CONTACTLESS DATA COMMUNICATIONS COUPLING
The exemplary embodiments of the present invention provide a high-speed contactless data coupling that is adaptable to use with mechanical rail car couplers. The exemplary embodiments utilize a primarily magnetic field coupling to communicate either baseband data or RF signals through a pair of signal coupling units that do not need to contact either other, which can be easily housed in two heads attached to each of two mechanical rail car couplers.
The present application is related to and claims priority of a provisional application entitled CONTACTLESS DATA COMMUNICATIONS COUPLER IN A TRAIN COUPLING ENVIRONMENT METHOD AND SYSTEM, filed Jul. 7, 2005, and assigned Ser. No. 60/697,317, which application is assigned to the present assignee, and which application is hereby fully incorporated by reference herein.
BACKGROUND OF THE INVENTION1. Field of the Invention
This invention generally relates to the field of contactless high-speed data signal coupling and more specifically to the field of contactless high-speed data signal coupling systems and devices optimized for a train coupler environment.
2. Description of the Related Art
Railroad cars, including trams, streetcars and light rail cars (hereinafter “cars”), are generally connected together by mechanical couplers. An electrical coupler head (hereinafter “head”), which comprises a box-like electrical insulator, is mounted to each mechanical coupler. The electrical insulator of the head has a plurality of approximately 0.375-inch diameter cylindrical openings for acceptance of metallic pins. Known electrical couplings for electrical power or low bandwidth data signals are generally accomplished through the use of ohmic contact between corresponding pins of two heads, each head mounted to a pair of coupled mechanical couplers. Without intensive signal conditioning, such electrical couplings are limited to conveying electrical power or low bandwidth data signals of less than one megabit per second because of a large difference between the impedance of high-speed data cable and the impedance of the pins and of the junction between the pins. Such coarse pin connections are also subject to electrical radiation and interference due to the large spacings between adjacent pins of a head. An electrical coupling through the use of pins is considered a quick-disconnect coupling, in that the electrical coupling is quickly broken when the mechanical couplers are uncoupled.
There is a need to provide higher bandwidth data communications between cars that are connected together to form a train, i.e., a “consist”. Providing, for example, real time video observation of the interior of one or more cars, real time observation of a multitude of system monitoring data values and other data communications among cars requires a data rate for data transmissions between cars greater than 50-Mbit/sec and sometimes greater than 90-Mbit/sec. The physical size, structure and environment of railroad couplers generally limit the ability to achieve such high data rate transfers through quick-disconnect pin couplings.
Other known methods of achieving high bandwidth data transfer between cars include using conventional RF communication. Conventional RF communication, however, is subject to interference and cross-talk between different consists because of the use of a common carrier frequency (e.g., 2.4-GHz in the case of 802.11g), especially when conventional antenna systems are used.
SUMMARY OF THE INVENTIONThe exemplary embodiments of the present invention provide a non-contact data connection that is adaptable to use in a mechanical rail car coupler environment using conventional electrical coupler heads. These embodiments utilize a primarily magnetic field coupling to communicate either baseband data or RF signals through a quick-disconnect electrical coupling device that can be easily mounted in an electrical coupler head.
The subject matter that is regarded as the invention is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The foregoing and other objects, features, and advantages of the invention will be apparent from the following detailed description taken in conjunction with the accompanying drawings.
Exemplary embodiments of the present invention utilize one of two different approaches for transferring high-speed data across two coupled cars using a signal coupling system that neither requires nor uses ohmic contact between the cars. Each approach is able to carry, for example, 100-Mbit/sec Ethernet signals from one car to another across signal coupling units that are easily incorporated into a head of a mechanical train coupler. The first of these approaches directly couples the Ethernet baseband signal through custom-designed magnetics within each signal coupling unit that are used in combination with specialized active signal conditioning circuitry of the system. This approach is capable of full-duplex Ethernet communication at 100-Mbits/sec. The second of these approaches incorporates an intermediate conversion to a radio frequency (RF) signal, such as an IEEE 802.11a wireless format, that operates in the vicinity of 5-GHz. The RF signal is transmitted across the signal coupling units through a specially designed short-range, near-field antenna-like coupling arrangement within each signal coupling unit. The RF approach is limited to half-duplex operation at 54-Mbits/sec (with standard equipment) or 108-Mbits/sec (with special non-standard equipment) in one direction at a time.
Referring now to
In both the Ethernet baseband network architecture 200 and RF-based network architecture 300, a control signal 222 and 322 enables a vehicle information controller 220 and 320, respectively, to disable the wireless coupling of the system at one or both ends of the car 202 and 302. This feature prevents unintentional radiation of signals from an uncoupled end of the car 202 and 302, and also aids in consist enumeration.
Equalization circuits 411, 412 and 413 (the first located in the segment interface unit 402 and the second two in the non-contact sending unit 108) together perform frequency equalization for the transmit path, compensating for the high-pass response of the transformer. The line matching and power injection circuits 421 and 422 provide line termination (impedance matching) and power injection for the non-contact sending unit 108 and for the non-contact receiving unit 106. The line matching and power extraction circuits 431 and 432 provide line termination (impedance matching) and power extraction for the non-contact sending unit 108 and for the non-contact receiving unit 106. A send amplifier 442, located in the non-contact sending unit 108, boosts the power of the transmitted Ethernet signal for the purpose of driving the primary winding, coil 401, of the transformer. A receive amplifier 451, located in the non-contact receiving unit 106, amplifies the attenuated Ethernet signal picked up by the secondary, coil 402, of the transformer, boosting the Ethernet signal for transmission back to the segment interface unit 402. A transformer load 404 is connected between the receive amplifier 451 and the coil 402. Voltage regulator circuits 461 and 462 (one in the non-contact sending unit 108 and one in the non-contact receiving unit 106) take unregulated power from the line matching and power extraction circuits 431 and 432, and present a constant voltage to the power terminals of the send amplifier 442 and of the receive amplifier 451, respectively. The send amplifier 471, located in the segment interface unit 402, provides the proper source impedance and signal voltage levels for driving the differential shielded cable 212 that connects the non-contact sending unit 108 to the segment interface unit. Receive amplifiers 472 and 473, located in the segment interface unit 402, boost the receive signal to a 2V peak-to-peak level required for driving the Ethernet LAN (CAT-5) cable connection. Isolation transformers 474 and 476, located in the segment interface unit 402, are standard printed-circuit-mounting Ethernet transformers similar to those used on network interface cards in personal computers. The isolation transformers 474 and 476 provide protection from stray voltages picked up on the CAT-5 cable through misconnection, static discharge, or electromagnetic interference. A voltage regulator circuit 477 provides regulated voltages to the other circuits in the segment interface unit 402, and provides an intermediate power bus for delivering power to the non-contact sending unit 108 and the non-contact receiving unit 106. The segment interface unit 204 uses Data Terminal Equipment (DTE) transmit and receive connections.
Advantageously, once the cars of a consist, such as cars 201 and 202, are joined together and the network devices in various cars have found one another and established communications, a train-wide network is formed and effectively functions as a single LAN.
It is important to note, that these embodiments are only examples of the many advantageous uses of the innovative teachings herein. In general, statements made in the specification of the present application do not necessarily limit any of the various claimed inventions. Moreover, some statements may apply to some inventive features but not to others. In general, unless otherwise indicated, singular elements may be in the plural and vice versa with no loss of generality.
Although a specific embodiment of the invention has been disclosed, it will be understood by those having skill in the art that changes can be made to this specific embodiment without departing from the spirit and scope of the invention. The scope of the invention is not to be restricted, therefore, to the specific embodiment, and it is intended that the appended claims cover any and all such applications, modifications, and embodiments within the scope of the present invention.
Claims
1. A rail car data signal coupling structure, comprising:
- a first electrical coupler head attached to a mechanical coupler of a first rail car;
- a second electrical coupler head attached to a mechanical coupler of a second rail car, the mechanical coupler of the first rail car able to couple to the mechanical coupler of the second rail car;
- a first data coupling unit located in the first electrical coupler head;
- a second data coupling unit located in the second electrical coupler head, wherein, when the mechanical coupler of the first rail car is coupled to the mechanical coupler of the second rail car, the first data coupling unit and the second data coupling unit are located in non-contact proximity to one another to provide non-ohmic coupling of data signals; and
- at least one signal equalization circuit, electrically connected to at least one of the first data coupling unit and the second data coupling unit, the at least one signal equalization circuit operating to provide frequency equalization to support baseband data communications up to a specified data rate through the non-ohmic coupling.
2. The rail car data signal coupling structure of claim 1, wherein the specified data rate is greater than 90 megabits/second.
3. A rail car data signal coupling system, comprising:
- a first electrical coupler head attached to a mechanical coupler of a first rail car;
- a second electrical coupler head attached to a mechanical coupler of a second rail car, the mechanical coupler of the first rail car able to couple to the mechanical coupler of the second rail car;
- a first data coupling unit located in the first electrical coupler head;
- a second data coupling unit located in the second electrical coupler head, wherein, when the mechanical coupler of the first rail car is coupled to the mechanical coupler of the second rail car, the first data coupling unit and the second data coupling unit are located in non-contact proximity to one another to provide non-ohmic coupling of data signals;
- at least one radio frequency transceiver capable of impressing baseband data onto a radio frequency carrier; and
- a network adaptor for permitting Ethernet data to be communicated to the radio frequency transceiver.
4. The rail car data signal coupling structure of claim 3, wherein the specified data rate is greater than 50 megabits/second.
5. A method for coupling data signals across rail cars, the method comprising the steps of:
- providing a first electrical coupler head attached to a mechanical coupler of a first rail car;
- providing a second electrical coupler head attached to a mechanical coupler of a second rail car, the mechanical coupler of the first rail car able to couple to the mechanical coupler of the second rail car;
- providing a first data coupling unit located in the first electrical coupler head;
- providing a second data coupling unit located in the second electrical coupler head, wherein, when the mechanical coupler of the first rail car is coupled to the mechanical coupler of the second rail car, the first data coupling unit and the second data coupling unit are located in non-contact proximity to one another to provide non-ohmic coupling of data signals; and
- connecting at least one signal equalization circuit to at least one of the first data coupling unit and the second data coupling unit, the at least one signal equalization circuit operating to provide frequency equalization to support baseband data communications up to a specified data rate through the non-ohmic coupling.
Type: Application
Filed: Jul 7, 2006
Publication Date: Feb 25, 2010
Inventors: Dennis K. Marvel (Boca Raton, FL), Jurgen Kruppa (Delray Beach, FL)
Application Number: 11/994,941
International Classification: B61G 5/00 (20060101);