A apparatus and method are disclosed for generating one or more clock signals. A clock signal is generated based on pattern signals and a reference clock signal. When the reference clock signal transitions high, the state of a first pattern signal is output, and when the reference clock signal transitions low, the state of a second pattern signal is output. Successive states of the first and second pattern signals, selected according to the reference clock signal, provide the generated clock signal.

1. Technical Field
The present disclosure relates to the field of clock signal generation, and more particularly to the generation of multiple phase-aligned clock signals.
2. Related Art
In an ideal synchronous circuit, all data transitions occur simultaneously and all components are synchronized by one or more related clock signals. Multiple clock signals are often used in a circuit because circuit components are designed to function (reliably) at different speeds. For example, a central processing unit (CPU) typically functions at a much higher speed than a peripheral/external interface data bus. It is important, however, that the frequency of the clock signal that drives the CPU be a multiple of the frequency of the clock signal that drives the data bus so that data bus operations are in synchronization with the operation of the CPU. For example, a CPU may function at 3 GHz and the system bus may function at 375 MHz, a ratio of 1:8. Operations that involve both the CPU and the data bus will succeed only if (1) the CPU and data bus clock signals maintain the 1:8 ratio and (2) each data bus clock signal transition occurs at the same time with respect to eight CPU clock signals, i.e., the CPU and data bus clock signals are phase-aligned.
High speed components and increasingly complex circuits have made it difficult to phase-align the different clock signals in a circuit. In addition, some circuits require three, four, or even more different clock signals, all of which must be phase-aligned. In such circuits, phase-alignment is partially aided by having all of the clock circuits (also referred to as clock dividers) derive their clock signals (also referred to as clock root signals) from a common signal, typically generated by a phase-locked loop (PLL) system. The PLL system, in turn, is driven by a chip's reference clock oscillator. Thus, all clock root signals are derived, either directly or indirectly, from a common reference clock oscillator.
One of the factors that determines the complexity of the clock dividers is the number of different clock root signals that must be phase-aligned. The greater the number of clock root signals, the less forgiving each clock divider can be to clock signal effects such as skew, jitter, and noise. Stability, predictability, and variance parameters of clock dividers are becoming increasingly stringent due to circuit designs that utilize high speed components and multiple clock root signals.
One technique for generating phase-aligned clock root signals is to "merge" the clock dividers into the PLL system design. However, this design approach typically involves highly sensitive analog and digital design considerations and leads to difficult verification and qualification processes.
Another technique for generating phase-aligned clock root signals is to provide the PLL system output to a series of cascaded multiplexer circuits, and have each multiplexer provide a different clock root signal. However, this design approach leads to long signal paths of varying lengths and, consequently, high jitter. It also requires large timing margins. An improved approach is desirable.

Apparatus and method for generating a clock signal


Photovoltaic (PV) cell structures are disclosed. In one example embodiment, a PV cell includes an emitter layer, a base layer adjacent to the emitter layer, and a back surface field (BSF) layer adjacent to the base layer. The BSF layer includes a first layer, and a second layer adjacent to the first layer. The first layer includes a first material and the second layer includes a second material different than the first material.

The field of the disclosure relates generally to solar energy conversion devices, and more particularly to a multi-layer back surface field layer in a solar cell structure.
Interest in photovoltaic ("PV") cells in both terrestrial and non-terrestrial applications has increased as concerns over pollution and limited resources continue. Regardless of the application of such cells, efforts have been ongoing to increase the output and/or increase the efficiency of PV cells.
Some known PV cell structures include a cell base with layers lattice matched to substrates with relatively high bandgaps. A back surface field (BSF) layer is often used between a cell base portion of a solar cell and the substrate or layers next to the base layer to reduce electron-hole recombination at the interface, block minority carriers from diffusing away from the pn junction and to thereby increase the cell's efficiency. The BSF layer is commonly lattice-matched to the cell lattice constant. The relatively large cell band gaps in such structures, however, reduce the efficiency of the solar cell structure.
Some multijunction terrestrial PV cell structures, utilize an upright metamorphic design with a larger lattice constant and a wider bandgap range to better split the solar spectrum, and therefore to increase efficiency. Some such PV cell structures may have a cell base bandgap range from about 0.7 eV to about 2.0 eV. To lattice match the BSF layer to the larger cell lattice constant in metamorphic PV cell structures, indium is often added to the BSF layer. For example, some known upright metamorphic PV cells use an AlGaInAs or ALGaInP BSF layer. In at least one known metamorphic PV cell structure, the BSF layer includes about twenty percent indium and about sixty percent aluminum. Although the added indium increases the lattice constant of the BSF layer, the indium also reduces the bandgap of the BSF layer. As a result, some known metamorphic PV cell structures have an indirect bandgap below 2.0 eV. At such a relatively low bandgap relative to the cell base bandgap, the BSF layer may not function as effectively as desired, and efficiency of such a PV cell may be reduced. Moreover, p-doping with carbon in the BSF layer is limited because of the indium etching effect of carbon. Thus, at least some known metamorphic PV cell structures that include indium in the BSF layer are limited to p-doping of less than about 1018 cm−3.

This patent is subject to a terminal disclaimer.

Multi-layer back surface field layer in a solar cell structure


A delay locked loop (DLL) circuit includes a delay line configured to generate a delay clock signal by delaying a reference clock signal in response to a delay control signal, the delay line having two or more initial activation points, wherein the initial activation points are selected according to an initial value of the delay control signal; a delay compensating unit configured to generate a feedback clock signal by delaying the delay clock signal for a predetermined time; a phase detecting unit configured to generate a phase detection signal by comparing a phase of the reference clock signal to a phase of the feedback clock signal; and a delay control unit configured to generate the delay control signal in response to the phase detection signal.

The present invention relates generally to semiconductor integrated circuits (IC) and, more particularly, to a delay locked loop (DLL) circuit included in a semiconductor IC.
A conventional semiconductor IC, such as synchronous dynamic random access memory (SDRAM), uses a clock signal to increase operational speed. For this, a semiconductor IC includes a clock buffer that buffers an externally input clock signal. In some cases, a semiconductor IC includes a delay locked loop (DLL) circuit or a phase locked loop (PLL) circuit to generate an internal clock signal in which the phase difference between the internal clock signal and the external clock signal has been corrected.
A DLL circuit delays a reference clock signal output from a clock input buffer using a delay line. A delay time, which is the delay of the reference clock signal by the delay line, is determined based on the result of a comparison between the phase of the reference clock signal and the phase of a feedback clock signal. The feedback clock signal is generated by delaying the output clock signal of the delay line by a delay value acquired by modeling the amount of delay occurring when the clock signal output from the delay line is transmitted to a data input/output buffer. To model this delay, a replica delayer is provided in the DLL circuit. With such a configuration, the DLL circuit outputs a clock signal having a phase that is earlier than that of the external clock signal by a predetermined time. Accordingly, the data input/output buffer can perform a buffering operation by using an internal clock signal whose timing coincides with the external clock signal.
FIG. 1 is a timing diagram shown for illustrating the operation of a known DLL circuit.
When referring to FIG. 1, it is possible to realize the phase relationship between a reference clock signal 'clk_ref' and a feedback clock signal during an initial operation of the DLL circuit. Herein, the feedback clock signal is represented as a first feedback clock signal 'clk_fb1' when the initial delay value of the delay line is at a minimum value; and the feedback clock signal is represented as a second feedback clock signal 'clk_fb2' when the delay line in an initial stage has a predetermined delay value. Generally, the delay line of the DLL circuit does not set the initial delay value to the minimum value. This purpose of this is to prevent a locking operation from being interrupted when the delay line must reduce the delay time after the initial operation. Typically, the initial delay value of the delay line of the DLL circuit is set to a delay amount that is half of the total delay amount of the delay line.
However, the second feedback clock signal 'clk_fb2' generated as a result of the predetermined initial delay value is also not synchronized with the first rising edge 'RE1' of the reference clock signal 'clk_ref'; and therefore, the second feedback clock signal 'clk_fb2' must be synchronized with a second rising edge 'RE2'. At this time, the total delay amount that the delay line must allocate to the reference clock signal 'clk_ref' for the locking operation exceeds one cycle of the reference clock signal 'clk_ref'. Thus, when the delay line is initially set to be delayed by the predetermined initial delay value, the delay line must have a total delay amount that is larger than one cycle of the reference clock signal 'clk_ref'. In actuality, the delay line is generally configured to have a total delay amount that is approximately two cycles against using a high-frequency clock signal.
Accordingly, the DLL circuit described above has limitations in that the length of the delay line increases. The length of the delay line has a problem not only in an area efficiency aspect, but also in that the length of the delay line causes an increase of an internal jitter component. Consequently, the operational stability of the above-described DLL circuit is reduced, thereby causing problems when attempting to realize high integration and increased speed of a semiconductor IC.


A method for serving an image from a server to a client, e.g., a computer having a browser or other graphics viewing engine. The user of the client first specifies a set of one or more bitmap characteristics for an image transfer, with at least one of the bitmap characteristics including a number of bits per pixel. Preferably, this specification is accomplished using an applet or other piece of code that is downloaded to the client from the server. Later, when the server receives a client request that includes data identifying a specified bitmap characteristic, a server processing routine (e.g., a servlet) generates a version of the image that conforms to the specified bitmap characteristic. This version is then delivered back to the client in response to the original request. In this way, the user of the client machine can control the particular characteristics of the image files that are delivered to his or her machine.

1. Technical Field
The present invention relates generally to transmission of image content in a computer network and, in particular, to a method for enabling a user of a client machine to negotiate the format of an image to be transferred to the client machine from a server in the network.
2. Description of the Related Art
The World Wide/Web is the Internet's multimedia information retrieval system. In the web environment, client machines effect transactions to web servers using the Hypertext Transfer Protocol (HTTP), which is a known application protocol providing users access to files (e.g., text, graphics, images, sound, video, etc.) using a standard page description language known as Hypertext Markup Language (HTML). HTML provides basic document formatting and allows the developer to specify "links" to other servers and files. In the Internet paradigm, a network path to a server is identified by a so-called Uniform Resource Locator (URL) having a special syntax for defining a network connection. Use of an HTML-compatible browser (e.g., Netscape Navigator or Microsoft Internet Explorer) at a client machine involves specification of a link via the URL. In response, the client makes a request to the server identified in the link and, in return, receives in return a document or other object formatted according to HTML. A collection of documents or objects supported on a web server is sometimes referred to as a web site.
Many web pages include high resolution images or graphics. When it is desired to transmit an image over the Internet, typically either the entire image is transferred or, alternatively, a smaller, low-resolution version is served. An example of a low-resolution image is a thumbnail image, which the user may review and then select to control the browser to fetch the full resolution image. Transmission of a thumbnail image instead of the full resolution image it represents conserves significant bandwidth and network resources.
It is also known in the prior art to provide software routines at both a client and a server in a distributed computer network to enable the amount of data in a graphical image that is to be transmitted (i.e. from server to client) to be customized in according with client and/or server-supplied information. Such a technique is described in U.S. Pat. No. 5,764,235 to Hunt et al. In this patent, each of the client and server include a dedicated handshake process that allows the machines to first determine whether they both support the image customization functionality. If so, then the server may then use an image customization process on images to be transmitted to the client to selectively modify the amount of data and the format of the graphical image files to be sent to the client in response to a request for the image. In performing the image customization process, the server makes use of server image control data and/or client image control data. The client image control data is data or information obtained from the client that is useful in determining both the suitable amount of data and/or format for the graphical image files to be sent. Typically, such data includes user data and client system data. The user data may include user preference, intended use, or a specific quality level. The client system data includes type of compression supported, transmission performance criteria, and equipment data (e.g., display format, printer format, or the like).
While the technique illustrated in Hunt et al. reduce image transmission time and save network bandwidth, the approach has certain disadvantages. Foremost, the technique proposed by Hunt et al. envisions that a given graphical image file be processed prior to receipt of the client request. According to the patent, the image file is processed to create a modified image file that is partitioned into various additive segments. As more and more of the segments are added together, a better quality image is created. Thus, for example, a first segment can be used for displaying the image as a high quality, thumbnail size image or a low quality, feature size image. By combining this segment with another segment, the resulting image can be used as a high quality, feature size image or a low quality, full screen size image.
Preprocessing the image in accordance with the teachings of the Hunt et al. patent effectively offsets the advantages that are otherwise achieved by sending the customized images. In particular, the generation of the custom segments consumes both processing and storage resources at the server, thus minimizing the value of the technique. In addition, the types of client image control data identified in the patent do not afford the user of the client machine sufficient flexibility to control the characteristics of the actual image transferred.
The present invention addresses these deficiencies of the prior art.

Method for enabling a client to specify the characteristics of an image to be downloaded from a server

International Business Machines Corporation


A planar waveguide laser crystal assembly includes an optical bench and a laser crystal mount mounted on the optical bench. The laser crystal mount includes an upper housing having an interior horizontal surface and an exterior horizontal, a lower housing coupled to the upper housing and having an interior horizontal surface and an exterior horizontal surface, and a cavity defined between the interior horizontal surfaces of the upper and lower housings. A laser crystal is mounted in the cavity of the laser crystal mount. Each of the exterior horizontal surfaces of the upper and lower housings is oriented parallel to a length of the laser crystal. The laser crystal assembly further includes a heat dissipating structure thermally coupled to at least one of the exterior horizontal surfaces of the upper and lower housings to dissipate heat transferred from the laser crystal mount.

High power lasers and laser amplifiers having very high beam quality are difficult to make because a number of factors degrade performance. One such factor is heat deposition within the laser material resulting from imperfect conversion of pump radiation input power into laser output power. Most frequently it is not absolute temperature rise that is of concern but, instead, spatial gradients within the material. It is well known that parameters, such as the refractive index, are temperature dependent, and consequently temperature gradients lead to refractive index gradients, which in turn degrade the performance of the laser or amplifier. Heat loads and poor mechanical mounting techniques also cause stresses in the materials that degrade performance by introducing wavefront distortions.
In an attempt to address problems associated with stresses generated during mounting, considerable efforts have been expended within the laser industry in finding ways to mount laser rods and slabs that optimize optical performance. Compounding the problem, often a relatively large amount of heat must be removed from the material during mounting, and as a result, implemented mounting techniques typically should provide a good heat conduction path to a heat sink or cold plate where the heat is removed through convection, conduction, or radiation. A further complication is that laser radiation must be extracted from the rod or slab through apertures and at least some of the laser material must be exposed to permit pump light to enter the material for absorption.
A number of techniques have been conceived to mount round laser rods, and these techniques are aimed at permitting good heat flow and at addressing stress production. Common to all these techniques is the assumption of round laser rods. Such circular geometries are attractive in part because of the ease of fabrication, but, unfortunately, these mounting techniques are not particularly well suited for slabs having a rectangular shape (or not being round in cross section).
Slab geometries are attractive for several reasons and are particularly useful in the generation of high optical output powers. First, they provide at least one rectangular flat surface through which pump light can enter. Second, with uniform pumping, slab geometries promote one-dimensional temperature gradients. Third, they provide a method to "zig-zag" a laser beam within the medium. The latter provides for a way to extract energy efficiently with good beam quality. In order to maximize the advantages inherent in such slab geometry, it is, however, important to design the mounting and cooling arrangements very carefully.
Some efforts have been made in the laser industry to address some of the challenges associated with mounting of slab geometries. For example, a number of prior disclosures describe methods of mounting slabs that incorporate a gas or liquid flow channel between the source of pump radiation and the slab. These methods or approaches have several drawbacks and do not adequately meet the needs of the laser industry. First, these methods assume the presence of a flowing cooling liquid and, therefore, preclude operating with a passive heat disposing mechanism. Second, these methods are often susceptible to the depositing of unwanted contaminants on the surface of the slab that may degrade the performance of the laser.
A somewhat more attractive solution may involve an arrangement in which passive heat spreaders and radiators are used without flowing coolants, such as cooling gas or liquid, being provided as an intrinsic part of the construction. For example, some prior art references discloses a method to sandwich a slab between transparent conductive heat sinks which also act as guides to transport pump light to the slab. However, the described method fails to solve the problem of removing large amounts of heat from the assembly. Also, the method includes bonding the slab to the conductive heat sinks, which does not work well at high thermal loads since it promotes stresses within the laser slab.
Self-Imaging Planar Waveguide (PWG) Lasers and Laser Amplifiers are used for various applications, including systems that require high laser output power, good optical beam quality, hermetic enclosures for high reliability, and excellent SWaPT (Size, Weight and Power, Thermal) characteristics. The optical pumping methods used with these laser systems result in heat being deposited into the laser crystals that can lead to thermo-optical aberrations, and high stress mounting of the laser crystals can lead to unwanted optical aberrations by way of strain birefringence effects. Left unmanaged, these aberrations reduce overall laser system efficiency and reduce laser output beam quality.
It is therefore desirable to develop methods to hold PWG laser crystals with low stress, but with mechanically adequate means for the environmental and system requirements. It is also necessary to provide thermal management pathways that uniformly and quickly dissipate heat so that minimal thermal defects are imprinted into the laser crystals from the downstream cooling system or from the optical pumping method. The cooling system also serves to reduce the magnitude of residual thermal aberrations and minimize the thermal transient timelines required to stabilize the laser outputs.

Systems and methods for planar waveguide mounting and cooling


A byte tracking system (60) has a 32-bit wide system data bus (34). System bus interface unit (48) connects the system bus (34) to the transmit FIFO buffer memory (42) to supply 4-byte data words (62) to the FIFO buffer memory (42). The FIFO buffer memory (42) has word write and read accessibility. A 4:1 multiplexer (64) is connected at the output side of the FIFO buffer memory (42) by a 32-bit wide bus (66). The multiplexer (64) is used to multiplex correct bytes (63) from the data words (62) to an 8-bit output bus (68). A byte tracker circuit (70) controls the multiplexer (64) and determines which byte (63) is to be sent to the output bus (68). The bytes (63) supplied to output bus (68) are converted by a parallel to serial converter (69) to a serial bit stream, which is supplied to Manchester encoder/decoder (36).

1. Field of the Invention
The present invention relates generally to a system and method for transferring data between two data busses having different widths. More particularly, it relates to such a system and method including a digital storage buffer designed to interface the two data busses, where information is passed to the buffer sequentially from one bus and retrieved from the buffer sequentially to the other bus. Most especially, the invention relates to such a system and method including a logic circuit to interface a first data bus to a second data bus, the second data bus having a size equal to an integral fraction of the first data bus, through a First-In-First-Out (FIFO) buffer memory.
2. Description of the Prior Art
In such systems data presented from the wider bus may contain a full word, which represents the full width of the bus, or a partial word, which means that only part of the bus has valid data associated with it. The interface must recognize the invalid data in the partial word and must not pass the invalid data to the second bus.
It is known to use a perfect data aligner to recognize and eliminate the invalid data before passing the aligned data to the FIFO memory buffer. The data aligner typically consists of a multiplexer which packs data to eliminate the invalid data fields. A temporary holding register is used to store data during the packing process. Any part of a word not written to the FIFO buffer memory immediately has to be stored in the temporary holding register, and any subsequent word has to be aligned with these stored data. The resulting logic requires a substantial amount of control logic, which is a speed limitation for a high speed bus interface.


In order to allow each of communication stations to execute impartial control of accesses to communication media by setting executable-communication ranges of their own independently of each other in a communication environment based on a CSMA method, the present invention provides a radio communication system in which each communication station is capable of checking the occupation state of communication media and setting such an executable-communication range of its own in accordance with the occupation state of the communication media that the number of communication stations coexisting in the executable-communication range is brought to a value within a predetermined range. For example, a specific communication station sets an executable-communication range of its own in order to limit the number of other communication stations capable of communicating with the specific communication station. In addition, a communication station sets an executable-transmission range suitable for an executable-reception range set by itself in order to reduce the degree of non-uniformity of the access control and to minimize the impact of interferences on other communication stations.

The present invention relates to a radio communication system, radio communication apparatus, a radio communication method and a computer program for carrying out communications between a plurality of radio communication stations as is the case with a radio LAN (Local Area Network). More specifically, the present invention relates to a radio communication system, radio communication apparatus, a radio communication method and a computer program, in which radio communication stations make accesses to communication media while avoiding collisions in accordance with detection of carriers on the basis of a CSMA (Carrier Sense Multiple Access with Collision Avoidance) method.
To put it in more detail, the present invention relates to a radio communication system, radio communication apparatus, a radio communication method and a computer program, in which every radio communication station operates by obtaining a desired communication opportunity in accordance with the state of occupation of the communication media. More specifically, the present invention relates to a radio communication system, radio communication apparatus, a radio communication method and a computer program, in which every radio communication station operates by obtaining a desired communication opportunity by dynamically controlling a communication range in accordance with the state of occupation of the communication media.
By constructing a LAN including a plurality of computers connected to each other, information such as files and data can be shared by the computers, peripheral equipment such as a printer can be shared by the computers and information can be exchanged between the computers in the form of transmitted emails and transferred data/contents.
Traditionally, a wired LAN is generally constructed by using optical fibers, coaxial cables or twist-pair cables. In this case, a work to lay out the cables must be done. Thus, it is difficult to construct the network as a simple work. In addition, the work to draw the cables is complicated. On the top of that, after the construction, a range in which equipment can be moved from a location to another is restricted due to limited lengths of the cables so that the work to move equipment is not convenient either.
As a system for freeing the user from LAN wiring problems caused by the wire-communication method as described above, attention is paid to a radio LAN. In accordance with the radio LAN, in a work space such as an office, most of wiring cables can be eliminated. Thus, a communication terminal such as a personal computer (PC) can be moved from a location to another with ease.
In recent years, with an increased speed and decreased cost of a radio LAN, the demand for a radio LAN has been rising substantially. In particular, a study of introduction of a personal area network (PAN) is being conducted recently. The PAN is a small-scale radio network built to connect a plurality of electronic apparatus existing in the immediate surroundings of users in order to allow the electronic apparatus to communicate information between them. As the PAN, different radio systems using radio bands requiring no license from a supervisory authority are prescribed. Examples of the radio band requiring no license are the 2.4 and 5 GHz.
Standard specifications for radio network include IEEE (The Institute of Electrical and Electronics Engineers) 802.11 described in documents such as non-patent document 1, HiperLan/2 described in documents such as non-patent document 2 or 3, IEEE302.15.3 and Bluetooth communication. There are some different versions of the IEEE802.11 standard due to differences in adopted radio communication method and used frequency band. An example of the versions is an IEEE802.11a standard described in documents such as non-patent document 4.
Transmission and Reception Procedures
In general, a local area network using a radio technology is constructed by adoption of method by which an apparatus to serve as a control station called an access point or a coordinator is provided in the area covered by the local area network and a network is constructed under integrated control executed by the control station.
In a radio network including an access point, an access control method is widely adopted for transmitting information from a communication apparatus. In accordance with the access control method, first of all, a reservation is made with the access point as a reservation for a band required for the transmission of the information. Then, a transmission line is utilized in accordance with the reservation to avoid collisions with information transmissions carried out by other communication apparatus. That is to say, by providing an access point in the radio network, it is possible to carry out synchronous radio communications in which communication apparatus in the network establish synchronization with each other.
If communication apparatus on transmitting and receiver sides in a radio network including an access point carry out an asynchronous radio communication, however, the communication must be performed through the access point. Thus, the asynchronous radio communication raises a problem that the utilization of the transmission line is reduced to a half.
As another method of constructing a radio network, on the other hand, there has been proposed ad-hoc communication of allowing terminals to carry out an asynchronous communication directly. In particular, in the case of a small-scale radio network including relatively few clients located at locations close to each other, ad-hoc communication is pondered to be suitable direct asynchronous communication between any terminals without using a special access point. In a radio LAN system conforming to the IEEE802.11 standard, for example, an ad-hoc mode is provided as a mode in which the system allows terminals to operate as autonomous terminals in a distributed-processing manner and on a peer-to-peer basis without requiring a control station.
In this case, when a plurality of users makes accesses to the same channel, it is necessary to avoid contentions. As a representative communication procedure for avoiding a contention, a CSMA (Carrier Sense Multiple Access with Collision Avoidance) method is known. The CSMA method is a connection method allowing several accesses to be made on the basis of carrier detection. Since it is difficult for a terminal to receive a signal transmitted by the terminal itself as a signal representing transmitted information, in place of a CSMA/CD (Collision Detection) method, a CSMA/CA (Collision Avoidance) method is adopted. In accordance with the CSMA/CA method, a transmission of information from a communication apparatus is started only after confirming the fact that there is no transmission of information from another communication apparatus so that a collision can be avoided.
A communication based on the CSMA/CA method is explained by referring to FIG. 33 below. In the following example shown in the figure, four communication stations STA0 to STA3 exists in a communication environment.
Every communication station having data to be transmitted monitors the state of communication media for a predetermined frame interval DIFS following detection of a last packet. The frame interval DIFS is also referred to as a DCF (Distributed Coordination Function) Inter Frame Space. Then, if the communication media is clear or there is no transmitted signal during this frame interval DIFS, the communication station enters a random back-off period. If there is no transmitted signal also during this back-off period, the communication station is given a right of transmission.
In the following example shown in the figure, communication station STA0 with a set back-off period shorter than those of the other communication stations obtains a transmission right and is thus capable of starting a transmission of data to communication station STA1.
In the transmission of the data, communication station STA0 serving as the sender of the transmission of data stores information on an application of an NAV (Network Allocation Vector) and the length of time it takes to complete the transaction of the data communication in a duration field of the header of a MAC frame. In the following description, the header of a MAC frame is also referred to as a MAC header.
Station STAL serving as the receiver of the data-frame transmission carries out an operation to receive the data destined for this station itself throughout the period stored in the MAC header as a duration to be described later. As the operation to receive the data is completed, communication station STA1 transmits an ACK packet to the communication station STA0 serving as the sender of the data transmission in response to the transmitted data.
In the mean time, communication stations other than communication station STA1 serving as the receiver of the data-frame transmission to receive data frames each decode the duration field of the MAC header, recognizing that the communication media is being occupied, and inhibit a transmission of data without monitoring the media till the current transmission is ended. This work is referred to as establishment of an NAV (Network Allocation Vector). The NAV is effective throughout a time period indicated by the duration field. Typically, the duration field shows a period of time that lasts till communication station STA1 serving as the receiver of the data-frame transmission transmits an ACK packet to communication station STA0.
As described above, in accordance with the CSMA/CA method, only one communication station is capable of obtaining a transmission right while avoiding contentions and, in addition, the other communication stations each inhibit an operation to transmit data during the time period of the current data communication in order to get rid of collisions.
In this case, as is already known, a concealed-terminal problem is raised in the radio LAN network of the ad-hoc environment. A concealed terminal is a communication terminal that cannot be heard by a specific communication station serving as a communication partner in a communication between specific communication stations but can be heard by the other specific communication station serving as the other partner in the communication. Since concealed stations are not capable of carrying out a negotiation between each other, with only the CSMA/CA method described above, it is quite within the bounds of possibility that transmission operations result in a collision.
As one of methodologies for solving the concealed-terminal problem, a CSMA/CA method based on an RTS/CTS procedure is known. This known methodology is also adopted in the IEEE802.11 standard.
In accordance with the RTS/CTS method, a communication station serving as a data sender transmits an RTS (Request To Send) packet making a request for transmission of data to a communication station serving as a data receiver and the communication station serving as a data receiver transmits a CTS (Clear to Send) packet as a response to the RTS packet to inform the communication station serving as a data sender that the RTS packet has been received before the transmission of the data is started. Then, when a concealed terminal receives at least either the RTS or CTS packet, a period during which the execution of a data transmission based on the CTS/RTS procedure is expected is set as a transmission-inhibiting period of time in order to avoid collisions.
FIG. 34 is an explanatory diagram showing typical operations of this RTS/CTS procedure. In the case of this radio communication environment, however, four communication stations STA0 to STA3 are assumed to exist in the environment. Communication station STA2 is capable of communicating with adjacent communication station STA0. Communication station STA0 is capable of communicating with adjacent communication stations STA1 and STA2. Communication station STA1 is capable of communicating with adjacent communication stations STA0 and STA3. Communication station STA3 is capable of communicating with adjacent communication station STA1. In this case, communication station STA2 is seen by communication station STA1 as a concealed terminal and communication station STA3 is seen by communication station STA0 as a concealed terminal.
Every communication station having data to be transmitted monitors the state of communication media for a predetermined frame interval DIFS following detection of a last packet. The frame interval DIFS is also referred to as a DCF (Distributed Coordination Function) Inter Frame Space. If the communication media is clear or there is no transmitted signal during this frame interval DIFS, the communication station enters a random back-off period. If there is no transmitted signal also during this back-off period, the communication station is given a right of transmission.
In the following example shown in the figure, after the frame interval DIFS, communication station STA0 with a set back-off period shorter than those of the other communication stations obtains a transmission right and is thus capable of starting a transmission of data to communication station STA1.
That is to say, an RTS (request to send) packet is sent from communication station STA0 about to transmit data to communication station STA1. In response to the transmission request RTS packet, communication station STA1 transmits a CTS (clear to send) packet to communication station STA1 within a shorter frame interval SIFS (Short IFS). Then, within a shorter frame interval SIFS after receiving the CTS packet, communication station STA0 starts a transmission of data packets. As the transmission of data packets is completed, communication station STA1 transmits an ACK packet to communication station STA0 within a shorter frame interval SIFS.
At that time, communication stations STA3 and STA2 located at positions of concealed terminals seen from communication stations STA0 and STA1 respectively each execute control to inhibit a transmission of data till the communication between communication stations STA0 and STA1 described above is completed as indicated by a result of monitoring the utilization of a transmission line. To put it concretely, communication station STA2 detects the start of a data transmission from communication station STA1 serving as a data sender as evidenced by transmission of an RTS packet. Communication station STA2 then decodes information recorded in the duration field in the MAC header of the RTS packet. This information will be described later. A period, which lasts till the transmission of subsequent data packets is completed as evidenced by the transmission of the ACK packet, is recognized as a period during which the transmission line is already occupied. During this period, an NAV (Network Allocation Vector) is established and communication station STA2 enters a state of waiting for a transmission opportunity.
On the other hand, communication station STA3 detects the start of a data transmission to communication station STA1 serving as a data receiver as evidenced by transmission of a CTS packet. Communication station STA3 then decodes information recorded in the duration field in the MAC header of the CTS packet. This information will be described later. A period, which lasts till the transmission of subsequent data packets is completed as evidenced by the transmission of the ACK packet, is recognized as a period during which the transmission line is already occupied. During this period, an NAV is established and communication station STA3 enters a state of waiting for a transmission opportunity.
As described above, receiving at least either an RTS or CTS packet, a concealed terminal sets a transmission-inhibiting period of its own as a period coinciding with a time interval during which a data transmission based on the RTS/CTS procedure is expected to take place. Thus, a collision can be avoided. It is to be noted that the transmission rates for frames of exchanged CTS, data and ACK packets basically conform to the transmission rate adopted for the RTS packet.
Configuration of the Frame Format
FIG. 35 is a diagram showing a typical configuration of the frame format prescribed in the IEEE802.11a standard, which is an extension standard of IEEE802.11.
A preamble is added to the head of each packet as information indicating the existence of the packet. The preamble defines a known symbol pattern in accordance with specifications. The receiver examines the preamble of a received signal to determine whether or not the preamble matches the known symbol pattern. If the preamble of a received signal matches the known symbol pattern, a packet is determined to exist in the received signal.
A field following the preamble is defined as a signal field. The signal field includes information required for decoding an information portion of the packet. The information required for decoding the information portion of the packet is referred to as a PLCP (Physical Layer Convergence Protocol) header. The PLCP header includes a rate field, a length field, a parity bit, an encoder tail bit and a service field. The rate field shows the transmission rate of the information portion, which includes the service field of the PLCP header. The length field shows the length of the information portion. The packet receiver is capable of carrying the work to decode the information portion included in the packet as a portion following the PLCP header on the basis of results of decoding the rate and length fields included in the header.
A signal portion including the PLCP header is encoded into a noise-proof portion prior to a transmission at a speed of 6 Mbps. On the other hand, the information portion of an ordinary packet is transmitted in a transmission-rate mode having a highest possible bit rate in a range generating no errors in accordance with factors such as an SNR of the receiver.
The IEEE802.11a standard defines 8 different transmission-rate modes, i.e., modes at transmission rates of 6, 9, 12, 18, 24, 36, 48, and 54 Mbps. Thus, if the receiver and the transmitter are located at places close to each other, a transmission-rate mode at a high bit rate is selected. For a communication station existing at a far location, on the other hand, this information cannot be obtained in some cases.
The information portion is passed on to a link layer at a higher level as a PSDU (Physical Layer Service Data Unit).
As shown in FIG. 35, a preamble is included in the head of a transmitted signal as known information used for indicating the existence of the signal. FIG. 36 is a diagram showing a typical structure of the preamble as prescribed in the IEEE802.11a standard. Pre-1 and pre-2 portions of the preamble shown in FIG. 35 form a known pattern signal indicating that energy is filled for every four sub-carriers. The pattern includes a series of repeated electric waveforms each having a length of 0.8 microseconds. On the other hand, pre-3 and pre-4 portions of the preamble form a known pattern indicating that energy is filled for 52 sub-carriers. The pattern includes a series of repeated electric waveforms each having a length of 3.2 microseconds. The recipient receiving the packet is capable of determining the existence of the signal representing the packet on the basis of a result of processing a signal included in the 8.0-microsecond portion at the head of the preamble.
The IEEE802.11 standard defines some frame types. FIG. 37 is a diagram showing a typical structure of the PSDU portion in each of the RTS, CTS, ACK and data frames used in the RTS/CTS procedure described above.
The different frames each have a frame-control field and a duration field, which are defined as common fields. The frame-control field includes information indicating, among others, the type and application of the frame. To put it concretely, the frame-control field includes information described in table 1 below. On the other hand, the duration field describes information on an NAV application. To put it concretely, the duration field shows the length of time it takes to complete the transaction of all the packets.
TABLE 1Field nameLength [bits]DescriptionProtocol Version2Information on aversionType/Subtype6Identifierindicating a frametypeTo DS, From DS2Identifierindicating whateach address showsMore Fragment1Flag indicatingthe end of afragmentRetry1Flag indicatingwhetherretransmission isnecessaryPower Management1Flag showing apower managementmodeMore Data1Flag indicatingthat more data hasbeen storedWEP1Flag showingutilization of aWEPOrder1
In addition to the frame-control and duration fields described above, an RTS frame includes a receiver address (RA), a transmitter address (TA) and a frame check sequence (FCS), which is a checksum. The receiver address (RA) and the transmitter address (TA) are the address of the receiver and the address of the transmitter respectively.
In addition to the frame-control and duration fields described above, CTS and ACK frames each include a receiver address (RA) and an FCS, which is a checksum.
In addition to the frame-control and duration fields described above, a data frame includes four address fields, a sequence field (SEQ), a frame body, and an FCS, which is a checksum. The four address fields are fields for identifying, among others, communication stations serving as the sender and the transmitter. The frame body is a field containing net information to be passed on to an apparatus on a high layer.
Take the case shown in FIG. 34 as an example. In this case, communication station STA0 transmits an RTS packet to communication station STA1. The type/subtype information included in the frame-control field of the RTS packet indicates that the packet is an RTS packet. The duration field of the RTS packet shows the length of time it takes to complete the transaction to transmit all packets. That is to say, the duration field shows the length of a period ending at a time T8. The RA field describes the address of communication station STA1 and the TA field describes an address of its own.
This RTS packet is also received by communication station STA2 adjacent to communication station STA0. Receiving the RTS packet, communication station STA2 detects the preamble of the packet and then starts a work to receive an RTS signal representing the RTS packet. Subsequently, on the basis of information obtained as a result of decoding the PLCP header, communication station STA2 decodes the PSDU. Then, from the frame-control field of the PSDU, communication station STA2 recognizes the fact that the received packet is an RTS packet and transmits some information to communication station STA0 to notify communication station STA0 that the RTS packet has been received. In addition, from the RA field, communication station STA2 is capable of recognizing the fact that communication station STA2 is not a communication station for which the RTS packet is destined. Then, communication station STA2 recognizes the fact that the communication media is being occupied, establishes a NAV and inhibits transmission operations without monitoring the communication media till the present transaction started by the RTS packet is completed so that the data transmission desired by communication station STA0 is not obstructed. The established NAV is effective during a period indicated by the duration field. Thus, communication station STA2 is put in a state of being incapable of transmitting data till the time T8.
On the other hand, this RTS packet is also received by communication station STA1 designated as the destination of the packet. By execution of a procedure similar to the one described above, communication station STA1 decodes the PSDU and, from the frame-control field, communication station STA1 recognizes the fact that the received packet is an RTS packet. In addition, from the RA field, communication station STA1 is capable of recognizing the fact that communication station STA1 itself is a communication station for which the RTS packet is destined. That is to say, as communication station STA1 recognizes the fact that communication station STA0 intends to transmit packets to communication station STA1, communication station STA1 transmits a CTS packet to communication station STA0 at a time T3 within a frame interval SIFS in response to the RTS packet. The frame-control field of the PSDU of the CTS packet shows that this packet is a CTS packet. On the other hand, the duration field shows the length of time it takes to complete the transaction, that is, the length of a period ending at the time T8. The RA field describes the address of communication station STA0 serving as the destination of the packet transmission. It is to be noted that the transmission-rate mode of the CTS packet must be the same as that of the RTS packet.
By the way, this CTS packet is also received by communication station STA3 adjacent to communication station STA1. Receiving the CTS packet, communication station STA3 detects the preamble of the packet and then starts a work to receive a CTS signal representing the CTS packet. Subsequently, on the basis of information obtained as a result of decoding the PLCP header, communication station STA3 decodes the PSDU. Then, from the frame-control field of the PSDU, communication station STA3 recognizes the fact that the received packet is a CTS packet. In addition, since the RA field describes the address of communication station STA0 other than communication station STA3 itself as the destination of the packet transmission, communication station STA3 is capable of recognizing the fact that packet reception by an adjacent communication station is scheduled. Then, communication station STA3 establishes a NAV and inhibits transmission operations till the present transaction started by the RTS packet is completed so that the packet reception desired by communication station STA1 is not obstructed. The established NAV is effective during a period indicated by the duration field. Thus, communication station STA3 is put in a state of being incapable of transmitting data till the time T8.
On the other hand, this CTS packet is also received by communication station STA0 designated as the destination of the packet. By execution of a procedure similar to the one described above, communication station STA0 decodes the PSDU and, from the frame-control field, communication station STA0 recognizes the fact that the received packet is a RTS packet. In addition, from the RA field, communication station STA0 is capable of recognizing the fact that communication station STA0 is a communication station for which the packet is destined. That is to say, communication station STA0 recognizes the fact that communication station STA1 has completed preparations for receiving packets from communication station STA0. Then, communication station STA0 starts a transmission of a data packet to communication station STA1 at a time T5 within a frame interval SIFS in response to the packet.
The transmission of a data packet is ended at a time T6. If communication station STA1 is capable of decoding the data correctly, communication station STA1 transmits an ACK packet at a time T7 within a frame interval SIFS to communication station STA0. Communication station STA0 receives the ACK packet and ends the transaction to transmit and receive packets at the time T8. At the time T8, adjacent communication stations STA2 and STA3 discontinue the NAV and return to a normal state of being capable of transmitting and receiving packets.
The control and data frames are transmitted and received through the same communication media and, basically, the transmission power is not controlled.
Typical Access Control in the CSMA Procedure
The basic operations of the access control based on the CSMA method have been described by referring to FIG. 33. By referring to FIGS. 38 and 39, the following description explains operations of the access control taking the existence of a communication station into consideration.
In the example shown in FIG. 38, four communication stations STA0, STA1, STA2, and STA3 exist. Communication station STA0 intends to transmit data to communication station STA2 while communication station STA1 is transmitting data to communication station STA3. In addition, all the communication stations transmit data through common communication media.
Before communication station STA0 transmits data to communication station STA2, communication station STA0 checks the state of media utilization. While communication station STA1 is transmitting data to communication station STA3, communication station STA0 is not capable of transmitting data to communication station STA2.
In the example shown in FIG. 39, four additional communication stations STA4, STA5, STA6, and STA7 exist as well. Communication station STA4 may be transmitting data to communication station STA5, or communication station STA6 may be transmitting data to communication station STA7. In addition, all the communication stations transmit data through common communication media.
Before communication station STA0 transmits data to communication station STA2, communication station STA0 checks the state of media utilization. While communication station STA1 is transmitting data to communication station STA3, communication station STA4 is transmitting data to communication station STA5, or communication station STA6 is transmitting data to communication station STA7, communication station STA0 is not capable of transmitting data to communication station STA2.
As is obvious from the above description, as the number of communication stations transmitting data through common communication media (or transmitting data within an executable-communication range) increases, it is natural that a communication station more likely loses a transmission opportunity. The technical term 'executable-communication range' used in this specification means a range in which communications can be carried out.
In addition, if a specific communication station holds pieces of information on surrounding communication stations existing in an executable-reception range of the specific communication station, it is necessary to set the maximum number of surrounding communication stations whose pieces of information can be held at a large value taking a worst case into consideration so that the actual number of surrounding communication stations whose pieces of information can be held does not exceed the large value. The technical term 'executable-reception range' used in this specification means a range in which receptions of data can be carried out.
The following description describes a study of problems raised in an access control method based on the CSMA technique including the RTS/CTS procedure described above.
(1) Access-Control Non-Uniformity Caused by Non-Uniformity of Transmission Powers
The access control method based on the CSMA technique including the RTS/CTS procedure raises a problem of access-control non-uniformity among communication stations having different transmission powers.
In an example shown in FIG. 40, four communication stations, namely, STA2, STA0, STA1, and STA3, exist in a communication environment. It is assumed that communication station STA1 intends to transmit data to communication station STA3 and communication station STA0 intends to transmit data to communication station STA2. It is also assumed that, in the example shown in the figure, basically, only communication stations adjacent to each other are located in a range that can be reached by a transmitted electric wave. In addition, the following description also assumes transmission-power non-uniformity. Since the transmission power of communication station STA0 is smaller than the transmission power of communication station STA1, a signal transmitted by communication station STA1 to communication station STA0 in the direction of STA1→STA0 can be received by communication station STA0, but a signal transmitted by communication station STA0 to communication station STA1 in the direction of STA0→STA1 cannot be received by communication station STA1.
First of all, at a time T1, communication station STA1 transmits an RTS signal to communication station STA0 after verifying that the communication media is clear during a predetermined frame period and completing a set back-off state.
Since a signal transmitted by communication station STA1 in the direction of STA1→STA0 can be received by communication station STA0 as described above, communication station STA0 receives the RTS signal and sets a NAV ending at a time T8 at which the transaction initiated by the RTS signal will be completed. During the NAV, communication station STA0 is not capable of transmitting data. Then, in accordance with the RTS/CTS procedure described earlier, communication station STA1 transmits data to communication station STA3 and ends the transaction at the time T8.
Thereafter, assume that communication station STA0 is capable of transmitting an RTS signal at a time T9 after verifying that the communication media is clear during a predetermined frame period and completing a set back-off state in the same way as communication station STA1 did as described above. Since a signal transmitted by communication station STA0 to communication station STA1 in the direction of STA0→STA1 cannot be received by communication station STA1 as described above, the RTS signal transmitted by communication station STA0 does not arrive at communication station STA1. Thus, communication station STA1 is capable of transmitting a signal independently of the transmission/reception state of communication station STA0.
In a word, communication station STA1 capable of transmitting data with a large transmission power is placed in an unconditionally favorable position in comparison with communication station STA0, which has only a small transmission power. As a result, a problem of non-uniform accesses is raised if impartial control of accesses among communication stations is to be implemented.
It is to be noted that a variable area ad-hoc network has been proposed as described in documents such as patent document 1. In the variable area ad-hoc network, prior to a transmission of a radio packet, a transmission power required for the transmission is determined. However, every radio communication apparatus in such a network determines a transmission power by considering a frequency utilization rate and necessary transmission time for each transmission path as well as the importance and type of information to be transmitted even though the occupation state of the communication media is not taken into consideration. In other words, the communication station is not capable of recovering a transmission opportunity, which has been lost due to a particular occupation state of the communication media.
(2) Fewer Transmission Opportunities for Many Adjacent Stations
In the access method based on the CSMA technique as shown in FIG. 38, the number of transmission opportunities decreases as the number of communication stations each making an attempt to transmit and receive data through the same communication media increases. Consider a case in which a particular communication station intends to communicate with another communication station, which is located at a location extremely close to the particular communication station and has a very small loss of a pass to the particular communication station in comparison with the loss of a pass between the particular communication station and any other communication station. Even in this case, while the other communication station is receiving a signal from a further communication station, the particular communication station is not allowed to communicate with the other communication station in order to avoid a collision.
(3) Limiting the Number of Managed Stations for Many Adjacent Stations
In a radio communication system, in which every specific communication station is linked with all other communication stations in a range reachable by an electric wave transmitted by the specific communication station, for example, the specific communication station needs to store information on the other communication stations.
In most general cases, however, the number of other communication stations on which information can be stored in the specific communication station is limited by a hardware restriction of the specific communication station or a system restriction. If the number of other communication stations exceeds the limit, it is feared that complicated processing such as exception processing needs to be carried out.
As a conceivable solution to the above problem, a worst-case value or a maximum value of the number of other communication station is set at a sufficiently large value so that it is not necessary to carry out exception processing. From the implementation point of view, however, allocation of an exhaustlessly large memory area is not desirable. In addition, in dependence on the system, if too many other communication stations exist, another communication station can probably no longer be accommodated.    [List of Documents]    [Patent Document 1]
Japanese Patent Laid-open No. 2001-128231    [Non-patent Document 1]
International Standard ISO/IEC 8802-11: 1999 (E) ANSI/IEEE Std 802.11, 1999 Edition, Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications    [Non-patent Document 2]
ETSI Standard ETSI TS 101 761-1 V1.3.1 Broadband Radio Access Networks (BRAN); HIPERLAN Type 2; Data Link Control (DLC) Layer; Part 1: Basic Data Transport Functions    [Non-patent Document 3]
ETSI TS 101 761-2 V1.3.1 Broadband Radio Access Networks (BRAN); HIPERLAN Type 2; Data Link Control (DLC) Layer; Part 2: Radio Link Control (RLC) sublayer    [Non-patent Document 4]
Supplement to IEEE Standard for Information technology-Telecommunications and information exchange between systems-Local and metropolitan area networks-Specific requirements-Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) specifications: High-speed Physical Layer in the 5 GHZ Band

Radio communication system, radio communication apparatus, radio communication method, and computer program


A touch sensor integrated color filter and a manufacturing method for the touch sensor integrated filter are disclosed. In the touch sensor integrated color filter, a touch sensor layer including a metal layer and a transparent conductive layer is formed on a black matrix of a flexible color filter.

As a touch input method attracts attention as a next generation input method, there have been attempts to introduce a touch input method to a wider variety of electronic devices. Accordingly, research and development of a touch sensor which can be applied to various environments and can accurately recognize a touch are actively performed.
For example, in the case of an electronic device having a touch-type display, an ultra-thin flexible display, which achieves light weight, low power and improved portability, has been attracting attention as a next generation display, and development of a touch sensor applicable to such a display has been required.
The flexible display is prepared on a flexible substrate that can bend, fold or roll without damage of its properties, and it may be in the form of a flexible LCD, a flexible OLED, electronic paper, etc.
A capacitive touch sensor panel overlaid on an LCD or an OLED may be used to apply a touch input method to the flexible display. Such capacitive touch sensor panel may be formed by a matrix of touch driving lines and touch sensing lines made of a substantially transparent conductive material such as ITO (indium tin oxide). These touch driving lines and touch sensing lines are arranged in rows and columns on a substantially transparent substrate. When an object such as a user's finger is near the intersection of the touch driving line and the touch sensing line, the capacitance between the touch driving line and the touch sensing line may change. This change in capacitance can indicate that a touch is occurring at this location.
However, when a capacitive touch sensor panel is overlaid on an LCD or an OLED, there are problems such as increase in thickness and weight of display, decrease in brightness, and increase in manufacturing cost.
Accordingly, an attempt has been made to integrate a touch sensor inside a display device.
The method disclosed in Korean Patent Publication No. 10-2014-0041949 uses an in-cell and/or on-cell touch sensor component including an in-cell and/or an on-cell black matrix material which also acts as a touch driving or sensing electrode.
However, in this method, a color filter layer is formed on a lower substrate on which a thin film transistor array is formed, and a black matrix material is formed on an upper substrate spaced apart with a liquid crystal layer interposed therebetween. Thus, the black matrix occupies a large area in order to distinguish and block the light between color filter pixels, which decreases the light efficiency of the display device.
On the other hand, Korean Patent Publication No. 10-2014-0070340 proposes a method of forming a touch sensor on a protective film on an OLED.
However, in such a method, a touch sensor must be formed using a transparent conductive material in order to ensure the visibility of the display device. In the case of transparent conductive material, the resistance value of the transparent conductive material is higher than that of a metal material, thereby deteriorating the performance of the touch sensor.

Touch sensor integrated color filter and manufacturing method for the same


A multiple-feed antenna system includes a first feed configured to communicate signals in a first frequency range of a plurality of frequency ranges and a second feed configured to communicate signals in a second frequency range of the plurality of frequency ranges. A subreflector assembly is configured to move among multiple positions that include a first position and a second position. When the subreflector assembly is in the first position, a first element of the subreflector assembly redirects a signal reflected by a primary reflector to the first feed. When the subreflector assembly is in the second position, a second element of the subreflector assembly redirects the signal reflected by the primary reflector to the second feed.

Tracking antenna systems are especially suitable for use aboard ships to track communications satellites while accommodating for roll, pitch, yaw, and turning motions of a ship at sea. For such systems to operate effectively they must point one or more antennae continuously and accurately toward a respective satellite.
For two decades, Sea Tel, Inc. has manufactured antenna systems of the type described in U.S. Pat. No. 5,419,521 to Matthews. Such antenna systems have a three-axis pedestal and employ a "Level Platform" or "Level Cage" in order to provide an accurate and stable horizontal reference for directing servo stabilized antenna controls to accurately track communications satellites.
Tracking antenna systems are especially well suited for the reception and transmission of satellite communication signals, which are typically in the C-band or the Ku-band, each band having its relative strengths and weaknesses. For example, C-band signals are susceptible to terrestrial interference, while Ku-band signals are affected by rain and ice crystals. Accordingly, it is desirable for an antenna system to be configured for operation in both C-band and Ku-band frequency ranges.
One such system is described in U.S. Pat. No. 9,000,995 ('995 patent), which describes various systems that include a large primary reflector for C-band satellites and a smaller secondary reflector for Ku-band satellites (see, e.g., '995 patent, FIGS. 15 and 16). Such systems are switchable such that the primary reflector is aligned with and tracks a C-band satellite in a C-band mode, and the secondary reflector is aligned with and tracks a Ku-band satellite in a Ku-band mode.
While such systems are compatible with known and planned satellite communication networks, one will appreciate that an antenna system having a single reflector that is configured to operate at both C-band and Ku-band signals would be desirable.

Multiple-feed antenna system having multi-position subreflector assembly


For the strengthening of an end portion of a yarn which extends on a spinning station of a spinning machine between a stopped spool package and a suction withdrawal device assigned to the spinning station, the yarn which projects into the withdrawal device is gripped, is lengthened by the winding-off of the yarn wound onto the spool package, and is then strengthened in an essentially stationary position by means of a twisting entered in the area of the yarn end. In the case of an arrangement provided for this purpose, particularly mechanically operating twisting devices are used.

This invention relates to a process and an arrangement for the strengthening of an end portion of a yarn which is produced at a spinning station of a spinning machine comprising a plurality of such spinning stations and which, after the interruption of the spinning operation, extends between a stopped spool package and a suction withdrawal device assigned to the spinning station.
In the case of yarn packages which are produced on a spinning machine, the end portion of a spinning yarn must have a certain strength so that, when used on machines which process it further, it can be processed without any disturbance, particularly without any yarn breakage. Particularly in cases where the feeding and threading of the yarn end portion with respect to the machine for the further processing is to take place by means of automatic devices, it is necessary that the yarn end portion has a particularly high strength along a certain length. This requirement exists particularly when the yarn has received only a slight strength during the spinning. This is likely to occur in the case of such yarns where the two yarn components of the yarn were only prestrengthened and were then wound onto the cross-wound package in side-by-side windings. Although the strength of this yarn will be sufficient for the later twisting, yarn breakages can very easily occur when this prestrengthened yarn is processed on the twisting machine or when it is conveyed to the twisting machine.
From the German Patent Document DE-A 39 09 420, it is known that the end portion of a prestrengthened double yarn which is to be placed on a spool package is strengthened during the formation of the final windings. In this case, the double yarn end to be strengthened is held by a machine-side suction withdrawal device and extends to the spool package which is folded away from its drive. A movably arranged servicing device, which is applied to the corresponding spinning station, is equipped with an auxiliary winding roller by means of which the spool package of the respective spinning station can be driven. By means of the auxiliary winding roller, the yarn end portion which is held by the machine-side suction withdrawal device is pulled out of the latter. The strengthening is provided along a length of 0.5 m in such a manner that the yarn portion to be strengthened during the winding-up is guided through a whirl nozzle which is mounted between the machine-side suction withdrawal device and the yarn package. At the whirl nozzle, a pneumatic twisting takes place of the double yarn which is guided through it.
It is an object of the invention to provide a process and an arrangement by means of which, in a simple manner, a particularly effective strengthening of the end portion of a yarn can be carried out.
With respect to the process, this object is achieved according to preferred embodiments of the invention in that the yarn end projecting into the suction withdrawal device is gripped, is lengthened by winding-of f the yarn wound onto the package, and is then strengthened in an essentially stationary position by means of a twisting entered in the area of the yarn end. As a result of these measures, a sufficiently long strengthened yarn end portion is obtained, on the one hand, and, on the other hand, a particularly effective strengthening is achieved because the yarn end portion receives a true twist because of the free yarn end. The twist, which is entered in the stationary position, contributes to a strengthening that can be carried out in a particularly targeted manner. By means of the corresponding winding-of f of the yarn from the package, the length of the yarn end portion which is to be strengthened can be determined.
In a further development of the invention, it is provided that the yarn end portion to be strengthened is held in a clamped fashion during the strengthening. This results in a particularly effective strengthening.
In a further development of the invention, it is provided that the strengthening takes place by a mechanical twisting of the yarn end portion situated between a clamping element and the package. Mechanical twisting is more effective than, for example, pneumatic twisting and can be carried out with fewer expenditures than other types of strengthening, such as the adding of an auxiliary yarn.
In a further development of the invention, it may be provided that the end portion of the yarn which is not intended to be strengthened is cut off. In this manner, it is possible to strengthen a yarn portion of a defined length irrespective of how much yarn is situated in the machine-side withdrawal pipe.
In a further development of the invention, it is provided that the length of the yarn to be strengthened can be determined by the application point of the twisting. As a result, it becomes possible to vary and precisely determine the length of the yarn portion to be strengthened.
In a further development of the invention, it is provided that the yarn end projecting into the suction withdrawal device is gripped by means of a gripping element; together with a yarn portion wound of f the package, is sucked into a suction pipe assigned to the spinning station; and is then strengthened by a twisting entered in the area of the yarn end. As a result of the vacuum acting inside the suction pipe, first a yarn loop is formed to the yarn end portion extending into the withdrawal pipe. When a sufficiently large loop has been sucked into the suction pipe, the gripping element is released so that now yarn wound off the package is taken in. The yarn portion sucked into the suction pipe can then be cut, in which case particularly the yarn portion which previously had projected into the machine-side withdrawal pipe is removed. Finally, the yarn portion extending between a clamping element and the package is strengthened in that the twisting is entered in the area of the yarn end. Thus, the yarn end portion receives a true twist. Since the yarn portion to be strengthened is housed completely in the suction pipe, it is easily possible to strengthen an arbitrary length of yarn without any catching of the yarn portion anywhere.
In the case of a preferred embodiment of an arrangement for carrying out the process, each spinning station of the spinning machine is provided with a withdrawal pipe connected behind a withdrawal device in the yarn travelling direction. Devices for uncoupling the drive are provided on the package receiving the spun yarn. Furthermore, the arrangement has a controllable gripping element which can be applied to the yarn projecting into the withdrawal pipe. By means of the gripping element, the yarn can be guided away from the withdrawal pipe. Furthermore, a twisting device is provided by means of which the yarn end portion leading onto the package can be strengthened by means of a twisting entered in the area of the yarn end. By means of an arrangement of this type, the yarn end portion can be provided with a true twist.
In a further development, it is provided that the twisting device is constructed with a clamping element for the yarn to be strengthened. By means of such a clamping element, the yarn is clamped and, during the strengthening, is situated in an essentially stationary position.
In a further development of the invention, it may be provided that the gripping element and the twisting device are assigned to a servicing arrangement which is movably arranged on the spinning machine and can be selectively applied to the spinning stations. On such movable servicing arrangements, which are known in principle, additional devices may be arranged for carrying out servicing operations. In particular, devices for eliminating a yarn breakage should be mentioned here.
In a further development of the invention, it may be provided that the gripping element and the twisting device are arranged on a common swivel arm which can be applied to the spinning station. The swivel arm, which is arranged on the servicing arrangement, is coupled with a controllable drive. During the travelling movement of the servicing arrangement, the swivel arm is situated inside the servicing arrangement. In the operating Position, the swivel arm is swivelled out of the servicing arrangement. The yarn end is gripped by the gripping element and is guided away from the intake device. The desirable length of the strengthened area can be varied by the swivel position of the swivel arm.
In a further development of the invention, it may be provided that a cutting device is assigned to the twisting device by means of which the end portion of the yarn which is not to be strengthened can be cut off.
In an advantageous embodiment of the invention, a suction pipe is provided which is assigned to the servicing arrangement, can be applied to the withdrawal pipe and, on its mouth opening facing away from the servicing arrangement, is provided with a yarn clamp and, on its opposite opening, is provided with a twisting device. The devices operate in that the yarn clamp constructed as a gripping element first grips the yarn portion in the area of the machine-side withdrawal pipe, in which case it is sucked into the applied suction pipe while forming a loop. As soon as the vacuum existing in the applied suction pipe is sufficiently large, the yarn clamp will release the yarn portion. In this case, another yarn portion, which had been wound off from the package by means of an auxiliary winding roller, is taken in. The yarn portion will then be cut off at a predetermined length and is twisted in the clamped condition. It may also be provided that the cutting device and the twisting device are arranged inside the suction pipe at some distance from its mouth opening. The twisting device may also be arranged such that it is situated at the end of the yarn portion to be twisted. It is also contemplated, however, to let the end of the yarn portion to be twisted enter farther into the suction pipe so that the length of the yarn portion to be twisted can be varied. The length of the yarn portion to be strengthened can be varied by the point of application of the twisting device. This point of application can be changed by the arrangement of the twisting device in the suction pipe, by changing the length of the suction pipe or by swivelling the suction pipe.
In the case of an advantageous further development, it is provided that the twisting device is designed as a rotatably driven tube into which the yarn to be strengthened can be introduced and to which a clamping element is assigned which can fix the yarn.
In an advantageous further development, two clamping devices are provided as the clamping element which can be introduced into the interior of-the tube and can be brought to rest against one another. In this case, the yarn portion to be twisted is brought, for example, sucked, into the interior of the tube. By means of the subsequently entered rotating movement of the tube, the yarn is clamped in by means of the clamping elements and is strengthened at the same time by providing the yarn end portion with a true twist.
It is also possible to establish the contact position of the clamping elements by means of a solenoid acting outside the tube.
In a further development of the invention, it is provided that the clamping elements are developed as wing-type double levers which are received in mutually opposite recesses of the tube and are pivotally arranged on pins in the recesses. The arrangement of the pins takes place in such a manner that a shorter and a longer leg respectively are formed on the double lever. Because of the centrifugal force which occurs when the tube is rotated, the longer legs are moved toward the outside and the shorter legs are therefore moved toward the inside. In this case, the yarn introduced into the pipe is clamped between the shorter legs.
In this case, it may advantageously be provided that the tube has a rectangular cross-section in the area in which the double levers are arranged.
It may also advantageously be provided that the double levers in their inoperative position completely fill the recesses of the tube. In the case of this construction, secondary air is avoided which could impair the suction effect of the tube with respect to the yarn. In the inoperative position of the twisting device, the suction air can flow freely through the clamping element without any impairment.
A particularly simple construction of the arrangement is achieved in that the clamping element of the twisting device is at the same time constructed as a gripping element. In the case of this development, the clamping element must be operable from the outside. The operating may expediently take place in an electromagnetic manner.
In the case of another advantageous development, the twisting device has a rotatably arranged drivable slotted disk with a radially arranged slot which extends to the center. The yarn to be strengthened can be inserted into this slot and can be fixed by means of a yarn clamp arranged on the slotted disk. The yarn to be strengthened is introduced into the slot up to the center and is held by the yarn clamp which can be operated from the outside. Then the disk is rotated. This twists the yarn portion held by the yarn clamp. Other than in the case of the above-described tube-shaped twisting device, in the case of this construction, the yarn portion to be twisted is introduced from the side, in which case it is also easily possible to apply the twisting device to the yarn. A twisting device of this type is recommended in cases where no additional suction pipe is to be used. The yarn clamp may expediently be operable from the outside by means of a solenoid or by means of mechanical devices. However, it is also contemplated to construct the yarn clamp such that it operates with centrifugal force.
In a further development of the invention, the slotted disk can be rotated by means of an assigned driving disk. The driving disk, which is coupled with a drive, transmits its rotating movement to the slotted disk. This provides the yarn which is introduced into the slot of the slotted disk with a true twist. It is also contemplated to arrange several driving disk on the slotted disk.
In an advantageous development, the slotted disk and the driving disk are magnetically connected with one another. Since a conventional radial bearing cannot be used on the slotted disk, the magnetic connection provided between the driving disk and the slotted disk prevents a lateral moving-away of the slotted disk.
In another advantageous development, the slotted disk can be driven by means of two magnetic driving disks which are applied to its circumference. The slotted disk can be secured against a radial displacement by being arranged between rims.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.

Process and an arrangement for the strenghtening of an end portion of a yarn


An integrated circuit chip includes a rectifier circuit configured to convert an alternating voltage supplied from an antenna into a direct-current voltage, a nonvolatile memory coupled to the rectifier circuit to operate by use of the direct-current voltage, a sensor circuit coupled to the rectifier circuit to operate by use of the direct-current voltage to collect measurement data, and a logic circuit configured to control the nonvolatile memory and the sensor circuit such that an access operation of the nonvolatile memory and a data collecting operation of the sensor circuit are not performed concurrently.

1. Field of the Invention
The present invention generally relates to integrated circuit chips, and particularly relates to an integrated circuit chip for use as a RFID and to an RFID system.
2. Description of the Related Art
RFID (Radio Frequency Identification) is the system which reads/writes ID information via radio communication from/to an IC tag provided with an IC chip (integrated circuit chip) serving as a record medium for storing information. If barcodes or the like used in commercial goods management are replaced with RFIDs, for example, it is possible to eliminate the need to manually scan the barcodes or the like, thereby significantly improving the efficiency of commercial goods management.
The application of RFID in various fields in addition to its use for the purpose of identifying commercial goods is expected. In particular, RFID having a sensor function to measure the state of the environment around the IC tag can be utilized to keep a record of the manufacturing process (production process) of commercial goods and/or to keep a record of conditions during distribution.
For example, an RFID tag with a temperature sensor may be attached to perishable goods or the like to keep a record of temperature changes during distribution and/or processing of goods. This makes it possible to achieve diligent management and control of freshness and quality. With such arrangement, it is possible to properly cope with problems such as the lowering of quality of goods and to provide safe and high quality merchandise. The types of sensors that can be incorporated in RFID are not limited to a temperature sensor, but may include a three-axis sensor, a pressure sensor, an acceleration sensor, etc.
In order to implement such a sensor-equipped RFID tag, there is a need to implement a circuit having a sensor function and a measured data processing function in addition to the existing RFID function as a single chip. Incorporating the RFID function and the sensor function in a single chip requires highly sophisticated technology for combining analog circuitry and digital circuitry. There is also a need to cope with the problem of power consumption.
The performance of RFID is generally measured in terms of communication speed and communication distance. As for the communication speed, standards require a certain communication speed to be satisfied, leaving the communication distance as a factor to differentiate RFID chips from each other in terms of their performance. In order to increase communication distance, RFID chips are required to reduce power consumption inside the chip as much as possible.
IC tags are classified into an active type that operates by use of an embedded battery as a power source and a passive type that operates by use of a magnetic field or electric field supplied from an exterior as a power source without having an embedded battery. The passive type is not suited for long distance communication, but can be implemented at low price in small size owing to the absence of a battery.
A passive-type RFID chip receives a electromagnetic wave transmitted from a separate reader writer for conversion into an electric power, and stores the electric power in a capacitor provided inside the chip for use as the power supply for chip operation. The smaller the power consumption inside the chip, the smaller the electric power of the received electromagnetic wave can be, thereby achieving long distance communication. In the case of a RFID chip equipped with a sensor function, the sensor-function-purpose circuit in addition to the RFID-function-purpose circuit consumes an electric power. This makes it difficult to maintain a desired communication distance.
[Patent Document 1] Japanese Patent Application Publication No. 2004-164050
Accordingly, there is a need for an RFID IC chip and an RFID system that can allow a sensor function to operate without dropping a communication distance.

RFID system and RFID chip equipped with sensor function


A self-leveling seat is provided including a vehicle having a seat with a horizontally oriented seat portion and a planar floor board. A tubular mounting frame includes a lower horizontal portion having a hollow cylindrical configuration. A pair of mounting brackets encompass the lower horizontal portion and are fixed to the floor board of the vehicle. A pair of upper vertical portions are each equipped with a hollow cylindrical configuration and have a bottom end connected to an associated end of the horizontal portion of the frame. The vertical portions extend upwardly therefrom to terminate at open top ends. The vertical portions are each in fluidic communication with the corresponding end of the horizontal portion. A pair of cylinders are each slidably situated within the top end of a corresponding one of the vertical portions of the frame and have a bottom end and a top end. The top end is coupled to a bottom surface of the seat portion of the seat. Lastly, a pneumatic assembly is situated within the horizontal portion for urging the cylinders upward in a eve orientation.

1. Field of the Invention
The present invention relates to pivoting seats and more particularly pertains to a new self-leveling seat for maintaining a scat level when a vehicle is situated on an incline.
2. Description of the Prior Art
The use of pivoting seats is known in the prior art. More specifically, pivoting seats heretofore devised and utilized are known to consist basically of familiar, expected and obvious structural configurations, notwithstanding the myriad of designs encompassed by the crowded prior art which have been developed for the fulfillment of countless objectives and requirements.
Known prior art pivoting seats include U.S. Pat. No. 4,515,337; U.S. Pat. No. 4,022,411; U.S. Pat. No. 4,095,770; U.S. Pat. No. 5,372,347; U.S. Pat. No. 5,054,729; and U.S. Patent Des. 309,815.
In these respects, the self-leveling seat according to the present invention substantially departs from the conventional concepts and designs of the prior art, and in so doing provides an apparatus primarily developed for the purpose of maintaining a seat level when a vehicle is situated on an incline.


An antenna apparatus includes a glass plate that is fixed to a flange of a vehicle body at a window opening portion of the vehicle body; a dielectric material; a conductive film provided between the glass plate and the dielectric material; and a monopolar feeding portion provided on the dielectric material at a surface opposite to a glass plate side and at a position capable of being capacitively coupled to the conductive film, the antenna apparatus being configured such that a clearance between an end portion of the flange of the vehicle body and an outer edge of the conductive film functions as a slot antenna, the conductive film being provided with a notch having one end as an open end at the outer edge of the conductive film in the vicinity of the feeding portion.

1. Field of the Invention
The present invention relates to an antenna apparatus using a clearance between an end portion of a flange of a vehicle body that forms a window opening portion of the vehicle body and a conductive film.
2. Description of the Related Art
FIG. 1 is a cross-sectional view of a vehicle laminated glass including glass plates 1 and 2, and a conductive film 3 and an intermediate film 4, sandwiched by the glass plates 1 and 2. The conductive film 3 is a protection film which suppresses transition of heat waves such as sunlight or the like. When the laminated glass is provided with an antenna conductor 5 for receiving radio waves at a vehicle interior side, there are cases where required reception characteristics cannot be sufficiently obtained as the radio waves coming from the outside of the vehicle are shielded by the conductive film 3.
To remove such a disadvantage, a window glass is known in which an antenna function is provided by using a conductive film (see, for example, Patent Documents 1, 2 and 3).


A flowerpot is disclosed. The flowerpot includes a main body configured to provide a planting space in which an upper portion is open and a central portion is passed through by a through portion in a front and rear direction, a self-watering module installed in the through portion to form water by condensing moisture in the air, and a water supply hole provided on a bottom of the through portion so as to guide the water formed by the self-watering module to the planting space provided in a lower side of the through portion.

One of the most important factors in plant growth is moisture. Therefore, as for planting plants, it is important to prevent the difficulty, which may occur in the growth of the plant, by securing a watering system in advance.
Accordingly, in recent years, researches have been conducted to reduce time and labor caused by watering work, and among the research, there is a method of collecting moisture in the air and supplying water corresponding to the collected moisture to plants.
Korean Patent Registration No. 10-1388951 discloses a watering system configured to supply water to plants using moisture in the air.
However, the watering system disclosed in the above patent document is a large system in which a structure for collecting moisture in the air, a structure for storing the collected water, and a structure for supplying the stored water to the plants are provided separately from plant cultivators, and thus the watering system has the complicated structure, which may cause the difficulty when being applied to an individual flowerpot.

REPUBLIC OF KOREA(MANAGEMENT: RURAL DEVELOPMENT ADMINISTRATION)