The present invention provides a technique for converting burst data to digital data, applying FFT operation to 2n (n is an integer) pieces of digital data in response to any start signal synchronized with a sector signal, applying a window function centered around data corresponding to a frequency of a burst data signal component before the FFT operation, and performing head positioning based on a result as the detected value of the burst data.

The present invention relates to a magnetic head or magnetic disk testing apparatus(an Inspection Apparatus and inspection method of magnetic disk or magnetic head). More particularly, the present invention relates to a technique for accurately detecting the amplitude of servo (hereinafter referred to as burst data) signals to provide accurate positioning of a magnetic head.
A magnetic head or magnetic disk testing apparatus is configured to determine the quality or other aspects of a magnetic head or a magnetic disk, by locating the magnetic head above the magnetic disk, writing and reading test data through the magnetic head on a target track, and measuring the characteristics of a signal read from the target track. Heretofore, servo control has been performed for accurately positioning the magnetic head on a target track of the magnetic disk.
To achieve the above, several techniques have been proposed, such as those described in JP-A No. 141807/1995 and JP-A No. 242152/2007. The technique of JP-A No. 141807/1995 is configured to transmit an amplitude detection signal of burst data through a band-pass filter, an analog to digital conversion circuit, and a digital filter. The technique of JP-A No. 242152/2007 is configured to apply Fast Fourier Transform (FFT) to burst data with a plurality of different frequency components, for detecting the amplitude ratio of each frequency component.

Inspection apparatus and inspection method of magnetic disk or magnetic head


An indicator for defining the relationship of a radiation beam to an object, such as a patient or associated apparatus, for example an X-ray film holder. The indicator includes a light source establishing a first light plane containing the beam and appliable to the object. A second light source establishes a second plane of light to contain the radiation beam or object. The intersection of the beams of light defines the radiation beam-object relationship.

1. Field of the Invention
The present invention is directed to an indicator for use with a projected beam employing a plurality of intersecting planes of light to obtain the indication.
2. Description of the Prior Art
Radiation therapy utilizes a beam of high energy radiation from a radiation source, such as a cobalt 60 supply or a linear accelerator. The portion of the patient to be treated is placed in the beam for a predetermined exposure time to obtain the desired therapeutic effect.
The radiation beam must be accurately positioned to ensure maximum benefit to the patient while minimizing undesirable side effects. Since the radiation beam is not visible to the human eye, various targeting devices have been utilized to ensure that the beam will impinge the correct portion of the patient. Typically, a target is placed on the patient's skin at the area to be treated. A light pattern, aligned with the path of the radiation beam, is positioned so that the light pattern is aligned with the target. The light pattern is then removed and the radiation beam established.
However, such a technique is often less than completely satisfactory. If the patient moves, for example, rolls about an axis normal to the radiation beam, diseased tissue within the body may move substantially out of the radiation beam but little misalignment can be noted. Even if the target and light pattern remain present during irradiation, the misalignment may not be detected. Under these circumstances, the effectiveness of the treatment may be substantially reduced.
Further, it is often necessary to ascertain the point at which the radiation beam exits the patient to insure that the patient and/or equipment are in proper alignment. Heretofore, a light has been mounted on the radiation source apparatus under the patient in opposition to the radiation beam to shine on the patient and mark the exit point of the radiation beam. However to properly position the light for all orientations of the radiation source is both expensive and awkward. In many cases, it restricts access to the patient by the medical personnel, preventing him/her from properly aligning the patient. The light is subject to damage from other equipment such as the patient bed.
The same concerns which apply to radiation therapy are also applicable to radiological diagnosis. That is, if the X-ray film sheet, patient and radiation beam are not properly positioned with respect to each other, the desired X-ray image on the film may not be obtained, requiring the X-ray to be taken over again and exposing the patient to additional radiation.

Indicator for use with projected beam of radiation


A radio communication system assigns use of a radio frequency communication resource comprising multiple communication channels in a way that minimizes the likelihood that a weakly received signal will be interfered with by a strongly received signal in an adjacent communication channel. The communication system determines a signal strength of a signal received from a user of the communication resource and, based on the signal strength determination, assigns the user one or more of the communication channels that are then available.

The present invention relates generally to wireless communication systems and, in particular, to assigning use of a radio requency communication resource.
Economics play an important role in the design of radio communication systems. Bandwidth is limited and equipment is expensive, and therefore many schemes have been developed for multiplexing multiple users over the same physical channel. One such scheme is time division multiple access (TDMA). In a TDMA system, the radio frequency (RF) signal carrying the information is segmented into intervals called time frames. Each frame is further partitioned into assignable user blocks of time called time slots. During each time slot, the assigned user of that slot is entitled to use the full spectrum of the RF signal. In multi-carrier communication systems, time slots exist in the same point in time on adjacent frequency channels. If two different users of communication units are being served by the same base site and are occupying simultaneously transmitted time slots in adjacent frequency channels, then power from the signal of one of the two different users can potentially couple into the adjacent channel and create undesired interference (i.e., adjacent channel coupled power interference, or ACCP) for the other user.
One solution to the problem of ACCP is to design communication systems with further reduced levels of adjacent channel coupled power. However, ACCP performance is difficult to improve and improvements will generally involve a significant investment in design time and cost and an increase in the component content and cost of the final product. Another solution, proposed in U.S. Pat. No. 4,794,635, issued to Hess, is to measure the communication quality factor, i.e., the signal-to-noise plus interference ratio, for signals already occupying each one of multiple communication channels in adjacent sectors and to select a channel that has the greatest margin between the desired communication quality factor for the channel and the minimum communication quality factor among the signals already occupying the channel. However, Hess does not address the ACCP problem where the assigned signal and the occupying signals are of significantly different signal strengths. If a strong signal and a weak signal with similar communication quality factors couple the same percentage of signal power into the other signal""s bandwidth, the strong signal will create a more significant ACCP problem for the weak signal than will the weak signal for the strong signal. Alternatively, a solution used by large system providers with an abundance of channels to select from is to avoid the use of adjacent frequency channels in the same base site. However, the latter solution results in a less than optimal use of system capacity and is not practical for systems that use a small number of frequency channels.
Therefore, a need exists for a method and apparatus for assigning use of a radio frequency communication resource in a manner such that ACCP is minimized while all communication channels are utilized.

Method and apparatus for assigning use of a radio frequency communication resource


A subterranean formation containing oil shale is prepared for in situ retorting by forming a fragmented permeable mass of formation particles containing oil shale in an in situ oil shale retort site. Formation is initially excavated from the retort site for forming one or more voids extending horizontally across the retort site, leaving a zone of unfragmented formation adjacent such a void. In one ambodiment, an array of rocks bolts are anchored in at least a portion of the roof adjacent such a void for providing reinforcement of unfragmented formation above the void. Vertical blasting holes are drilled in the zone of unfragmented formation adjacent the void. Explosive is placed in the blasting holes and detonated for explosively expanding the zone of unfragmented formation toward the void, including the rock bolted portion of the roof, for forming at least a portion of a fragmented permeable mass of formation particles containing oil shale in an in situ oil shale retort. Surprisingly, the rock bolting does not interfere with, and in some instances can improve, fragmentation compared with comparable blasts without such rock bolts. The reinforcement provided by the rock bolts can reduce or eliminate the need for roof support pillars in horizontal voids at intermediate levels of the retort site.

This invention relates to in situ recovery of shale oil from formation containing oil shale, and more particularly to the use of rock bolting techniques in unfragmented formation adjacent a horizontal void in a method for forming an in situ oil shale retort.
The presence of large deposits of oil shale in the Rocky Mountain region of the United States has given rise to extensive efforts to develop methods for recovering shale oil from kerogen in the oil shale deposit. It should be noted that the term "oil shale" as used in the industry is in fact a misnomer; it is neither shale, nor does it contain oil. It is a sedimentary formation comprising marlstone deposit with layers containing an organic polymer called "kerogen", which, upon heating, decomposes to produce liquid and gaseous products. It is the formation containing kerogen that is called "oil shale" herein, and the liquid hydrocarbon product is called "shale oil".
A number of methods have been proposed for processing oil shale which involve either first mining the kerogen-bearing shale and processing the shale on the ground surface, or processing the shale in situ. The latter approach is preferable from the standpoint of environmental impact, since the treated shale remains in place, reducing the chance of surface contamination and the requirement for disposal of solid wastes.
The recovery of liquid and gaseous products from oil shale deposits has been described in several patents, such as U.S. Pat. Nos. 3,661,423; 4,043,595; 4,043,596; 4,043,597; and 4,043,598, which are incorporated herein by this reference. These patents describe in situ recovery of liquid and gaseous hydrocarbon materials from a subterranean formation containing oil shale, wherein such formation is explosively expanded to form a stationary, fragmented permeable body or mass of formation particles containing oil shale within the formation, referred to herein as an in situ oil shale retort. Retorting gases are passed through the fragmented mass to convert kerogen contained in the oil shale to liquid and gaseous products, thereby producing retorted oil shale. One method of supplying hot retorting gases used for converting kerogen contained in the oil shale, as described in U.S. Pat. No. 3,661,423, includes establishing a combustion zone in the retort and introducing an oxygen-supplying retort inlet mixture into the retort to advance the combustion zone through the fragmented mass. In the combustion zone, oxygen from the retort inlet mixture is depleted by reaction with hot carbonaceous materials to produce heat, combustion gas, and combusted oil shale. By the continued introduction of the retort inlet mixture into the fragmented mass, the combustion zone is advanced through the fragmented mass in the retort.
The combustion gas and the portion of the retort inlet mixture that does not take part in the combustion process pass through the fragmented mass on the advancing side of the combustion zone to heat the oil shale in a retorting zone to a temperature sufficient to produce kerogen decomposition, called "retorting". Such decomposition in the oil shale produces gaseous and liquid products, including gaseous and liquid hydrocarbon products, and a residual solid carbonaceous material. The liquid products and the gaseous products are cooler by the cooled oil shale fragments in the retort on the advancing side of the retorting zone. The liquid hydrocarbon products, together with water produced in or added to the retort, collect at the bottom of the retort and are withdrawn. An off gas is also withdrawn from the bottom of the retort. Such off gas can include carbon dioxide generated in the combustion zone, gaseous products produced in the retorting zone, carbon dioxide from carbonate decomposition, and any gaseous retort inlet mixture that does not take part in the combustion process. The products of retorting are referred to herein as liquid and gaseous products.
It is desirable to form a fragmented mass having a reasonably uniformly distributed void fraction, i.e., a fragmented mass of reasonably uniform premeability, so that retorting gas can flow generally uniformly through the fragmented mass during retorting operations. Techniques used for excavating void spaces in a retorting site and for explosively expanding formation toward the voids can affect the uniformity of particle size or permeability of the fragmented mass. A fragmented mass having reasonably uniform permeability in horizontal planes across the fragmented mass can avoid bypassing portions of the fragmented mass by retorting gas, which can otherwise occur if there is gas channelling through the fragmented mass owing to non-uniform permeability.
U.S. Pat. No. 4,043,598 discloses a method for explosively expanding formation containing oil shale toward horizontal free faces to form a fragmented mass in an in situ oil shale retort. According to a method disclosed in that patent, a plurality of vertically spaced apart voids of similar horizontal cross-section are initially excavated one above the other at intermediate levels within the retort site. A plurality of vertically spaced apart zones of unfragmented formation are left between adjacent voids, and explosive is placed in blasting holes drilled in the zones of formation and detonated, preferably in a single round, to explosively expand each unfragmented zone into the horizontal voids on either side of it to form a fragmented mass. Retorting of the fragmented mass is then carried out to recover shale oil from the oil shale.
Techniques for expanding roof-supporting pillars along with horizontal zones of formation in a horizontal free face system are described in Application Ser. No. 929,250, filed July 31, 1978, now U.S. Pat. No. 4,192,554 and Application Ser. No. 951,527, filed Dec. 16, 1978 now abandoned. Those applications are owned by the assignee of this application and are incorporated herein by this reference.
In some embodiments it is necessary to leave one or more pillars within each horizontal void for providing temporary roof support for unfragmented formation overlying each void. The pillars can be explosively expanded prior to explosively expanding the unfragmented zones toward the voids. Such prior expansion of the pillars can form a reasonably continuous horizontal free face adjacent such a void. The need to form pillars and the need to explosively expand such pillars in the horizontal voids can contribute to the overall cost and complexity of mine excavation and explosive expansion operations.

Rock bolting techniques for forming an in situ oil shale retort


A laser alignment tool positioning system, includes a magnetically susceptible laser platform having a first mounting surface and an opposing second surface; a mounting post extending from the laser platform; a target on the mounting surface marking the mounting post centerpoint, and a plurality of mounting post adaptors. The laser platform may include magnets proximal to the mounting post base. A semi-rigid offset portion with threaded ends is provided, with an adaptor having a threaded portion to couple to the threaded ends and a slip fitting to couple to the mounting post adaptor. The mounting post may include an interior threaded portion to couple to the offset portion threaded ends. The target includes concentric circles indicating selected pipe sizes, with the concentric circles and mounting post adaptors including color coding corresponding to the selected pipe sizes. The positioning system may include a level indicator mounted to the laser platform.

Electricians and mechanical contractors are frequently required to install long runs of conduit or pipe through open areas requiring precise installation of support racks and precise installation of the receiving point. For example, electrical conduit and mechanical piping is generally pre-installed or "stubbed" so that they are in place when a building foundation or concrete floor is poured. The electrician then must extend the conduit from that stub through a ceiling which is anywhere from fifteen to fifty feet above the stub, or even greater distances. Aligning the penetration through the ceiling, which is often also the next floor of a multi-story building, requires great precision. In addition, an electricians and mechanical tradesmen must often run electrical conduit or piping in very tight confined spaces which cannot accommodate misalignments. Slight misalignments at each stage can accumulate to cause major installation problems: the stubs must be precisely aligned because they cannot generally be adjusted after concrete is poured; penetrations through ceilings/floors or walls must be precise because they cannot interfere with equipment layouts on the opposite sides; runs must be precisely aligned so as to not interfere with intersecting runs of piping and conduit, etc.
Similarly, long horizontal runs of conduit or pipe must be sighted with great precision. Precise alignment is required to prevent interference with other runs of conduit or piping, whether parallel runs or intersecting runs. Additionally, horizontal piping runs require a precise slope depending on the pipe design and fluid. Drain lines for example, require a minimum slope of ⅛ inch drop per 1 foot of run, and may also be restricted by a maximum slow of ¼ inch drop per foot in order to control flow rates, flushing action, and fluid velocity. Even piping or conduit not requiring precise slopes require precise placement to intersect with branch lines and to align with locations where they are to penetrate through another wall, floor, or connect to installed equipment. Support racks must be constructed prior to installing the piping or conduit and require the same precise alignment as the runs they support.
Traditionally, alignment of long vertical runs required a team of installers and expensive lifting equipment. Several installers working on lifts or scaffolding would be required to measure and locate the upper penetration point, then drop a plum line from that point to determine the proper location for the stub, or to determine the required offset. Lifting equipment is expensive, the process is time consuming, and labor costs are high due to the number of installers required. Worse still, the end product is often misaligned due to the difficulty in coordinating people and taking measurements off of different reference points.
Similarly, traditional methods for aligning long horizontal runs require multiple installers and significant equipment. The support racks often are fabricated on-site using supporting beams suspended from an overhead. The standard material used for the supporting beams is UNISTRUT® or similar modular metal framing systems which are provided in standard dimensioned cross-sections. Each support rack must be sighted and aligned vertically, requiring multiple installers using plum lines and measuring tapes. Again, the end result is often misalignment even when performed by experienced install teams.
Laser alignment tooling and sighting systems have greatly improved the productivity and precision of install teams, but often the inability to easily align the laser to the start point necessitates ad hoc solutions which, in addition to adding labor and time costs, result in precise but ultimately inaccurate measurements. The laser devices themselves are not able to mount directly to a conduit or pipe such that the laser can be centered in the pipe or conduit cross section itself. For support racks, the laser needs to be centered at the midpoint of the support beam, or the top or bottom edge.
Magnetic mounting means have been provided for many laser devices, but generally cannot be used to mount directly to conduit or piping, or a support rack. Additionally, often conduit, piping, and support racks are made from non-magnetic materials, so even laser devices with magnetic mounting systems can't be mounted directly to the structures for sighting. Additionally, even if the laser could be mounted directly to a conduit end, for example, there is no easy way to incorporate an offset into the laser spotter when required. The result is that, even with laser alignment tooling and spotting devices, install teams require extra bodies and extra equipment—and time—to sight conduit and pipe runs.
Thus, there is a need for a positioning system for laser devices that (1) is compatible with most magnetically mounted laser devices; (2) provides the ability to align a magnetic mounted laser spotter for direct centering over a conduit or pipe; (3) provides the ability to align a magnetic mounted laser spotter for direct centering on a supporting beam; (4) is inexpensive to manufacture; (5) is simple to use; (6) is universally adaptable to any standard conduit size or support beam size; (7) reduces the number persons required for an installation; (8) reduces the time required for an installation; (9) reduces the number of man-lifts or scaffolding systems required and the time they are required for an install; (10) provides improved accuracy for sighting installations; (11) provides the ability to easily measure angular offsets or provide templates for fabricating offsets.
A number of devices have provided magnetically mounted laser devices, but lack the simplicity, inexpensiveness, broad interoperability, and accuracy of the present invention. Presently known art attempts to address this problem, but has not completely solved the problem.
Thus, while the foregoing body of art indicates it to be well known to have a laser alignment tooling device, the art described above does not teach or suggest a positioning system which has the following combination of desirable features: (1) compatible with most magnetically mounted laser devices; (2) provides the ability to align a magnetic mounted laser spotter for direct centering over a conduit or pipe; (3) provides the ability to align a magnetic mounted laser spotter for direct centering on a supporting beam; (4) is inexpensive to manufacture; (5) is simple to use; (6) is universally adaptable to any standard conduit size or support beam size; (7) reduces the number persons required for an installation; (8) reduces the time required for an installation; (9) reduces the number of man-lifts or scaffolding systems required and the time they are required for an install; (10) provides improved accuracy for sighting installations; (11) provides the ability to easily measure angular offsets or provide templates for fabricating offsets.

Positioning system for laser alignment tools


A monolithically integrated optoelectronic device is provided which integrates a vertical cavity surface emitting laser and either a photosensitive or an electrosensitive device either as input or output to the vertical cavity surface emitting laser either in parallel or series connection. Both vertical and side-by-side arrangements are disclosed, and optical and electronic feedback means are provided. Arrays of these devices can be configured to enable optical computing and neural network applications.

This invention relates generally to the field of integrated optoelectronics, and more particularly, to a vertical cavity surface emitting lair integrated with electrically or optically sensitive interactive components, such as a photodetector, a transistor, or diode. One embodiment of the invention is an optical-input/optical-output device in either a vertical or side-by-side geometry suitable for use in one- and two-dimensional arrays and as individual elements in optoelectronic integrated circuits (OEICS). Another embodiment of the invention is an electrical-input/optical output device in either a vertical or side-by-side geometry suitable for use in one- and two-dimensional arrays.
Devices integrating photodetector and photoemitting components with light-emitting components are known, and the following references discuss multilayer devices or combinations of devices that receive optical inputs, convert them to electrical signals, and then use the electrical signal to cause light emission. These particular devices are prone to latch-up, that is, although the devices can be turned on with a light pulse, they can't be turned off without significantly decreasing the electrical current flowing through the device because of either optical or electrical excessive positive feedback. This is viewed as a disadvantage for a system where all signals are optical. Photodiodes are inefficient in converting electrical power to optical power and are not as directional as lairs. Edge-emitting lasers are not readily fabricated into two-dimensional arrays.
The reference of Beneking, H., GaAs-GaAlAs phototransistor/laser light amplifier, ELECTRON. LETT. 16(15): 602-603, 1980 July 17, discusses the integration of phototransistors on top of edge-emitting lasers tier use as a light amplifier. Beneking, H. Full Solid State Image Converter Based on Integration of Phototransistors and light-emitting diodes, ELEC. DEV. LETT. EDL-2(4): 99-100, 1981 April 4, discusses arrays of phototransistors and light-emitting diodes one on top of the other for purposes of converting an image from one wavelength to another.
Sasaki, A. and M. Kuzuhara, in GaAsP-InP Heterojunction Phototransistors and Light Amplifiers, JAPAN J. OF APPL. PHYS. 20(4): L283-L286, 1981 April discusses the vertical integration of a phototransistor and a light-emitting diode. Although the configuration disclosed prevents electrical feedback to avoid latching operation, it does not discuss optical feedback which would indeed cause the device to latch.
Taylor, G. W., J. G. Simmons, A. Y. Cho and R. S. Mand, A new double heterostructure optoelectronic switching device using molecular beam epitaxy, J. APPL. PHYS. 59(2): 596-600, 1986 Jan 15, discuses a multilayer device closely related to p-n-p-n structures such as thyristors to be used for optical logic and memory. In some ways these devices can be thought of as an light-emitting diode (p-n junction) placed next to a phototransistor, a n-p-n device, but if these devices are connected in such a way that both electrons and holes flow between them, they latch-up when turned on. Taylor also specifically mentions that while his devices emit spontaneous emission, like that from light-emitting diodes, they could be made to lase (stimulated emission) by configuring the layers in a cavity. The reference, however, does not provide the teaching for the implementation of either the edge-emitting or the vertical cavity surface emitting type lasers.
Kasahara. K., Y. Tashiro, N. Hamao, M. Sugimoto and T. Yanase, Double heterostructure optoelectronic switch as a dynamic memory with low-power consumption, APPL. PHYS. LETT. 52(9): 679-681, 1988 Feb 29, addresses making electrical contacts to interior layers of a p-n-p-n device like Taylor's above, in order to improve the electrical switching speed and increase flexibility.
Tashiro, Y., N. Hamao, M. Sugimoto, N. Takado, S. Asada, K. Kasahara and T. Yanase, Vertical to surface transmission electrophotonic device with selectable output light channels, APPL. PHYS. LETT. 54(4): 329-331, 1989 Jan 23, discusses a p-n-p-n layered device formed into an edge-emitting laser with multiple outputs. It also presents laser emission out of the surface of the wafer by turning the emission from the edge of lasers using integral 45.degree. mirrors. This approach has the disadvantage of requiting more surface area on the wafer and requiring vertical facets formed either by cleaving or sophisticated dry etching techniques.
Lin, S. H., J. H. Kim, J. Katz and D. Psaltis, integration of high-gain double heterojunction GaAs bipolar transistors with a light-emitting diode for optical neural network application, IEEE/CORNELL CONFERENCE ON ADVANCED CONCEPTS IN HIGH SPEED SEMICONDUCTOR DEVICES AND CIRCUITS, 344-352, 1989, addresses integrating multiple transistors and phototransistors with light-emitting diodes in arrays for neural network applications. The devices are laid out side-by-side which is required for the multiple electrical connections when more than one transistor is used to drive the light-emitting diode.
U.S. Pat. No. 4,891,093, entitled "Processes For the Manufacture of Laser Including Monolithically Integrated Planar Devices," to Smith, Jan. 2, 1990, discloses a method and a structure suitable for monolithic integration of an edge-emitting laser and another device, e.g. a field-effect transistor in a laterally offset planar region. Although Smith discloses a laser monolithically integrated with other devices capable of driving the laser, the actual laser used is an edge-emitting laser. The method disclosed in Smith '093, moreover, is most applicable to planar devices requiring low doping concentrations, e.g. the field-effect transistor, and the devices are positioned laterally.
U.S. Pat. No. 4,910,571, entitled "Optical Semiconductor Device," Kasahara et al., Mar. 20, 1990, teaches an optical semiconductor device for receiving and emitting light at laterally separated points to facilitate alignment of light axes for multiple inputs or outputs. Although the device disclosed in the patent reference has optical inputs and optical outputs, and uses layers of semiconductor materials that have an overall doping structure of p-n-p-n, its purpose is to provide a plurality of laterally separated regions of light reception and emission, instead of a single receiving and single outputting region that are laterally coincident. The device of Kasahara '571 requires that the light inputs and outputs be on the same side of the substrate and produces optical output from a light-emitting diode, which is an incoherent light source. The device of Kasahara '571 latches so that it emits light even after the input light is removed until the electrical supply is removed.
U.S. Pat. No. 4,879,250, entitled "Method of Making a Monolithic Interleaved light-emitting diode/PIN Photodetector Array," to Chan, Nov. 7, 1989 discloses arrays of different types photoelectric devices (e.g. photodiodes and light-emitting diodes) fabricated from the same epitaxial layers, but these arrays have light inputs and outputs on the same side of the substrate. The photodiodes provide no electrical gain, are inefficient in electronic to optical conversion, and are not as directional as lasers.
U.S. Pat. No. 4,833,511, entitled "Phototransistor Device," to Sugimoto, May 23, 1989, discloses an optically controllable device where the level of the input signal changes the absorption in the device and hence the amount of transmitted light. The device of Sugimoto '511 controls optical output signals with optical input signals, and uses optical signal paths perpendicular to the substrate, and use phototransistors to amplify the current generated by low levels of input signal. Sugimoto's device, however, contains no emitting element for converting electrical signals into optical signals. The light output is always smaller than the light input because the output is just the unabsorbed portion of the input. Moreover, the device has as an object of its design a bistable or hysteretic behavior.
U.S. Pat. No. 4,888,625, entitled "Optoelectronic Coupling Element, and Method of Making Same," to Mueller, Dec. 19, 1989 discloses an optocoupler of solid construction formed by affixing a chip of light emitting elements to one side of an optic coupling medium and a chip of light detecting elements to the other. The light emitting elements are intended to direct their light output to the light detecting elements attached to the same piece of optic coupling medium. It takes an electrical input, converts it to light which passes through the optic coupling medium to a detector which converts the light to electricity. While the device of Mueller '625 uses light emitting and detecting elements which direct their light perpendicular to the plane of the devices, and uses stacked geometries with the two elements at the same lateral point, its purpose is to convert an input electrical signal to an output electrical signal using elements that are optically connected, rather than acting upon an input signal to produce an output optical signal using elements that are electrically connected.
U.S. Pat. No. 4,947,400. entitled "Laser-Photodetector Assemblage," to Dutta, Aug. 7, 1990, discloses a monolithic integration of an edge-emitting laser and a phototransistor situated side-by-side so that the phototransistor responds to light leaking out of the laser. The electrical signal from the phototransistor is used as a monitor of the laser power. The use of the phototransistor, in Dutta '400, is to sense the output of a laser, rather than to control the lair. The geometry of these devices is also a side-by-side arrangement.
The operation of the heterojunction phototransistor as an individual component has been described in the literature, see e.g., J. C. Campbell, Phototransistors for Lightwave Communication, in SEMICONDUCTORS AND SEMIMETALS, Vol. 22, Part 2, pp. 389-447 (1985); and the operation of the vertical cavity surface emitting laser as an individual component was described in Jewell. J. L. et al., Low-Threshold Electrically Pumped Vertical-Cavity Surface-Emitting Microlasers, ELECT. LETT., Vol. 25, No. 17, Aug. 17, 1989, pp. 1123-1124.
It is thus an object of the invention to provide an optical inputs/optical outputs or electrical inputs/optical outputs device suitable for use in arrays, and as individual elements in optoelectronic integrated circuits. This object is achieved by the integration of a photodetector, transistor, diode, or other photo- or electro-active components with a vertical cavity surface emitting laser in a either a vertical or a side-by-side arrangement. The vertical and the side-by-side geometry provides for small, compact, and densely-spaced arrays and individual elements in optoelectronic integrated circuits (OEICS) which enable, for example, optoelectronic interconnects, laser-scanning printing and projection, optical communication, neural networks, and optical computing. Additionally, the geometry simplifies the required electrical contacts between the components.
It is yet another object of the invention to provide an integrated optoelectronic device with high optical gain. In the photodetector/vertical cavity surface emitting laser embodiment, this object is achieved by either using a photodetector with intrinsic electronic gain, such as a phototransistor, or by using a photodetector such as a PIN photodiode in combination with a separate component, such as an electronic amplifier. The vertical cavity surface emitting laser further contributes to the increased optical gain by having efficient electronic-to-photonic conversion and lasing action. The mulitmilliwatt optical output of the vertical cavity surface emitting laser advantageously enables a fan-out capability because the light can be split and redirected. In addition, cascadability can be achieved if the output of the vertical cavity surface emitting laser or the output interactive component drives a similar but separate device. Cascadability facilitates optical computing and neural networks. Additional advantages achieved by the particular components is that the device is less sensitive to small fluctuations in power, and the device is much faster because more power is available to drive the next device.
Yet, still another object of the invention to provide a fundamental optical device characterized by high contrast and stability. High contrast is the ratio of the maximum optical output power of the device turned on to the power of the light emitted when the device is just below threshold for turn on. The feature of the invention that achieves this object is that the vertical cavity surface emitting laser has a threshold current, and the nonlinear response of the vertical cavity surface emitting laser to current input. In addition, an interactive component such as a phototransistor, may be designed for a nonlinear response. These features of the invention enable compatibility with digital or sigmoidal (smooth) switching applications. Moreover, the device is less susceptible to noise or fluctuations in the supply voltage, or in optical or electronic fluctuations in individual components of the device. Specific applications requiring a nonlinear response, such as neural network and sigmoidal switching applications, are also available.
It is yet another object of the invention to provide an optoelectronic device with controlled optical and electrical feedback and/or input/output isolation. One way to control the optical feedback within the vertical cavity surface emitting laser is to design the mirrors within the lair to have specific reflectivities to obtain optically non-hysteretic, hysteretic, or latching capabilities which will be discussed in further detail. Additionally, an absorbing layer or absorbing mirrors can be placed between the vertical cavity surface emitting laser and the photoactive element. To minimize optical feedback when the interactive component is a phototransistor, the two optical devices may be made to be sensitive to different wavelengths or placed side-by-side so that the optical output of the vertical cavity surface emitting laser does not intersect the photo interactive component. Electrical feedback is provided by a semiconductor layer between the vertical cavity surface emitting laser and the interactive component to prevent minority carrier transport. In an array, complete electronic isolation between the individual devices controls electrical feedback. Advantages realized by these structural features of the invention is that the device may be turned on or off only with optical signals, rather than reversing or stopping the flow of current, thereby facilitating optical computing. Because the device can be designed to have no latching, the device has faster response time because it does not have to overcome positive feedback when switching on and off. Moreover, the device can be designed to adjust the feedback to control variable hysteresis. Arrays using these devices can also be configured as latching devices by allowing optical feedback from the vertical cavity surface-emitting laser to be absorbed in, for example, the base/collector regions of a heterojunction phototransistor or by replacing the heterojunction phototransistor by a thyristor or photodetector/electronic amplifier combination in which case they would function as image memories capable of capturing and storing a two-dimensional image until the array is reset.
Still another object of an embodiment of the invention is to be able to control the wavelengths of the optical signal compared to the wavelength of the output optical signal. When the interactive component is a heterojunction phototransistor, the device can be designed so that the heterojunction phototransistor is sensitive to a wavelength other than that emitted by the vertical cavity surface emitting laser. Moreover, within the heterojunction phototransistor, the bandgaps of the emitter, base, and collector can be adjusted to control the wavelength range over which the phototransistor may be photoactivated. Those features of the surface emitting laser that can be used to control the wavelength of the device include adjusting the bandgap of the laser and adjusting the length of the laser cavity.
It is still another advantage to provide a fundamental optical device suitable for fabrication into large arrays of similar elements in a configuration compatible with parallel optical signal processing. Other advantages achieved are that the device array may be readily fabricated with microfabrication technology, be microscopic in size, and be integrable with other optoelectronic components without being adversely affected by feedback.
Still another object of the invention is to provide an optoelectronic device having an electrical input/optical output. This objective is achieved by the integration of an electroactive component, such as a transistor or dime or other current or voltage controlled components with a vertical cavity surface emitting laser. In particular, both field effect transistors (voltage controlled) and bipolar transistors (current controlled) are examples of such transistors. This vertical or side-by-side geometry provides for an electrical input/optical output component suitable as a building block upon which to build OEICS such as optoelectronic interconnects for computing, electrically driven vertical cavity surface emitting laser arrays for laser-printing, -scanning, and -projection.

Integration of photoactive and electroactive components with vertical cavity surface emitting lasers


A system of surge suppressor units is connected at multiple locations on a power transmission and distribution grid to provide grid level protection against various disturbances before such disturbances can reach or affect facility level equipment. The surge suppressor units effectively prevent major voltage and current spikes from impacting the grid. In addition, the surge suppressor units include various integration features which provide diagnostic and remote reporting capabilities required by most utility operations. As such, the surge suppressor units protect grid level components from major events such as natural geomagnetic disturbances (solar flares), extreme electrical events (lightning) and human-generated events (EMPs) and cascading failures on the power grid.

Current surge suppression systems have been developed to protect equipment from voltage transients on one side of a three-phase power supply bus used in industrial settings such as in plants, factories, or other large scale systems. In one known voltage surge suppressor, three single-phase transformers are provided with terminals that are each connected through a fused disconnect to a respective single-phase power supply on the power-supply bus. This surge suppressor protects against voltage transients, which can severely damage or destroy equipment connected to the effected three phase circuit or can cause power outages throughout the plant. The surge suppressor circuit operates as a surge and fault protector for any equipment on the power bus. This surge suppressor system is usable with 480 volt distribution systems powered by a 2000 to 3000 kVA ungrounded delta power transformer that feeds approximately 1000 ft of bus duct, so as to generally have about 1 to 3 Amperes of charge current. This charge current may generally be just over 2 Amperes by actual amperage determined by readings in the field, wherein the variations are due to the lengths of the feeder cable and bus duct as well as the number and size of the electric motors and power factor correction capacitors operating at any given time. More typically, resistance grounding circuits constantly bleed this charge to ground to help prevent grounding problems. The known surge suppressor is connected to the bus bars and does not bleed this energy to ground, but uses this charge energy to help stabilize and balance the phase voltages to ground.
This known surge suppressor is installed in and protects equipment connected to a power supply bus at the facility level. However, there is a need for a surge suppressor system for medium and high voltage electrical systems on the grid located outside of and remote from an industrial bus bar power supply system.
A power grid is comprised of many components that are generically described as generators, transformers, transmission and distribution wires and controls. Generators are driven by many forms of energy such as coal, natural gas, nuclear fission, hydro, solar and even wind to name a few. Once power is created at a relatively low voltage around 6,000 volts it is stepped up to high voltage (often in the hundreds of thousands) using large power transformers (LPTs) which allow the electricity to be more effectively delivered over miles of high tension (transmission) wires. Once the electricity reaches the general area where it will be used it is then stepped back down closer to the final voltage at sub/distribution stations. Distribution lines carry near-low voltage electricity on roadside power poles or underground to the final transformer before being delivered into buildings for use.
The present invention is a surge suppressor system that improves upon existing phase adder circuit products, is designed to provide grid-level protection to residences and industrial facilities prior to delivery of the power to these structures so they can withstand higher voltages, provide monitoring and communication from remote settings, and provide more robust installation platforms, and configures the system of surge protection devices in parallel to protect grid level applications on both sides of a power system where the need exists to step power either up or down.
On a medium or high voltage system, the current invention would be configured to handle large and rapid energy "drain offs", prevent interference from high voltage/high magnetic flux, allow remote performance maintenance, and increase protection, as required, from physical attacks and severe over voltages. When the invention is installed in parallel with critical grid infrastructure, the components of the grid are protected against:
Transients: An impulsive transient is what most people are referring to when they say they have experienced a surge or a spike. Many different terms, such as bump, glitch, power surge, and spike have been used to describe impulsive transients. Causes of impulsive transients include lightning, poor grounding, the switching of inductive loads, utility fault clearing, and Electrostatic Discharge (ESD). The results can range from the loss (or corruption) of data to physical damage of equipment. Of these causes, lightning is probably the most damaging. The surge suppressor devices of the current invention provide grid-level protection against such transients.
Interruptions: An interruption is defined as the complete loss of supply voltage or load current. The causes of interruptions can vary but are usually the result of some type of electrical supply grid damage, such as lightning strikes, animals, trees, vehicle accidents, destructive weather (high winds, heavy snow or ice on lines, etc.), equipment failure, or a basic circuit breaker tripping. While the utility infrastructure is designed to automatically compensate for many of these problems, it is not infallible.
Sag/Under-voltage: A sag is a reduction of AC voltage at a given frequency for the duration of 0.5 cycles to 1 minute's time. Sags are usually caused by system faults and are also often the result of switching on loads with heavy startup currents.
Swell/Over-voltage: A swell is the reverse form of a sag, having an increase in AC voltage for a duration of 0.5 cycles to 1 minute's time. For swells, high-impedance neutral connections, sudden (especially large) load reductions, and a single-phase fault on a three-phase system are common sources.
Frequency Variations: There are all kinds of frequency issues from offsets, notching, harmonics, and inter-harmonics; but these are all conditions that occur largely in the end user's power system. These variations happen because harmonics from loads are more likely in smaller wye type systems. The high frequency variations that may lead to massive interconnected grid failure would come from the sun or enemy attack. Damage to only a few key infrastructure components could result in prolonged blackouts and collateral damage to adjoining devices. Solar flares are natural occurrences that vary in severity and direction. This "solar weather" is sent out from the surface of the sun throughout our solar system in all directions. These flares contain large amounts of magnetic energy and depending on how they hit the earth can cause component damage on the surface or by temporarily changing the properties of the planet's magnetic core. Either way, a direct hit of large proportion could cause equipment failure and black out entire regions. Electromagnetic Pulses (EMP) can be used in similar fashion but directed by enemy combatants in the form of a high altitude nuclear explosion. A well-executed detonation over Cincinnati, Ohio could black out 70% of the American population. Damage to large power transformers or generators could take months to repair. The high frequency disturbance of nuclear explosions can destroy unprotected components much like an opera singer's voice can break a glass. The magnitude of each disturbance may depend on the source but each can be mitigated effectively through the use of a phased voltage stabilization system such as the invention.
Current surge suppression technology may attempt to address these disturbances on the facility side of the power distribution system, so as to directly protect equipment in a facility, and also at a grid level but these technologies possess drawbacks in protecting against these disturbances.
As one example of a known surge suppression technology, capacitors are thin conductors separated by even thinner layers of insulation. Capacitors have a design rating for current and voltage. If this rating is not exceeded they will typically operate for 10 to 15 years. One high voltage spike may (and generally will) cause catastrophic failure of capacitors. In factories with 4,000 power factor correction capacitors, it is not uncommon to have 300 to 500 capacitors fail each year due to high harmonic current or high voltage spikes.
In another example, SPD (Surge Protective Devices) are solid state devices constructed in various sizes. Like capacitors, their ratings are also in current and voltage. When the MOV (Metal Oxide Varistor) is hit with many low-level voltage spikes it degrades, and the "clamping voltage" will rise as the MOV breaks down, allowing the clamping voltage to continue to rise until it no longer protects the equipment it was installed to protect. When a voltage spike hits the MOV above the rated voltage, it starts to conduct thousands of amps to ground, causing noise on the ground system and very high heat within the SPD. If the event is longer than a few millionths of a second, the MOV could be destroyed, and therefore would no longer protect the equipment it was installed to protect.
Further, Faraday cages have been used for many years to house and protect computer hardware and sensitive data in factories, as well as some government and military buildings. They recently have been touted as a solution to solar flares, lightning and EMP pulse issues. However, most buildings are not built within a metal enclosure and it is difficult and expensive to properly design and build these enclosures. Most automobiles, trucks, trains and planes are totally enclosed by metal, but they offer no protection from any of these events. By design, the metal enclosure must have a suitable solid ground connection as it relies heavily on enclosing and shielding the sensitive electrical equipment and removing the energy by draining it to ground. The power company uses the Faraday cage design in some of their grid tie substations. They are extremely large and expensive.
The greatest threat to the grid/LPTs is the presence of an electromagnetic pulse (EMP) or geomagnetic disturbance (GMD), the latter would originate as a solar flare and the prior would be from enemy weaponry. Either threat could cause an overworked LPT to be saturated with power and cause the transformer to burn out. With an EMP, saturation could happen in less than a second so detection systems are worthless.
GMD is slower to cause damage so detection systems could reduce the load on a transformer which could allow it to ride out the GMD incident. This brown out or temporarily blacked out condition could last minutes, hours or days depending on the severity of the solar storm. In the case of the 1869 Carrington Event the Earth was pummeled with solar magnetic energy for nearly a month. While the grid could survive such an event if properly managed it would hardly be well received by citizenry to be without power that long.
Simply, Large Power Transformers cannot be protected with old technology like Faraday Cages. The hundreds of miles of wire that connect the LPT to sub stations way down the line act like antennae and harvest EMP with such efficiency that the Faradays would have no value. Surge protecting devices are not fast enough to arrest an EMP which occurs in a millionth of a second or handle the massive electron flow that occurs at the transmission level without allowing current bleed through to the LPT which would ultimately have the same effect as an unprotected system. Grounding systems would try to route surplus current from an EMP to earthen ground probes or mats but that excess energy would likely find its way back into the power system through the ground bus and result in burnout as well.
The present invention relates to a system of surge suppressor units connected at multiple locations on the grid to provide grid level protection against various disturbances before such disturbances can reach or affect facility level equipment. The effect of the invention is significant for protecting grid level applications. With the unique application and design of the present application, the surge suppressor units of the present invention would effectively prevent major voltage and current spikes from impacting the grid. In addition, the surge suppressor units included various integration features which provide diagnostic and remote reporting capabilities required by most utility operations. As such, the surge suppressor units protect the grid level components from major events such as natural geomagnetic disturbances (solar flares), extreme electrical events (lightning) and human-generated events (EMPs) and cascading failures on the power grid. The invention also provides significant protection against arc flashes and reduces voltage harmonics that exists in "normal" grid operations.
The reporting features of the inventive surge suppressor unit are also unique to protecting medium and high voltage systems that are often in remote or isolated settings. Unlike devices designed to protect local low voltage equipment and infrastructure, real time diagnostic reporting from the surge suppressor unit is critical to ensure it is working effectively and providing the continuous protection needed to protect power systems like the US power grid.
As discussed, various known technologies (such as MOVs, Faraday cages, even similar devices designed with fused disconnects) attempt to also correct voltage imbalances. These devices either do not provide the scalability to the voltage requirements at the grid level or "burn out" when significant voltage is applied. These technologies also do not provide reporting, remote diagnostics, or protection from ancillary dangers such as arc flashes or localized voltage overflow. The surge suppressor system of the present invention provides each of these benefits and is also completely scalable for various grid level applications.
Other objects and purposes of the invention, and variations thereof, will be apparent upon reading the following specification and inspecting the accompanying drawings.
Certain terminology will be used in the following description for convenience and reference only, and will not be limiting. For example, the words "upwardly", "downwardly", "rightwardly" and "leftwardly" will refer to directions in the drawings to which reference is made. The words "inwardly" and "outwardly" will refer to directions toward and away from, respectively, the geometric center of the arrangement and designated parts thereof. Said terminology will include the words specifically mentioned, derivatives thereof, and words of similar import.

This patent is subject to a terminal disclaimer.

Surge suppression system for medium and high voltage


A bundling tie for use in looping about a plurality of cables includes a locking head and elongate strap. A pair of locking barbs are movably supported in the head, each barb having an engagement portion for locking engagement with a strap end upon insertion of the strap ends into the head. Each barb includes a knife-like element for biting insertion into the strap and a blunt stop wall adjacent the knife-like element for limiting the depth of insertion of the knife-like element into the strap.

The use of bundling ties to bundle a plurality of elongate objects such as electrical wires or cables has long been known. One early example of such a bundling tie is shown in U.S. Pat. No. 3,102,311. Typically, bundling ties include a strap which may be looped around a bundle of articles and secured in a head portion which locks the strap thereto.
Locking mechanisms used in bundling ties basically take two forms. One approach has been the use of integrally formed locking means pivotally carried by the head of the tie. Such locking means includes a toothed plastic pawl which engages corresponding teeth on the tail of the strap. Advantages of locking means of this type are readily apparent in that the strap can be integrally molded with no secondary operation needed for providing the locking means. An example of such a bundling tie is shown and described in U.S. Pat. No. 3,486,201. One distinct disadvantage of a tie of this construction is that it requires intricate molding techniques to form the tie. Both the pawl and the tail must include complimentary ratchet teeth thereon for locking purposes. Deformation of the interlocking plastic teeth could cause undesirable pullout of the tail from the tie head. Also, the teeth and the tail form stress points which weaken the tie and could cause undesired breakage.
A second technique for forming locking means in a bundling tie head includes the use of a metallic barb embedded into the base of the tie head at an angle to the inserted tail. This provides a self-clinching device which bites into the tail of the tie to securely retain the strap in the head. An example of a bundling tie having a metallic barb is shown and described in U.S. Pat. No. 3,186,047. The metal barb of the tie of the '047 patent actually bites into the inserted tail. Thus, there is no need to provide complimentary teeth on the tail as is necessary with the device of the '201 patent. The biting engagement of the metal barb into the tail portion of the strap provides superior pullout resistance and results in a smooth body tail which has superior strength. However, since locking engagement of the head and the tail is achieved by the metal barb actually digging into the strap, there could be a tendency for the metallic barb to dig too deeply into the strap, thus weakening the strap at the point of engagement. It is therefore desirable to provide a barb for a bundling tie head which will limit the depth of insertion of the barb into the strap, thereby preventing the severing of the strap thereat and increasing tensile and shear strength of the tie.


An over-voltage protection circuit assembly includes a connector and an over-voltage protection circuit. The connector includes a power terminal. The over-voltage protection circuit includes a voltage input terminal, and a voltage output terminal. The voltage output terminal connected to the voltage input terminal via a resistor. A relay includes an inductance coil and a switch. The inductance coil is connected between the voltage input terminal and ground. A warning unit is connected in series with the switch of the relay between the voltage input terminal and ground. A voltage regulating diode is connected between the voltage output terminal and ground. The anode of the voltage regulating diode is connected to ground, and the cathode of the voltage regulating diode is connected to the voltage output terminal.

1. Field of the Invention
The present invention relates to an over-voltage protection circuit.
2. Description of Related Art
Generally speaking, connectors are used for joining electronic circuits together and transmitting power or data therebetween. Quality of the connectors may affect not only reliability of signal transmission among electronic circuits, but also the overall operation of electronic equipment. Usually, a four pin connector has 12V and 5V voltage terminals. Users may mis-plug the connector and provide an over-voltage to the electronic circuits. If 12V is provided to a 5V circuit, the circuit may be damaged or destroyed.
What is desired, therefore, is to provide an over-voltage protection circuit.


The present invention relates to a media processing system that comprises a bus for communicating digital signals thereon with a media processor connected to the bus, for processing signals supplied thereon. The system further has a display device connected to the bus for displaying digitized images thereon, received from the bus. The system has an audio transmitter connected to the bus, for wirelessly transmitting audio digital signals from the bus. The system further has a connectable memory for connecting to the bus and for supplying signals representing digitized images and audio digital signals to the bus. Finally the system has a receiver to receive encoded digitized images or audio digital signals for supplying the received signals to the bus for storage in the memory.

Wireless transmission and receipt of streaming data typically includes transmission, processing, buffering and receiving performed as a function of clock information, such as clock recovery and bit clock data, or by related tracking loop information. In selecting most efficient transmission mechanisms/schemes, for example, typical systems make measurements at the data sink or receiver on values like packet or bit error rate, or signal strength. However, since the transmission mechanisms/schemes are selected based on such time domain observations, the capabilities of selecting and diversifying the transmission are limited. Drawbacks of these systems surround the failure of utilizing combinations of spatial, frequency, and time mechanisms/schemes to achieve the full breadth of transmission diversity available.
Other existing systems for processing and receiving streaming data sometimes include specialized tracking components implemented to process such information even during times when it is changing very rapidly. However, such components generally must be realized via complex and/or dedicated hardware such as application specific hardware. Components such as these are unable to be developed readily and easily, and they are difficult to modify after production.
Further, many existing tracking components operate based on theories of clock recovery. These systems are directed to situations where receiving elements track only at a rate at which the physical bits are being clocked into the system, such that data is drawn from a receiving buffer at a rate that matches the rate of the data source. These systems do not address concerns where mere clock rate tracking fails to enable accurate receipt of wireless data.
In addition, if there are errors in the transmission, e.g. in the medium, with a fixed clock rate in the receiver to clock out the bits received in the buffer of the receiver, an underflow condition might occur whereby data is clocked faster than it is received.
In sum, there is a need for systems and methods that can adequately transmit and receive streaming data by, for example, including buffering and diversity transmission features that overcome such drawbacks while maintaining low system complexity.
Systems for the display of digital still or video images are also well known in the art. Typically, such system have included a media processor, connected to a bus, with a display (such as an LCD display) and to a connector, connectable to a removable non-volatile memory, such as NAND memory having digital images stored thereon. The non-volatile memory can also store audio files of music and the like, such as MP3 files, for playback by the media processor, either alone or in connection with the display of the digital images. Typically, however because such a system is a compact system (used to display images that typically are the size of a photo frame), the quality of the speakers of the system to output the audio files is wanting. Thus, there is the need to have quality of speakers that can output the high quality digital audio files that can be processed by the media processor in such a system.

Digital display system with media processor and wireless audio


A pump assembly which comprises a vane pump and a second hydraulic pump driven together with this vane pump. The vane pump has a suction region in which first pressure spaces between the vanes and second, rear pressure spaces behind the vanes become larger and a pressure region in which the pressure spaces become smaller and in which the pressure spaces are fluidically connected to a pressure outlet. This vane pump is intended particularly for supplying operating cylinders of a hydromechanical transmission of a motor vehicle with pressure fluid under relatively high pressure. The second hydraulic pump has positively driven displacement elements and is intended for supplying a circuit having a relatively low system pressure, in particular a lubricating-oil circuit of the motor vehicle, with pressure fluid. So that the vane pump also begins to deliver at low outside temperatures and with highly viscous pressure fluid even at low rotational drive speeds, the rear pressure spaces of the vane pump are connected in the suction region to the pressure outlet of the second hydraulic pump.

The invention is based on a pump assembly which comprises a vane pump, which, in particular, is to serve to supply operating cylinders of a hydromechanical transmission of a motor vehicle with a pressure fluid under high pressure, and a second hydraulic pump, the displacement elements of which are positively driven and which serves to supply a circuit having a low system pressure, in particular a lubricating-oil circuit of the motor vehicle, with the pressure fluid. The two hydraulic pumps therefore work with the same operating medium.
A pump assembly which comprises a vane pump and a second hydraulic pump whose displacement elements are positively driven has already been disclosed by EP 0 128 969 A1. In this publication, the oil flow of the vane pump serves to supply pressure medium to a power-assisted steering system. The second hydraulic pump is a radial piston pump, the oil flow of which serves a device for regulating the level of the vehicle. The two hydraulic pumps of the known pump assembly are located in two pressure-fluid circuits which only have the oil supply tank in common.
A vane pump generally has a suction region in which first pressure spaces between the vanes and second, rear pressure spaces behind the vanes become larger and receive pressure fluid in the process. In a pressure region, the pressure spaces become smaller, as a result of which pressure fluid is displaced to a pressure outlet. For satisfactory functioning of the vane pump, it is necessary for the vanes, which are guided in radial slots of a rotor, to bear against a stroke ring. Centrifugal forces which act on the vanes are utilized for such a unit, the effect of which centrifugal forces requires a substantial pressure balance between the front side bearing against the stroke ring and the rear side of the vanes in the slots. This condition is met due to the fact that the rear pressure spaces are also connected in the pressure region to the pressure outlet of the pump. In the suction region, both the first pressure spaces and the second pressure spaces are normally connected to the suction inlet of the vane pump, so that the same pressures again prevail in them.
The higher the viscosity of the pressure fluid, this viscosity increasing with decreasing temperature, the higher are the centrifugal forces which are required for bringing the vanes to bear against the stroke ring. This means that a vane pump of a conventional type of construction only begins to deliver at a rotational speed which is all the higher, the lower the temperature of the pressure fluid is. In particular, the engine and transmission oil of a motor vehicle, in particular of a farm tractor, may become so viscous at low ambient temperatures that the vane pump only begins to deliver at unacceptable high rotational speeds.
The object of the invention is to develop a pump assembly according to the preamble of patent claim 1 in such a way that satisfactory operation is possible even at low ambient temperatures and thus at a high viscosity of the pressure fluid.
According to the invention, this object is achieved in a pump assembly of the introductory mentioned-type in that the rear pressure spaces of the vane pump are connected in the suction region to the pressure outlet of the second hydraulic pump. Since the displacement elements of the second hydraulic pump are positively driven, the second hydraulic pump starts to deliver when it is driven, irrespective of the viscosity of the pressure fluid. The pressure building up at its pressure outlet is then also present in the rear pressure spaces of the vane pump and produces at the vanes a force which, in addition to the centrifugal force, presses the vanes radially outward against the stroke ring. The system pressure in the circuit which is supplied by the second hydraulic pump is relatively low and may be within the region of, for example, 5 bar. The frictional force between the vanes and the stroke ring therefore increases only slightly in the suction region of the vane pump, so that the wear on these parts continues to remain low.
DE-B 17 28 276 has certainly already disclosed a pump assembly which comprises two hydraulic pumps and in which the rear pressure spaces at the vanes of a first hydraulic pump formed as a vane pump are connected in their suction region to the pressure outlet of the second hydraulic pump. Here too, however, the second hydraulic pump is a vane pump which fails with highly viscous pressure fluid, so that the problem underlying the invention is not removed in the pump assembly disclosed by DE-B 17 28 276.
Thus, the vane pump is preferably one with a variable displacement volume, since the consumption of non-utilizable energy can thereby be reduced compared with a vane pump having a constant displacement volume. Since, in particular when used in motor vehicles, in addition to being economical with primary energy, it is very important that the individual components are inexpensive, the vane pump according to patent claim 3 is advantageously directly controlled and, upon reaching a set maximum pressure with its displacement volume, returns to such an extent that, at the maximum pressure, only the small quantity lost due to internal leakage is replaced. The power loss which then results from the product of the maximum pressure and the leakage quantity is slight, since the leakage quantity is slight.
The second hydraulic pump is advantageously a gear pump, in particular an internal gear pump without a filling piece, which gear pump works quietly, is favorable in production and can also be configured in its construction in such a way that it can be combined with the vane pump to form a construction unit without great outlay, as specified in patent claim 6.

Pump assembly comprising two hydraulic pumps


In an ultrasound transducer arrangement having an electroacoustic transducer part, at least one acoustic matching layer is allocated to the transducer part. The acoustic matching layer is composed of an electrically conductive skeleton having interspaces connected to one another. The skeleton is constructed of particles connected to one another. The size of the particles is smaller than the wavelength of an acoustic wave in a matching layer, as a result of which no significant scattering of the wave occurs in the matching layer. The interspaces are filled with a curable casting compound.

1. Field of the Invention
The present invention is directed to an ultrasound transducer arrangement having an electroacoustical transducer part to which at least one acoustic matching layer is allocated.
2. Description of the Prior Art
Matching layers are employed in ultrasound technology in order to reduce reflections outside an examination subject at boundary surfaces between two materials having different impedance, or to transmit the ultrasound energy from the transducer part into the examination subject and back with as little loss as possible. To that end, at least one matching layer is arranged between the two materials. For example, matching layers are employed for acoustic matching of an electroacoustic transducer part to an examination subject. In addition, an acoustic sump or damping member having at least one matching layer can be adapted to the transducer part.
U.S. Pat. No. 4,717,851 discloses an ultrasound transducer arrangement of this type. For acoustic matching of the electroacoustic transducer part to an examination subject or to an acoustic propagation medium, matching layers are arranged in the sound propagation path, their acoustic impedance lying between that of the transducer part and that of the examination subject or propagation medium. Matching layers composed of a synthetic resin such as, for example, epoxy resin, wherein superfine particles of a mineral or metallic material are imbedded, are standard. The acoustic impedance of the matching layer is thereby essentially set by the quantity and the material of the added particles. A uniform distribution of the particles in the synthetic resin, however, cannot always be achieved over larger volume regions. As a result, the reproduceability of the function-determining acoustic properties is limited. Moreover, inhomogeneities and voids must be accepted under certain circumstances. Such matching layers are electrically non-conductive; the transducer part must therefore be additionally electrically contacted and/or shielded.
European Application 0 031 049 discloses an acoustic transducer arrangement for testing materials that is suitable for employment at high temperatures. The transducer arrangement includes a lead part composed of a metallic member having high specific attenuation. A sintered metal is proposed as the material for this member. The high specific attenuation is thereby decisively influenced by the porosity. A high specific attenuation, however, is undesirable in acoustic matching layers, particularly in medical applications.

Ultrasound transducer arrangement having an acoustic matching layer


A satellite-broadcasting receiving converter includes a plurality of output terminals each of which is connected to an external receiver, to each of which a selection control voltage in which a high-frequency voltage is superposed on a DC voltage is sent from the external receiver, and from each of which one type of a receiving signal is selected according to the selection control voltage and output; and a regulator for generating a power-source voltage from the selection control voltage. Since a high-frequency attenuation unit is connected in series between each output terminal and the regulator in the satellite-broadcasting receiving converter, even if a plurality of selection control voltages are input in common to the regulator, the plurality of selection control voltages different from each other do not affect each other and thereby only one regulator is required.

1. Field of the Invention
The present invention relates to satellite-broadcasting receiving converters with a plurality of output terminals, connected to satellite-TV-broadcasting receivers (hereinafter just called receivers).
2. Description of the Related Art
Satellite TV broadcasting uses, for example, a frequency band ranging from 10.7 GHz to 12.75 GHz, with 10.7 GHz to 11.7 GHz for analog broadcasting and 11.7 GHz to 12.75 GHz for digital broadcasting. A horizontal-polarization wave and a vertical-polarization wave are used for both analog broadcasting and digital broadcasting. In other words, four types of satellite TV broadcasting are used in combinations of analog broadcasting and digital broadcasting, and a horizontal-polarization wave and a vertical-polarization wave.
Satellite-broadcasting receiving converters receive satellite TV broadcasting signals sent from broadcasting satellites and convert a received frequency to a lower frequency.
When a satellite-broadcasting receiving antenna (not shown) receives a signal, the signal is divided into a horizontal-polarization wave and a vertical-polarization wave by a waveguide (not shown) and input to a satellite-broadcasting receiving converter.
FIG. 2 shows a conventional satellite-broadcasting receiving converter. The conventional satellite-broadcasting receiving converter includes a received-signal amplifier circuit section 51 for separately amplifying a horizontal-polarization wave and a vertical-polarization wave, a demultiplexer circuit section 52 for demultiplexing each amplified received signal into two signals with a boundary frequency of 11.7 GHz, a filter section 53 for attenuating the image signal of each demultiplexed received signal, a frequency-conversion section 54 for converting the frequency of each received signal output from the filter section 53, an amplifier circuit section 55 for amplifying each frequency-converted received signal, signal selection means 56 for selecting a received signal of one type from the received signals output from the amplifier circuit section 55, and two regulators 57 and 58 for supplying power-source voltages to the received-signal amplifier circuit section 51 to the signal selection means 56.
The received-signal amplifier circuit section 51 has two amplifiers 59 and 60. The horizontal-polarization wave is input to the amplifier 59 through an input end 51a and is amplified, and the vertical-polarization wave is input to the amplifier 60 through an input end 51b and is amplified.
The demultiplexer circuit section 52 has two demultiplexers 61 and 62, and demultiplexes the polarized waves amplified by the received-signal amplifier circuit section 51 into analog received signals A1 and A2 having a frequency of 11.7 GHz or less and digital received signals D1 and D2 having a frequency of 11.7 GHz or more. With this demultiplexing, the received signals are demultiplexed into the four received signals and output from the demultiplexer circuit section 52.
The filter section 53 has four band-elimination filters (BEFs) 63 to 66. The received signals A1, A2, D1, and D2 output from the demultiplexer circuit section 52 are input to the BEFs 63 to 66, respectively.
Among these BEFs, the BEFs 63 and 64 attenuate signals having frequencies of 7.8 GHz to 8.8 GHz, which correspond to the frequency band of the image signals of the analog received signals A1 and A2, and the BEFs 65 and 66 attenuate signals having frequencies of 8.45 GHz to 9.5 GHz, which correspond to the frequency band of the image signals of the digital received signals D1 and D2.
The received signals whose image signals are attenuated by the BEFs 63 to 66 are input to the frequency converter section 54.
The frequency converter section 54 has four mixers 67 to 70 and two oscillators 71 and 72. The received signals A1, A2, D1, and D2 are input to the mixers 67 to 70 provided correspondingly to the BEFs 63 to 66, respectively.
The oscillator 71 inputs an oscillation signal having a frequency of 9.75 GHz into the mixers 67 and 68, and the oscillator 72 inputs an oscillation signal having a frequency of 10.6 GHz into the mixers 69 and 70. The frequencies of the analog received signals A1 and A2 input into the mixers 67 and 68 are converted to those in a range from 950 MHz to 1950 MHz, and the frequencies of the digital received signals D1 and D2 input into the mixers 69 and 70 are converted to those in a range from 1100 MHz to 2150 MHz. The frequency-converted received signals a1, a2, d1, and d2 are input to the amplifier circuit section 55.
The amplifier circuit section 55 has four amplifiers 73 to 76. The frequency-converted received signals a1, a2, d1, and d2 are input to the amplifiers 73 to 76 provided correspondingly to the mixers 67 to 70, respectively. The received signals amplified by the amplifiers 73 to 76 are input to the signal selection means 56.
The signal selection means 56 has a signal switching circuit 77, two switching control circuits 78 and 79, and two output terminals 56a and 56b. The signal switching circuit 77 selects one of the outputs of the amplifiers 73 to 76 according to the control of the switching control circuit 78 and connects it to one terminal 56a, and selects one of the outputs of the amplifiers 73 to 76 according to the control of the switching control circuit 79 and connects it to the other output terminal 56b.
The output terminals 56a and 56b are connected to different receivers (not shown). Each receiver sends a selection control voltage used for operating each circuit section of the satellite-broadcasting receiving converter and for controlling the signal selection means 56. This selection control voltage is set to a first DC voltage of, for example, 18 V to select a horizontal-polarization wave, and is set to a second DC voltage of, for example, 14 V to select a vertical-polarization wave. To select a digital received signal d1 or d2, a 22-kHz high-frequency voltage is superposed on the corresponding DC voltage.
More specifically, to select the horizontal-polarization analog broadcasting signal a1, the first DC voltage is sent; to select the vertical-polarization analog broadcasting signal a2, the second DC voltage is sent; to select the horizontal-polarization digital broadcasting signal d1, the first DC voltage on which the high-frequency voltage is superposed is sent; and to select the vertical-polarization digital broadcasting signal d2, the second DC voltage on which the high-frequency voltage is superposed is sent to the corresponding output terminal 56a or 56b as a selection control signal.
A selection control voltage sent to the output terminal 56a is input to the switching control circuit 78 and the regulator 57 through a high-frequency choke coil 80. In the same way, a selection control voltage sent to the output terminal 56b is input to the switching control circuit 79 and the regulator 58 through a high-frequency choke coil 81.
The regulators 57 and 58 supply a power-source voltage of, for example, 8 V to the circuit sections 51 to 56. These two regulators 57 and 58 have the same structure and each have a voltage stabilizer circuit formed of an integrated circuit. The output ends of the regulators 57 and 58 are connected to a power-source-voltage output terminal 84 through reverse-current-prevention diodes 82 and 83, respectively. Therefore, even if one receiver is stopped, this satellite-broadcasting receiving converter is ready to operate since the power-source voltage is supplied to the circuit sections 51 to 56. Since the two regulators 57 and 58 are connected in series between the two output terminals 56a and 56b, the switching control circuits 78 and 79 operate only by the switching control voltage sent from one of the output terminals 56a and 56b.
As described above, since the conventional satellite-broadcasting receiving converter is provided with the two regulators 57 and 58 so as to be ready to operate even if one of two receivers connected to the two output terminals 56a and 56b is stopped, the converter is expensive.
Accordingly, it is an object of the present invention to provide an inexpensive satellite-broadcasting receiving converter.
The foregoing object is achieved according to the present invention through the provision of a satellite-broadcasting receiving converter including a plurality of output terminals each of which can be connected to an external receiver, to each of which any one of four types of selection control voltages specified according to the combinations of high and low DC voltages and whether a high-frequency voltage having a predetermined frequency is superposed is separately sent from the external receiver, and from each of which a satellite-broadcasting receiving signal of a type selected according to the selection control voltage is separately output to the external receiver; signal selection means for selecting one type of a receiving signal according to the selection control voltage from four types of satellite-broadcasting receiving signals different in modulation-signal form and polarization direction from each other for each output terminal to output it; a regulator for receiving the selection control voltage sent from each output terminal in common and for converting the selection control voltage to a predetermined power-source voltage to output it; and a plurality of high-frequency attenuation means each connected in series between each output terminal and an input end of the regulator.
Since each of the high-frequency attenuation means is connected in series between each output terminal and the input end of the regulator, the selection control voltage sent to each output terminal reaches the input end of the regulator with its superposed high-frequency voltage being sufficiently attenuated by the high-frequency attenuation means. The selection control voltage does not flow reversely into other output terminals from the input end of the regulator. A type of a receiving signal is separately selected and output to each output terminal. Therefore, only one regulator is required for a plurality of types of selection control voltages sent from a plurality of output terminals.
The satellite-broadcasting receiving converter may be configured such that each of the plurality of high-frequency attenuation means includes a transistor and a low-pass filter having a cutoff frequency lower than the frequency of the high-frequency voltage.
In this case, the high-frequency voltage is attenuated by a simple circuit.
The satellite-broadcasting receiving converter may be configured such that the low-pass filter is formed of a resistor and a capacitor which determine the cutoff frequency; and the selection control voltage is input to the collector of the transistor, the resistor is connected between the collector and the base, the base is grounded through the capacitor, and the emitter is connected to the input end of the regulator.
In this case, a ripple-voltage attenuation effect is great and the signal selection means is positively operated with its erroneous operation being prevented.
Alternatively, the satellite-broadcasting receiving converter may be configured such that a high-frequency choke coil and a reverse-current-prevention diode are connected to each other in series between the output terminal and the collector of the transistor.
In this case, even if a high reverse voltage is applied to the high-frequency attenuation means, the transistor is not destroyed by the reverse voltage.

Satellite-broadcasting receiving converter with a plurality of output terminals


A first message is transmitted over a communication channel to initiate a transaction. The first message contains a random number and a public key of a device. Continuing the transaction, a second message is received. The second message also contains a random number and a public key of a second device. At least one message is received that contains a proof-of-possession of the device's password, along with a credential that is encrypted with a credential key.

Wireless communication between computing devices has enjoyed wide adoption and significant growth as a flexible and cost-effective alternative to traditional hard-wired network infrastructure. Wireless technologies such as WiFi (a common name for several related standards proposed by the Institute of Electrical and Electronics Engineers, "IEEE") and Bluetooth permit data transfer via radio signals in 2.4 GHz, 5 GHz, and other bands. New standards and improved equipment have increased data rates of wireless networks, but the technology has some issues that have not been satisfactorily addressed. Configurability and security of wireless networks are two of these.
Wireless networks rely on encryption of packets to prevent eavesdropping and unauthorized use of network resources. For example, the Wired Equivalent Policy ("WEP"), which is a part of IEEE standard 802.11 describing wireless communications, specifies the encryption to be used in WiFi networks. Likewise, Wi-Fi Protected Access (WPA) is an alternative encryption and authentication standard based on mechanisms defined in the IEEE 802.11i standard. However, products supporting WEP, WPA, and similar security standards typically are difficult to configure correctly, so wireless networks are often run in unencrypted, "open" mode. Furthermore, even when encryption is enabled on a wireless local area network ("WLAN"), the participating systems often lack a standardized way to change the security configuration. Easy-to-use, broadly-applicable procedures to configure and manage WLAN participants may be of considerable value in the field.

Method for secure device discovery and introduction


Disclosed is an electron-emitting device, an electron source, and an image-forming apparatus that have uniform electron-emitting characteristics, emit electron beams whose diameters are small, have simple constructions, and are easy to be manufactured. The electron-emitting device comprising: a first electrode arranged on a surface of a substrate; an insulating layer arranged on the first electrode; a second electrode arranged on the insulating layer; and an electron-emitting film arranged on the second electrode, where the second electrode has two side surfaces that oppose each other in a direction parallel to the surface of the substrate, and the electron-emitting film is arranged so as to be shifted toward one of the two side surfaces.

1. Field of the Invention
The present invention relates to an electron-emitting device, an electron-emitting apparatus using the electron-emitting device, an electron source in which a plurality of the electron-emitting devices are arranged, and an image-forming apparatus constructed using the electron source.
2. Related Background Art
There have been conventionally known two types of electron-emitting devices: thermionic cathode electron-emitting devices and cold cathode electron-emitting devices. The cold cathode electron-emitting devices include, in the category thereof, devices of electric field emitting type (hereinafter referred to as the "FE" type), devices of metal/insulating layer/metal type (hereinafter referred to as the "MIM" type), and surface conduction electron-emitting devices. The FE type electron-emitting devices include devices of diode type that extract electrons using anode electrodes and devices of edge emitter type that emit electrons from edge portions of emitters.
As the diode type electron-emitting devices, there has been known an device disclosed in U.S. Pat. No. 5,551,903.
As the edge emitter type electron-emitting devices, there have been known devices disclosed in Japanese Patent Application Laid-open No. 10-289650 and Japanese Patent Application Laid-open No. 8-298068.

Method of driving image-forming apparatus and apparatus thereof


A flat rectangular rear holder having groovelike wire inserting parts and a thickness. On a side surface of the rear holder are retaining projections for retaining a housing and a releasing hole for inserting a releasing jig. The rear holder is engaged with the housing that has a plurality of terminal accommodating chambers on a rear end thereof and retaining holes corresponding to the retaining projections along the peripheral wall thereof. With the rear holder engaged with and retained by the housing, an upper end part of the rear holder is projected from the rear end of the housing, so that the upper part of the releasing hole is exposed. This exposed part has an opening area so large as to allow a rear holder releasing jig to be inserted thereinto.

1. Field of the invention
The invention relates to a rear holder that prevents a connection terminal inserted into a connector housing (hereinafter referred to simply as "housing") from coming off the rear end of the housing, the connector housing being used for connecting an electrical wiring system of an automobile or the like. More particularly, the invention is directed to a rear holder structure adapted for the operation of releasing the rear holder during maintenance.
2. Related art
Various connectors used for the connection of wire harnesses in an electrical system of an automobile or the like are designed such that a rear holder is engaged with the rear end of the housing so as to prevent a wired connection terminal accommodated within the housing from coming off or being displaced due to externally applied impact and the like. That is, the rear holder is engaged with the rear end of the housing after the wired connection terminal has been accommodated in the housing, so that the connection terminal is doubly retained from the rear as well. A conventional example having such a doubly retained mechanism is shown in FIG. 10.
As shown in FIGS. 10 and 11, a rectangular rear holder 51 has retaining projections 53 on the side surface, and is engaged with a housing 30 having retaining holes 31 on the rear end. A conventional procedure for releasing the rear holder 51 from the housing 30 using a rear holder releasing jig 20 during maintenance will hereunder be described.
The plurality of retaining projections 53 provided on the side surface of the rear holder 51 are retained by the plurality of retaining holes 31 provided on the rear end of the housing 30. As a result, the rear holder 51 is engaged with and held by the housing 30. That is, the rear holder 51 is engaged with the housing 30 without being projected from the rear end of the housing 30.
Further, as shown in FIGS. 10 and 11, in order to disengage the rear holder 51 from the housing 30, a rear holder releasing jig 20 is used to release the retaining projections 53 from the retaining holes 31 of the housing 30 one by one. That is, the rear holder releasing jig 20 is inserted into a clearance between the housing 30 and the rear holder 51 which are engaged with each other, and force is then applied in a direction D to remove the rear holder 51 from the housing 30.
FIG. 12 is a perspective view showing a state in which the retainment of the rear holder 51 has been released from the housing 30.
However, the aforementioned conventional releasing method suffers from the problem that the retaining projections 53 and the retaining holes 31 on the side of the housing 30 are damaged by the releasing jig since the operation of releasing the retainment is performed by locally applying force to the retaining projections made of a low-hardness resin using a sharp-edged releasing jig made of metal. In addition, when there is a large number of retainment projections much time is required for complete removal of the rear holder from the housing, which in turn has impaired impairs maintenance operability.

Rear holder having a releasing hole which extends beyond a rear end of a connector housing


A method of providing special functions includes receiving from a host a first normal command and a first address, and identifying a first special function based on the first normal command and the first address when the first address is in an address range established for special functions according to a predefined rule.

Embodiments of the inventive concept described herein relate to a semiconductor memory, and more particularly, to a method of issuing a command to a memory and a method of processing a command of the memory.
A semiconductor memory device is a memory device fabricated using semiconductor materials such as silicon (Si), germanium (Ge), gallium arsenide (GaAs), indium phosphide (InP), and the like. Semiconductor memory devices may be classified into volatile memory devices and nonvolatile memory devices.
Volatile memory devices lose contents stored therein when powered off. Examples of volatile memory devices include random access memory (RAM), static RAM (SRAM), dynamic RAM (DRAM), and synchronous DRAM (SDRAM). Nonvolatile memory devices retain stored contents even when powered off. Examples of nonvolatile memory devices include read only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable and programmable ROM (EEPROM), a flash memory device, phase-change RAM (PRAM), magnetic RAM (MRAM), resistive RAM (RRAM), and ferroelectric RAM (FRAM).

Command issue method for issuing command to memory and command processing method of memory