This application claims the benefit of priority under 35 U.S.C. 119(e) to the filing date of Cyr, U.S. provisional patent application No. 61/300,738 entitled “Reduced Crosstalk in a Multi-Channel Conductive Body Connector,” which was filed Feb. 2, 2010, and is incorporated herein by reference in its entirety.
This disclosure relates to crosstalk in multi-channel connectors.
Connectors are present in many electronic applications and can operate to join electrical circuits or signals together. Due to the electrical properties, alternating electrical current (AC) or other time-varying current distributes itself within a conductor so that current density near the surface of the conductor is greater than at its core. This electromagnetic phenomenon is often referred to as the skin effect. The skin effect allows a single conductive body to be used in connectors with multiple radio frequency (RF) channels because return ground currents will flow along an inside surface of an internal cavity into a respective ground pin. The conductive body connector attaches to the end of the cavity with interfaces such as an electronic circuit board, cable, or another connector. However, as the density for RF connectors increases, the problem of crosstalk becomes increasingly problematic.
Crosstalk is a phenomenon that produces an undesirable effect from one circuit or channel of an electrical transmission system to another circuit or channel. Crosstalk can be caused by capacitive, inductive or conductive coupling. In telecommunications and telephony, crosstalk can be signals induced on a connection that include components of speech or signal tones from another connection. In analog circuitry, crosstalk can distort nearby signals at the source or destination of the transmission. In wireless communications, crosstalk can be co-channel or adjacent-channel interference. In integrated circuit design, crosstalk can be an electrical signal affecting another nearby electrical signal in many environments such as, for example, a circuit board, an integrated circuit, a handheld computational device, a transmission cable, or a connector.
Return current induced crosstalk in a multi-channel conductive body connector is generated when the return ground current of one channel flows to the signal pin and/or ground pin of another channel. This return current induced crosstalk is exacerbated by a conductive path available at the bottom edge of the conductive body connector, which can be exacerbated further as connector density increases or as a result of imperfect ground pin contacts. Although methods exist to remedy this problem, such as reducing impedance (including but not limited to effective resistance) to the ground pin(s), creating independent conductive bodies, or placing an insulator on the conductive connector body, such methods can be ineffective and/or cost prohibitive.
Like reference numbers and designations in the various drawings indicate like elements.
In some implementations of this disclosure, apparatus and methods can operate to reduce crosstalk in a multi-channel conductive body connector by reducing current flow between ground and/or signal pins. The connector can include elements such as a conductive body, signal pins, signal pin insulators, ground pin(s), and selectively resistive material used to reduce crosstalk. In some implementations, the connector can be manufactured with multiple channels in a conductive body. A multi-channel connector includes two or more channels within a single conductive body and/or connector. In some implementations, the conductive body can be comprised of a single material. The conductive body can be made of a conductive metal such as, for example, zinc or brass alloys and plated with nickel or tin alloys and/or finished in palladium, silver and/or gold. In other implementations, the conductive body can be made of a selectively resistive material and plated with a conductive material to enable signal transmission while retaining an un-plated portion of the selectively resistive conductive body to operate to reduce crosstalk in a multi-channel conductive body connector.
The multi-channel connector includes at least two signal pins embedded inside the conductive body and operable to transmit or receive signals. The signal pins can be made of a conductive metal such as, for example, copper alloy plated in tin, nickel, palladium, silver and/or gold. A signal pin can be surrounded by an embedded signal pin insulator operable to provide mechanical support to the center single pin conductor. The signal pin insulator material can be, for example, Teflon, nylon polyester, polystyrene, or another plastic material. Moreover, a signal pin can have one or more associated embedded ground pin formed from or connected to the conductive body and operable to transfer return ground current from a channel. In some implementations, the ground pin can be made of a separate material than the conductive body and attached to the conductive body during manufacturing. In other implementations, the ground pin can be formed from the conductive body. In still further implementations, the insulator can be an air gap separating the conductive body and signal pins.
Connector design often provides a path for return ground current to transfer back to the transmission source. In a system or apparatus using AC electrical current (in which the flow rate of electric charge alternates in direction) or other time-varying electrical current (in which the flow rate of electric charge changes over time), the skin effect dominates current flow and associated crosstalk. Thus, in this disclosure AC electrical current includes but is not limited to 60 Hz, 110/120V AC power source commonly used in North America and non-power source time-varying currents. In addition, other time-varying current sources that change the direction and/or magnitude of current flow may benefit from this disclosure. These benefits are especially useful for systems including but not limited to electric signal communication systems that induce crosstalk on nearby electric signal communication systems, media, or channels.
A selectively resistive material can be applied between selected signal pins and/or ground pin(s) and operate to reduce crosstalk by increasing the effective resistance between signal pins and/or ground pin(s). The effective resistance of the selectively resistive material can include effective resistances greater than the effective resistance of the conductive body and less than the effective resistance of the insulator material. The selectively resistive material may vary based on the effective resistance of the conductive body and/or ground pin(s). In some implementations, the selectively resistive material can be embedded into the conductive body. In other implementations, the selectively resistive material can be applied on the surface of the connector during the manufacturing process. In still further implementations, the selectively resistive material can be an epoxy, metal plate, or coating. In alternative implementations, the conductive body can be made of the selectively resistive material and coated and/or plated with a more conductive material in areas that can allow the area of un-plated resistive material to reduce crosstalk.
In this example, two signal pins 110a-b are embedded in the conductive body 105. These signal pins 110a-b can operate to transmit and/or receive data in the form of electrical signals. The signal pins 110a-b can be comprised of aluminum, copper, titanium, iron, nickel alloy, other metal, or another substantially conductive material. Signal pin insulators 115a-b can be embedded in the conductive body 105 and surround signal pins 110a-b. Signal pin insulators 115a-b can operate to maintain signal quality and shield external noise or interference. Signal pin insulators 115a-b also can operate to separate the signal pin from the ground and/or other signals and also can provide mechanical support. Signal pin insulators 115a-b can be made of insulative materials including, for example, nylon, foam, polyester, or fiberglass. It should be understood that the signal pin insulators 115a-b are not required for the connector.
Two ground pins 120a-b can be embedded in the conductive body 105 of the connector 100 and can operate to transfer return ground currents 125a-b. The ground pin(s) 120a-b can be formed from the conductive body 105 or can be made of a separate material such as aluminum, copper, titanium, iron, or nickel alloy, and subsequently connected to the conductive body 105. In some implementations, one ground pin can operate to transfer return ground currents 125a-b.
The signal pins 110a-b can operate to transmit and/or receive signals to/from one end of the connector to the device, connector, or apparatus to the other end. In addition, the ground pin(s) 120a-b can operate to transfer return ground current 125a-b from the signal transmission. A return ground current 125a from one channel is intended to flow to its respective ground pin 120a along the surface of the conductive body 105 based upon the skin effect. Correspondingly, the adjacent channel return ground current 125b is intended to flow to its respective ground pin 120b.
Return current induced crosstalk 130a-b occurs when return ground current from one channel (e.g., aggressor channel 135) flows to an adjacent channel's signal pin 110b and/or ground pin 120b (e.g., victim channel 140). The resulting crosstalk 130a-b can affect signal quality and transmission. In some implementations, return ground current can be shared among multiple signal pins and a single ground pin or multiple ground pins. In alternative implementations, the conductive body 105 can be made of the selectively resistive material and coated and/or plated with a more conductive material in areas that can allow the area of un-plated resistive material to reduce crosstalk.
Return current induced crosstalk 245 (e.g., crosstalk 130a-b of
In some implementations, two signal pins 310a-b can be embedded into the conductive body 305. In other implementations, more than two signal pins are embedded in a conductive body 305. The signal pins 310a-b can operate to transmit and/or receive data in the form of electrical signals. In some implementations, the signal pins 310a-b can be made of one or more of aluminum, copper, titanium, iron, nickel alloy, other metal, or another substantially conductive material. Signal pin insulators 315a-b can be embedded in the conductive body 305 and can surround signal pins 310a-b. Signal pin insulators 315a-b can operate to maintain signal quality and shield external noise or interference. Signal pin insulators 315a-b also can operate to separate the signal pin from the ground and/or other signals and also can provide mechanical support. Signal pin insulators 315a-b can be made of insulative materials including, for example, nylon, foam, polyester, or fiberglass. It should be understood that the signal pin insulators 315a-b are not required for the connector.
In some implementations, two ground pins 320a-b can be embedded in the conductive body 305 of the multi-channel connector 300 and operate to transfer return ground currents 325a-b. In other implementations, more than one ground pin can be embedded in the conductive body 305 of the multi-channel connector 300. In some implementations, the ground pins 320a-b can be formed from the conductive body 305 and thus comprise the same material. In other implementations, the ground pins 320a-b can be made of a separate material such as aluminum, titanium, iron, or nickel alloy, and subsequently connected to the conductive body 305. In still further implementations, a single ground pin can be imbedded in the conductive body 305.
The signal pins 310a-b can operate to transmit and/or receive signals to/from one end of the connector to the device, connector, or apparatus to the other end. In addition, the ground pins 320a-b can operate to transfer return ground current 325a-b from the signal transmission. One channel's return ground current 325a can be designed to flow to its respective ground pin 320a based upon the skin effect. Correspondingly, an adjacent channel's return ground current 325b is intended to flow to its respective ground pin 320b.
Crosstalk 330a-b can occur occurs when return ground current from one channel (e.g., signal pin 310a of aggressor channel 335) flows into an adjacent channel's return current path (e.g., signal pin 310b and/or ground pin 320b of victim channel 340), resulting in reduced signal quality. A selectively resistive material 345 can be applied between signal pins 310a-b, signal pin insulators 315a-b, and/or ground pins 320a-b to reduce crosstalk. The effective resistance of the selectively resistive material 335 can be greater than the resistance of the conductive body 305 and less than the resistance of an insulating material.
In some implementations, the selectively resistive material 345 can be embedded in the connector during the manufacturing process. In other implementations, the selectively resistive material 345 can be applied to the surface of the connector with an epoxy, metal plate, or coating. It should be understood that the selectively resistive material 345 can be variable in shape or size. Moreover, the selectively resistive material 345 can be placed in various spatial configurations on the conductive body 305 to reduce crosstalk. In alternative implementations, the conductive body 305 can be made of the selectively resistive material and plated with a more conductive material in areas that can allow the area of un-plated resistive material to reduce crosstalk.
Return current induced crosstalk 445 (e.g., crosstalk 330a-b of
To reduce crosstalk, a selectively resistive material 460 (e.g., selectively resistive material 345 of
The signal pins 510a-c can operate to transmit and/or receive data in the form of electrical signals. In some implementations, the signal pins 510a-b can be made of aluminum, copper, titanium, iron, nickel alloy, other metal, or another substantially conductive material. Signal pin insulators 515a-c can be embedded in the conductive body 505 and can surround signal pins 510a-c. Signal pin insulators 515a-c can operate to maintain signal quality and shield external noise or interference. Signal pin insulators 515a-c also can operate to separate the signal pin from the ground and/or other signals and also can provide mechanical support. The insulative materials used to make the signal pin insulators 515a can include, for example, nylon, foam, polyester, or fiberglass, among many others. In some implementations, the signal pin insulators 515a-c are not required in the connector. It should be understood that the signal pin insulators 515a-c are not required for the connector.
In some implementations, the ground pins 520a-c can be formed from the conductive body 505 and thus comprise the same material. In other implementations, the ground pins 520a-c can be made of a separate material such as aluminum, titanium, iron, or nickel alloy, and subsequently connected to the conductive body 505. In some implementations, a single ground pin can be constructed.
The signal pins 510a-c can operate to transmit and/or receive signals to/from one end of the connector to the device, connector, or apparatus to the other end. In addition, the ground pins 520a-c can operate to transfer return ground current 525a-c from the signal pins 510a-c, respectively. Return ground current 525a from one channel can be designed to flow to its respective ground pin 520a based on the skin effect. Correspondingly, an adjacent channel's return ground current 525b-c can be designed to flow to its respective ground pin 520b-c.
Crosstalk 530a-b can occur when return ground current from one channel flows to an adjacent channel signal and/or ground pin. Crosstalk 530a-b typically results in reduced signal quality. A selectively resistive material 535a-b can be applied between signal pins 510a-c, signal pin insulators 515a-c, and/or ground pins 520a-c to reduce crosstalk. The effective resistance of the selectively resistive material 535a-b can be greater than the resistance of the conductive body 505 and less than the resistance of an insulating material. The originator of the offending return ground current can be identified as an aggressor channel. The receiver of offending return ground current can be identified as a victim channel. Channels 540/545/550 in this connector may act as an aggressor or a victim.
In some implementations, the selectively resistive material 535a-b can be embedded in the connector during the manufacturing process. In other implementations, the selectively resistive material 535a-b can be applied to the surface of the connector after manufacturing with an epoxy, metal plate, or coating. It should be understood that the selectively resistive material 535a-b can be variable in shape or size. Moreover, the selectively resistive material 535a-b can be placed in various configurations on the conductive body 505 to reduce crosstalk. In alternative implementations, the conductive body 505 can be made of the selectively resistive material and plated with a more conductive material in areas that can allow the area of un-plated resistive material to reduce crosstalk.
At stage 610 a selectively resistive material can be applied to the surface of the single conductive body between adjacent connector signal pins, signal pin insulators, and/or ground pin(s). The selectively resistive material (e.g., selectively resistive material 535a-b in
At stage 615, a signal pin insulator is embedded in the conductive body. The signal pin insulators (e.g., signal pin insulators 515a-c in
At stage 620, at least one ground pin is formed from or connected to the conductive body. The ground pin(s) (e.g., ground pins 520a-c in
At stage 625 at least two signal pins are embedded in the conductive body. The signal pins (e.g., signal pins 510a-c in
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