The publication relates to a depth compensated actuator, for a transportable inline depth compensated heave com-pensator for subsea lifting operations. The actuator comprises a cylinder shaped body and a piston with a piston rod, the piston rod being intended for exposure to external water pressure, a first and second connection means associated with the actuator. Further, the actuator comprises a depth compensator comprising a cylinder, a piston and a piston rod, the end of which being exposed to surrounding water; and conduit means between at least one volume in the actuator and one volume in the depth compensator. The pistons and piston rods are shaped as any of: hollow piston rod, ring shaped piston, ring piston rod. The depth compensated actuator solves the problem if improving depth compensation performance regarding size, weight, required fluid consumption, internal/inherent friction and adaptability. Further, use of a depth compensated actuator is claimed.

Prior art depth compensated actuators do exist. US 2008/0251980 A1 relates to a depth compensated passive heave compensator. This prior art heave compensator consists of three major components: an actuator device; an accumulator and a depth compensator. The actuator consists of a first cylinder provided with a piston and piston rod, the first cylinder being connected directly or by means of a crane at its upper end to a vessel. The piston rod extends from a piston located within the first cylinder through the lower end thereof and is connected to subsea equipment or a payload to be lifted or lowered. The accumulator consists of a second cylinder containing a movable piston, while the depth compensator consists of a third cylinder containing a movable piston and a piston rod, the piston rod extending down through the lower end of the cylinder and is provided with a surface exposed to the surrounding water pressure. The upper volume of the actuator is in fluid communication with the upper volume of depth compensator, while the lower volume of the actuator is in fluid communication with the volume beneath the piston of the accumulator. When exposed to increasing water pressure due to increasing water depths, the external water pressure will act on the free surface of the exposed piston rod of the third cylinder, forcing the piston upwards, forcing the liquid above the piston out of the third cylinder and into the upper volume of the first cylinder, affecting the position of the actuator piston. When the external water pressure decreases, the opposite effect will occur. In such manner, the effect of the external pressure on the heave compensator is eliminated or at least mitigated.
The prior art compensation is performed utilizing a pressure intensifier principle in the form of an external cylinder to compensate the effect of the water pressure acting on the piston rod. This requires a second hydraulic cylinder the depth compensator) connected to the main hydraulic cylinder (actuator). Compared to embodiments of the present invention, the main disadvantages of the prior art are:                larger space requirement        larger weight        larger friction        lack of free pressure surface for active piston rod control.

Depth compensated actuator and use of same in association with a transportable heave compensator


Apparatus for cutting carpet mounted on a supporting surface into elongated strips includes a frame having forward and rearward ends, a handle extending from the frame for guiding and maneuvering the apparatus, a horizontally disposed drive roller, rotatable about a drive roller axis mounted between the forward and rearward frame ends for propelling the apparatus in a forward direction as the drive roller is rotated engaging a plurality of generally radially extending carpet engagement members for non-slippingly engaging the carpet between the drive roller and supporting surface, and a pair of knives spacedly mounted about the forward end of the apparatus for cutting the carpet into an elongated strip as the carpet stripping apparatus is propelled forward.

It is current practice to strip carpet glued to a concrete surface or other supporting surface manually or automatically. The manual method requires workmen physically separating small sections of carpet using various hand tools, is time consuming and therefore expensive.
Automatic methods utilize carpet stripping machines in which a section of carpet is fed between a plurality of rollers mounted on the machines. As one or more of the rollers are driven, the carpet is drawn between the rollers propelling the machine forward. The forward motion of these machines may be used to cut the carpet into an elongated strip as knives mounted on the front of the machine are slid through the carpet. These automatic carpet stripping machines are also designed to lift the carpet off the supporting surface as the carpet is passed over one of the rollers.
These automatic machines require a substantial amount of horsepower to perform the operations of cutting and stripping in this fashion. Occasionally the motor used to supply the driving force for the rollers is stalled due to the power required to cut and lift the carpet in a cutting and stripping operation. Therefore, large motors are used in these machines making them expensive and also heavy for an operator or workman to handle during movement of a machine from job to job.
In addition, these machines have also had their forward motion stalled by the slipping of the carpet between the rollers.


A genetic process is used to tune servo parameter values in a disk drive. An initial population of individuals is generated each including a value for each of a plurality of servo parameters. Fitness values are then calculated for each of the individuals in the initial population. Individuals from the initial population are then chosen for mating based on the calculated fitness values. The chosen individuals are manipulated using genetic operators to produce a new population of individuals. Fitness values are then calculated for the new population and the cycle is repeated. The process is continued until a predetermined criterion has been met. After the process has ended, an individual is chosen based on fitness values and the servo parameters of the disk drive are set accordingly.

The present invention relates in general to data storage systems and, more particularly, to the optimization of system parameter values in a data storage system.
A disk drive is a data storage device that stores data in concentric tracks on a disk shaped medium. Data is read from the medium by spinning the medium about a central axis while positioning a transducer near a target track of the medium to sense the data. The transducer provides an electrical signal representative of the sensed data to data processing circuitry within the disk drive which converts the electrical signal to a format that is recognizable by an attached host unit. The converted data signal is then delivered to the host unit for use thereby. Disk drives can store data in any of a number of different forms, such as magnetic data storage and optical data storage.
To accurately transfer data to/from the target track, the transducer must first be moved from a present location to the vicinity of the target track and then the transducer must be held relatively steady above the target track. Preferably, the transducer element performing the transfer will be substantially centered above the target track during the data transfer. To position the transducer with respect to the track, a servo positioning system is generally implemented. The servo positioning system uses position feedback information read from the surface of the disk by the transducer and a plurality of servo parameter values to perform the desired servo positioning operations. If the servo parameter values used by the servo positioning system are not adequately tuned, the resulting servo positioning operations will be inaccurate and disk drive performance will be compromised.
In the past, servo parameter values were generated by first developing a mathematical model describing the specific servo system being implemented. The mathematical model was then used to determine theoretical ideal settings for the various servo parameters of the system. The theoretical settings would then be applied to the system and the performance measured. If the resulting performance was not as theoretically predicted, as was often the case, further refinement of the mathematical model and/or manual adjustment of system parameters would be undertaken. As can be appreciated, this process of determining an acceptable set of servo parameter values can be complex and time consuming. Manual adjustment of the servo parameter values is difficult because many of the parameter settings in the servo system are dependant on other parameter settings so that adjustment of one parameter value affects the optimal setting for one or more other parameter values. Because of the inherent complexity of the process, the parameter values resulting from such a process are generally far from optimal. In addition, because of variations in physical characteristics between disk drives, optimal servo parameter values for one disk drive are often sub-optimal in other disk drives having the same design.
Therefore, there is a need for a method and apparatus for rapidly, accurately, and efficiently tuning servo parameter values in a disk drive.
The present invention relates to a system that is capable of rapidly tuning servo parameter values in a disk drive. The system makes use of a genetic process for adaptively tuning the parameter values based on simulated evolution. The system requires no complex math calculations and is simple enough to be resident on the drive itself. Because of its speed and simplicity, the system can be used to tune servo parameter values in each individual disk drive in a manufacturing operation. Thus, the system is capable of significantly improving average disk drive servo performance in a high volume manufacturing environment. In addition, the system can be implemented within the disk drive itself, thus allowing periodic parameter re-calibrations to be performed in the field.
In one embodiment of the invention, an initial population of individuals is first generated, each individual including a value for each of a plurality of servo parameters. Fitness values are then calculated for each of the individuals in the initial population. Individuals from the initial population are then chosen for mating based on the calculated fitness values. The chosen individuals are manipulated using genetic operators to produce a new population of individuals. Fitness values are then calculated for the new population and the cycle is repeated. The process is continued until a predetermined criterion has been met. After the process has ended, an individual is chosen based on fitness values and the servo parameters of the disk drive are set accordingly.

Method and apparatus for optimization of servo parameter values in a data storage device


A method of performing a directional shifting event in a hydrostatic drive work machine, and a hydrostatic drive work machine is provided. The method includes the step of adjusting a pump displacement of a variable displacement pump coupled with an engine and a hydraulic motor of the work machine, at a rate based at least in part on one or both of a predetermined acceleration limit and a predetermined jerk limit of the work machine. The work machine includes an electronic control module having a computer readable medium with a directional shifting control algorithm recorded thereon. The control algorithm is operable to adjust a pump displacement in a hydrostatic drive of the work machine at a rate based at least in part on one or both of the predetermined acceleration limit or jerk limit of the work machine.

Hydrostatic or "hystat" drive refers generally to a drive train or portion of a drive train in a work machine utilizing hydraulic fluid pressurized by engine rotation as the motive force for propelling the work machine. In a typical design, a pump is driven with an output shaft of the engine and provides pressurized hydraulic fluid to a hydraulic motor, in turn coupled with one or more axles of the work machine. In most hystat drive work machines, the pump and motor each have a variable displacement, allowing the relative torque and speed of a drive shaft to be continuously varied.
Where it is desirable to provide a relatively high torque to the work machine wheels or tracks, the displacement of the motor will be relatively large such that at a given hydraulic pressure from the pump, a relatively large force is transferred to the drive shaft and wheels or tracks for each stroke of the motor. Similarly, where it desirable to provide a relatively lower torque to the work machine wheels or tracks, for example, when operating the work machine at relatively higher velocity, the relative displacement of the motor can be decreased. Displacement of the pump can be similarly adjusted, creating a continuously variable coupling between the engine and the ground engaging wheels or tracks of the work machine.
While the combination of a variable displacement pump and variable displacement motor in a hystat work machine imparts tremendous flexibility in operation, there is room for improvement. Particularly in work machine applications that require relatively frequent directional changes, for example, loader operations, the wear and tear on the work machine and even the operator can be significant.
Most if not all traditional hystat work machines require the operator to manually control one or more of the hydrostatic drive components. In many common hystat designs, the direction of fluid flow between the pump and motor is reversed to change the direction of motor rotation, and in turn change the direction of rotation of a drive shaft. In order to change fluid flow direction where the pump is manually controlled, the operator must decrease the fluid flow in the first flow direction, then increase fluid flow in the opposite direction. Wheel brakes, engine brakes, or other slowing means may be simultaneously employed to slow the work machine to a stop prior to reversing directions.
Reducing pump displacement, or "downstroking" the pump also provides a retarding force on the work machine. Increasing pump displacement, or "upstroking" the pump tends to accelerate the vehicle. Meanwhile, engine rotation continues to drive the pump, the engine speed being based predominantly on throttle position, also controlled by the operator, and a load on the engine. Accordingly, where an operator wishes to switch directions, he or she must attempt to integrate all of the various accelerating and decelerating forces applied to the work machine to execute a smooth and efficient directional change, often a challenging or impossible task.
It is generally desirable for an operator to perform a directional shift relatively quickly, simply to maximize the rate at which the work machine can move around the work environment and perform its various tasks. Thus, operators will typically attempt to slow the work machine, reverse fluid flow between the pump and motor, and accelerate as quickly as possible. However, the various hystat components, and the work machine itself are not without limitations.
Where an operator adjusts the pump or motor too quickly, he or she risks stalling or overspeeding the engine, or accelerating the work machine too quickly. Where the rate of work machine acceleration changes too quickly, the work machine can jerk. Overly large accelerations or changes in acceleration can be not only uncomfortable for the operator, but can risk spilling loads carried by the work machine.
Highly skilled operators can typically execute directional shifts relatively rapidly and smoothly. However, many modern hystat systems simply have too many variable components for a single operator to attend to both shift duration and shift smoothness without sacrificing one for the other. For instance, no skill level can enable an operator to optimally control a changing pump displacement, motor displacement, throttle position, etc., all simultaneously. In other words, even operators with many years of experience can find it difficult or impossible to consistently reverse travel directions in the work machine without jerking or overly accelerating the same, or overly extending shift duration to avoid excessive acceleration or jerk.
In an attempt to assist operators in performing directional shifts both smoothly and efficiently, designers have developed various systems wherein an electronic controller performs the adjustments of one or more of the components in the hydrostatic drive during shifting. While these systems have shown some improvements over earlier designs, the operator is still responsible for controlling certain of the components. The operator's control can thus still limit shifting speed, for example, if the operator adjusts the pump or motor too slowly, or compromise smoothness, for example, if the pump or motor is adjusted too quickly. Moreover, different operators can have different personal shifting preferences. While one operator may be willing to undergo significant jostling during a shift, if the shifting duration is minimized, other operators may be unwilling or unable to tolerate jerks or rapid accelerations.
Co-owned U.S. Pat. No. 5,624,339 shows a method for controlling shift points in a continuously variable transmission that includes a hydrostatic drive path or a combined hydrostatic and mechanical transmission drive path. The mechanical transmission includes a planetary summing arrangement that appears to allow for smooth shift without disruption of torque. Although this strategy and structure appears promising, there always remains room for improving upon the overall combination of work efficiency with rider comfort.
The present disclosure is directed to one or more of the problems or shortcomings set forth above.

Directional shift in hydrostatic drive work machine


In one aspect, drag-reducing apparatus for cargo containers are described herein. Cargo containers usable with such apparatus can have a top surface, a first side surface having a first rear door attached thereto by at least one first hinge, and a second side surface having a second rear door attached thereto by at least one second hinge. In some embodiments, drag-reducing apparatus comprise a first flexible airfoil, a plurality of first fasteners, a second flexible airfoil, and a plurality of second fasteners. In some other embodiments, an apparatus described herein comprises a first vertical guide member, a second vertical guide member, a flexible airfoil, and a plurality of fasteners.

Commercial transport vehicles such as tractor-trailers are frequently used for long-distance cost-efficient transport of cargo. However, space-efficient designs of such vehicles often pose problems relating to aerodynamic efficiency that can result in decreased fuel efficiency. Specifically, cargo containers designed for use with commercial transport vehicles are generally rectangular in shape, and a rear end or rear portion of a cargo container can provide sub-optimal air flow around the transport vehicle. The square or rectangular shape of a rear portion of a cargo container often results in vortices that generate drag. In many cases, the drag generated by the cargo container's shape is on the order of hundreds of pounds at highway speed. While efforts have been made to produce attachments for these cargo containers to minimize drag, such attachments come with drawbacks of their own. For example, prior attachments/apparatus are difficult to deploy or are difficult to open or close in a manner permitting loading/unloading of the cargo container. Therefore, there is a need for improved attachments or apparatus to reduce drag imposed on a cargo container, particularly a cargo container in use with a commercial transport vehicle.

Drag-reducing apparatus for cargo containers


The present invention provides a method and an apparatus for reducing noise. The apparatus includes a phase detector adapted to determine a phase difference between a first and a second signal, a first circuit adapted to generate a control signal based upon the determined phase difference, and a second circuit. The second circuit is adapted to receive a third signal, receive a fourth signal, modify the fourth signal based upon the control signal, and provide the third signal and the modified fourth signal to the phase detector as the first and second signals.

1. Field of the Invention
This invention relates generally to the synchronization of periodic signals, such as clock signals. More particularly, the invention relates to a phase detector for reducing noise.
2. Description of the Related Art
Many high speed electronic systems possess critical timing requirements that dictate the need to generate a periodic clock waveform possessing a precise timing relationship with respect to some reference signal. The improved performance of computing integrated circuits and the growing trend to include several computing devices on the same board present a challenge with respect to synchronizing the time frames of all the components.
While the operation of various components in the system should be highly synchronized, i.e., the maximum skew in time between the significant edges of the internally generated clocks of the components should be minimized, it is not enough to feed the reference clock of the system to these components. This is because different chips may have different manufacturing parameters, which, when taken together with additional factors such as ambient temperature, voltage, and processing variations, may lead to large differences in the phases of the respective chip generated clocks. Conventionally, synchronization is achieved by using digital delay locked loop (DDLL) circuits to detect the phase difference between clock signals of the same frequency and produce a digital signal related to the phase difference. By feeding back the phase difference-related signal to control a delay line, the timing of one clock signal is advanced or delayed until its rising edge is coincident with the rising edge of a second clock signal.
The phase differences are typically detected by a phase detector included in the digital delay locked loop circuit. The phase detector compares an input, or reference, signal to a feedback signal and then generates a signal proportional to the phase difference between the reference and feedback signals. The signal proportional to the phase difference is then provided to a so-called "delay line" that may introduce a variable delay into the delay path of the input signal. Conventional digital delay lines include a number of discrete delay elements, each of which may be capable of introducing a single unit delay into the delay path. For example, a conventional delay element may be an inverter that introduces a unit delay of about 200 picoseconds into the delay path. Thus, the phase detector signal typically corresponds to a series of "up" and "down" signals that indicate that a delay element should be introduced into, or removed from, the delay path, respectively.
When the phase difference between the input signal and the reference signal becomes close to, or less than, one unit delay, conventional phase detectors generate a series of alternating "up" and "down" signals. If several clock cycles are required for a signal to propagate through the delay path and feedback to the phase detector, the series of adjustments indicated by the alternating "up" and "down" signals may create noise that may cause loop stability problems in the digital delay locked loop. The series of adjustments performed in response to the alternating signals may also cause the phase of the output clock signal to advance and retreat on successive clock cycles, creating noise, such as jitter, in the output clock signal. Noise in the output clock signal may reduce the stability of, or cause an error in, the digital device relying on the output clock.


A system and method to select a software distribution server to download content from a server to a client, and to execute content on the server for the client, is described. The system and method include a client able to couple to any of the regions of a multi-region network. The client queries a server system for an identification of network software distribution servers. The client and/or server system select the software distribution server according to criteria that include in one implementation the network location of the client and the software distribution servers. In one implementation, the network is a multi-LAN network and the client and/or server system select the software distribution server coupled to the same LAN as the client. In one implementation, the client queries a server for an identification of network management servers on the network, selects a network management server coupled to the same LAN as the client, and queries the selected network management server for an identification of a software distribution server.

An enterprise network typically includes sites each comprising a Local Area Network (LAN). Each site includes a site server infrastructure, and ports to couple the LAN to managed client computers. The server infrastructure includes a network management server function and a software distribution server function. The network management server function administers managed client computers. The software distribution server function both stores client software for remote execution from or download to client computers, and selectively downloads the stored software content over the network to the managed client computers.
Enterprise LANs are selectively connected, commonly in a hierarchical structure, by Wide Area Networks (WANs). A managed client is typically assigned to a specific site, specifically to both a site network management server and a site software distribution server. As the use of mobile computers such as laptops increases within enterprises, managed clients now regularly move between different network localities. If these moving clients obtain content from the assigned site, irregardless of location within the network, the transmission path from a site software distribution server to the client will include a connecting WAN, and the transmission rate though the WAN will limit the download rate to the client.
A WAN typically includes regions connected by routing devices and the like. A managed client coupled to the WAN is typically assigned to a network management server, and to a software distribution server, each coupled to specific sub-regions of the WAN. A moving processing unit however may couple to the WAN at a sub-region that is at least one hop from the assigned software distribution server sub-region. If the moving processing unit obtains content from the assigned software distribution server, the transmission path from the software distribution server to the processing unit thus includes at least one hop. The transmission from the software distribution server to the client may be degraded by being coupled to a different sub-region than the software distribution server is coupled.

System and method of network content location for roaming clients


An apparatus in the form of a test strip is useful for determining the presence of one or more components in a fluid sample. The test strip can be used by itself or in conjunction with an associated housing assembly. The test strip provides a rapid volume, timing and temperature independent visually readable strip for the semi-quantitative detection of a component, such as an analyte.

This invention relates to an apparatus in the form of a test strip, which is useful for determining the presence of one or more components in a fluid sample. The test strip can be used by itself or in conjunction with an associated holding assembly.
The chemical analysis of fluids, including body fluids such as blood, serum, urine and the like; water; fluid food stuffs; etc. is often desirable and frequently necessary. Safety concerns, medical diagnosis, forensics, drug testing and other fields rely on determinations, either qualitative or quantitative, of the components of fluids. These determinations, or assays, must be rapid, reliable and accurate.
A major field of chemical analysis is devoted to "dry chemistry" determination of components and liquid samples. This refers to an apparatus that is dry to the touch. Generally, these apparatus take the form of monolayer and multi-layer test strips and other analytical test elements. These analytical test elements have excellent storage and handling properties, are convenient to use and provide accurate and reliable results.
The determination of a component, for example an analyte, in a fluid sample typically involves reacting the analyte with a binder. The binder undergoes some type of change following the reaction, which leads to a detectable signal. While the change may be caused directly by a reaction with the analyte, the change can also, and usually does, result from some property produced by the interaction between the analyte and the product of the reaction, where the interaction does not exist in unreacted components.
Many types of assays have been developed that utilize the above principles. One important type is the immunoenzymometric assay. This test involves the binding of an analyte of interest with a reaction or binding partner, where the binding partner carries a label. The binding partner is contained in a test strip or other apparatus so that it is non-reactive unless and until its partner analyte contacts the test strip. When this happens, the analyte and labelled binding partner bind to each other, forming a complex. This is accomplished by reacting the label carried by the binding partner with another substance, to form a detectable signal. When the label is an enzyme, as it frequently is, the substance is a substrate for the enzyme. The substrate for the enzyme either forms a visible color or changes color. Measuring the change or amount of color provides a measure of the produced complex, and hence of the analyte.
A problem with the above system is that one must have a sufficient amount of label binding partner to bind essentially all of the analyte in the sample. However, the amount of analyte is generally unknown. Thus, it is necessary to provide excess amounts of labelling binding partner, some of which will not react with the analyte, but carries the label. It nonetheless forms a detectable signal. Thus, unless one separates reacted label carrier from the unreacted portion, no readily perceivable test result can be achieved.
An additional feature of the immunoenzymometric assay is that after the sample has been contacted by the labelled binding partner and some of the partner has been bound to form the complex, the mixture of the complex and unreacted labelled binding partner contacts a sample of solid phase bound analyte or an analyte analog. This analog binds to the uncomplexed labelled binding partner. One can then make a clean division of the labelled partner bound to the analyte and excess labelled binding partner bound to the solid phase. The addition of substrate to either of these gives a color, so a determination can be made.
The immunoenzymometric assay is not the only type of assay used for an analytical system. For example, a competitive assay uses a sample of labelled analyte corresponding to the analyte to be determined, rather than labelled binding partner. A solid phase bound reactant is the binding partner for the analyte and the labelled analyte. If any of the analyte is in the sample that is tested, competition for the binding sites ensues. One then measures the amount of label either in the solid phase or the liquid phase, in the same manner described above for the immunoenzymometric assays, to determine the analyte.
In a displacement assay, a labelled analyte is already bound to a solid phase. When the sample contacts a test strip containing the bound labelled analyte, some of the labelled analyte will be displaced by the binding between the sample analyte and the solid phase bound binding partner.
A sandwich assay is another analytical system for carrying out a chemical analysis. Sandwich assays encompass a broad range of assay types; however, most refer to a formation of a complex between the analyte to be determined, a labelled epitopically active first antibody (Ab.sub.1 .cndot., where .cndot. indicates that the antibody is a labelled antibody), and a nonlabelled second antibody (Ab.sub.2), such as a whole monoclonal second antibody (mAb) or fragment thereof. The sandwich, which forms when the analyte contacts a test strip containing the diffusible second antibody Ab.sub.2 and first antibody Ab.sub.1 .cndot. is Ab.sub.2 --An--Ab.sub.1 .cndot. The sandwich then contacts a solid phase containing another antibody, which binds to the second antibody, but not to the first antibody. The result of this is separation of the complexed first antibody from the uncomplexed first antibody, which permits a determination in the same manner as discussed above.

Test strip apparatus and method for determining presence of analyte in a fluid sample


A pick for a string instrument is manufactured by the use of a hot stamp press. A pick blank is mounted on a support surface of the press with a front side of the pick blank disposed upwardly. A heated die head is moved against the front side of the pick blank and maintained in that position a sufficient time to imprint a pattern configuration into the front side to thereby form a gripping surface on the front side. A film may be disposed between the front side and the die head. A pattern may also be imprinted into the rear side.

Various string instruments such as guitars, mandolins, banjos, harpsichords, etc. are played with the aid of a pick. Generally, such picks are flat disks of triangular shape where the corners of the triangle are rounded and the perimeter of the pick itself is a single smooth curve. The pick would be held at the wide portion of the triangle and the narrow portion would make contact with the strings of the instrument.
It is known to provide such picks with a gripping surface to enhance the handling of the picks. Conventionally, various methods are used such as machining or laser cutting or manual operations to form the gripping surface on the pick. It would be desirable if a reliable, yet less expensive method of manufacturing could be used for forming such gripping surfaces.

Method of manufacturing pick for stringed instrument


An element for treating a fluid flowing through the element which comprises at least two filter medium layers helically wrapped around a pervious, hollow tube, with the filter medium layers forming an overall graded pore structure for the fluid treatment element and/or at least one diffusion layer positioned between the filter medium layers.

A typical fluid treatment element, for many uses, comprises a hollow, generally cylindrical, filter element with appropriate end caps to direct a fluid, e.g., a gas or liquid, through the filter medium of the filter element. The precise nature of the filter medium will vary with the specific treatment to be given the fluid, and, to that end, the filter element may include a demineralizer or sorbent for separating ionic or chemical components in addition to the filter medium for removing particulates.
The fluid to be treated is generally forced to flow inwardly from the exterior to the interior of such a fluid treatment element, although there is no requirement that such be the case. It should be noted that irrespective of the normal flow of fluid through the fluid treatment element, it is not unusual to have the fluid flow reversed, either accidentally (e.g., due to a surge in fluid pressure downstream from the filter element) or intentionally (e.g., to flush an accumulated cake of particulate matter from the surface of the filter element).
While tubular fluid treatment elements typically have a uniform pore structure, one such fluid treatment element, the Profile.RTM. filter element (Pall Corporation), utilizes a filter medium of a graded or tapered porosity whereby the pore size of the filter medium decreases in the direction of fluid flow. The filter medium of the Profile.RTM. filter element comprises a continuous series of fibers of varying diameter which are layered upon themselves to form a filter medium of a graded pore structure with a constant void volume. Such a medium is disclosed in U.S. Pat. Nos. 4,594,202 and 4,726,901.
A variety of other fluid treatment element configurations have been proposed and utilized over the years, including string wound filter elements, sintered stainless steel powder filter elements, multiple layer filter elements, spiral wrapped fluid treatment elements, and helical wrapped filter elements. Despite these various configurations, there remains a need for a tubular fluid treatment element characterized by a relatively high strength, low pressure drop, high dirt capacity, and long life, and which is nonetheless economical to manufacture and utilize.
It is an object of the present invention to provide such a fluid treatment element. These and other objects and advantages of the present invention, as well as additional inventive features, will be apparent from the description of the invention provided herein.


An atomic oscillator includes: a gas cell in which a gaseous metal atom is sealed; heating units heating the gas cell to a predetermined temperature and being a first heater and a second heater; a light source of exciting light exciting the metal atom in the gas cell; a light detecting unit detecting the exciting light which has passed through the gas cell; a substrate including at least a temperature controlling circuit for the heating units; a first heater wiring coupling the first heater and the substrate; a second heater wiring coupling the second heater and the substrate; and a third heater wiring coupling the first heater and the second heater. In the atomic oscillator, the gas cell includes a cylindrical portion; and windows which respectively seal openings at both ends of the cylindrical portion and constitute an incident surface and an emitting surface on an optical path of the exciting light. The first heater and the second heater are respectively formed on the windows at an incident surface side and an emitting surface side and made of transparent heating materials.

1. Technical Field
The present invention relates to an atomic oscillator, in particular, relates to an atomic oscillator that includes a gas cell, of which degradation of heating efficiency is suppressed, has high accuracy, and can be miniaturized.
2. Related Art
Atomic oscillators using alkali metals such as rubidium and cesium need to keep alkali metal atoms in a vapor state with buffer gas in a gas cell when the oscillators use energy transition of the atoms. Therefore, the oscillators operate while maintaining the gas cell, in which the atoms are sealed, at a high temperature. An operating principle of the atomic oscillators is broadly classified into a double resonance method utilizing light exciting alkali metal atoms and micro waves (refer to JP-A-10-284772, as a first example), and a method utilizing quantum interference effect (hereinafter, refereed to as coherent population trapping: CPT) produced by two kinds of interfering light (refer to U.S. Pat. No. 6,806,784 B2, as a second example).
FIG. 6A schematically shows a structure of a related art atomic oscillator utilizing the CPT. An atomic oscillator 250 shown in FIG. 6A includes an optical system that is composed of a semiconductor laser 230 as a light source, a gas cell 210, and a light detector 240 as a light detecting unit, as disclosed in the second example. In the gas cell 210, alkali metal atoms (not shown) such as a rubidium atom and a cesium atom that are quantum absorbers are sealed. The semiconductor laser 230 produces two kinds of laser light (coupling light and probe light) having different wavelengths from each other and outputs the laser light to the gas cell 210. The atomic oscillator 250 detects how much laser light made incident on the gas cell 210 is absorbed by metal atom gas with the light detector 240 so as to detect atomic resonance, and allows a reference signal of a quartz crystal oscillator and the like to synchronize with the atomic resonance at a control system such as a frequency control circuit 220, obtaining an output. The light detector 240 is positioned at an opposite side of the side, at which the semiconductor laser 230 is positioned, of the gas cell 210.
FIG. 6B shows energy levels of the quantum absorbers. The energy levels of the quantum absorbers are expressed by a three-level system (Λ type level system, for example) including two ground levels (a first ground level and a second ground level) and an excitation level. When a difference between two frequencies (ω1 and ω2) of two beams, which are simultaneously radiated, of the resonance light (first resonance light and second resonance light) precisely matches an energy difference between the first ground level and the second ground level, the three-level system can be expressed by a coherent state between the first ground level and the second ground level. That is, the excitation to the excitation level is stopped.
Namely, as shown in an optical absorption spectrum of FIG. 6C, the quantum absorbers in the gas cell 210 absorb the laser light radiated from the semiconductor laser 230 and an optical absorption property (transmission) varies depending on frequency difference between the two kinds of light. When the frequency difference between the coupling light and the probe light has a specific value, neither of two kinds of the light is absorbed but transmits. This phenomenon is known as electromagnetically induced transparency (EIT) phenomenon. The CPT uses the EIT phenomenon so as to detect and use a phenomenon, in which the light absorption is stopped in the gas cell when a wavelength (wavelengths) of one of or both of the two kinds of resonance light (the first resonance light and the second resonance light) is (are) varied, as an EIT signal having a shape like δ function.
Here, when atomic concentration within the gas cell is varied in the atomic oscillator, a degree of absorption of light to the atomic gas is varied, causing an error of detection of the atomic resonance or an impossibility of detection. Therefore, atomic oscillators that are put into practical use include a heating unit for maintaining vapor of atoms within a gas cell at a constant temperature (80° C., for example) and a temperature controlling system controlling the heating unit. However, due to a demand of miniaturizing an electronic apparatus including an atomic oscillator is increased, the atomic oscillator needs to be miniaturized. Therefore, the heating unit of the gas cell is also required to be miniaturized and have a function to maintain the gas cell at a constant temperature.
In response to such demand of miniaturization, US 2006/002276 A1, as a third example, proposes an atomic oscillator having such structure that a film-like heater composed of a transparent heat element having optical transparency is provided at windows, which respectively constitute an incident surface and an emitting surface of light from a light source in an optical path, of a gas cell.
FIG. 7 shows a schematic section of an atomic oscillator (atomic frequency reference) 150 of the third example. The atomic oscillator 150 includes: a gas cell 110 in which gaseous metal atoms are sealed; a first heater 112 and a second heater 113 as heating units which heat the gas cell 110 at a predetermined temperature; a semiconductor laser 130 as a light source of exciting light exciting the metal atoms in the gas cell 110; and a light detector 140 as a light detecting unit which detects the exciting light transmitted through the gas cell 110.
The gas cell 110 is a sealed container having a cylindrical (tubular) shape. The gas cell 110 includes a cylindrical portion 101 as a first layer; a window 102 as a second layer; and a window 103 as a third layer. The window 102 and the window 103 respectively seal both ends of the cylindrical portion 101 and respectively constitute an incident surface and an emitting surface of exciting light in an optical path (shown by an arrow in the drawing). Thus a cavity T2 is formed inside the gas cell 110. Further, on respective outer surfaces of the window 102 and the window 103, the first heater 112 and the second heater 113 are provided. Incident light from the semiconductor laser 130 disposed at the outer side of the window 102 which constitutes the incident surface in the optical path in the gas cell 110 excites the metal atoms while passing through the cavity T2 in the cylindrical portion 101, and the exciting light is emitted toward the light detector 140 disposed at the outer side of the window 103 that constitutes the emitting surface. The window 102 and the window 103 respectively constituting the incident surface and the emitting surface of the exciting light are made of a material having optical transparency such as glass. Therefore, the first heater 112 and the second heater 113 respectively provided on the window 102 and the window 103 need to be made of a transparent heating material having optical transparency. As the heating material having optical transparency, a transparent electrode film made of indium tin oxide (ITO), for example, can be used. Thus the heater 112 and the heater 113 having a film-like shape are used as the heating units, enabling miniaturization of the gas cell 110 and the atomic oscillator 150 including the gas cell 110.
The third example has no description on heater wiring coupling the first heater 112 and the second heater 113 with a controlling circuit substrate including a temperature controlling circuit which controls the heaters 112 and 113. However, since the first heater 112 and the second heater 113 are independently formed respectively on the window 102 and the window 103, the heaters 112 and 113 are separately controlled. Therefore, two heater wirings are required for each of the heaters 112 and 113, that is, four heater wirings in total are required. That is, as shown in FIG. 7, the first heater 112 requires heater wirings 122a and 122b, and the second heater 113 requires heater wirings 123a and 123b.
The heater wirings can be heat leaking paths from the respective heaters. Therefore, as the number of heater wirings is increased, heating efficiency of the gas cell may be deteriorated to increase power consumption, or temperature distribution may occur in the gas cell to deteriorate accuracy of the atomic oscillator. Therefore, the number of heater wirings of heaters provided in the gas cell should be decreased as much as possible.
Further, as the number of the heater wirings is increased, a wiring space is enlarged to make it hard to miniaturize the atomic oscillator and the controlling circuit substrate disadvantageously has a complex circuit structure.


The electronic access control strike can have a bolt socket, a bolt path leading to bolt socket, a keeper movably mounted to a frame in a manner to be moveable into and out of interference with the bolt path, a cam member moveable for selectively blocking or unblocking the movement of the keeper, and an anti-preload member which is moveable into interference between the keeper and the cam member for preventing the keeper from conveying a preload force onto the cam member when the cam member is in the blocking position, and moveable out from interference between the keeper and the cam member when the cam member is in the unblocking position to allow the keeper to be moved out from interference with the bolt path.

Electronic access control strikes are a type of strike in which the keeper is normally blocked and prevents movement of the bolt out of the bolt socket, thereby preventing the opening of the associated door. The strike is provided with an actuator which allows to unblock the keeper. An input module is provided to receive a user input, and some form of authenticating function is provided which triggers the unblocking of the keeper via the actuator only if the user input is authenticated.
Various models of electronic access control strikes are available on the market, the details of which can vary. For instance, some electronic access control strikes have a pivotable keeper, others have a slidable keeper, some use keypads for user input, others use card readers (e.g. RFID), and some others use more elaborate forms of user input such as fingerprint readers or retinal scanners for instance, but some generalities of electronic access control strikes are constant from one model to another. These devices are commonly referred to as electronic access control strikes as they typically (but not necessarily) involve some form of electronics to perform the input receiving, authenticating, and/or controlling functions. Moreover, some or all of these functions can be performed or assisted by some form of computer.
A problem encountered in many applications is that in some cases, a force, which will be referred to herein as a preloading force, is exerted by the door, and more specifically the bolt, onto the keeper, which jams the keeper unblocking mechanism, and prevents the normal keeper unblocking action upon authentication of the user input. Such a force can have various sources: air pressure from the HVAC system, twisted door frames, warped doors, thick weather strippings are a few examples.
Accordingly, while existing electronic access control strikes were satisfactory to a certain degree, there remained room for improvement.

Electronic access control strike and preload resistant module therefore


The invention relates to a colorant composition comprising humic acid and/or fulvic acid and a water soluble dye. The invention in particular relates to a colorant composition and method for imparting color to turf grass.

Turf grasses are widely used in recreational areas, parks, golf courses, bowling greens, athletic fields and domestic lawns. There is a demand for turf to have a uniform green colour so as to provide a pleasing appearance. This is particularly so for televised sporting events where it is desirable that a playing field have a healthy looking and uniform green colour. However, under adverse conditions such as drought and frosts, grass can lose its natural colour and in some circumstances change to an undesirable appearance. Turf colorants that can impart a green colour to discoloured turf have been developed with a view to artificially returning a playing field to a desirable colour or to simply make the turf appear more robust and healthy. Green colorants are also used to colour sand and in particular, divot sand as used on golf courses.
A green colorant that is widely used commercially is a pigment based colorant comprising a water insoluble pigment suspended in an aqueous solution. In practice, application problems may be experienced when applying pigment based colorants. Such problems include blockage of application nozzles and equipment cleaning difficulties.
Other colorants for use in the agricultural industry are also available. Such colorants are based on water soluble dyes. As the dyes are water soluble, the above-mentioned application difficulties associated with pigment based colorants are generally not experienced. The dye based colorants typically contain blue or red dyes and are used as markers for spraying herbicides, insecticides and the like. Blue colorants are also used to impart a blue colour to water features. The blue dyes may also be used on turf but impart a blue colour, which is generally not considered desirable.
However, there are some concerns regarding repeated use of pigments on playing fields and the like for a number of reasons. First, there are potential toxicity problems to those spraying the dyes and those playing on, or otherwise using the field. Although pigments commonly used to colour turf are considered safe to human health, there are few, if any, studies on long term exposure of these chemicals. Still further, there may be potential environmental hazards associated with build up of these chemicals in the environment as a result of repeated spraying. Generally a respray is necessary whenever the grass is cut. In some cases, a playing field may be sprayed at weekly or fortnightly intervals immediately prior a match or game being played on the field.
It is therefore an object of the present invention to provide an alternative colorant composition that is suitable for use on turf or other suitable surfaces.

This patent is subject to a terminal disclaimer.

Colorant for foliage of humic and/or fulvic acid, and dye


An improved gate oxide protected level shifter is provided which has a higher speed of operation than is traditionally available. The level shifter includes a first capacitor coupled between a first output terminal and the input of an inverter and a second capacitor coupled between a first node and the output of the inverter. As a result, the speed of the transitions at the gates of the pair of cross-coupled P-channel MOS transistors is increased several times.

This invention relates generally to level shifter circuitry and more particularly, it relates to a gate oxide protected level shifter which has a higher speed of operation than is traditionally available.
As is generally well-known, digital logic circuits are widely used in the areas of electronics and computer-type equipment. However, the various digital logic circuits that must communicate with one another may have different power supply voltages. For example, a first circuit that operates with logic levels between 0V (L) and 2.0V (H) may need to communicate with a second circuit that operates with logic levels between 0V (L) and 3.3V (H). Thus, when a first digital logic circuit of one power supply voltage is required to interface with a second digital logic circuit of another power supply voltage there is typically needed a voltage conversion or translation between the two different power supplies so that they will be compatible with each other and not drain static current. A level shifter circuit is provided to perform this function.
In FIG. 1, there is shown a schematic circuit diagram of a prior art level shifter 2 which may be used for performing a voltage conversion. The level shifter 2 is comprised of a pair of cross-coupled P-channel MOS transistors P1 and P2, a pair of input N-channel MOS transistors N1 and N2, and a CMOS inverter I1. The first P-channel transistor P1 has its source connected to an upper predetermined I/O buffer power supply voltage VDDIO, which is typically at +3.3 volts, and its drain connected to the drain of the first N-channel transistor N1 and to the gate of the second P-channel transistor P2. The gate of the first P-channel transistor P1 is connected to the drain of the second P-channel transistor P2 and to the output terminal OUT. The second P-channel transistor P2 has its source also connected to the power supply voltage VDDIO. The drain of the transistor P2 is connected also to the output terminal OUT and to the drain of the second N-channel transistor N2. The gate of the transistor P2 is connected to the drain of the transistor P1 and to the drain of the transistor N1.
The gate of the first N-channel transistor N1 is connected to an input terminal IN for receiving an input signal and to the input of the inverter I1. The output of the inverter I1 is connected to the gate of the second N-channel transistor N2. The sources of the N-channel transistors N1 and N2 are connected to a lower predetermined or reference power supply voltage VSSIO (ground) or 0 volts. The CMOS inverter is conventional and is formed of a P-channel transistor and an N-channel transistor whose gates are connected together defining its input and whose drains are connected together defining its output. The source of the P-channel inverter transistor is connected to a supply potential VDD. The p-type substrate of the N-channel transistors N1, N2 is tied to ground, and the n-type substrate of the P-channel transistors P1, P2 is tied to the power supply voltage VDDIO.
In operation, when then input signal at the input terminal IN is at 0 volts the transistors N1 and P2 will both be turned OFF and the transistors N2 and P1 will be turned ON. As a result, the level shifter 2 will produce a voltage level of 0 volts at the output terminal OUT. On the other hand, when the input signal at the input terminal IN is at 2.0 volts, the transistors N1 and P2 will both be turned ON and the transistors N2 and P1 will be turned OFF. Thus, the level shifter 2 will provide a voltage level of +3.3 volts at the output terminal OUT.
However, in view of the developments made in CMOS technologies the thickness of the transistor gate oxides for forming the CMOS transistor devices are becoming thinner and thinner. In the typical semiconductor process, where the thickness of the gate oxide is reduced to approximately 60 .ANG. (angstrom) or below a voltage difference higher than about +2.4 volts-+2.5 volts applied across the gate and the bulk of the transistor devices will cause a breakdown in the gate oxide to occur, thereby resulting in a failure. For example, when the input signal of 0 V is applied to the gate of the first input N-channel transistor N1 the level shifter 2 of FIG. 1 will generate a voltage level of 0 V at the output terminal OUT. As can be seen, a voltage difference of 3.3 V will exist between the drains and the gates of the P-channel transistors P1, P2. Therefore, if the gate oxide thickness is equal to or lower than 60 .ANG. the gate oxide will experience a breakdown and the level shifter 2 will fail. In order to overcome this problem, there have been provided in the prior art gate oxide protected level shifter circuits utilizing a plurality of PMOS and NMOS transistors so as to limit the voltage difference at the gate oxide to be below a breakdown voltage magnitude.
In FIG. 2, there is illustrated a schematic circuit diagram of a prior art gate oxide protected level shifter 4. The level shifter 4 is also comprised of a pair of cross-coupled P-channel MOS transistors P1, P2; a pair of input N-channel transistors N1, N2; and a CMOS inverter I1 which are identical to the components in the level shifter 2 of FIG. 1. In addition to these components, the level shifter 4 of FIG. 2 further includes PMOS transistors P3, P4 and NMOS transistors N3, N4 which function to prevent the gate oxide voltage of any transistor from exceeding a breakdown voltage. If the thickness of the gate oxides is assumed to be approximately 60 .ANG., then the voltage difference at any gate oxide of the level shifter 4 will not exceed approximately +2.5 V.
The PMOS transistor P3 and the NMOS transistor N3 are connected together in series and between the drain of the transistor P1 (node S1) and the drain of the transistor N1 (node S2). Similarly, the PMOS transistor P4 and the NMOS transistor N4 are connected together in series and between the drain of the transistor P2 (node S3) and the drain of the transistor N2 (node S4). The gates of the transistors P3, P4 are connected to a PMOS reference voltage VREF11, and the gates of the transistors N3, N4 are connected to an NMOS reference voltage VREF22. The reference voltages REF22 and REF11 can be generated by a reference voltage generation circuit which is illustrated and described in detail in co-pending application Ser. No. 08/861,039 filed on May 21, 1997 entitled "Reference Voltage Generation Scheme for Gate Oxide Protected Circuits" and assigned to the same assignee as the present invention.
It is assumed that the upper predetermined I/O buffer power supply voltage VDDIO is on the order of +3.3 V and the lower predetermined power supply voltage VSSIO is on the order of 0 V. Further, the reference voltage VREF22 is approximately +2.2 V and the reference voltage VREF11 is approximately +1.1 V. The supply potential VDD is on the order of +2.0 volts. It will be noted that there is required a predetermined amount of time for the input signal on the input terminal IN to switch from an initial voltage level of +2.0 V (or 0 V) to a final voltage level of 0 V (or +2.0 V). In response to this switching operation on the input terminal, there will be required a predetermined amount of time for the pper non-inverted output signal OUT.sub.-- LSP and the upper inverted output signal OUTB.sub.-- LSP at the respective nodes S3 and S1 to switch from an initial voltage level of VDDIO (or VREF11+.vertline.V.sub.tp .vertline.) and a final voltage of VREF11+.vertline.V.sub.tp .vertline. (or VDDIO). Likewise, there will be required a predetermined amount of time for the lower non-inverted output signal OUT.sub.-- LSN and the lower inverted output signal OUTB.sub.-- LSN at the respective nodes S4 and S2 to switch from an initial voltage of VREF22-V.sub.tn (or VSSIO) and a final voltage of VSSIO (or VREF22-V.sub.tn).
The level shifter 4 suffers from the disadvantage that it takes a relatively long time for the nodes S1 and S3 to switch between its initial voltages and its final voltages in response to the switching of the input signal. This is due to the fact that the nodes S1 and S3 are required to be pulled down through three transistors. For example, the node S1 is serially connected to the transistors P3, N3 and N1. Similarly, the node S3 is serially connected to the transistors P4, N4 and N2. In view of this, it can therefore take a relatively long period of time for the gates of the transistors P1 and P3 to resolve their "full" logic levels of VDDIO (H) and VREF11+.vertline.V.sub.tp .vertline. (L).
The inventors of the present invention have developed a way of increasing the switching speeds at the gates of the transistors P1 and P3 (nodes S1 and S3) in the level shifter 4 of FIG. 2. This is achieved by modifying the level shifter 2 so as to include first and second capacitors operatively interconnected for speeding up transitions at the gate of the transistors P1 and P2.

High speed gate oxide protected level shifter


Various embodiments of systems and methods for providing external device support for a device driver abstraction layer are disclosed. Some embodiments of a method may involve: accessing attribute information associating each of several keys with a respective device attributes, where each of the keys identifies a respective device; and configuring an interface to a device driver for communication with a device dependent on which device attributes the attribute information associates with the key that identifies the device. Configuring the interface may configure the interface to include one or more of interface features. Each of the interface features may support a respective device attribute.

1. Field of the Invention
This invention relates to device drivers and, more particularly, to updating a device abstraction layer to support a new device.
2. Description of the Related Art
Many ISV (Independent Software Vendors) have software products that need to interact with various devices through device drivers. These device drivers are typically specific to a particular OEM (Original Equipment Manufacturer) as well as to a specific operating system platform. If a software product is to be compatible with 10 operating system platforms and devices provided by 10 different OEMs, 100 drivers are needed. Maintaining such a large number of device drivers may itself be difficult. Additionally, updating device drivers each time a new device is released by an OEM may consume a large amount of time, programming resources, and testing resources.
FIG. 1 illustrates the typical process by which a driver is updated to provide compatibility with a new device. A vendor may provide a new device to an ISV that wants to provide support for that new device, as indicated at 11. The ISV may update device driver source code in order to add the device's inquiry string (e.g., a string formed from the devices vendor ID and product ID) to an existing driver so that the device driver recognizes the new device, as shown at 13.
If the device is a rebadge of an already supported device, qualification testing may be skipped, as indicated at 15–17. Otherwise, qualification testing may be performed to see if the device driver operates properly with the new device, as shown at 17. During qualification testing, the device driver source code may again be updated (e.g., to support a special feature implemented by the new device that was not previously supported by the device driver).
Additionally, the driver may need to be regression-tested to ensure that any modifications to the source code have not caused an incompatibility with a previously-supported device, as indicated at 19. If the regression testing fails, as determined at 21, the qualification testing and/or regression testing may be repeated until the regression testing passes. Additionally, the regression testing may be repeated for each operating system with which the driver is operable. If the regression testing passes, the ISV may then release the updated driver to customers, as shown at 23.
Often, a new device has the same or similar functionality as an existing device for which the ISV already provides support. For example, in order reduce the time and effort required to support new devices, a driver may use an external mapping table to map new devices to a particular device type. The driver may handle requests targeting that device according to which device type is associated with that device in the mapping table. In order to provide support for a new device that operates similarly to an already-supported device, the external mapping table may be updated to map the new device to the device type of the already supported device. Accordingly, by providing a new mapping table, support for new devices may be provided without needing to update the actual source code of the driver.
One complication that arises when using a table to determine how to handle a device occurs when a new device does not map to any of the already-supported device types. For example, different vendors often rebadge the same OEM's device. Each vendor may write new firmware for the device, which may lead to hybridized devices that behave differently than devices of the same type and OEM that are released by other vendors. For example, a vendor may write new firmware for a device made by a particular OEM and resell that device with a new vendor ID and product ID. Due to the firmware changes, the rebadged device may behave differently than other devices made by the same OEM. Furthermore, the device may also not behave exactly like any of the vendor's other devices. As a result, no existing device type may adequately match the functionality of the new device, and it may be impossible to provide support for the new device without updating the device driver.

External device support for device abstraction layer


In a solid-state imaging apparatus in which a first substrate formed on a first semiconductor wafer and a second substrate formed on a second semiconductor wafer are bonded via a connection portion configured to electrically connect the first and second substrates, the first substrate includes a first pixel region in which a plurality of first photoelectric conversion elements partially transmit incident light and are arranged in a two-dimensional shape. The second substrate includes a second pixel region in which a plurality of second photoelectric conversion elements are arranged in a two-dimensional shape in at least a partial region of a region corresponding to the first pixel region. The first photoelectric conversion elements generate imaging signals, and the second photoelectric conversion elements generate signals to be used in imaging preparation.

1. Field of the Invention
The present invention relates to a solid-state imaging element and a solid-state imaging apparatus.
This application is based upon and claims the benefit of priority from prior Japanese Patent Application No. 2012-120629, filed May 28, 2012, the entire contents of which are incorporated herein.
2. Description of Related Art
As one of auto focus (AF) methods to be performed using an imaging signal acquired by an imaging element, a contrast method (hill climbing method) is known (for example, see Japanese Unexamined Patent Application, First Publication No. 2010-256924). In the contrast method, the imaging signal is acquired while a lens is moved (extended or retracted), a position at which its high-frequency component (contrast value) peaks is determined to be a focusing position, and the lens is moved to the position.
A processing procedure of a specific AF process will be described with reference to FIG. 14. FIG. 14 is a graph illustrating a relationship between a position of a lens and a contrast value known in the related art. In the illustrated graph, the horizontal axis represents the position of the lens and the vertical axis represents the contrast value. When the AF process is started, an increase/decrease in the contrast value is first determined by driving the lens in an arbitrary direction (Y1; direction determination process). Subsequently, the lens is driven in a direction in which the contrast value is increased based on the direction determination result and the contrast value moves from an increase direction to a decrease direction, so that it is determined that the lens has passed the focusing position (Y2; focusing position passage determination process). Thereafter, the AF drive process ends by restoring the lens to a maximum position (peak position) of the contrast value, that is, a focusing position (Y3; focusing position restoration process).
Next, processing timings of the imaging process and the AF process will be described. FIGS. 15A and 15B are timing charts illustrating the processing timings of the imaging process and the AF process known in the related art. FIG. 15A is a timing chart illustrating the timing of the image process, that is, the drive timing of the imaging element. When the imaging process is performed in the illustrated example, an operation of resetting the imaging element is performed after the AF process has been completed. Subsequently, an exposure/accumulation operation is performed. Subsequently, a signal is read from the imaging element. Thereafter, the process waits until the AF process is completed.
FIG. 15B is a timing chart illustrating the timing of the AF process, that is, the timings of contrast evaluation and lens drive processes. In the illustrated example, the contrast evaluation is first performed, the focusing position is subsequently calculated based on a signal obtained in the contrast evaluation, and a subject is focused by performing the lens drive process based on the calculation result. Thereafter, the AF process is performed after the imaging process has been completed.
Because the process is performed using a signal output by the imaging element in the AF process using a contrast method, it is difficult to acquire a signal necessary for the contrast evaluation while the imaging element performs the imaging process. Thus, as illustrated in FIGS. 15A and 15B, the AF process (the contrast evaluation and lens drive processes) is performed until the reset process of the imaging element is started after a process of reading the imaging signal from the imaging element in the imaging process is completed.
In addition, because an auto exposure (AE) process is also performed using a signal output by the imaging element, it is difficult to acquire a signal necessary for the AE process while the imaging element performs the imaging process as in the AF process. Thus, the AE process (contrast evaluation and lens drive processes) is performed until the reset process of the imaging element is started after a process of reading the imaging signal from the imaging element in the imaging process is completed.
In general, a sum time of several tens of milliseconds (ms) is necessary for the contrast evaluation and lens drive processes in the AF process. FIG. 16 is a timing chart illustrating processing timings when an imaging apparatus known in the related art captures an image. In the illustrated example, processing timings when a time necessary for the AF process is 100 ms and a time necessary to read a signal from the imaging element is 100 ms are illustrated. In this case, when the AF process is performed every time before shooting, a continuous shooting rate is about 5 shots/sec.
In addition, in order to improve the continuous shooting rate, a method of performing the AF process only once immediately before continuous shooting is started is known. FIG. 17 is a timing chart illustrating processing timings in the case in which the imaging apparatus known in the related art performs the AF process once immediately before continuous shooting is started when capturing an image. In the illustrated example, processing timings when a time necessary for the AF process is 100 ms and a time necessary to read a signal from the imaging element is 100 ms are illustrated. In this case, because the AF process is performed only once immediately before the continuous shooting is started, the continuous shooting rate is improved as compared to that of the case illustrated in FIG. 16.

Solid-state imaging element having substrates formed on semiconductor wafers and solid-state imaging apparatus having the same solid-state imaging element


A filterbank system is provided for reordering subbands of a wideband digital signal. The filterbank system extracts the subbands from a wideband digital input signal into an even channel number group of even channel number subbands and an odd channel number group of odd channel number subbands. The separation of even and odd channel number subbands provides an even channel grouping with guard bands between the even channel number subbands and an odd channel number grouping with guard bands between the odd channel number subbands. The filterbank system then reorders the even channel number subbands and the odd channel number subbands. The reordered subbands are then combined by combining the reordered even channel number subbands and odd channel number subbands into a wideband digital output signal.

Filterbanks have been employed in many applications such as transmultiplexers, audio/image compression, and adaptive filtering. A typical perfect reconstruction filterbank is designed to filter a wide band signal comprised of a plurality of subbands or subchannels into the subbands or subchannels, process the subbands or subchannels (e.g., compress/decompress), and then recombine the subbands or subchannels into a wide band signal with an attempt to minimize distortion. Oversampled filterbanks are widely employed to reduce the computational complexity of signal processing algorithms, such as subband adaptive filtering techniques utilized in many audio/image compression techniques. After the signal channeling and signal combining algorithms are performed, the wideband signal is typically transmitted over a radio frequency (RF) wireless link to one or more other radio devices (e.g., user terminals). The transmission frequency of the RF wireless link is at a substantially higher frequency than the processing frequency of the wideband signal.
In certain situations it is desirable to reorder the subchannels or introduce subchannels from one or more independent filterbanks. For example, in satellite transmissions the transmission frequencies (e.g., downlink frequencies) are different than the receiving frequencies (e.g., uplink frequencies). Therefore, signals that are received from ground stations with subchannels over certain frequency bands are retransmitted to user terminals over different frequency bands. Additionally, in certain applications is desirable to reorder the subchannels based on transmission order which requires the channels to be reordered not only into different frequency bands but into different frequency locations. These requirements cannot be met with conventional modulated filterbanks due to aliasing distortion of the signal caused by recombining the signal into a wideband signal.
Conventional oversampled modulated filterbanks employ "aliasing cancellation" methods to remove the aliasing distortion. This works quite well as long as the subchannels are not reordered. When the subchannels are reordered, "aliasing cancellation" cannot be utilized. Furthermore, algorithms that employ alias cancellation, when combined with subchannel switching, exhibit amplitude and group delay distortion. The distortion results because, during signal re-synthesis, the adjacent subchannels can be from different sources and do not necessarily contain the information needed for aliasing cancellation.

Efficient and flexible oversampled filterbank with near perfect reconstruction constraint


A wavelength tunable semiconductor laser light source, which has an external resonator semiconductor laser source unit; an optical filter for selecting an output beam of the external resonator semiconductor laser source unit in a single mode; a drive unit for changing wavelength of a transmitted beam or of a reflected beam, from the optical filter; and a control unit for controlling the drive unit; a first beam splitting device for receiving the output beam of the external resonator semiconductor laser source unit as one of incident beams and for outputting it into two branches; an etalon for receiving one of output beams from the first beam splitting device; a measuring unit for etalon transmittance, for measuring a transmittance of the etalon to transmit it to the control unit; and a wavemeter for specifying a wavelength of the output beam of the semiconductor laser source unit with an accuracy in a free spectral range of the etalon, on the basis of the output beam of the semiconductor laser source unit or on the basis of information from the drive unit, to output the specified wavelength to the control unit.

1. Field of the Invention
The present invention relates to a semiconductor laser light source tunable in wavelength, which is used in any technical field which requires a light signal source, in particular, in an optical telecommunication or a coherent optical measuring technical field.
2. Description of Related Art
In the coherent optical measuring technical field, an external resonator type of semiconductor laser (hereinafter, may be simply referred to LD) is generally used as a light source unit in a light source tunable in wavelength. An optical filter which is a wavelength selection element is disposed in the external resonator thereof to get a singlemode oscillation.
Such a technique enables wavelength scanning in a wide range by mechanically varying the transmitted (or reflected) wavelength from the optical filter.
FIG. 11 shows a construction example of a conventional wavelength tunable LD light source. In this figure, the reference numeral 1 denotes an external resonator type of LD light source unit, 2 denotes an optical filter, 3 denotes a drive unit, 4 denotes a control unit, and 20 denotes an origin switch.
In the wavelength tunable LD light source in FIG. 11, first, when a power source is turned on, the drive unit 3 is moved to a position at which the origin switch 20 is operated thereby, by the control unit 4. When the origin switch 20 is operated, the drive unit 3 is reset and the position thereof is used as the origin.
The wavelength of the output of the wavelength tunable LD light source when the drive unit 3 is at the origin is measured in advance by using a precise wavemeter and is memorized as the origin wavelength.
The drive unit 3 can mechanically change wavelength of the transmitted beam or of the reflected beam, from the optical filter 2, and when occasion demands, it carries out also adjustment for the length of an external resonator.
The relationship between the state of the drive unit 3 and the oscillation wavelength of the external resonator is already known. In the control unit 4, a wavelength set is carried out on the basis of a formula showing the known relationship. The control unit 4 also controls the LD drive current in order to control the optical output level of the LD light source unit 1.
FIG. 5 shows a construction example of an external resonator type of LD light source unit 1. In FIG 5, the reference numeral 101 denotes a diffraction grating; 102, 105 and 107 denote lenses; 103 denotes an anti-reflection film; 104 denotes an LD; 106 denotes an optical isolator; 108 denotes an optical fiber; and 109 denotes an LD driving circuit.
In the external resonator type of LD light source unit 1, shown in FIG. 5, the diffraction grating 101 which corresponds to the above-described optical filter 2, as shown in FIG. 4, also functions as a mirror in one side of the external resonator.
That is, the external resonator is formed by the end surface B of the LD and the diffraction grating 101. When denoting the intersection of the surface of the diffraction grating 101 and the optical axis X with A, the length of the resonator is defined by the segment AB of a line.
An anti-reflection film 103 is formed on an end surface in the side of the diffraction grating 101, of the LD 104 in order to remove unnecessary reflection.
Each of the lenses 102 and 105 is a collimator for changing the output beam of the LD 104 to a collimated beam.
The output beam from the external resonator LD 104, which is obtained from the side of the LD end surface B, is condensed through the lens 107 and is taken out by the optical fiber 108.
In order to generate no noise due to external feedback beam from a following optical system, the optical isolator 106 is disposed on the way in the output side.
The LD driving circuit 109 feeds an LD driving current corresponding to a desired optical output level.
Although only the diffraction grating 101 is shown in FIG. 5, as the optical filter 2, it is possible to use an optical element other than the diffraction grating 101, for example, to use an interference filter or the like, as the optical filter 2. When occasion demands, combination of a plurality of optical elements can be also used as the optical filter 2.
Next, the characteristics of an optical filter will be explained as follows.
FIG. 6 shows an optical system of a diffraction grating 101. In this FIG., .theta. is the angle of the normal N.sub.gr to the diffraction grating 101 with the optical axis, d is the pitch of the diffraction grating, and the incident light and the reflected (diffracted) light are set on the same optical axis X, like the above-described external resonator shown in FIG. 5.
The spectrum of the reflected light when an incident white light came into the diffraction grating 101 is the filter characteristics of the diffraction grating. A filter characteristics is obtained, as shown in FIG. 7.
The reflection peak wavelength .lambda..sub.gr is given by the following Bragg's formula: EQU .lambda..sub.gr =2d.times.sin (.theta.) (1)
The characteristics of the interference filter 201 in the optical system shown in FIG. 8 has periodic transmittance peaks, as shown in FIG. 9.
In FIG. 8, "D" is the thickness of the interference filter 201, and "n" is the refractive index thereof.
The wavelength of each transmittance peak is given by the following formula : EQU k.lambda..sub.k =2nD.times.cos (.theta.) (2)
where .theta. is the angle of the normal N to the interference filter 201 with the optical axis in the interference filter, and k is an integer.
When L is the length of the external resonator and m is an integer, like the case of an interference filter, the oscillation longitudinal mode of the external resonator is expressed as follows: EQU m.lambda..sub.m =2L (3)
Next, an example of characteristics of wavelength tunable LD light source, using an optical filter comprising a combination of a diffraction grating and an interference filter is illustrated in FIGS. 10A to 10E.
FIG. 10A shows a gain characteristics of LD, which generally has a gain in a wavelength range not less than 100 nm.
FIG. 10B shows a resonator mode corresponding to the formula (3), which are oscillation longitudinal modes.
Several modes are selected by using the filter characteristics of the diffraction grating shown in FIG. 10C, among the oscillation modes.
Then, a single mode is selected by using the filter characteristics of the interference filter shown in FIG. 10D. As a result, a single mode oscillation is obtained, as shown in FIG. 10E.
By changing each of the characteristics shown in FIGS. 10B, 10C, and 10D, that is, by changing L, .theta., and .phi. suitably, it is possible to carry out wavelength scanning.
The relationship between the wavelength and L, .theta., and .phi. is found on the basis of previous measurements. According to the relationship, the drive unit 3 having a combination of a motor, a rotary table, a directly linear-moving mechanism and the like realizes a state of particular values of L, .theta., and .phi., corresponding to the set wavelength.
The so-called WDM (Wavelength division multiplexing) of optical communication system which is recently focused on is one multiplexing several wavelengths with a difference of wavelengths of about 1 nm. For example, when the wavelengths difference is finely adjusted at a level of about 0.1 nm, wavelength accuracy having a level of about 0.01 nm which is taken a figure down in comparison with that of the wavelengths difference is required.
On the contrary, although the obtained set resolving power in the former art is a level of 0.001 nm, the set wavelength accuracy thereof is about a level of .+-.0.1 nm because of error factors, e.g., a backlash or a hysteresis on the mechanism, or set condition reproducibility including a fluctuation in temperature, a change with the passage of time or the like.
Therefore, in order to improve the set wavelength accuracy, it was required to prepare not only an external resonator type of wavelength tunable LD light source but also an expensive wavemeter, to measure the wavelength of the light source output by the wavemeter, and to correct the setting.

Wavelength tunable semiconductor laser light source


A system and method for detecting a passing vehicle is disclosed. A video sequence comprising a plurality of image frames is received. Image intensity is measured and image motion is estimated in each image frame. A hypothesis model describing background dynamics is formulated. The measured image intensity and motion estimation is used to determine if the background dynamics has been violated in a given image frame. If the background dynamics has been violated, motion coherency is used to determine whether the violation of the background dynamics is caused by a passing vehicle.

Machine-vision-based obstacle detection and tracking is an important component in autonomous vehicle systems. In a typical driving scene, the obstacles include vehicles, pedestrians and any other objects that are either moving or rising above the road plane. The purpose of obstacle detection is to separate moving objects from the driving scene, the obstacles including vehicles, pedestrians and any other objects that are either moving or rising above the road plane. Such information is required by a number of automotive applications, e.g., adaptive cruise control, forward collision avoidance and lane departure warning. By fusing the results of detecting and tracking individual objects, it is possible to achieve sufficient perception of the driving environment.
In a monocular vision system designed for driver assistance, a single camera is mounted inside the ego-vehicle to capture image sequence of forward road scenes. Various vehicle detection methods have been developed to detect vehicles in the central field of the view. Such methods can be used in passing vehicle detection. In passing vehicle detection, vehicles that are passing the ego-vehicle upon the left or right and entering the field of view at a higher speed are detected. Passing vehicle detection plays a substantial role in understanding the driving environment. Because of the potentially unsafe driving situation that an overtaking vehicle could create, it is important to monitor and detect vehicles passing by.
Since passing vehicles need to be detected earlier on while they are entering the view and only partially visible, appearance information cannot be completely relied upon. Instead, characteristic optical flows are generated by a vehicle passing by. Hence, motion information becomes an important cue in detecting passing vehicles. Several known obstacle detection methods using optical flow have been used to detect passing vehicles. In these methods, a predicted flow field calculated from camera parameters and vehicle velocity is compared with the actual image flows calculated from motion estimation. An obstacle is declared if the actual flows do not match the predicted flows. These methods work well if neither strong noise nor illumination change is present. However, in practical situations, structured noise and strong illumination are quite common which cause spurious image features and unreliable flow estimates. There is a need for a method for detecting passing vehicles which is capable of robust motion estimation.

System and method for detecting a passing vehicle from dynamic background using robust information fusion


An interleaving method and apparatus provides parallel access in a linear and interleaved order to a predetermined number of stored data samples. A memory array with a plurality of memory devices is addressed by applying a first portion of an address to memory devices and by using a second portion of the address to select at least one memory device to be accessed, wherein the position of the first and second portions within the address is changed in response to a change between the linear order and the interleaved order. Due to the fact that the memory array is split into several individually addressable memory devices, each of these memory devices can be accessed in a linear and interleaved order by changing an allocation of a chip selection portion and a chip addressing portion of the address.

1. Field of the Invention
The present invention relates to an interleaving method and apparatus for providing parallel access in linear and interleaved order to a predetermined number of stored data samples, such as a turbo interleaver for a turbo decoder in mobile communication systems.
2. Description of the Related Art
Code concatenation is a practical technique for obtaining a code with a very long block length and a large error-correction capability. This is accomplished by combining two elementary codes. These codes have two distinct levels of encoding and decoding. The advantage of this coding scheme is that sequential decoding of the different codes can be performed. Thus, the decoding complexity of the overall code depends on the complexity of the decoder associated to each separate code used. This leads to a reduction of the decoding complexity.
The concept of turbo codes is an iterative decoding of two codes concatenated either in parallel or in serial using a Soft Input Soft Output (SISO) elementary decoder. Each elementary decoder therefore provides a decision and a likelihood ratio which quantifies the probability that the decision is correct. This information is passed to the next decoding stage in order to improve the bit error rate at each iteration. A turbo decoder can be implemented as certain number of pipelined identical elementary decoders depending on the number of iteration.
Turbo codes are able to achieve performances with a signal to noise ratio close to Shannon's theoretical limit, provided that the code is long enough and that a sufficiently large number of iterations is used in the iterative decoding process. Convolutional turbo codes are built using a parallel concatenation of two Recursive Systematic Convolutional (RSC) codes separated by a large random interleaver. The elementary decoder used in the iterative decoding process consists of two constituent SISO decoders, one for each RSC encoder, an interleaver and a deinterleaver. Further details are described for example in "Near Shannon limit error-correction coding: Turbo-Codes", C. Berrou et al, in Proc. IEEE ICC'93, Geneva, Switzerland, pp. 1064–1070, May 1993, incorporated herein by reference.
In general, the interleaver randomizes an address of an input information or codeword and improves a distance property of the code word. It has been decided to use a turbo code in data transmission channels of third generation mobile communication systems, e.g. in a data channel of UMTS (Universal Mobile Telecommunications System) proposed by ETSI (European Telecommunication Standards Institute).
FIG. 1 shows a schematic block diagram of a conventional interleaver as for example disclosed in document WO 00/70771 for interleaving frame data. An address generator 150 generates a read address for changing the sequence of input data bits according to an input frame data size and an input clock CLK, and provides an interleaver memory 100 with the generated read address RA. The interleaver memory 100 sequentially stores input data DI in a write mode of operation, and outputs the stored data as output data DO according to the read address provided from the address generator 150 in a read mode of operation. A counter 130 counts the input clock and provides the clock count value to the interleaver memory 100 as a write address WA. Thus, the interleaver sequentially stores input data in the interleaver memory 100 in the write mode of operation, and outputs the data stored in the interleaver memory 100 according to the read address provided from the address generator 150 in the read mode of operation. Alternatively, it is also possible to change the sequence of the input data bits before storing them in the interleaver memory in the write mode of operation, and sequentially read the stored data in the read mode of operation.
If such an interleaver scheme is to be provided with a parallel access to the stored data in linear and interleaved order, multiport random access memory (RAMs) are used with K (K>1) reading ports. However, such multiport RAMs require large chip areas and are very expensive. Moreover, multiport RAMs with K reading ports may not be available from each ASIC (Application Specific Integrated Circuit) vendor, or the maximum number of available ports is at least limited at several vendors.

Interleaving method and apparatus with parallel access in linear and interleaved order