugs) used to provide interconnections in twisted pair telecommunications systems are particularly susceptible to crosstalk interference.

Fig. 1 shows a prior art panel 20 for use with a twisted pair telecommunications system. The faceplate 20 includes a plurality of receptacles 22. Each receptacle 22 includes a port 24 for receiving a standard telecommunications plug 26. For terminating each jack 22 to four twisted pairs of transmission wires. As shown in fig. 2, each receptacle 22 includes eight contact springs, position labeled 1-8. In use, contact springs 4 and 5 are connected to a first pair of wires, contact springs 1 and 2 are connected to a second pair of wires, contact springs 3 and 6 are connected to a third pair of wires, and contact springs 7 and 8 are connected to a fourth pair of wires. As shown in fig. 3, a typical plug 26 also has eight contact points (labeled 1-8) for interconnection with corresponding eight contact points of the receptacle 22 when the plug is inserted into the port 24.

To increase circuit density, it is necessary to bring the contact points of the socket and plug relatively close to each other. The contact areas of the jack and plug are therefore particularly sensitive to crosstalk. Also, some contacts are more sensitive to crosstalk than others. For example, the first and third pairs of contacts in the plug and receptacle are typically most susceptible to crosstalk.

To address the problem of crosstalk, the jack is designed with a contact spring configuration for reducing the capacitive coupling generated between the contact springs in order to minimize crosstalk. An alternative approach involves specifically generating a kind of crosstalk, the strength and phase of which is used to compensate or correct for the crosstalk induced at the plug or socket. Typically, crosstalk compensation may be provided by manipulating the position of the contact points or the conductors of the jack, or may be provided on a circuit board used to electrically connect the contact springs of the jack to the insulation displacement connectors of the jack.

The telecommunications industry is always striving for larger signal frequency ranges. As the transmission frequency range becomes wider, crosstalk becomes more problematic. Therefore, further development of crosstalk remediation is needed.

Disclosure of Invention

One aspect of the present disclosure relates to a circuit board layering configuration for supporting efficient crosstalk compensation in a telecommunications jack.

Another aspect of the present disclosure relates to compensating for the return loss caused by the crosstalk compensation device with a high impedance line.

Another aspect of the present disclosure relates to the use of capacitive coupling to overcome the problem of return loss caused by crosstalk compensation devices.

Another aspect of the present disclosure relates to a crosstalk compensation apparatus and a method for designing a crosstalk compensation apparatus.

Various other inventive aspects will be set forth in the description that follows. The inventive aspects may relate to individual features and 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.

Drawings

Fig. 1 is a perspective view of a prior art telecommunications panel;

FIG. 2 is a schematic view of a prior art socket;

FIG. 3 is an illustration of a prior art plug;

FIG. 4 is a front perspective view of a telecommunications jack featuring an example of an inventive aspect in accordance with the principles of the present disclosure;

FIG. 5 is an exploded view of the receptacle of FIG. 4;

FIG. 6 is a side view of the circuit board, insulation displacement connector and contact springs of the telecommunications jack of FIG. 4;

FIG. 7 is a side view of the circuit board, contact spring and insulation displacement connector of FIG. 6;

FIG. 8 is a top view of the circuit board and contact springs of FIG. 6;

FIG. 9 is a cross-sectional view of FIG. 8 along section line 9-9;

fig. 10 is a schematic diagram illustrating a crosstalk compensation scheme incorporated into the telecommunications jack of fig. 4;

fig. 11 is a schematic diagram showing a compensation arrangement for providing crosstalk compensation between the telecommunications jack pairs 4-5 and 3-6 of fig. 4;

fig. 12 is a schematic vector diagram illustrating a compensation arrangement for providing crosstalk compensation between the telecommunications jack pairs 1-2 and 3-6 of fig. 4;

FIG. 13 is a graph depicting how certain factors affect return loss in the receptacle of FIG. 4 over the entire frequency range;

fig. 14 is a trace overlay of a circuit board for use in the telecommunications jack of fig. 4;

FIG. 15 shows a front conductive layer of a circuit board for use in the telecommunications jack of FIG. 4;

fig. 16 shows a middle conductive layer of a circuit board for use in the telecommunications jack of fig. 4; and

fig. 17 shows a rear conductive layer of a circuit board for use in the telecommunications jack of fig. 4.

Detailed Description

Fig. 4 and 5 illustrate a telecommunications jack 120 (e.g., a telecommunications connector) having features in accordance with an example of an inventive aspect of the principles of the present disclosure. The receptacle 120 includes a dielectric housing 122 having a front piece 124 and a rear piece 126. The front and rear blocks 124, 126 may be interconnected by a snap-fit connection. The front block 124 defines a front port 128 that is sized and shaped to receive a conventional telecommunications plug (e.g., an RJ type plug such as an RJ45 plug). The rear block 126 defines an insulation displacement connector interface and includes a plurality of towers 130, the towers 130 being configured to receive insulation displacement connector blades/contacts. Socket 120 further includes a circuit board 132 that housesBetween front and rear pieces 124, 126 of the housing 122. A plurality of contact springs CS₁-CS₈Terminating to the front of the circuit board 132. IDC for multiple insulation displacement connector blades₁-IDC₈Terminating behind the circuit board 132. Contact spring CS₁-CS₈Extends into the front port 128 and is adapted to electrically connect to corresponding contact points provided on the plug when the plug is inserted into the front port 128. Insulation displacement connector blade IDC₁-IDC₈Is disposed within the tower 130 of the rear block 126 of the housing 122. The circuit board 132 has a trace T₁-T₈(e.g., traces, see FIGS. 14-17) that respectively contact the spring CS₁-CS₈IDC electrically connected to insulation displacement connector blade₁-IDC₈。

In use, the IDC is connected by inserting the wire into the insulation displacement connector blade pair₁-IDC₈To electrically connect the electric wire to the contact spring CS₁-CS₈. Blade pair IDC when inserting wire into insulation displacement connector₁-IDC₈In between, the blade passes through the insulation of the wire and makes electrical contact with the intermediate conductor of the wire. Thus, electrically connected to the contact spring CS by traces on the circuit board₁-CS₈IDC of insulation displacement connector₁-IDC₈A contact spring CS for electrically connecting the twisted pair wires to the socket 120 is provided₁-CS₈Is effective.

The contact spring CS is more clearly shown in fig. 6-8₁-CS₈. Contact spring CS₁-CS₈Preferably, provides some initial crosstalk compensation at the receptacle 120.

Circuit board 132 of receptacle 120 is preferably a multi-layer circuit board. For example, fig. 9 shows a circuit board 132 that includes a first conductive layer 140, a second conductive layer 142, and a third conductive layer 144. The first and second conductive layers 140, 142 are separated by a first dielectric layer 146. The second and third conductive layers 142, 144 are separated by a second dielectric layer 148. The first conductive layer 140 is located on the front side of the circuit board 132 toAnd a third conductive layer 144 is located on the back of the circuit board 132. Contact spring CS₁-CS₈Mounted on the front of the circuit board 132 and insulation displacement connector blades IDC₁-IDC₈Mounted behind the circuit board 132. The vias extend to the first and second dielectric layers 146, 148 to provide electrical connections between the conductive layers 140, 142, and 144. By conductive tracks T₁-T₈(see fig. 14-17) to electrically define the conductive layers 140, 142, and 144. Tracks T are formed (e.g., etched or provided) on the dielectric layers 146, 148₁-T₈。

The circuit board 132 preferably includes structure for compensating for near-end crosstalk occurring at the jack/plug interface. In some embodiments, the structure for compensating for near-end crosstalk includes providing capacitive coupling between the first and second conductive layers 140, 142. In a preferred embodiment, the capacitive coupling is provided by a combination of opposing, generally parallel capacitive plates located at the first and second conductive layers 140, 142. In order to increase the strength of the capacitive coupling provided between the capacitive plates of the first and second conductive layers 140, 142, it is desirable to make the first dielectric layer 146 relatively thin. For example, in some embodiments, the thickness t of the first dielectric layer 146₁And may be 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 t₁And may 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 t₁Approximately 0.002 inches.

In some embodiments, the first dielectric layer 146 may be composed of a material having a relatively low dielectric constant. As used herein, the dielectric constant is the dielectric constant relative to air. In some embodiments, the dielectric constant of the first dielectric layer 146 may be equal to or less than about 5. In other embodiments, the dielectric constant of the first dielectric layer 146 may be less than or equal to about 4 or less than or equal to about 3. An exemplary material for making the first dielectric layer 146 is a fire-resistant 4(FR-4) circuit board material. FR-4 circuit board material is a composite of epoxy resin reinforced with a mesh fiberglass mat.

Second dielectric layer 148 is preferably used to insulate third conductive layer 144 from first and second conductive layers 140, 142. The second dielectric layer 148 may have a thickness t that is equal to the thickness t of the first dielectric layer 146₁Different thickness t₂. 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 other embodiments, the second dielectric layer 148 is at least 10 times thicker or at least 20 times thicker than the first dielectric layer 146. In one exemplary embodiment, the thickness t of second dielectric layer 148₂In the range of 0.050 inches to 0.055 inches. In another example embodiment, the thickness t of the second dielectric layer 148₂In the range of 0.040 inch to 0.050 inch.

The second dielectric layer 148 may also be made of a different material than the first dielectric layer 146. In certain embodiments, the second dielectric layer 148 may have different dielectric properties compared to the first dielectric layer 146. For example, in certain embodiments, the dielectric constant of the first dielectric layer 146 may be greater (e.g., at least 1.5 times greater or at least 2 times greater) than the dielectric constant of the second dielectric layer 148. In one example, the second dielectric layer 148 may be fabricated from a material such as FR-4. Of course, it will be appreciated that other suitable materials may be used.

The circuit board 132 includes a plurality of capacitive couplings of strength and location suitable for compensating 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, trace T is provided_4-5And a track T_3-6Three interdependent compensation zones are used. As shown in FIG. 10, the three interdependent compensation zones include a first compensation zone Z_A1A second compensation zone Z_A2And a third compensation zone Z_A3. First compensation zone Z_A1Comprising a track T₃And a track T₅Capacitive coupling C1 between and track T₄And a track T₆C2 between. Second compensation zone Z_A2Comprising a track T₃And a track T₄Capacitive coupling C3 between and track T₅And a track T₆C4 between. Third compensation zone Z_A3Comprising a track T₃And a track T₅Capacitive coupling C5 between and track T₄And a track T₆C6 between.

Fig. 11 is a schematic diagram of a compensation arrangement for providing crosstalk compensation between 4-5 and 3-6 pairs. As shown in fig. 11, the compensation means comprises a first vector 100, a second vector 102, a third vector 102 and a fourth vector 106. The first vector 100 and the third vector 104 have positive polarity, while the second vector 102 and the fourth vector 106 have negative polarity. The first vector 100 has a strength M and corresponds to crosstalk introduced at the plug. The second vector 102 has an intensity of-3M and corresponds to the first compensation zone Z_A1To the induced crosstalk. The third vector 104 has an intensity of 3M and corresponds to the second compensation zone Z_A2To the induced crosstalk. The fourth vector 106 has an intensity-M and corresponds to a third compensation zone Z_A3To the induced crosstalk. It will be appreciated that each vector is the sum of the total crosstalk provided at each respective compensation zone, with the vector being located at the middle or midpoint of the compensation zone.

In the design of the compensation scheme of FIG. 11, a number of factors are taken into account when determining the location of the compensation zone. One factor includes the necessity to allow signals to travel in both directions (i.e., forward and reverse) in the traces on the circuit board. To allow forward and reverse transmission through the circuit board, the compensation scheme preferably has a forward and reverse symmetrical configuration. It is also desirable that the compensation scheme provide optimized compensation over a relatively wide transmission frequency range. For example, in one embodiment, performance is optimized for a frequency range from 1MHz to 500 MHz. It is also desirable that the compensation means take into account the phase shift caused by the time delay due to the signal travelling between the compensation zones.

In order to minimize the effect of phase shift in the compensation means, it is preferred to place the second vector 102 as close as possible to the first vector 100. In fig. 11, the time between the first vector 100 and the second vector 102 is setThe inter-delay is shown as x. In one exemplary embodiment, for a transmission speed of 3 × 10⁸Meters per second signal, x may be about 10 picoseconds.

To maintain forward and reverse symmetry, the time delay between the third vector 104 and the fourth vector 106 is preferably about the same as the time delay between the first vector 100 and the second vector 102. As shown in fig. 11, the time delay between the third and fourth vectors is shown as x.

The time delay y between the second vector 102 and the third vector 104 is chosen such that it best optimizes the overall compensation effect of the compensation scheme over a relatively wide frequency range. The amount of compensation provided by the different frequencies is varied by varying the time delay y between the second vector 102 and the third vector 104 to vary the phase angle of the first and second compensation zones. In one example embodiment, to design the time delay y, the value of the time delay y is typically initially set to a value equal to x (e.g., the time delay between the first vector 100 and the second vector 102). The system is then tested or simulated to determine if an acceptable level of compensation is provided over the entire frequency range of the signal intended for use. If the system meets the crosstalk requirements by setting the value y equal to x, no further adjustment of the value y is required. If the compensation scheme does not meet the crosstalk requirements at higher frequencies, the time delay y can be shortened to improve performance at higher frequencies. If the compensation scheme does not meet the crosstalk requirements at lower frequencies, the time delay y can be increased to improve the performance of the lower frequencies. It is to be appreciated that the time delay y can be varied without changing the symmetry of the forward and reverse directions.

It has been determined that when the strength of the second and third vectors 102, 104 are-3M and 3M, respectively, the distance y is preferably greater than the distance x to provide optimized crosstalk compensation. However, if the strength of the vectors 102, 104 is reduced below-3M and 3M (e.g., to-2.7M and 2.7M), then the distance y is preferably less than the distance x to provide optimized crosstalk compensation.

Between the 1-2 and 3-6 pairs, cross-talk can also be a problem. In particular toOn the track T₂And a track T₃Substantial cross-talk can be generated. As shown in fig. 10, two-zone compensation means are used to compensate for crosstalk. The compensation means of the two zones comprise a first compensation zone Z_B1And a second compensation zone Z_B2. First compensation zone Z_B1Comprising a track T₁And a track T₃Capacitive coupling C7 between and track T₂And a track T₆C8 between. Second compensation zone Z_B2Comprising a track T₁And a track T₆C9 between. Fig. 12 is a vector diagram showing a compensation arrangement for use between pairs 1-2 and 3-6. As shown in fig. 12, three crosstalk vectors are considered. The first crosstalk vector 110 represents the crosstalk generated at the plug. The second vector 112 represents the first compensation zone Z_B1To provide crosstalk. The third vector 114 represents the second compensation zone Z_B2The resulting crosstalk. The first and third vectors 110, 114 have positive polarity and an intensity of about N. The second vector 112 has a negative polarity and a strength of about 2N. In the test of the compensation means provided between the tracks 1-2 and 3-6, it is determined that the second compensation zone Z is present_B2Track T of₂And a track T₃Without providing discrete capacitive coupling therebetween, improved results are obtained. However, in an alternative embodiment, at track T₂And a track T₃May also maintain symmetry by providing discrete capacitive coupling therebetween. It will be appreciated that M (shown in fig. 11) is typically much larger in intensity than N (shown in fig. 12).

Compensation means for both zones may also be used to provide crosstalk compensation between the 4-5 and 7-8 pairs. For example, FIG. 10 depicts a first compensation zone Z of compensation between pairs 4-5 and 7-8_C1And a second compensation zone Z_C2. First compensation zone Z_C1Comprising a track T₈And a track T₅C10 between. Second compensation zone Z_C2Including capacitive coupling C11 between traces 8 and 4. First and second compensation zones Z_C1And Z_C2There may be a sequence of intensities 1-2-1 similar to the compensation arrangement of the two zones described in relation to tracks 1-2 and 3-6.

Instead of the multi-zone compensation means described above, a plurality of single-zone compensations may also be used. For example, zone Z_D1Is included in the track T₂And a track T₅The capacitive coupling provided therebetween C12. By running on the track T₆And T₈C13 to provide another single zone compensation Z_E1. Track T₅And a track T₆With another capacitive coupling C14 compensating for unwanted cross-talk generated within the circuit board itself.

To solve the cross-talk problem between the 4-5 and 3-6 pairs, a relatively large amount of capacitance is used. This large amount of capacitance can result in a jack with unacceptable levels of return loss. Several methods may be used to improve the return loss performance. For example, the trace T of the circuit board can be increased₃、T₄、T₅And T₆To improve return loss performance. It is preferable to increase the impedance of the tracks over the first, second and third compensation zones and after the first, second and third compensation zones. Can be minimized by the trace T₃、T₄、T₅And T₆To increase the impedance. Exemplary cross-sectional areas of the traces are in the range of 13 to 16 square mils (1 mil — 0.001 inch). It is also possible to maintain the track T by routing the track T₃And T₄Between and track T₅And T₆With a relatively large spacing therebetween to increase impedance. In one embodiment, trace T₃-T₆Is greater than 100 ohms. In another embodiment, the impedance is equal to or greater than 120 ohms. In another embodiment, the track T₃-T₆Is equal to or greater than 150 ohms. In a further embodiment, track T₃-T₆Is equal to or greater than 175 ohms. In a further embodiment, track T₃-T₆Is equal to or greater than 200 ohms.

Or by adding on spring CS₃-CS₆And insulation displacement connector IDC₃-IDC₆In the meantimeSupply track T₃-T₆To increase the length of the track T₃-T₆The impedance of (c). In some embodiments, the track T can be used₃-T₆To provide such a length increase. In some embodiments, the contact spring CS is positioned at an extension₃-CS₆And their corresponding insulation displacement connector blades IDC₃-IDC₆Between the tracks T₃-T₆In time, the track T can be arranged₃-T₆To spring CS₃-CS₆And their corresponding insulation displacement connector blades IDC₃-IDC₆At least 1.5 times or at least twice the linear distance therebetween. In other embodiments, the track T₃-T₆May be at least a contact spring CS₃-CS₆And their corresponding insulation displacement connector blades IDC₃-IDC₆Three or four times the linear distance therebetween.

Also by increasing/maximizing the track T₄And a track T₅Space between and track T3 and track T₆Spacing therebetween to increase track T₃-T₆The impedance of (c). In one embodiment, due to the tracks T₄And T₅Secondary contact spring CS₄And CS₅Extend outward, so that the track T₄And T₅Away from each other and then due to the tracks T₄And T₅IDC approaching insulation displacement connector blade₄And IDC₅And re-converge. Therefore, the track T will be routed₄And T₅Are placed relatively far apart from each other. In one embodiment, at track T₄And T₅Define a spacing of at least 0.1 inches therebetween, measured in a direction parallel to the width W of the circuit board. In certain embodiments, the spacing represents at least 1/4 of the width of the circuit board. It is to be appreciated that tracks T can be provided₃And a track T₆With similar spacing therebetween to increase impedance.

Referring again to fig. 10, it is also possible to provide the track T with a track₃And a track T₆BetweenProviding capacitive coupling C15 and at track T₄And a track T₅A capacitive coupling C16 is provided to improve return loss. In order for the capacitive couplings C15 and C16 to improve and not deteriorate return loss, the couplings C15, C16 should be placed far enough away from the three compensation zones Z_A1-Z_A3So that the phase of the capacitance introduced by coupling C15 and C16 is along track T at higher frequencies₃-T₆Counteracting the return loss.

Fig. 13 is a graph depicting how different factors affect return loss in a jack over the entire frequency range. In the figure, return loss is plotted on the y-axis and frequency is plotted on the x-axis. Line 400 represents the maximum allowable return loss over the entire frequency range. Line 402 represents the trace T when a standard 100 ohm trace of standard length is used to provide an electrical path between the contact spring and the insulation displacement connector blade₃-T₆The reflux loss occurs in (1). Line 404 shows the return loss that occurs in a standard length trace when that trace is replaced with a high impedance line. As shown by line 404, the return loss is improved as compared to line 402, but again does not meet the level of return loss set by line 400. Line 406 shows the return loss in the trace as the length of the high impedance trace extends between the contact spring and the insulation displacement connector blade. As shown by line 406, the lengthened, high impedance trace greatly improves return loss at lower frequencies, but worsens return loss at higher frequencies (e.g., frequencies greater than 300 MHz). Lines 408A, 408B, and 408C show track T being₃And a track T₆Inter and track T₄And a track T₅Capacitive coupling C15 and C16 are added between the two contact springs CS₃-CS₆And insulation displacement connector blade IDC₃-IDC₆With the influence of relatively long, high impedance traces. In order to comply with the return loss level set by the line 400, it is important that the capacitive coupling distance compensation zone Z_A1-Z_A3The distance of the center of (c). If the capacitive couplings C15, C16 are too close to the compensation zone ZA₁-ZA₃Electricity (D) fromCapacitive coupling, then the return loss will fail at low frequencies (as shown by line 408A). If the capacitive coupling C15, C16 is placed away from the compensation zone Z_A1-Z_A3Too far, the return loss failure will occur at a higher frequency, as shown by line 408C. By selecting the capacitive couplings C15, C16 and the compensation zone Z_A1-Z_A3The distance is such that the capacitive coupling C15, C16 effectively cancels the return loss at frequencies in the 200-500MHz range, as shown by line 408B, the receptacle can meet the return loss parameter set by line 400 over the entire frequency range.

Fig. 14-17 illustrate exemplary circuit board layouts for implementing the compensation arrangement of fig. 10. Fig. 15-17 illustrate front, middle and rear conductive layers 140, 142 and 144, respectively, of the circuit board 132. Fig. 14 is an overlay of the three conductive layers 140, 142, and 144. The circuit board 132 defines contact springs CS₁-CS₈308 to contact the spring CS₁-CS₈Terminating to the circuit board 132. The circuit board also defines IDCs for receiving the insulation displacement connector blades respectively₁-IDC₈Opening 401 of the connector 408 for insulation displacement connector blade IDC₁-IDC₈Is terminated to a circuit board. Vias extend through the circuit board for electrically interconnecting the traces between layers 140, 142, and 144. For example, via V_6A、V_6BAnd V_6CFor interconnecting tracks T₆At portions of different layers 140, 142, and 144. Also, via V_5AAnd V_5BFor interconnecting tracks T₅At portions of different layers 140, 142, and 144. Furthermore, via hole V_4AAnd V_4BFor interconnecting tracks T₄Portions at different layers 140, 142, and 144. Further, via V₃For interconnecting tracks T₃At portions of different layers 140, 142, and 144. Providing tracks T on a single layer of the circuit board 132₁、T₂、T₇And T₈Each of which. For example, providing track T at layer 140₁And T₂And track T is provided at layer 144₇And T₈。

Referring to fig. 14-16, by providing opposing capacitive plates C1 at layers 140 and 142, respectively₅And C1₃To provide a first compensation zone Z_A1C1. By opposing capacitor plates C2 provided at layers 140 and 142, respectively₄And C2₆To provide a first compensation zone Z_A1C2. By opposing capacitor plates C3 provided at layers 140 and 142, respectively₄And C3₃To provide a second compensation zone Z_A2C3. By opposing capacitor plates C4 provided at layers 140 and 142, respectively₅And C4₆To provide a second compensation zone Z_A2C4. By opposing capacitor plates C5 provided at layers 140 and 142, respectively_5AAnd C5_3ATo provide a third compensation zone Z_A3C5. Or by finger C5 of an inter-digital capacitor provided at layer 144_5BAnd C5_3BTo provide capacitive coupling C5. By opposing capacitor plates C6 provided at layers 140 and 142, respectively_6AAnd C6_4ATo provide a third compensation zone Z_A3C6. Or by interdigital capacitor finger C6 provided at layer 144_6BAnd C6_4BTo provide capacitive coupling C6.

By opposing capacitor plates C7 provided at layers 140 and 142, respectively, of the circuit board₁And C7₃To provide a first compensation zone Z_B1C7. By opposing capacitor plates C8 provided at layers 140 and 142, respectively, of the circuit board₂And C8₆To provide a first compensation zone Z_B1C8. By providing interdigitated capacitor fingers C9 at layer 140 of the circuit board₁And C9₆To provide a second compensation zone Z_B2C9.

By opposing capacitor plates C10 provided at layers 140 and 142, respectively, of the circuit board₅And C10₈To provide a first compensation zone Z_C1C10. By interdigital capacitor fingers C11 provided at layer 144 of the circuit board₄And C11₈To provide a second compensation zone Z_C2C11.

By interdigital capacitor fingers C12 provided at layer 140 of the circuit board₂And C12₅To provide a compensation zone Z_D1C12. By parallel capacitor finger C13 provided at layer 144 of the circuit board₈And C13₆To provide a compensation zone Z_E1C13. By interdigitated capacitor fingers C14 provided at layer 144 of the circuit board₅And C14₆To provide capacitive coupling C14. By opposing capacitor plates C15 provided at layers 140 and 142, respectively, of the circuit board₃And C15₆To provide capacitive coupling C15. By opposing capacitor plates C16 provided at layers 140 and 142, respectively, of the circuit board₄And C16₅To provide capacitive coupling C16.

Referring again to FIGS. 14-17, note that track T will be routed₄And T₅The wires are routed away from each other over most of their length in order to increase the impedance of the traces to account for return loss. Similarly, track T will be routed₃And T₆The wires are routed away from each other over most of their length to increase the impedance of the traces to account for return loss. Also note that track T₃-T₆It is also preferable to have an extended length to increase resistance to improve return loss performance. For example, referring to FIG. 14, trace T₃With contact from spring CS₃IDC of corresponding insulation displacement connector blade extending to it₃And bent or curved into a loop. Track T₃Also includes a loop 900 for further increasing the track T₃Length of (d). Referring again to FIG. 14, trace T₄With contact from spring CS₄IDC of corresponding insulation displacement connector blade extending to it₄And bent or curved into a loop. With further reference to FIG. 14, trace T₅Follow the contact spring CS₅IDC of corresponding insulation displacement connector blade extending to it₅And bent back and forth. In addition, the track T₅There is a loop back 902 for further increasing the length of the trace. Referring again to FIG. 14, trace T₆With contact from spring CS₆IDC of corresponding insulation displacement connector blade extending to it₆And bent or curved into a loop.

Referring again to fig. 14, the routing configuration of the traces on the circuit board also places the capacitive couplings C15 and C16 relatively far from the three compensation zones Z_A1-Z_A3At the center of the provided capacitance. For example, to provide this additional distance, loop extensions 904 and 906 have multiple loops to increase the capacitive coupling C15, C16 and compensation zone Z_A1-Z_A3The spacing of the centers of the provided capacitances.

The circuit board also has a structure for improving manufacturing efficiency. For example, the first plate of each set of opposing plate capacitors is larger than the corresponding second plate such that a portion of the first plate extends outwardly beyond the boundary of the second plate. This facilitates increased manufacturing efficiency since accurate alignment between the plates is not required. In addition, some plates have stubs 910 that can be laser trimmed to accurately tune the capacitance so that the jack can meet the associated crosstalk requirements. The capacitance can also be tuned using a combination of capacitor plates and parallel capacitor fingers of one compensation zone. Also, some sockets have pins 912, which pins 912 may be used during design of the circuit board to manually change the length of the socket. In this way, the effect of varying certain track lengths can be estimated empirically.

The above description provides examples of how certain inventive aspects may be put into practice. It will be appreciated that the inventive aspects may be practiced otherwise than as specifically illustrated and described without departing from their spirit or scope.

Claims (18)

1. A telecommunications jack for use in a twisted pair system, the telecommunications jack comprising:

a housing defining a port for receiving a plug;

a plurality of contact springs for making electrical contact with the plug when the plug is inserted into the port of the housing;

a plurality of wire termination contacts for terminating wires to the socket;

a circuit board including conductive traces for electrically connecting the contact springs to the wire terminal contact points; and

a crosstalk compensation device for providing crosstalk compensation between selected traces of the circuit board, the selected traces including two pairs of traces, wherein each pair of traces diverge from each other as the traces extend from their corresponding contact springs to their corresponding wire terminal contact points, the selected traces further having a high impedance portion with an impedance greater than 100 ohms, wherein between each pair of traces a capacitive coupling is provided at a location between the crosstalk compensation device and the wire terminal contact points, the capacitive coupling being positioned sufficiently far from the crosstalk compensation device to reduce return loss of the selected traces for signal frequencies in the range of 200 and 500 MHz.

2. The telecommunications jack of claim 1, wherein the impedance of the high impedance portion of the selected trace is greater than 150 ohms.

3. The telecommunications jack of claim 1, wherein the high-impedance portion of the selected trace has an impedance greater than 175 ohms.

4. The telecommunications jack of claim 2, wherein the high impedance portion of the selected trace extends from the crosstalk compensation device to the wire termination contact.

5. The telecommunications jack of claim 2, wherein the selected traces include two pairs of traces, and wherein the crosstalk compensation device includes at least three compensation zones provided between the two pairs of traces.

6. The telecommunications jack of claim 2, wherein the high impedance portion of the selected trace has a length that is at least 1.5 times the linear distance between the contact spring and the wire termination contact point.

7. The telecommunications jack of claim 2, wherein the high impedance portion of the selected trace has a length that is at least 2 times the linear distance between the contact spring and the wire termination contact point.

8. The telecommunications jack of claim 2, wherein the high impedance portion of the selected trace has a length that is at least 3 times the linear distance between the contact spring and the wire termination contact point.

9. The telecommunications jack of claim 2, wherein the high impedance portion of the selected trace has a loop back portion between the crosstalk compensation device and the wire termination contact for increasing the length of the high impedance portion.

10. The telecommunications jack of claim 9, wherein the loop portion has a curved configuration.

11. The telecommunications jack of claim 2, wherein:

the plurality of contact springs includes a first contact spring, a second contact spring, a third contact spring, a fourth contact spring, a fifth contact spring, a sixth contact spring, a seventh contact spring, and an eighth contact spring arranged in series for making electrical contact with the plug when the plug is inserted into the port of the housing;

the plurality of wire terminal contact points includes a first wire terminal contact point, a second wire terminal contact point, a third wire terminal contact point, a fourth wire terminal contact point, a fifth wire terminal contact point, a sixth wire terminal contact point, a seventh wire terminal contact point, and an eighth wire terminal contact point for terminating a wire to the receptacle;

the circuit board comprises a first wire, a second wire, a third wire, a fourth wire, a fifth wire, a sixth wire, a seventh wire and an eighth wire, which are respectively used for electrically connecting the first contact spring, the second contact spring, the third contact spring, the fourth contact spring, the fifth contact spring, the sixth contact spring, the seventh contact spring and the eighth contact spring to the first wire terminal contact point, the second wire terminal contact point, the third wire terminal contact point, the fourth wire terminal contact point, the fifth wire terminal contact point, the sixth wire terminal contact point, the seventh wire terminal contact point and the eighth wire terminal contact point;

providing a first compensation region comprising a first capacitive coupling and a second capacitive coupling, the first capacitive coupling being generated between the third trace and a fifth trace, the second capacitive coupling being generated between the fourth trace and a sixth trace;

providing a second compensation region comprising a third capacitive coupling and a fourth capacitive coupling, the third capacitive coupling being generated between the third trace and a fourth trace, the fourth capacitive coupling being generated between the fifth trace and a sixth trace;

providing a third compensation region comprising a fifth capacitive coupling and a sixth capacitive coupling, the fifth capacitive coupling being generated between the third trace and a fifth trace, the sixth capacitive coupling being generated between the fourth trace and a sixth trace; and

the selected wires include the third wire, the fourth wire, the fifth wire and the sixth wire.

12. The telecommunications jack of claim 11, wherein the high impedance portion of the selected trace has a length that is at least 1.5 times the linear distance between the contact spring and the wire termination contact point.

13. The telecommunications jack of claim 11, the high impedance portion of the selected trace having a loop back portion between the crosstalk compensation device and the wire termination contact for increasing the length of the high impedance portion.

14. The telecommunications jack of claim 11, wherein capacitive couplings are provided between the fourth and fifth traces and between the third and sixth traces at locations between the crosstalk compensation device and the wire termination contact for reducing return loss of the selected trace for signal frequencies in the range of 200 and 500 MHz.

15. A telecommunications jack for use in a twisted pair system, the telecommunications jack comprising:

a housing defining a port for receiving a plug;

a plurality of contact springs for making electrical contact with the plug when the plug is inserted into the port of the housing;

a plurality of wire termination contacts for terminating wires to the socket;

a circuit board including conductive traces for electrically connecting the contact springs to the wire terminal contact points, the conductive traces including a first pair of traces and a second pair of traces for carrying twisted pair signals, the first pair of traces including a first trace and a second trace, and the second pair of traces including a third trace and a fourth trace;

a crosstalk compensation device for providing crosstalk compensation between the first pair of traces and the second pair of traces; and

and the capacitive coupling comprises a first capacitive coupling between the first trace and the second trace and a second capacitive coupling between the third trace and the fourth trace, and the first capacitive coupling and the second capacitive coupling are arranged far enough away from the crosstalk compensation device so as to reduce the return loss of the first trace and the second trace for the signal frequency within the range of 200 and 500 MHz.

16. The telecommunications jack of claim 15, wherein the plurality of contact springs includes eight contact springs arranged in series at position one, position two, position three, position four, position five, position six, position seven, and position eight, wherein the first pair of traces corresponds to the contact springs at position four and position five and the second pair of traces corresponds to the contact springs at position three and position six.

17. The telecommunications jack of claim 15, wherein the first capacitive coupling is formed between first and second spaced-apart capacitive plates and the second capacitive coupling is formed between third and fourth spaced-apart capacitive plates.

18. A method of compensating for crosstalk and return loss in a conductive pair for carrying a twisted pair signal, the conductive pair comprising a first conductive trace and a second conductive trace, the method comprising:

applying a crosstalk compensation capacitance provided by a crosstalk compensation device to the first and second conductive traces in one or more compensation regions to reduce crosstalk; and

applying a return loss compensation capacitance between the first trace and the second trace at a location sufficiently far from the crosstalk compensation device to reduce return loss.