High Bandwidth Modular Slip Ring with Embedded Error Correction

Abstract

There is provided a non-contact rotary joint for transmitting and receiving electrical signals comprising: a transmitter having a plurality of emitters positioned in a generally circular pattern, the plurality of emitters operable to transmit signals; a receiver positioned a distance from the transmitter, the receiver including a plurality of cells operable to receive signals over a non-contact interface; and a signal source in communication with the transmitter, wherein the plurality of emitters form a plurality of data channels that is less than the number of emitters.

Description

[Technical field]

[0001] The present disclosure relates generally to slip rings, and more particularly, to slip rings operable to transmit signals across a contactless interface. [Background technology]

[0002] Devices for transmitting electrical signals between two relatively rotatable members are known in the art. Such devices, commonly known as rotary joints or rotary electrical interfaces, include slip rings and twist capsules, among others. Slip rings are typically used when unlimited rotation is required between two relatively rotatable members, whereas twist capsules are typically used when only limited rotation is required between two relatively rotatable members.

[0003] A slip ring is an electromechanical device that allows for the transmission of power and signals between a stationary and a rotating structure. Slip rings can be used in electromechanical systems that require rotation while transmitting power and / or signals. Slip rings can also improve mechanical performance, simplify system operation, and eliminate fragile wires dangling from moving joints. Traditionally, slip rings are designed for data transmission over only a very small portion of the slip ring area.

[0004] Conventional slip rings typically use sliding electrical contacts between two relatively rotatable members. These slip rings using sliding electrical contacts have inherent weaknesses that limit their electrical performance at higher frequencies. Non-contact slip rings are also known in the art. These non-contact rotary joint systems allow for the transmission of high frequency electrical signals between a rotor and a stator without sliding electrical contacts. Such non-contact rotary joint systems include devices operable to recover electromagnetic energy transmitted across space between a signal source and a signal receiver. In radio frequency ("RF") communication systems, such devices are called antennas (or antennae) and typically operate in conventional far-field electromagnetic radiation in free space. Summary of the Invention [Problem to be solved by the invention]

[0005] Conventional devices are limited in their data rate capabilities and use only a small portion of the slip ring area. The present disclosure provides slip rings with increased aggregate data rates. [Means for solving the problem]

[0006] The present disclosure provides a non-contact rotary joint configured to simultaneously transfer data in one or more data channels around substantially the entire circumference of the rotary joint.

[0007] In an exemplary embodiment, a non-contact rotary joint (100) for transmitting and receiving electrical signals includes a transmitter (102) having a plurality of emitters (110) positioned in a generally annular pattern, the plurality of emitters operable to transmit signals, and a receiver (112) positioned a distance from the transmitter, the receiver including a plurality of cells (114) operable to receive signals over a non-contact interface. The non-contact rotary joint further includes a signal source (104) in communication with the transmitter, the plurality of emitters forming a plurality of data channels (126) that are fewer than the plurality of emitters.

[0008] In another exemplary embodiment, a slip ring for transmitting and receiving data includes a rotating component having a longitudinal axis and a plurality of emitters positioned about the longitudinal axis, the plurality of emitters being positioned in a continuous ring configuration and configured to transmit data, and a stationary component having a plurality of receivers positioned about the longitudinal axis adjacent the plurality of emitters of the rotating component, the plurality of receivers being configured to receive transmitted data from the plurality of emitters of the rotating component, each receiver of the plurality of receivers being associated with a data channel, each data channel being associated with a cell, the cells being configured to be active cells or inactive cells, the active cells and inactive cells being positioned in an alternating order.

[0009] The accompanying drawings are incorporated herein as part of this specification. The drawings described herein show examples of the presently disclosed subject matter and serve to explain selected principles and teachings of the present disclosure. However, the drawings do not show every possible implementation of the presently disclosed subject matter and are not intended to limit the scope of the present disclosure in any way. [Brief description of the drawings]

[0010] [Figure 1]FIG. 1 is a schematic diagram of a slip ring having a rotating component and a stationary component according to an exemplary embodiment of the present disclosure. [Figure 2A] FIG. 2 is a schematic top view of a slip ring transmitter in accordance with an exemplary embodiment of the present disclosure. [Figure 2B] FIG. 2B is a schematic top view of a portion of the slip ring transmitter according to FIG. 2A. [Figure 3A] FIG. 2 is a schematic diagram of a data channel having an emitter in an ON state and an OFF state, according to an exemplary embodiment of the present disclosure. [Figure 3B] FIG. 2 is a schematic diagram of a data channel having an emitter in an ON state and an OFF state, according to an exemplary embodiment of the present disclosure. [Figure 4] FIG. 2 is a top view of a slip ring receiver according to an exemplary embodiment of the present disclosure. [Diagram 5] 1 is a flow chart of the operation of a slip ring according to an exemplary embodiment of the present disclosure. [Figure 6] FIG. 2 is a block diagram of a small slip ring according to an exemplary embodiment of the present disclosure. [Figure 7] FIG. 2 is a block diagram of a large slip ring according to an exemplary embodiment of the present disclosure. [Figure 8A] FIG. 2 is a top view of a portion of a slip ring transmitter in accordance with an exemplary embodiment of the present disclosure. [Figure 8B] FIG. 2 is a top view of a portion of a slip ring transmitter in accordance with an exemplary embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] It should be understood that the present invention can assume various alternative orientations and sequences of steps unless expressly stated to the contrary. It should also be understood that the specific assemblies and systems illustrated in the attached drawings and described in the following specification are merely exemplary embodiments of the inventive concepts defined herein. Thus, specific dimensions, orientations, or other physical characteristics relating to the disclosed embodiments are not to be considered as limiting, unless expressly stated otherwise. Additionally, similar elements in the various embodiments described herein may generally be referred to with similar reference numerals within this section of the application, although they may not be.

[0012] Those skilled in the art will recognize that the elements and techniques described herein can be practiced without one or more of the specific details, or with other methods, components, materials, and the like. In some cases, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring certain aspects of the disclosure. Throughout this specification, "one embodiment," "one embodiment," or "exemplary embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment is included in at least one embodiment of the disclosure. Thus, appearances of the phrases "in one embodiment" or "in one embodiment" do not necessarily refer to the same embodiment throughout this specification. However, particular features, structures, or characteristics described may be combined in any suitable manner in one or more embodiments.

[0013] As used herein, the terms "first", "second", etc. do not necessarily denote an ordinal, order, or priority relationship, but are merely used to more clearly distinguish one element or set of elements from another element or set of elements, unless otherwise specified.

[0014] As used herein, the term "coupling" in the optical context refers to the path by which light travels from one optical medium or device to another optical medium or device.

[0015] As used herein, the term "about" when accompanying a value is intended to mean within the tolerance of the equipment used to generate the value, i.e., in some instances, unless otherwise specified, plus or minus 10%, or plus or minus 5%, or plus or minus 1%.

[0016] As used herein, the term "approximately" is intended to mean within the tolerance of the equipment used to generate the value, i.e., in some instances, unless otherwise specified, plus or minus 10%, or plus or minus 5%, or plus or minus 1%.

[0017] Examples of slip rings and systems using slip rings are described herein. Slip rings can be used with rotating objects to transfer analog or digital signals containing data. Slip rings have applications in, but are not limited to, use with computed tomography (CT) scanners, baggage scanners, forward looking infrared (FLIR) systems, air traffic control, amusement park rides, cranes, marine moorings, non-destructive testing equipment, and industrial 3D imaging equipment.

[0018] Referring now to the drawings, FIG. 1 shows a simplified diagram of a slip ring 100 according to an exemplary embodiment. The slip ring 100 is a non-contact rotary joint operable to transmit high speed data signals across an interface between two relatively movable members without the use of sliding electrical contacts in the signal path. As shown in FIGS. 1-7, in one embodiment, the slip ring 100 can be implemented with printed circuit board ("PCB") technology and can support multi-gigabit data transmission speeds with frequency domain bandwidth. The slip ring 100 can be a platter-type slip ring. In another embodiment, the slip ring 100, 200 includes a printed circuit board (PCB) segment. In yet another embodiment, the slip ring 100, 200 can be drum-type.

[0019] The slip ring 100 includes a transmitter 102. In one embodiment, the transmitter 102 is a circular platter PCB transmitter. A signal source 104 is operable to deliver high-speed digital data signals to a number of emitters 110. In one embodiment, the emitters 110 form a continuous ring of individual transmitters. For example, the continuous ring of transmitters 110 may be electronically split into multiple channels, where the signal propagates across a gap (e.g., an air gap) to a number of receivers 114. The signal transmitted by the emitter 110 is sampled by a number of adjacent individual receivers 114 coupled with the slip ring receiver 112. In one embodiment, the slip ring receiver 112 is a circular platter printed circuit board suspended at a predetermined distance above the transmitter 102 to allow free rotation of the slip ring 100 without physical contact. Thus, a number of receivers 114 are suspended at a distance above the emitter 110. The signal recovered across the air gap by the receiver 114 is delivered to receiver electronics 124 of the slip ring receiver 112. In the receiver electronics 124, the signal may be detected, amplified, and the signal data recovered. Figure 1 shows only a few portions of the transmitter 102 and receiver 112, with the receiver 112 offset from the transmitter 102 for clarity.

[0020] In one embodiment, the transmitter 102 is a rotating component including a rotor and the receiver 112 is a non-rotating component including a stator. In another embodiment, the transmitter 102 is a non-rotating component and the receiver 112 is a rotating component. The location of the emitter 110 and the location of the receiver 114 may depend, at least in part, on the application of the slip ring 100. The multiple receivers 114 include data channels 126B to facilitate data transfer in the slip ring 100. In one embodiment, the emitter 110 defines 32 active communication channels 126A and the receivers 114 include 32 corresponding data channels 126B.

[0021] Emitters and Receivers 2A-5, in one embodiment, the slip ring transmitter 102 includes 128 emitters 110 positioned in a circular configuration. The emitters 110 may be, but are not limited to, light emitting diodes (LEDs), micro LEDs, capacitive emitter cells, inductive emitter cells, ultrasonic emitter cells, and radio frequency (RF) emitter cells. In one embodiment, the LED emitters 110 are coupled to the transmitter 102 in a circle, however, it is contemplated that the LED emitters 110 may be positioned around the transmitter 102 in any shape or form suitable for data transmission.

[0022] In an exemplary embodiment, the emitters 110 form a plurality of data channels 126A. As shown in FIGS. 3A-3B, in one embodiment, four emitters 110 form one data channel 126A. In each data channel 126A, the two circumferentially inner emitters 110A are active (ON) while each of the circumferentially outer emitters 110B is inactive (OFF). In one embodiment, the four emitters 110 forming each data channel 126A are operable such that the emitters 110 form an alternating pattern of two ON emitters 110A and two OFF emitters 110B. In FIGS. 3A-3B, the active emitters 110A are shown as white and the inactive emitters 110B are shown as black. In an embodiment having a ring of 128 emitters 110, the slip ring transmitter 102 includes 32 data channels 126A. The deliberate use of inactive emitter cells 110B in each data channel 126A prevents adjacent signal crosstalk. In other embodiments, the active emitter cells 110A and inactive emitter cells 110B may alternate in sequence for single emitter cells 110 or for groups of emitter cells 110.

[0023] In one embodiment, when the slip ring transmitter 102 is rotated, steering electronics are used to translate and electronically rotate the active data channel emitter 110A in a manner that maintains alignment of the data channel 126A with the multiple (e.g., 32) individual stationary receivers 114 of the data channel 126B. The multiple receivers 114 can be, but are not limited to, LED receiver cells, micro LED receiver cells, photodiodes, capacitive receiver cells, inductive receiver cells, ultrasonic receiver cells, and radio frequency (RF) receiver cells. For example, as shown in FIG. 3B, when the slip ring transmitter 102 is rotated 1 / 128 of a mechanical rotation in a clockwise direction, the emitter 110′ that was active before the 1 / 128th of a rotation becomes inactive after the 1 / 128th of a rotation to maintain each data channel 126A in a static position relative to the stationary receivers 114 and data channel 126B. This design provides one active emitter 110A for each data channel 126A at all times during rotation.

[0024] In one embodiment, as shown generally in Figures 2A and 2B, the steering electronics used to maintain the relative positions of the data channels 126A, 126B include a rotation register 130, a clocked stationary register 132, and encoder position sensor rings 134A, 134B. As shown in Figures 5 and 6, in one embodiment, the rotation register 130 and the clocked stationary register 132 are provided within an integrated circuit that includes a Field Programmable Gate Array (FPGA) 148 and / or within a serializer / deserializer (SERDES) of the FPGA 148. In one embodiment, in operation, data bits are parallel loaded into the rotation register 130 and concatenated from multiple bytes received from the SERDES. The data bits are then transferred from the rotation register 130 through the stationary shift register 132 where the data bits are "clocked" based on commands from the encoder position sensor rings 134A, 134B. In another embodiment, the shift register 132 is a parallel-to-serial bidirectional wrapping shift register with a priority arbiter. The slip ring 100 includes a 4-bit demultiplexer 136 operable to output one of four bit positions that match the two least significant bits (LSBs) of the encoder position sensor rings 134A, 134B. The encoded bit positions are then used by an FPGA "OR" gate 138 to determine which two emitters 110 to activate for each bit to maintain the relative positions of the data channels 126A, 126B. With each clock pulse, the active emitters 110 are shifted one position to either the right or left depending on the direction of rotation.

[0025] The FPGA 148 is operable to address adjacent data transfers (e.g., signal crosstalk) between the multiple emitters 110 and the multiple receivers 114. The FPGA 148 enables high density, high speed logic switching for the multiple data channels 126.

[0026] In one embodiment, the aggregate data transmission rate of the slip ring 100 is determined by the switching (ON / OFF) time of the emitters 110, the bandwidth of the receiver 114, and the total number of data channels 126A, 126B. The achievable data transmission rate is a function of the available data transfer surface area. Data transfer occurs simultaneously across each (e.g., 32) data channel 126A, 126B of the slip ring 100. For example, multiple emitters 110 transmit data at the transmitter 102 around the entire circumference of the ring formed by the emitters 110. For certain slip ring designs, as discussed later in this specification, the error correction bandwidth of a single data channel stripe 140 exceeds 20 Gbps. In one embodiment, the design of the slip ring 100 includes multiple concentric data channel stripes 140.

[0027] In an embodiment in which the emitters 110 include LEDs (i.e., optical transmission media), the slip ring 100 is operable to increase the aggregate data transmission rate by increasing the number of data channels 126 using spectral channel differentiation. In one embodiment, the slip ring transmitter 102 includes a ring of LED emitters 110 operable to emit light in at least two different wavelength ranges. For example, the LED emitters 110 may be operable to emit infrared light (generally having a wavelength in the range of 700 nanometers to 1 millimeter) and green light (generally having a wavelength in the range of 560 to 520 nanometers). Spectral filtering may also be used to ensure separation of the data channels 126. Thus, a data channel 126A may include two adjacent LED emitters 110, such that every third emitter 110 alternates the wavelength emitted. In one embodiment having 128 emitters 110, the slip ring 102 may include 64 data channels 126. Spectral channel differentiation can be used for one-way and two-way data transmission applications.

[0028] As with spectral channel differentiation, the slip ring 102 may utilize RF, capacitive, or inductive technologies, and may use RF filtering and information modulation techniques to further increase the bit rate per channel of multiple data channels 126 for a particular bandwidth.

[0029] In one embodiment, the slip ring 100 includes multiple communication pipes divided in bandwidth of the aggregate data channel 126 of a single data stripe 140 or multiple data stripes 140. This may be accomplished by the data configurator circuit board 152. For example, the slip ring 100 may include at least two RS232 / 422 serial channels 126 in addition to two 10Gbps serial channels 126 in a single data stripe 140. In an exemplary embodiment, the single data stripe 140 may include 82 individual LED channels or antenna patch (RF) parallel bit transmissions assigned to the stator 112. The multiple data channels 126 of the slip ring 100 are protocol agnostic and may be used for Ethernet transport protocols (10 / 100 / 1G / 10G), USB protocols, and SMPTE (3G, 6G, 12G SDI, 292M, 424M).

[0030] Modular & Large Slip Rings 7 and 8A-8B, in one embodiment, the slip ring 200 includes a modular architecture. The individual nature of the multiple data channels 126 formed by the multiple emitters 110 and receivers 114 allows large slip rings to be formed utilizing slip ring transmitters 202 and / or slip ring receivers 212 with individual modular PCB sections 250. Having multiple data channels 126 facilitates slower data transmission rates per data channel 126 and reduces the need for clock skew correction away from the signal source 104. The embedded encoder position sensor rings 134A, 134B can also be sectioned by PCB sections 250. The embedded encoders 134A, 134B can be constructed using PCB components with the required resolution equal to or better than the angle subtended by a single emitter cell 110. In one embodiment, approximately 1-2 mm of mounting space is utilized between PCB sections 250 with a nominal read head spacing of 3-4 mm.

[0031] In one embodiment, replacement PCB section 250 is operable to connect to other PCB sections 250 via mechanical connectors (e.g., "snap" connectors) positioned on the underside of PCB section 250. The PCB section connectors provide alignment position indications such that PCB sections 250 can be individually replaced without requiring any realignment. In one embodiment, slip ring 200 is created as a single instantiation into a ring set.

[0032] As shown in FIGS. 7 and 8A-8B, in one embodiment, the slip ring 200 includes a slip ring transmitter 202 having a plurality of PCB sections 250A. The PCB sections 250A include a first data stripe 140A. The PCB sections 250A are positioned generally around the periphery of the slip ring transmitter 202 and each include a plurality of emitters 110 and an encoder sensor 134A, 134B. The PCB sections 250A may be referred to herein as a primary transmission PCB. The slip ring transmitter 202 also includes a plurality of PCB sections 250B positioned radially inward of the PCB section 250A. The PCB section 250B includes a second data stripe 140B that includes a plurality of emitters 110. The slip ring transmitter 202 also includes a plurality of PCB sections 250C positioned radially inward of the PCB section 250B. PCB section 250C includes a third data stripe 140C that includes a plurality of emitters 110. The slip ring transmitter 202 further includes a plurality of PCB sections 250D positioned radially inward of PCB section 250C. PCB section 250D includes a fourth data stripe 140D that includes a plurality of emitters 110. Because the rotary encoder information is provided by PCB section 250A, it is not necessary for PCB sections 250B, 250C, 250D to include encoder sensors 134A, 134B. PCB sections 250B, 250C, 250D may be referred to herein as secondary transmission PCBs.

[0033] In one embodiment, as shown in FIG. 8A, the slip ring transmitter 202 may include one or more additional data stripes 140 in each PCB section 250. In one embodiment, the PCB sections 250A, 250B, 250C, and 250D are approximately 2 inches wide. The PCB section 250A includes a fifth data stripe 140E. The PCB section 250B includes a sixth data stripe 140F. The PCB section 250C includes a seventh data stripe 140G. The PCB section 250D includes an eighth data stripe 140H. The slip ring 200 may further include a complex programmable logic device (CPLD) 252 positioned in one of the PCB sections 250A, 250B, 250C, and 250D on an opposite side of the plurality of emitters 110. In one embodiment, a "light blocking" wall is included with the slip ring transmitter 202. The data stripes 140 can be positioned side-by-side using the "light blocking" wall and / or spectral light differences (e.g., different light spectra for each data stripe 140 and appropriate filters at the receiver 114).

[0034] Increasing the total number of PCB sections 250A, 250B, 250C, 250D reduces the data transfer rate of the data channels 140 corresponding to the PCB sections 250A, 250B, 250C, 250D. Increasing the total number of PCB sections 250A, 250B, 250C, 250D requires more data channels 140 to power the total number of PCB sections 250A, 250B, 250C, 250D. Reducing the total number of PCB sections 250A, 250B, 250C, 250D increases the data transfer rate of each PCB section 250A, 250B, 250C, 250D. For example, if there is a single ring of PCB sections 250A covering the slip ring 200, one data channel 140A is required to power the slip ring 200. However, in this embodiment, the data transfer rate corresponds to the incoming data transfer rate. For example, the data rate may be a function of the switching time of the transmitter 110 .

[0035] In one embodiment, the slip ring 200 conveys a data stream through each PCB section to a separate PCB section 250A, 250B, 250C, 250D. For example, if a pass-through scheme is utilized, a waterfall approach may be used. In this embodiment, serial data comes in through connector pins 1 and 2 of the first PCB section 250A, but passes through and exits through pins 3 and 4 on the other side of the same PCB section 250A. In this embodiment, each PCB section 250A, 250B, 250C, 250D contains eight data streams, so pins 1, 2; 3, 4; 5, 6; 7, 8; 9, 10; 11, 12; and 13, 14 all "pass through" and exit the PCB section 250A, 250B, 250C, 250D on the other side, one set of pins down. Thus, data received at pins 15, 16 is used by that particular PCB section 250A, 250B, 250C, 250D. The CPLD 252 (i.e., data configurator) drives eight data streams (i.e., channels) on the clockwise (CW) side and eight data streams (i.e., channels) on the counter-clockwise (CCW) side of the slip ring 200. In this embodiment, the data transfer rate for each segment PCB section 250A, 250B, 250C, 250D is approximately 1 / 16 the incoming data transfer rate for the CPLD 252. In an exemplary embodiment, the slip ring 200 can be used in a bidirectional data transmission application, where multiple LEDs 110 are used for transmission and multiple LEDs 110 are used as receivers.

[0036] In the exemplary embodiment, slip ring 200 includes a slip ring transmitter 202 having an outer diameter of 5.5 feet and a single data stripe 140A spanning 16 PCB sections 250A. Data stripe 140A has a diameter of 5 feet and a circumference of 15.7 feet. For example, PCB section 250A of slip ring transmitter 202 is 2 inches wide. In the exemplary embodiment, data stripe 140A includes 2560 transmitters 110, with 160 transmitters 110 per PCB section 250A. This embodiment of slip ring 200 provides approximately 20 Gbps per 2 inch PCB section 250A. Sixteen PCB sections 250A are repeated around the slip ring transmitter 202, with each PCB section 250A transporting 40 data channels 126 (e.g., 32 data channels, 7 Forward Error Correction (FEC) channels, and 1 spare channel). For example, each data channel operates at 40 Mbps, with a 20 Mhz transmitter / receiver switch frequency resulting in 1280 Mbps per PCB section 250A. In an exemplary embodiment, if a transmitter 110 or receiver 114 fails, data transmission can be switched from the affected channel to a spare (e.g., unused) channel. The slip ring 200 includes an aggregate of 512 data channels (i.e., 16 PCB sections 250A x 32 data channels) around the slip ring 200 (slip ring 200 includes 640 channels counting the FEC channel). In an alternative embodiment, the slip ring transmitter 202 includes a 10 inch wide PCB section 250A having additional data stripes 140 (e.g., a total of five data stripes 140) for an aggregate data rate of approximately 102 Gbps, including FEC.

[0037] Error correction and bit error rate The slip ring 100, 200 provides aggregate bandwidth performance that exceeds conventional data input stream rates. The slip ring 100, 200 thereby provides bandwidth for slip ring internal error detection and correction schemes such as forward error correction (FEC). The FEC monitors the system health of the slip ring 100, 200. In an exemplary embodiment, run-length coded FEC includes 32-bit single / double bit detection and optional single bit correction. When FEC is included in the design of the slip ring 100, 200, data transfer performance is reported in terms of bit-error rate (BER) while running the application exposed to electrical noise, vibration, and thermal environments in the field. In addition, the slip ring 100, 200 may include further circuitry to determine service identification of faults due to wear or mechanical damage to the non-rotating parts 112 or the rotating parts 102.

[0038] Another advantage of the slip rings 100, 200 is that the continuous transfer of data between multiple emitters 110 and multiple receivers 114 takes into account and considers radial and axial runout, which is a typical issue with larger slip rings, thus having runout limits in the 1 mm range. The slip rings 100, 200 can tolerate radial and axial runout in the 4-5 mm range.

[0039] Conventional slip ring designs may not meet emerging standards and regulations for electromagnetic compatibility (EMC). For example, industry regulations include IEC 60601-1-2 4th Edition. Further examples of tests that existing slip ring designs have difficulty passing include radiated immunity at 9-28V / m (3V / m) at 385-6000Mhz, Electrostatic Discharge (ESD) at 15kV air discharge (8kV air discharge), and Magnetic Field Immunity (MFI) at 30A / m (3A / m). Advantageously, the slip ring 100, 200 is able to pass all of the above requirements and tests while providing a high bandwidth solution, with improved immunity due to FEC capabilities and the ability to use low cost RF-immune sources for switching.

[0040] One or more features of the embodiments described herein may be combined to produce further embodiments not shown. It should be understood that certain features of the slip rings 100, 200 that are described for clarity in the context of separate embodiments may also be provided in combination in a single embodiment. Conversely, various features of the slip rings 100, 200 that are described for brevity in the context of a single embodiment may also be provided separately or in any suitable combination. Although various embodiments have been described in detail above, it should be understood that such embodiments are presented by way of illustration and not limitation. It will be apparent to those skilled in the art that the disclosed subject matter may be embodied in other specific forms, variations, and modifications without departing from the scope, spirit, or essential characteristics thereof. The above-described embodiments are therefore to be considered in all respects as illustrative and not restrictive. The scope of the present invention is indicated by the appended claims, and all changes that come within the meaning and range of equivalents thereof are intended to be embraced therein.

Claims

1. 1. A non-contact rotary joint for transmitting and receiving electrical signals, the non-contact rotary joint comprising: a transmitter having a plurality of emitters positioned in a generally annular pattern, the plurality of emitters operable to transmit a signal; a receiver positioned at a distance from the transmitter, the receiver including a plurality of cells operable to receive the signal over a contactless interface; a signal source in communication with the transmitter; Including, A non-contact rotary joint for transmitting and receiving electrical signals, wherein the plurality of emitters form a plurality of data channels that are fewer than the plurality of emitters.

2. 10. The non-contact rotary joint for transmitting and receiving electrical signals of claim 1, wherein the plurality of emitters are operable to emit one or more wavelengths of light.

3. 2. The non-contact rotary joint for transmitting and receiving electrical signals according to claim 1, wherein each of the plurality of data channels includes four emitters.

4. 4. The non-contact rotary joint for transmitting and receiving electrical signals according to claim 3, wherein each of the plurality of data channels includes two active emitters and two inactive emitters, and one inactive unit is positioned on each side of the two active emitters in each of the plurality of data channels.

5. The transmitter an encoder position sensor ring; a rotary register; a static register, wherein bits from the signal source are parallel loaded into the rotary register and clocked by a signal from the encoder position sensor ring in the static register; further comprising 5. The non-contact rotary joint for transmitting and receiving electrical signals according to claim 4, wherein the active emitter is shifted by one position by rotation of the transmitter or the receiver for each interval of the stationary register.

6. 5. The non-contact rotary joint for transmitting and receiving electrical signals according to claim 4, wherein each of the plurality of data channels is operable to simultaneously transmit data.

7. 2. The non-contact rotary joint for transmitting and receiving electrical signals of claim 1, wherein each of the plurality of data channels is operable to transmit data between the transmitter and the receiver with a radial or axial runout of 5 millimeters.

8. 5. The non-contact rotary joint for transmitting and receiving electrical signals according to claim 4, wherein the non-contact rotary joint further includes an integrated circuit operable to control the plurality of data channels, the integrated circuit including one or more field-programmable gate arrays operable to manage data transfer between the plurality of emitter and receiver cells.

9. 5. The non-contact rotary joint for transmitting and receiving electrical signals according to claim 4, wherein the plurality of data channels are formed of a plurality of concentric data channel stripes.

10. 2. The non-contact rotary joint for transmitting and receiving electrical signals of claim 1, wherein the plurality of emitters are one of light emitting diode emitters, capacitive emitters, inductive emitters, and radio frequency emitters.

11. 3. The non-contact rotary joint for transmitting and receiving electrical signals of claim 2, wherein the emitter is operable to emit light in at least a first wavelength range and a second wavelength range, and wherein spectral channel differentiation is operable in unidirectional and bidirectional data transmission.

12. 5. The non-contact rotary joint for transmitting and receiving electrical signals of claim 4, wherein the plurality of data channels includes one or more forward error correction channels operable to monitor system performance.

13. 10. The non-contact rotary joint for transmitting and receiving electrical signals of claim 1, wherein the transmitter comprises a separate printed circuit board (PCB) section.

14. 14. The non-contact rotary joint for transmitting and receiving electrical signals of claim 13, wherein the transmitter includes an embedded encoder position sensor ring, the encoder position sensor ring being sectioned by the respective PCB section of the transmitter.

15. 14. The non-contact rotary joint for transmitting and receiving electrical signals according to claim 13, wherein a mounting space of 2 mm or less is positioned between the transmitter PCB sections.

16. 14. The non-contact rotary joint for transmitting and receiving electrical signals according to claim 13, wherein the transmitter includes two or more concentric PCB sections, a data stripe positioned on each concentric PCB section, and the emitter is in electrical connection with each data stripe.

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