A method for fabricating an LCD device includes providing first and second substrates and has a contact hole exposing a portion of the source and drain regions formed by removing a portion of the first and second insulation layers and removing the second insulation layer of the upper portion of the pixel electrode. The method also includes forming a third conductive layer on the first substrate; forming source and drain electrodes electrically connected to the source and drain regions through the contact hole by patterning the third conductive layer and exposing the second conductive layer of the upper portion of the pixel electrode; and forming a liquid crystal layer between the first and second substrates.

1. Field of the Invention
The present invention relates to a liquid crystal display (LCD) device and its fabrication method, and more particularly, to an LCD device and its fabrication method capable of simplifying a fabrication process and enhancing yield by reducing the number of masks used for fabrication of a polycrystalline silicon thin film transistor.
2. Description of the Related Art
Recently, as research and development of information displays and demand for using a portable (mobile) information medium increase, research on and commercialization of a light thin film type flat panel display (FPD) which can substitute for the existing display device CRT are actively ongoing.
Of the FPDs, in particular, an LCD, a device for producing an image by using the optical anisotropy of liquid crystal, exhibits excellent resolution, color display and picture quality, so it is popular in notebook computers, desktop monitors or the like.
The liquid crystal display panel includes a color filter substrate, namely, a first substrate, an array substrate, namely, a second substrate, and a liquid crystal layer formed between the color filter substrate and the array substrate.
As a switching device of the liquid crystal display device, the thin film transistor (TFT) is used, and as a channel layer of the TFT, an amorphous silicon thin film or a polycrystalline silicon thin film is used.
In a process for fabricating the LCD device, a plurality of masking processes (namely, photolithography process) are required for fabricating the array substrate including the TFT, so a method for reducing the number of masking processes is on demand in terms of productivity.
The structure of the general LCD device will now be described with reference to FIG. 1.
FIG. 1 is a plan view illustrating a portion of an array substrate of the general LCD device. Although actual array substrate includes the M×N number of pixels as the N number of gate lines and the M number of data lines cross each other, only one pixel is illustrated in FIG. 1 for the sake of explanation.
As illustrated, a gate line 16 and a data line 17 are arranged vertically and horizontally on an array substrate 10, defining a pixel region. A TFT as a switching device is formed at the crossing of the gate line 16 and the data line 17. A pixel electrode 18 is formed at each pixel region.
The TFT includes a gate electrode 21 connected to the gate line 16, a source electrode 22 connected to the data line 17 and a drain electrode 23 connected to the pixel electrode 18. The TFT also includes a first insulation film (not illustrated) and a second insulation film (not illustrated) for insulating the gate electrode 21 and source/drain electrodes 22 and 23, and an active pattern 24 for forming a conductive channel between the source electrode 22 and drain electrode 23 by a gate voltage supplied to the gate electrode 21.
Through the first contact hole 40A formed at the first and second insulation films, the source electrode 22 is electrically connected with a source region of the active pattern 24 and the drain electrode 23 is electrically connected with a drain region of the active pattern 24.
A third insulation film (not illustrated) having a second contact hole 40B is formed on the drain electrode 23, so that the drain electrode 23 and the pixel electrode 18 are electrically connected through the second contact hole 40B.
The process of fabricating the array substrate constructed as described will now be explained with reference to FIGS. 2A to 2F.
FIGS. 2A to 2F are sequential sectional views of the process for fabricating the array substrate of FIG. 1 taken along line I-I′. The illustrated TFT is a polycrystalline silicon TFT which uses polycrystalline silicon as a channel layer.
As illustrated in FIG. 2A, the active pattern 24 is formed as a polycrystalline silicon thin film on the substrate 10 by using a photolithography process (a first masking process).
Next, as illustrated in FIG. 2B, a first insulation film 15A and a conductive metal material are sequentially deposited on the entire surface of the substrate 10 with the active pattern 24 formed thereon, and then, the conductive metal material is selectively patterned by using the photolithography process (a second masking process) to form the gate electrode 21 over the active pattern 24 with the first insulation film 15A interposed therebetween.
Thereafter, p+ type or n+ type source/drain regions 24A and 24B are formed at certain regions of the active pattern 24 by injecting a high density impurity ion by using the gate electrode 21 as a mask. The source/drain regions 24A and 24B are formed for ohmic contact with source/drain electrodes (to be described).
And then, as illustrated in FIG. 2C, a second insulation film 15B is deposed on the entire surface of the substrate 10 with the gate electrode 21 formed thereon, and then, a portion of the first and second insulation films 15A and 15B is removed through the photolithography (a third masking process) to form the first contact hole 40A exposing a portion of the source/drain regions 24A and 24B.
Subsequently, as illustrated in FIG. 2D, a conductive metal material is deposited on the entire surface of the substrate 10 and then patterned by using the photolithography process (a fourth making process) to form the source electrode 22 connected with the source region 24A and the drain electrode 23 connected with the drain region 24B through the first contact hole 40A. In this case, a portion of the conductive metal layer constituting the source electrode 22 extends in one direction to form the data line 17.
And then, as illustrated in FIG. 2E, a third insulation film 15C is deposited on the entire surface of the substrate 10, and then, a second contact hole 40B is formed, exposing a portion of the drain electrode 23 by using the photolithography process (a fifth masking process).
Finally, as illustrated in FIG. 2F, a transparent conductive metal material is deposited on the entire surface of the substrate 10 with the third insulation film 15C formed thereon and then patterned by using the photolithography process (a sixth masking process) to form a pixel electrode 18 connected with the drain electrode 23 through the second contact hole 40B.
As mentioned above, in fabricating the array substrate including the polycrystalline silicon TFT, a total of six photolithography processes are required to pattern the active pattern, the gate electrode, the first contact hole, the source/drain electrodes, the second contact hole and the pixel electrode.
The photolithography process is a process of transferring a pattern formed on a mask onto the thin film-deposited substrate to form a desired pattern, including a plurality of processes such as applying a photosensitive solution, exposing and developing process. As a result, the plurality of photolithography processes degrade a production yield and cause a high possibility that a fabricated TFT is defective.
In particular, the mask designed to form the pattern is expensive, so the increase in the number of masks applied to the process would lead to an increase in a fabrication cost proportionally.

Liquid crystal display device with prevention of defective disconnection of drain/pixel electrodes by forming two conductive layers on top of entire pixel electrode and then removing a portion of both therefrom


An apparatus and program product generate difference data representative of modifications made to one release of a standard code base to facilitate the adaptation of later releases of the standard code base. The difference data is generated at least in part in connection with canonical parsing of a modified version of a release of a standard code base such that the difference data is representative of semantic changes made in the modified version.

As computers and the computer software that runs on such computers increase in performance and complexity, the development of computer software becomes increasingly expensive, difficult and time consuming. One predominant manner of combating the difficulties of software development is through increased reliance on pre-existing code. Object-oriented software design is premised in large part on the concept of code reuse, where software is compartmentalized into objects that are individually created, tested and refined, and where more complex objects are built by assembling together simpler objects to leverage the prior efforts of others, and avoiding the need to develop new software entirely from scratch.
The software executing on a computer is often highly layered, with program code resident in one layer relying on the services of program code resident in lower layers. As an example, a computer application may rely on one or more libraries of commonly-used functions, which themselves often rely on an underlying operating system to provide lower level services to the application and/or the libraries. Likewise, an operating system may rely on drivers to facilitate the management, control and access to various hardware resources in a computer, as well as extremely low level kernel and BIOS code to support the fundamental memory and task management duties for the computer.
To facilitate the reuse of code in a given software layer, it is often necessary for the software layer to provide a consistent interface to program code that may be resident in higher layers. An interface typically refers to the names or identities of the functions that are accessible in a given layer of software, as well as the expected inputs and outputs for those functions. As a result, even if the underlying code is updated, extended or otherwise modified, so long as the same interface is maintained in a given layer of code, higher layers of code that access that layer of code will often still be able to access the functions in that layer of code with little or no modification.
Another manner in which software reuse can be leveraged is through the adaptation of the same software on different types of computers. Software is often written, for example, in a relatively system-agnostic and human readable source code format, and then compiled by a compiler into a system-specific and machine readable object code format. In many instances, if compilers exist for multiple types of computers, the same source code can be compiled by different compilers into system-specific object code for execution on those different types of computers. Further, in many instances such compilation can occur with little or no customization of the source code for a particular computer type.
Still another manner of leveraging software reuse is through the use of virtual software machines such as supported by the Java programming language developed by Sun Microsystems. Rather than being compiled for a particular type of computer, Java programs are typically compiled into an intermediate format that is system-independent. Java virtual machines, specifically developed for and resident on different types of computers, then interpret or further compile the intermediate format versions of Java programs to permit the same intermediate format version of a Java program to run without modification on the various different types of computers.
Software that is intended to be compiled, interpreted or otherwise configured to execute on different types of computers often takes the form of a standardized code base. In many instances, however, and despite efforts to implement a code base as generically as possible, substantial modifications may nonetheless be required to specifically adapt a standardized code base to operate accurately and efficiently on a particular type of computer. Particularly when the standardized code base is adapted for a particular type of computer by an entity other than that which developed the original standardized code base, substantial efforts may be required on the part of that other entity.
As an example, the Java programming language supports a number of libraries that often must be specifically adapted for use on different types of computers. The Java Abstract Window Toolkit (AWT), for example, is a library package that provides a number of graphical user interface capabilities for Java programs, such as the creation and manipulation of windows, menus, buttons, etc. The Java AWT package is generically designed to run on a single-user computer, whereby the display of graphical user interface components occurs on the same computer upon which a Java program is executing. In some computer environments, e.g., in client/server computer environments, the display of graphical user interface components may occur on a different computer than that upon which a Java program is executing. As a result, in such environments, the Java AWT package must be adapted to operate in a distributed manner, so that requests in a program running on one computer to perform such operations as creating or updating windows, buttons, etc., are forwarded over a network to another computer for display.
While such adaptation can be costly and time consuming, it can be manageable if the underlying standard code base remains constant. For example, automated tools may be usable in some instances to adapt certain portions of a code base for a particular target platform. Of note, however, it has been found that such automated tools are often limited in capabilities, and some degree of manual adaptation is almost always required.
However, if the standard code base is updated or revised from time to time, the specialized adaptations of the code base will likewise need to be updated for compatibility with the updates to the standard code base. Reproducing such adaptations, however, has traditionally required manually reapplying the same changes made to an earlier version of a standardized code base to the later version of the same. Over time, repeated updates to a standardized code base can place significant support burdens on the entities that maintain the specialized adaptations of that code base. To the extent that the adaptation of a standard code base could be automated, the burdens associated with performing such adaptations could be dramatically reduced. As such, a need exists in the art for a manner of automating the adaptation of standard code bases to specialized adaptations thereof.
In some programming environments, system dependent changes in source code may be accounted for using "conditional compilation" constructs. With such constructs, sections of system-specific code for multiple systems can be incorporated into the same source code, with compiler commands used to filter out unneeded code during compilation for a particular target platform.
Using conditional compilation, system specific changes to a shared or standard code base can be safely saved directly in that code base, without affecting other system specific changes, given that irrelevant system-specific changes will effectively be filtered out during compilation for a particular platform. Moreover, by using conditional compilation, system specific changes made in a code base can often be made available in subsequent releases of that code base with little additional effort.
In some programming environments, however, conditional compilation is not supported. As a result, system specific changes often cannot be saved back in the standard code base, and every iteration of the development cycle (for system specific changes) must effectively start from scratch, with many if not all of the same adaptations made to the prior version of the code base having to be manually applied to the new version of the same. Even where automated tools are used to automatically adapt portions of a code base for use on a particular target platform, the remaining manual adaptations that are practically always required still must be applied.
It has been found, however, that such manual changes can be difficult to reconstruct, particularly given the realities of the business world, where programmers may come and go, and where code documentation may not be as comprehensive as it should be. Reproducing some of the changes made to a prior version of an adapted code base into a new version of the adapted code base may therefore require substantial study of the previous version of the adapted code base, as well as additional testing to ensure that all adaptations have been properly incorporated.
In addition, certain software version control environments support the ability to maintain multiple versions of software through storage of only the differences between versions. Such environments, however, typically rely on a rudimentary line-by-line analysis of software versions, so that different versions of software can be recreated simply by reapplying difference information to prior versions of the software. However, line-by-line analysis cannot distinguish between semantic differences (i.e., differences that alter the program structure or operation) and non-semantic differences. As a result, even irrelevant changes such as the ordering of methods or classes, changes in comments, and/or the addition or elimination of line breaks, will be identified by line-by-line analysis, often rendering such analysis useless for identifying semantic changes made to a version of software.
A significant need therefore exists in the art for a manner of facilitating the adaptation of a standard code base, and in particular, to reduce the degree of manual intervention required to adapt updated versions of a standard code base.

This patent is subject to a terminal disclaimer.

Automated semantic-based updates to modified code base

International Business Machines Corporation


A method and apparatus for testing integrated circuits by subjecting the circuits to an electromagnetic disturbance. A probe is provided, equipped with a horn cover designed to be applied to a printed circuit on which an integrated circuit is mounted. Within this horn cover, a core shield channels the electrical field that is deployed in a zone in which connections from the integrated circuit to the printed circuit that it carries are situated. The effectiveness of the electromagnetic interference injected in the integrated circuit is increased to the point that a true measurement of the resistance of this integrated circuit to the electromagnetic interferences may be carried out.

Currently known techniques for characterizing the immunity of integrated circuit components are grouped into two main families: direct injection techniques, and radiation injection techniques.
The direct injection techniques are themselves separated into two main types: the DPI (Direct Power Injection) technique, and the BCI (Bulk Current Injection) technique. The DPI technique consists of developing a specific printed circuit for the component, to which the possibilities of injecting a parasite signal may be added. One then monitors if the component is disturbed in the presence of the injected signal. The BCI technique consists of inserting a cable that transports the functional signals from the component, or from a card that has several components, in a transformer. The object of the transformer is to insert electrical power over driving sides of this cable, and in this way verify the interference or the non-interference of the component(s).
The DPI technique has the advantage of fine characterization of the susceptibility of a function of an integrated circuit for localized injection. Its defect is it does not easily allow simultaneous injection over several inputs of a component. Conversely, the BCI technique allows all the accesses of a component to be bombarded simultaneously. But, the BCI technique uses jumper wires of minimal length due to the very fact that the transformer volume does not allow high frequency connection, in practice not above 500 MHz.
Radiation injection techniques utilize TEM (Transverse Electromagnetic Mode), or GTEM (Gigahertz TEM) resonant cells, or even MSC (Mode Stirred Chamber) mode stirred cells, to excite printed circuit type electronic cards that carry components. Or rather, these cells excite the specific cards carrying a component to be tested to verify its subfield susceptibility. In every case, to characterize the susceptibility of a component, these techniques require the manufacture of a particular card, and necessitate, due to the fact of the relative remoteness of the field sources with respect to the components, significant power sources. Furthermore, control of the part of the disturbance power effectively received by the component is not easy, or even debatable.

European Aeronautic Defence and Space Company Eads France and Eads CCR Groupement d'Interet Economique


A method and computing system for establishing a broadcast account for a user of an internet-based broadcasting system. An initial trust level is assigned to the broadcast account. The initial trust level is chosen from a plurality of predefined trust levels. A trust score is determined for the broadcast account. The trust score is based, at least in part, upon one or more activities of the user. The initial trust level is adjusted based, at least in art, upon the trust score.

The Internet currently allows for the free exchange of ideas and information in a manner that was unimaginable only a couple of decades ago. One such use for the Internet is as a communication medium, whether it is via one-on-one exchanges or multi-party exchanges. For example, two individuals may exchange private emails with each other. Alternatively, multiple people may participate on a public website in which they may post entries that are published for multiple people to read. Examples of such websites may include but are not limited to product/service review sites and topical blogs.
The Internet also provides users with the ability to broadcast (e.g., stream) live video/audio to a wide audience. Traditionally, this ability was licensed to only a limited number of broadcasters (e.g., media/broadcast companies). With this enhanced ability to broadcast comes a measure of risk to the technology provider with respect to claims of abusive use and copyright violations.


A network management apparatus and method for determining the topology of a network in which a Spanning-Tree protocol is implemented, is disclosed in which address table data is obtained from the ports of the core network devices on the network, and the identity of the ports of the core network devices are determined. Spanning-Tree protocol information is obtained from the core network devices and used to process the address table data to remove data relating to ports having links which are inactive. The topology of the network is then determined using the processed data by first selecting one of the core network devices as a root network device, and then using the processed address table data to build a network tree from the selected root device.

1. Field of the Invention
The present invention relates generally to network management systems and more particularly to a network management apparatus and method capable of determining the topology of a network.
2. Description of the Related Art
The following description is concerned with a data communications network, and in particular a local area network (LAN), but it will be appreciated that the present invention has more widespread applicability to other managed communications systems and networks including wide area networks (WANs) and wireless communications networks.
Data communications networks typically comprise a plurality of network devices (computers, peripherals and other electronic devices) capable of communicating with each other by sending and receiving data packets in accordance with predefined network protocols. Each network device is connected by at least one port to the network media, which in the case of a LAN network may be coaxial cable, twisted pair cable or fibre optic cable. Each device on the network typically has hardware for media access control (MAC) with its own unique MAC address. Data packets are sent and received in accordance with the MAC protocol (e.g. CSMA/CD protocol as defined by the standard IEEE 802.2, commonly known as Ethernet). Data packets transmitted using the MAC protocol identify the source MAC address (i.e. the MAC address of the device sending the data packet) and the destination MAC address (i.e. the MAC address of the device for which the data packet is destined) in the header of the data packet.
A network is generally configured with core devices having a plurality of ports, which can be used to interconnect a plurality of media links on the network. Such devices include hubs, repeaters, routers and switches which forward data packets received at one port to one or more of its other ports, depending upon the type of device. For example, a switch forwards a data packet, received at one port, only to a port known to be connected to the destination device specified in the data packet. Such core devices can either be managed or unmanaged.
A managed device is capable of monitoring data packets passing through its ports. For example, a managed device can learn the physical or MAC addresses of the devices connected to its ports by monitoring the source address of data packets passing through the respective ports. Identified source addresses transmitted from a port of a managed network device, such as a router, hub, repeater or switch, are stored in a respective "address table" associated with the port, as described further below.
Managed devices additionally have the capability of communicating using a management protocol such as the Simple Network Management Protocol (SNMP), as described in more detail below. Whilst the following description is concerned with the SNMP management protocol, the skilled person will appreciate that the invention is not limited to use with SNMP, but can be applied to managed networks using other network management protocols.
SNMP defines agents, managers and MIBs (where MIB is Management Information Base), as well as various predefined messages and commands for communication of management data. An agent is present in each managed network device and stores management data and responds to requests from the manager. A manager is present within the network management station of a network and automatically interrogates the agents of managed devices on the network using various SNMP commands, to obtain information suitable for use by the network administrator, whose function is described below. A MIB is a managed "object" database which stores management data obtained by managed devices and is accessible to agents for network management applications.
It is becoming increasingly common for an individual, called the "network administrator", to be responsible for network management, and his or her computer system or workstation is typically designated the network management station. The network management station incorporates the manager, as defined in the SNMP protocol, i.e. the necessary hardware, and software applications to retrieve data from MIBs by sending standard SNMP requests to the agents of managed devices on the network.
Network management software applications are known which can determine the topology of a network, i.e. the devices on the network and how they are linked together. In order to determine the network topology, the application retrieves MIB data from the managed devices on the network, which can provide information about the devices connected to the managed devices, for instance the aforementioned "address tables". MIB data retrieved from managed devices can also provide information about device type, device addresses and details about the links. Using such data, the application can usually determine the topology of the entire network.
An example of a known network management software application capable of determining network topology is the 3Com® Network Supervisor available from 3Com Corporation of Santa Clara, Calif., USA.
This system, and other similar systems, determines the topology of the network by building a "network tree". In particular a network device or "node" is selected as a "root node" (which is typically a managed switch or bridge) and the system uses the MIB data to determine the identity of all the "child nodes" of each of the ports of a root node.
The child nodes of a given port are the devices, the addresses of which the port has learnt by monitoring the source addresses of data packets passing through the port. In other words, the child nodes are network devices which are connected on a "branch" of the network to the relevant port, and which have sent data packets to network devices on other branches of the network through the root device.
The process is then repeated for each of the child nodes, to determine which nodes are children of each child node, their orientation with respect to each other and thus the structure of the branch. This process builds up the "network tree". More details of the manner of determining network topology in this way can be found in RFC 2108 "Definitions of Managed Objects for IEEE 802.3 Repeater Devices using SMIv2", which is incorporated herein by reference.
A problem with this method of determining network topology is encountered when the topology of a network is not a "tree", but includes a "loop". A loop is formed when an additional link is introduced in the network topology to provide an additional network path between network devices. Such additional links are often included to provide additional resilience to the network, i.e. to enable data packets to be communicated between devices even when a link between the devices is inactive (e.g. physically broken).
However, a loop can give rise to problems on a network. In particular, since there is more than one path between two network devices, data packets may be duplicated, since core network devices, such as switches, will send packets along all possible paths to the destination device, leading to excessive network traffic.
To overcome this problem, a Spanning-Tree Protocol is employed to ensure that only one active path exists between any two network devices. This is achieved by making the other possible paths redundant. A known Spanning-Tree Protocol is defined in the IEEE 802.1D Bridge Protocol standard, which is incorporated herein by reference. The skilled person will appreciate that other suitable Spanning-Tree protocols may be employed.
This Spanning-Tree Protocol (STP) is a link management protocol implemented in managed network devices, in particular, switches. STP defines Spanning-Tree data packets which are exchanged by switches during a negotiation process, as described below. STP additionally defines the following possible states for a port of a switch: blocking; listening; learning; forwarding and disabled. A port in the blocking state discards received data packets, and discards data packets passed to the port by the switch for forwarding, and is thus "inactive". This state is effective to prevent duplication of data packets where two possible paths exist to the destination device. As previously indicated, a problem arises with the above described method of determining network topology by the network management system if loops are present on the network. Even if STP is implemented, prior to completion of the negotiation process, data packets will be passed along the possible different paths to the same network device. Consequently, ports which are eventually placed in the blocking state still learn and store addresses in their address tables at this stage. Thus, in attempting to build a "tree" using the aforementioned method, the network management system will find, for instance, that several devices on different branches of the tree share a child device. The resulting conflicting information can make it impossible to determine the network topology.
The present invention aims to address this problem.

Network management apparatus and method for determining the topology of a network


A sheet feeding unit includes a supporting member configured to rotatably support a rotary feeding member, a first retaining member configured to push the supporting member upward from the underside to retain the rotary feeding member at a waiting position, and a second retaining member protruding on the underside of the supporting member when the first retaining member retains the supporting member. The retention of the supporting member by the first retaining member is released in association with the mounting of a sheet storage portion in the mounting position, and then the retention of the supporting member by the second retaining member is released.

1. Field of the Invention
This disclosure relates to a sheet feeding unit configured to feed sheets, and an image forming apparatus provided with the sheet feeding unit.
2. Description of the Related Art
Examples of image forming apparatus such as an electrophotographic copying machine include an apparatus configured to allow a sheet feeding cassette containing sheets to be supplied to an image forming unit in a stacked manner to be inserted in and drawn out from a main body of the image forming apparatus (hereinafter, referred to as an apparatus body). In the image forming apparatus, a feeding roller moves downward to a feeding position for feeding the sheet in association with mounting of the sheet feeding cassette and comes into abutment with the sheet in the sheet feeding cassette. Then, in accordance with a feeding signal, the feeding roller rotates in a sheet feeding direction, sheets are fed to downstream from a topmost sheet in sequence.
Some of the image forming apparatus are configured in such a manner that the feeding roller moves upward to a waiting position with the sheet feeding cassette in a state of being drawn out, and the feeding roller moves downward in mid-course of completion of mounting of the sheet feeding cassette on the apparatus body. In this configuration, however, the feeding roller may be moved downward to the feed position before the completion of mounting of the sheet feeding cassette to the apparatus body, thereby coming into press-contact with a topmost sheet in the sheet feeding cassette.
In such a case, the sheet feeding cassette is pushed further inward with the feeding roller in a state of being in press-contact with the topmost sheet. Accordingly, wrinkles may be formed on the topmost sheet and the posture of the sheet gets out of alignment. In particular, in the case where the direction of movement of the sheet feeding cassette matches an axial direction of the feeding roller, a phenomenon of formation of wrinkles notably occurs because a sheet is pinched between a side regulating plate configured to regulate side ends of the sheets and the feeding roller. If the sheet is fed in a state of being out of alignment, the wrinkles of the sheet are collapsed by the roller and hence become more apparent, or the sheet are skewed. Consequently, feed failure may result.
In the related art, Japanese Patent Laid-Open No. 2004-292093 discloses an elevating mechanism of a pickup roller (feeding roller) including a sheet feeding cassette. The sheet feeding cassette includes a first lever configured to be moved in conjunction with a mounting action with respect to a main body of a sheet feed unit, a second lever configured to support the pickup roller via the first lever, and a torque limiter including a coil spring disposed on a coupling portion with respect to the first and second levers. In this sheet feed unit, if the sheet feeding cassette is inserted into the main body of the sheet feed unit, the inserted sheet feeding cassette and the first lever come into abutment with each other, and the abutment pivots the first lever in association with the movement of the sheet feeding cassette in a mounting direction. At this time, the coil spring that couples the first lever and the second lever is increased in diameter if the first lever rotates by being pressed by the sheet feeding cassette. Therefore, the pivotal movement of the first lever is not transmitted to the second lever. If the first lever is further pivoted and the support of the second lever is released, the second lever pivots downward under its own weight and the inner diameter of the coil spring is reduced. Consequently, the first and the second levers move in conjunction with each other to move the pickup roller downward.
In this manner, the sheet feeding unit of Japanese Patent Laid-Open No. 2004-292093 includes the torque limiter to retard timing of pivot of the second lever with respect to timing of abutment between the sheet feeding cassette and the first lever and thus retard timing of downward movement of the pickup roller. However, since the torque limiter used here includes the coil spring, the timing of the pickup roller moved downward is changed depends on accuracy of the coil spring.

Sheet feeding unit and image forming apparatus


The application discloses an adjustable head stack comb having adjustable first and second comb plates. The adjustable comb plates include at least one tooth segment which cooperatively form a comb having at least one tooth. The first and second comb plates are adjusted to adjust dimensions of the at least one tooth cooperatively formed by the tooth segments of the first and second comb plates. In the embodiments disclosed, a relative position of the first and second comb plates is adjusted to adjust a thickness dimension of the at least one tooth formed by the at least one tooth segments of the first and second comb plates. Also in illustrated embodiments, the comb plates are cooperatively adjusted to adjust an elevation or z-height of the at least one tooth of the comb.

Data storage devices include heads to read digitally encoded information from a disc or data storage medium and/or write digitally encoded information to the disc or data storage medium. Heads are typically coupled to an actuator or E-block to form a head stack assembly including a plurality of heads to read information from or write information to a plurality of discs of a disc stack. The plurality of heads of the head stack assembly are merged with the plurality of discs of the disc stack to read data from and/or write data to the plurality of discs of the disc stack.
Heads are coupled to the E-block or actuator via a plurality of suspension assemblies or suspension arms. Typically, the head includes an air bearing slider to provide a dynamic fly height (along a z-axis) for the head above the disc surface. The head or slider is coupled to the suspension assembly or suspension arm via a gimbal spring or gimbal device to allow the head or slider to pitch and roll relative to a load point of the suspension assembly to follow the topography of the disc surface. The head and gimbal spring collectively form a head gimbal assembly and the head and suspension collectively form a head suspension assembly.
Manufacturing tolerance variations can introduce variations to static dimensions of the suspension assembly and head. For example manufacturing tolerance variations can introduce variations to pitch static attitude (PSA), roll static attitude (RSA) or z-height parameters of the head or slider. PSA and RSA can vary based upon variations in flexure or relative stiffness of suspension components. Variations in PSA and RSA parameters can affect pitch, roll and z-height parameters of the head or slider relative to the disc surface and fly height parameters for read or write operations of the data storage device.
To control manufacturing tolerance variations, static dimensions, such as PSA and RSA are measured. For measurement, a head stack comb assembly is used to hold suspension arms relative to a static measurement position corresponding to an elevational or z-height of the head or suspension assembly after loaded or merged with a disc. Head stack combs include a plurality of teeth having a thickness dimension sized to hold the suspension arms relative to the static measurement position of the head or assembly. Accuracy of the thickness dimension of the teeth and position and elevation thereof is important for accurate measurement.
For example, static measurements can vary depending upon the height at which the suspension arm is held by the teeth of the comb. Determining optimum dimensions of the comb and thickness of the comb teeth is difficult. Manufacturing a variety of combs having different tooth dimensions and parameters can be tedious and expensive. The present invention addresses these and other problems and offers solutions not previously recognized nor appreciated.


A surgical gown folded in a unique pattern that provides for a smaller sized gown that can be packaged in a smaller sized outer wrap as well as provide for an easily donnable gown that maintains its sterility. The fold pattern provides for the interior surfaces of the gown to be visible, and preferably, a portion of the interior surfaces, while maintaining sterility of the exterior surfaces by keeping them inside of the gown. A method of folding the gown in this new pattern is provided herein as well as a method of donning the folded gown.

Surgical gowns are often worn by medical personnel and doctors during surgical and medical procedures to maintain sterility in the medical setting by protecting the patient from contamination that may be found on the clothes of the wearer as well as protecting the clothes of the wearer from becoming saturated with blood or other fluids that may be present during these medical procedures. Such gowns are used frequently by health care professionals to act as a barrier between the wearer and the medical environment/patient to minimize the spread of infectious diseases.
Surgical gowns are often provided in a folded arrangement for ease of transportation and/or to preserve sterile surfaces. Many of these prior folded gowns are provided with additional features, such as a grasp or pull-tab, that is an extra section of the gown or an extra piece of material manufactured onto the gown to be used as a handhold to pull down upon when unfolding the gown or donning the gown, essentially used as an anchoring point for the wearer to either pull on or use as a handhold to unfold the gown. This grasping pull-tab can create an extra step for the wearer when having to unfold and don the gown as well as an extra step in manufacturing when an extra piece has to be added onto the gown.
In some instances, the folded gown size may end up being large due to the need to be able to easily unfold the gown when in the medical setting and in an effort to avoid complicated folding patterns. Another issue with folded gowns is that there can be wrinkles present in the folds. The gowns may be loosely folded, such that after they are unfolded from their overwrap the gowns become wrinkled, giving the gown a look like it has been used or is not clean. Moreover, the larger folded gown size requires larger packaging and cases for shipping, which can increase the cost of the gowns.

Folded surgical gown and method of folding same


A device is dynamically programmable to generate at least a first magnetic field during a first time interval, and at least a second magnetic field during a second time interval thereby causing the particles exposed to the change in the magnetic field to aggregate to a target region. The device is further dynamically programmable to switch between the first and second magnetic fields for any number of cycles. Optionally, the device includes a multitude of conductors that receive a first current during the first time interval to generate the magnetic field, and a second multitude of conductors that receive a second current during the second time interval to generate the second magnetic field. The second multitude of conductors may be substantially parallel to the first multitude of conductors. A controller disposed within the device is adapted to vary the frequency of switching between the first and second magnetic fields.

Particles may be moved mechanically, or by application of electric or magnetic fields or fluidic energy. Magnetic particle manipulation using magnetic tweezers is known to have been used in cell separation and tissue engineering. However, such system, among other disadvantages are costly, require complicated setups, have small active areas, are not scalable, and difficult to image.
Traditional tumor treatment therapies, such as surgery, chemotherapy, and radiation therapy, damage peripheral tissue and are ineffective in treating privileged organs such as the brain and central nervous system. Immunotherapy, utilizing functionalized nanoparticles, has been shown to be a promising treatment for intracranial gliomas, which is the most common type of malignant brain tumor. However, the retention and delivery of immune cells and nanoparticles to the tumor site remains a challenge.
Particle movement and aggregation is important in a number of applications as it allows for delivery of cargo to a point in space. The cargo may be different depending on the desired application. For example, cancer immunotherapy can be greatly enhanced through the delivery of adjuvants directly to the tumor site. In tissue engineering, the particles may be used to transport stem cells to a desired location to form more complex cellular structures. In the medical diagnostics industry, the particles may be coated with reporter molecules and traversed through a collection of points in a biological sample for determining the presence of a target. Such particles may also be coated with capture molecules to gather a sample.
The particles may be used to induce flow or vortices inside a medium. The size of such particles may vary greatly depending on the application. In transporting the particles from one location to another, a feedback method is typically used to track the particle's position. This allows the particle to be steered toward a location when a stable aggregation point cannot be achieved. Tracking a particle's position using a feedback loop adds to the cost and complexity of the systems.

Method and apparatus for particle actuation in a space


A vehicle body structure includes longitudinally extending elements such as roof side rail outer and inner members, a reinforcement member and a gusset that are part of a side impact energy management system for vehicles that include a sunroof. A laterally extending cross member is connected to the roof side rail members, and the roof side rail members are connected to an upper portion of an approximately vertical B-pillar. The cross-member is connected to the roof side rail members approximately perpendicular to the B-pillar, but longitudinally offset from the B-pillar. The reinforcement member extends between the roof side rail members to the cross-member.

1. Field of the Invention
The present invention generally relates to reinforcement of a vehicle body structure. More specifically, the present invention relates to a vehicle support structure that includes a sunroof.
2. Background Information
A variety of vehicle body constructions are broadly classified into two categories: (1) a unibody or unitized construction in which a self-supporting body has a plurality of rigidity members integrated therewith; and (2) a frame on chassis or framed construction in which a separate body is connected to a structural framework. The framed construction is mainly applied to commercial vehicles and trucks. Most passenger vehicles utilize a conventional unitized (self-supporting) vehicle body that is built from sheet metal components onto which body panels are welded. Generally, the structural configurations of these unitized vehicle bodies are continuously being improved for a variety of reasons. For instance, these unitized vehicle bodies have been developed so as to simplify the assembly process, and thereby reducing manufacturing costs. Moreover, these unitized vehicle bodies have been extensively redesigned over the years to improve the strength and rigidity of the vehicle in the event of impact from the side.
In the case of vehicle roof structures, a center cross member is typically included as part of the roof structures beneath a roof panel of the vehicle to provide lateral support as well as to support the roof panel. The center cross member is often positioned at a point coinciding with the B-pillars of the roof support structure. The B-pillars are typically upright support structures supporting the roof and doors at a location between front and rear side windows of the vehicle. However, when a sunroof is included in the vehicle roof support structure, the center cross member is often repositioned such that the center cross member is longitudinally offset from the B-pillars. Specifically, instead of joining side rail members at a point coinciding with the B-pillars, the center cross member joins the side rail members rearward from the B-pillars. Thus, the transfer of load across the roof during side impact can be less effective for sunroof vehicles.
In view of the above, it will be apparent to those skilled in the art from this disclosure that there exists a need for an improved vehicle support structure for roof structures with a sunroof. This invention addresses this need in the art as well as other needs, which will become apparent to those skilled in the art from this disclosure.

Nissan Technical Center North America, Inc.


The present invention provides a compound of the following formula and salts thereof:

Type II topoisomerases catalyse the interconversion of DNA topoisomers by transporting one DNA segment through another. Bacteria encode two type II topoisomerase enzymes, DNA gyrase and DNA topoisomerase IV. Gyrase controls DNA supercoiling and relieves topological stress. Topoisomerase IV decatenates daughter chromosomes following replication and can also relax supercoiled DNA.
Bacterial type II topoisomerases form a heterotetrameric complex composed of two subunits. Gyrase forms an A2B2 complex comprised of GyrA and GyrB whereas topoisomerase forms a C2E2 complex comprised of ParC and ParE. In contrast eukaryotic type II topoisomerases are homodimers. Ideally, an antibiotic based on the inhibition of bacterial type II topoisomerases would be selective for the bacterial enzymes and be relatively inactive against the eukaryotic type II isomerases.
The type II topoisomerases are highly conserved enzymes allowing the design of broad-spectrum inhibitors. Furthermore, the GyrB and ParE subunits are functionally similar, having an ATPase domain in the N-terminal domain and a C-terminal domain that interacts with the other subunit (GyrA and ParC respectively) and the DNA. The conservation between the gyrase and topoisomerase IV active sites suggests that inhibitors of the sites might simultaneously target both type II topoisomerases. Such dual-targeting inhibitors are attractive because they have the potential to reduce the development of target-based resistance.
Type II topoisomerases are the target of a number of antibacterial agents. The most prominent of these agents are the quinolones. The original quinolone antibiotics included nalidixic acid, cinoxacin and oxolinic acid. The addition of fluorine yielded a new class of drugs, the fluoroquinolones, which have a broader antimicrobial spectrum and improved pharmacokinetic properties. The fluoroquinolones include norfloxacin, ciprofloxacin, and fourth generation quinolones gatifloxacin and moxifloxacin. The coumarins and the cyclothialidines are further classes of antibiotics that inhibit type II topoisomerases, however they are not widely used because of poor permeability in bacteria, eukaryotic toxicity, and low water solubility. Examples of such antibiotics include novobiocin and coumermycin A1, cyclothialidine, cinodine, and clerocidin. However, the continuous emergence of antibiotic resistance demands that novel classes of antibiotics continue to be developed and alternative compounds that inhibit bacterial topoisomerases are required.
WO2007/148093 and WO2009/074812 describe compounds that inhibit bacterial gyrase activity. The applicant has now identified a class of related compounds that includes a carbocyclic or heterocyclic ring comprising an α-substituted carboxylate or amide. Compounds of this class appear to possess a number of advantages including enhanced solubilities at physiologically acceptable pH, in particular, advantageous solubilities for intraveneous (IV) administration and/or advantageous pharmacokinetic properties.

Abstract: Also provided is the use of these compounds as antibacterials, compositions comprising them and processes for their manufacture.


An apparatus for the transmission of a deflection of an actuator, in particular of a piezoelectric actuator of an injection valve, comprises at least one first lever device which has a first transmission element which transmits the deflection of the actuator. In this case, there is provision for at least one first spring element to be provided for guiding or mounting the first transmission element.

Actuators based on the piezoelectric principle are suitable for the highly accurate and very rapid control of actuating operations, such as are expedient, for example, for the activation of injection apparatuses or injection valves of internal combustion engines. In order to implement pronounced linear deflections of the piezoelectric actuators, these must consist of a multiplicity of individual piezoelectric elements stacked one on top of the other. The disadvantage of this is that the overall size assumes inadmissible dimensions for many applications. Thus, for example, the installation space for injection valves in the cylinder head of an internal combustion engine is limited in such a way that there is, as a rule, no room for piezoelectric actuators in the length dimension necessary for the desired actuating movements. For this reason, smaller piezoelectric actuators are used, the linear deflections of which are stepped up into larger deflections by suitable lever devices.
WO 99/17014 discloses, for example, an injection valve in which, for transmitting a deflection of a piezoelectric actuator to an actuating member and for stepping up this deflection, mechanical transmission elements are provided, which are essentially in the form of a cylinder, the boundary surfaces of which are of essentially triangular design, the corners being rounded. Sheetlike bearing regions are in this case formed as a result of the width of the transmission elements.
For example in conjunction with control valves for injection apparatuses, it is necessary for the actuator space to be sealed off with respect to other regions of the control valve. O-rings have already been used for this purpose. The use of O-rings presents problems, however, in as much as O-rings can be damaged relatively easily. This problem is aggregated further in that damage to an O-ring cannot readily be detected reliably during subsequent tests.
Compared with O-ring sealing off, a metallic sealing off of the actuator space therefore affords advantages, and, in preferred embodiments, there may be provision for the sealing surfaces to run perpendicularly with respect to the actuator axis. The surface pressure required for the sealing function may be applied, for example, via a connecting thread. In embodiments of this type with a metallic sealing off of the actuator space, however, there is the problem that the guide of the transmission element is not fastened nonpositively with respect to the actuator, but can move spatially within the play tolerance. This moveability may cause kinematic variations and therefore dispersions in the stroke step-up.

Apparatus for the transmission of a deflection of an actuator


Classifying and detecting original images on a roll of film so that a photographer can describe and identify to the photofinisher the type of images of interest to the photographer and to identify which images by category on the roll of film are to receive certain customer requested procedures such as multiple prints, enlargements or no printing of that image at all.

1. Field of the Invention
The present invention relates to an image-forming apparatus and more particularly to a multiple image-forming system for synthesizing and forming a plurality of images having different characteristics identified in the original scanning of the film.
2. Description of the Prior Art
Generally, originals may be classified to help in the detection and recognition of several types of images on a roll of film. This classification process is used to expose the photographic paper properly to produce more pleasing prints.
U.S. Pat. No. 3,790,275, issued to Huboi et al on Feb. 5, 1974, discloses both a method and apparatus with a capability of automatically identifying the type of image present in the originals. Based on the results of such identification, the image-forming apparatus selects the proper light-sensitive materials and exposure conditions according to the type of the original of interest and to expose the photographic paper properly in order to produce the most pleasing prints of that subject matter.
U.S. Pat. No. 3,708,676, issued to Huboi et al on Jan. 2, 1973, discloses an apparatus that samples the density of central portions of a frame on a negative and determines the optimum exposure setting for printing that frame onto photographic paper. In calculating the optimum exposure setting, the average color densities in the red, green and blue channels are considered simultaneously to prevent color subject failures.
U.S. Pat. No. 5,053,808, issued in the name of Takagi on Oct. 1, 1991, describes a photographic copier using as its input reflection documents. By pre-scanning the document on its platen, the copier discriminates three different types of input images such as: photographs, printed material and black-and-white images. Based on the type of input, it corrects the exposure step to ensure proper copying. It also teaches how to use histograms to isolate document areas from non-document areas when undersized prints are copied.
U.S. Pat. No. 4,785,330, issued to Yoshida et al on Nov. 15, 1988, describes a black-and-white electrophotographic copier that through a pre-scan cycle discriminates between three types of inputs on a single sheet. The types of input recognized are text and charts on normal white background, text and charts on non-white background (newspaper clippings) and photographs. For each type of input detected, the copier reproduces that input with a complete electrophotographic cycle specifically tuned for that type. This type procedure requires three separate exposures, three development cycles, three image transfers and three fusing operations to create a single sheet that contains normal text, newspaper text and photographs. The recognition algorithm analyzes the entire pre-scan data and based on predetermined density levels, decides which of those input conditions are present and where each input type is located.
None of the methods or apparatus set forth above that determine image content recognition based on pre-determined density levels are able to identify the contents of typical scenes exposed on photographic films. Identification of image content is not used to respond to customer generated requests, but instead are used to improve print quality.

Method and apparatus for using film scanning information to determine the type and category of an image


A mobile device mobility state is included in device reporting to a radio access network for mobility event and load balancing purposes. Respective load conditions and respective coverage areas of a first set of devices of a first network and a second set of devices of a second network are analyzed. In addition, a mobility state of a mobile device, a first signal strength associated with the first set of devices, and a second signal strength associated with the second set of devices are also analyzed. The mobility state is a function of a movement pattern of the mobile device and a speed at which the mobile device is being moved. Network traffic of the mobile device is routed to a set of network devices selected from the first set of devices and the second set of devices, as a result of the analysis.

The use of mobile devices and the resulting mobile traffic has been growing at a very fast pace and the trend shows no signs of stopping. To meet the mobile traffic growth and improve the end user experience, mobile service providers are actively looking for mechanisms to improve network efficiency, system capacity, and end user experience. To meet the demand of higher traffic and to improve the end user experience, mobile telecommunications operators are deploying metro cells (also referred to as small cells) in an attempt to help improve coverage and capacity. Mobile telecommunications operators have also been adding more carriers to meet the traffic demand.

Network based speed dependent load balancing


Various embodiments provide methods for configuring a phase-change random-access memory (PCRAM) structures, such as PCRAM operating in a single-level-cell (SLC) mode or a multi-level-cell (MLC) mode. Various embodiments may support a PCRAM structure being operating in a SLC mode for lower power and a MLC mode for lower variability. Various embodiments may support a PCRAM structure being operating in a SLC mode or a MLC mode based at least in part on an error tolerance for a neural network layer.

A phase-change random-access memory (PCM or PCRAM) is a form of non-volatile random-access computer memory. PCRAM technology is based upon a material that can be either amorphous or crystalline at normal ambient temperatures. During conditions in which the material is in the amorphous state, the material has a high electrical resistance. The amorphous state can be referred to as a high resistance state (HRS). During conditions in which the material is in the crystalline state, the material has a low electrical resistance. The crystalline state can be referred to as a low resistance state (LRS).
In order to control the state of the material, the material may be heated and cooled. By heating the material above its crystallization point, the material enters its crystalline state. The material may be heated, for example, by passing current through a heating element. As the material cools, it enters an amorphous state. The change of phase in a PCRAM cell and the resulting change in electrical resistance can be used to store data in the PCRAM cell.
To change the phase of the PCRAM cell, a SET operation switches the material of the PCRAM cell to the crystalline phase and a RESET operation switches the material of the PCRAM into the amorphous phase. The SET operation crystallizes the material of the PCRAM by heating it above its crystallization temperature, and the RESET operation melt-quenches the material of the PCRAM to make the material amorphous. The SET operation and the RESET operation can be associated with different electrical current profiles or voltage profiles, such as one type of pulses for the RESET operation that heat the material of the PCRAM above its melting temperature and another type of pulses for the SET operation to heat the material of the PCRAM above its crystallization temperature but below its melting temperature.

Methods of controlling PCRAM devices in single-level-cell (SLC) and multi-level-cell (MLC) modes and a controller for performing the same methods

Taiwan Semiconductor Manufacturing Company Limited


The invention relates to apparatus for filtering, decimating and transposing into baseband, the apparatus being of the entirely digital type, and serving both to extract and transpose into baseband one of the channels, referred to as the xe2x80x9cchannel of interestxe2x80x9d, of a frequency multiplex of channels, and also to reduce the oversampling factor of said channel of interest, each channel being associated with a distinct carrier. The said apparatus comprising at least two stages in cascade (401 to 40L), each stage comprising filter means (42) and decimation means (43), said filter means being placed upstream from said decimation means and enabling a portion of the spectrum to be purged at locations where the decimation means produce aliasing. According to the invention, each stage (401 to 40L) also comprises transposition means (41) placed upstream from said filter means (42) and associated with a transposition frequency (ft,i) previously selected from a set of N possible distinct transposition frequencies so as to transpose the carrier (p0) associated with said channel of interest as close as possible to zero frequency.

The field of the invention is that of data transmission, in particular of the frequency division multiple access (FDMA) type, consisting in transmitting a frequency multiplex of channels.
In general, each channel of the multiplex is associated with a carrier frequency and with a data rate. In the present case, the carrier frequency and the data rate of each channel can be completely arbitrary.
More precisely, the invention relates to a digital method and to digital apparatus for filtering, decimating, and transposing into baseband a particular channel of a frequency multiplex. In other words, the present invention relates to a method and to apparatus serving to extract a particular channel referred to as the xe2x80x9cchannel of interestxe2x80x9d from a frequency multiplex of channels, and to transpose it into baseband, and to do so while reducing the oversampling factor of said channel of interest.
In conventional manner, the operations of filtering, decimation, and transposition are implemented in a demodulator capable of receiving a frequency multiplex, and they are performed prior to other operations, for example operations such as filtering, reception, interpolation, synchronization, decoding, etc.
Also in conventional manner, it is assumed below in the present description that the frequency multiplex has already been transposed to an intermediate frequency or indeed is already in baseband. It is recalled that when a multiplex is in baseband that does not necessarily mean in any way that the channel of interest within said multiplex is itself in baseband. Consequently, it is clear that the invention (which seeks to bring the channel of interest into baseband) is applicable to both of the above cases.
The present invention relates solely to digital type processing (filtering, decimating, and transposing). In order to take maximum advantage associated with digital technology (reproducibility, precision, flexibility of design rules, . . . ), it is desirable for certain tasks that have traditionally been performed in the analog domain to be performed in completely digital manner.
This means that the frequency multiplex as a whole has already been digitized (sampled and subjected to analog-to-digital conversion). In other words, the entire frequency multiplex has been sampled at a rate that is relatively high because its band is still complete (for example the sampling rate may lie in the range 40 MHz to 60 MHz).
Since the channel of interest (the channel that is to be extracted and transposed into baseband) is of narrow width compared with the sampling frequency, it is desirable to reduce the oversampling on said channel of interest to a moderate value (4 to 8 samples per symbol, for example). Typically, the data rates processed lie in the range 10 kbit/s to 500 kbit/s, for example.
This reduction of oversampling is performed by an operation known as xe2x80x9cdecimationxe2x80x9d which consists in selecting one out of every n samples. The factor n is referred to as the xe2x80x9cdecimationxe2x80x9d factor.
In conventional manner, the operation of decimation is preceded by a filtering operation. Decimation produces aliasing. Efficient filtering purges the frequency band in those locations where information-carrying spectrum components are going to be aliased.
It is also desired to transpose the channel of interest into baseband so as to make subsequent processing possible (filtering, reception, interpolation, synchronization, decoding, etc.). The channel of interest is located at an arbitrary frequency within the multiplex and indeed there is no guarantee that the multiplex is itself centered on zero frequency.
A digital demodulator can solve the problem of frequency divided channels by using a decimating filter that has a tree structure. Each stage of the structure has two branches, each branch performing filtering on a sub-band equal to half the total band it receives, followed by decimation by two. The tree structure makes it possible to extract simultaneously as many distinct channels as it possesses outputs, i.e. 2E distinct channels where E is the number of stages. It is also important to observe that the tree structure does not require any specific transposition means, since the filtering and decimation performed at each stage bring the carriers of the various channels progressively towards zero frequency.
Unfortunately, such a tree structure suffers from the major drawback of being unsuitable for use with an arbitrary multiplex. A tree structure requires the channel carriers to be distributed in a very specific manner within the multiplex. More precisely, each channel carrier must occupy an initial position within the multiplex such that at each stage it is to be found exactly within one of the two filtering sub-bands. It will be understood that if at the input to a given stage (i.e. at the output from the decimator of the preceding stage) a carrier lies at the boundary between the sub-bands associated with the two filters of the stage (overlap of transition zones), then it runs the risk of being conserved by neither of the two filters.
Furthermore, the tree structure is designed to extract all of the channels of the multiplex and such a structure is therefore excessive when only one channel is to be extracted from a plurality of channels.
In the state of the art, solutions are also known relating solely to the pair of operations comprising filtering and decimation. Those prior solutions recommend avoiding only one step of filtering for high rates of decimation. Such an approach would require a large fraction of the frequency band to be filtered so as to leave room for the large amount of aliasing produced by high rates of decimation. Unfortunately, such a constraint means that the transition zone of the filter performing the rejection operation is narrow, which can only be achieved by a digital filter that is defined by a large number of coefficients, with each of the coefficients also needing to be quantified with precision, i.e. it can only be achieved at the cost of a large number of elementary operations on bits.
Known filtering and decimation solutions tend rather to subdivide the filtering function into two or three stages. This provides advantages in terms of overall complexity, since the number of operations performed in each stage is significantly reduced. However, in those known solutions, the configuration of the various successive stages is specific to the carrier and to the data rate of the channel that is to be extracted. In other words, at each stage, filtering is adapted to the characteristics (carrier and data rate) of a particular channel. Consequently, as a general rule, two successive stages are not identical. In addition, a given filtering and decimation apparatus is not simple to use for two distinct channels of interest. Under such circumstances, all of the filtering and decimation parameters in each stage need to be updated individually.
In other words, those known solutions for filtering and decimation suffer from the major drawback of requiring large capacity storage for storing several sets of filtering and decimation coefficients, and also of requiring a mechanism for selecting between pertinent sets of coefficients. In addition, since the stages are completely different from one another, there is no possibility of implementing them by sharing a common computation resource.
Elsewhere, for the problem of transposition, a commonly adopted solution consists in transposing the entire multiplex once so as to center the channel of interest on zero frequency. In this way, the above-mentioned known solutions for filtering and decimation in which filtering is centered likewise on zero frequency, can be used to extract the channel of interest and to decimate it.
Such transposition is not very advantageous. It needs to be performed immediately after the analog-to-digital converter, and therefore at the high sampling frequency that is imposed thereby. Unfortunately it would be more advantageous to minimize the sampling frequency before proceeding with transposition into baseband. It is recalled that the values that are accessible by frequency transposition are, by their very nature, quantified, and that as a result, for given precision, the fineness of such transposition decreases with increasing sampling frequency. This precision is represented by the size of the memory for storing the accessible transposition values. In addition, since the band is still complete at this stage, the width of the frequency range to which the transposition must be applied is at its maximum.
A particular object of the invention is to mitigate those drawbacks of the prior art.
More precisely, an object of the present invention is to provide a digital method and apparatus for filtering, decimating, and transposing into baseband, which method and apparatus are of hardware cost that is reduced compared with the above-mentioned known solutions.
Another object of the invention is to provide such apparatus and such a method that impose no constraint on the frequency multiplex (and in particular do not require any particular distribution of channel carriers within the multiplex).
Another object of the invention is to provide such apparatus and such a method in which it is possible for some of the stages to be identical in terms of design structure and hardware.
A further object of the invention is to provide such apparatus and such a method in which the number and the configuration of the various stages are not specific either to the carrier or to the data rate of each channel that is to be extracted, but depend solely on the initial and final oversampling factors.
These various objects, and others that appear below, are achieved by the invention by means of apparatus for filtering, decimating and transposing into baseband, the apparatus being of entirely digital type, and serving both to extract and transpose into baseband one of the channels, referred to as the xe2x80x9cchannel of interestxe2x80x9d, of a frequency multiplex of channels, and also to reduce the oversampling factor of said channel of interest, each channel being associated with a distinct carrier,
the said apparatus comprising at least two stages in cascade, each stage comprising filter means and decimation means, said filter means being placed upstream from said decimation means and enabling a portion of the spectrum to be purged at locations where the decimation means produce aliasing,
the apparatus being characterized in that each stage also comprises transposition means placed upstream from said filter means and associated with a transposition frequency previously selected from a set of N possible distinct transposition frequencies so as to transpose the carrier associated with said channel of interest as close as possible to zero frequency.
The general principle of the invention thus consists in sharing frequency transposition between the various stages of the structure. Thus, the channel of interest is transposed into baseband in successive steps, and each transposition step can be wide. The transposition means of each stage can therefore be less complex than when transposition is performed on a single occasion only.
If necessary, the last stage can be followed by fine transposition means so as to perfect transposition into baseband.
The invention puts no constraints on the frequency multiplex. In other words, the carrier and the data rate of the channel of interest can be arbitrary. The transposition performed at the input to each stage ensures that the channel of interest is correctly filtered (i.e. without any information being lost).
The invention also makes it possible to use transposition means that are not very complex because of the synergy that exists between the transposition performed in a given stage and the decimation performed in the preceding stage. Because of the decimation performed in the preceding stage, the sampling frequency of a given stage is less than that of the preceding stage. Consequently, for the same granularity of transposition (i.e. for the same difference between two transposition frequencies, expressed as a function of the sampling frequency), the transposition performed at a given stage is finer than that performed at the preceding stage. In other words, decimation produces a magnifying-glass effect which avoids the need to make transposition more and more precise on going from stage to stage.
Advantageously, said decimation means are identical in all of the stages. In this way, the channel of interest can be changed without modifying the decimation means.
Advantageously, the decimation means of each stage have a decimation factor equal to two. Thus, the filtering performed at each stage does not need to be very powerful.
Preferably, said filter means perform half-band lowpass filtering. Thus, the invention can be implemented using half-band filters, which are the simplest filters to make.
Advantageously, the filter means of a given stage perform half-band lowpass filtering with a transition zone that is at least as narrow as that of the half-band lowpass filtering performed by the filter means of the stage preceding said given stage.
In this way, the filters can be simpler the closer they are to the beginning of the system, and this point is advantageous since the early stages operate at higher speeds than the later stages. In other words, this makes it possible for the filters in the earlier stages to relax specifications for oscillation in the band, and thus makes it possible to reduce the number of coefficients they use.
In a preferred embodiment of the invention, said transposition means of each stage perform complex multiplication by a transposition coefficient:
C=exe2x88x92jxc2x72xcfx80xc2x7ftxc2x7kTe
ft being said transposition frequency of said stage as previously selected from a set of N possible distinct transposition frequencies so as to transpose the carrier associated with said channel of interest as close as possible to zero frequency; and
kTe being the case sampling instant, k being an integer that increases with time, and Te=1/fe with fe being the sampling frequency of said stage.
It is recalled that the fineness of the transposition performed in a stage increases with increasing number N of possible distinct transposition frequencies (and thus with deceasing transposition granularity).
Advantageously, said transposition frequency ft of said stage is written: ft=(lxc2x7fe)/N, where l is an integer lying in the range 0 to Nxe2x88x921.
In an advantageous variant, said transposition frequency ft of said stage is written: ft=(fe/(2N))xc2x7(2l+1), where l is an integer lying in the range 0 to Nxe2x88x921.
It should be observed that in the above two cases, the granularity of the transposition performed at each stage is equal to fe/n, and the transposition coefficient C can take on N distinct values (modulo N) for N successive sampling instants.
Preferably, at least two successive stages, including the first stage, are identical, with only said transposition frequency being specific to each stage, and said at least two successive identical stages are implemented using a single hardware cell whose transposition, filter, and decimation means are shared by said at least two successive identical stages.
The term xe2x80x9cidentical stagesxe2x80x9d is used to mean stages having transposition means, filter means, and decimation means that are identical. For the transposition means, this implies that the sets of N possible transposition frequencies of the various stages are identical. Naturally, this does not mean that the selected transposition frequency is the same for all of the identical stages.
Thus, by sharing hardware resources for implementing identical stages, a significant saving in computation power is achieved (and thus in ASIC surface area). All identical stages are implemented using a single hardware cell that operates fast enough to be able to perform all of the processing in parallel. This parallel processing is made possible by the fact that each successive stage operates more slowly than the preceding stage (because of the decimation).
Preferably, the fineness of the transposition performed by the transposition means of a given stage is greater than or equal to the fineness of the transposition performed by the transposition means of the stage preceding said given stage.
In this way, transposition can be simpler closer to the start of the system, and this point is advantageous since the early stages operate faster than the later stages. In other words, transpositions that require more computation (i.e. that are finer) are performed at slower operating speeds (or sampling frequencies).
Advantageously, as a function of the initial and final oversampling factors of said channel of interest, respectively at the input to and at the output from said apparatus, said frequency multiplex of channels is applied directly to an appropriate stage situated downstream from the first stage.
In other words, depending on the initial amount of oversampling, it can be decided to avoid passing the signal through one or more of the first stages, by passing it directly into an intermediate stage.
The invention also provides a method of filtering, decimating and transposing into baseband, the method being of the entirely digital type and enabling both a particular channel referred to as the xe2x80x9cchannel of interestxe2x80x9d in a frequency multiplex of channels to be extracted and transposed into baseband, and also the oversampling factor of said channel of interest to be reduced, each channel being associated with a distinct carrier,
the method being characterized in that the operations of filtering, decimation, and transposition into baseband are performed in at least two successive processing stages where each processing stage comprises the following successive steps:
transposition enabling the carrier associated with said channel of interest to be transposed as close as possible to zero frequency;
filtering; and
decimation, said filtering step serving to purge a portion of the spectrum in locations where the decimation step produces aliasing.
Advantageously, said method comprises a preliminary stage of determining the number of successive processing stages and the transposition, filter, and decimation characteristics of each of said processing stages, the decimation factor of each stage being assumed to be known, the initial oversampling factor input to the first stage being assumed to be known, a maximum oversampling factor at the output from the last stage being imposed,
said preliminary stage comprising the following steps:
with respect to the last processing stage: the optimum transposition characteristics (in terms of fineness of transposition) and filtering characteristics (in terms of difference from ideal filtering) are determined that enable said imposed maximum oversampling factor at the output from said last processing stage to be obtained;
with respect to the penultimate processing stage:
on the basis of the decimation factor of the last processing stage and on the basis of the maximum oversampling factor imposed at the output from the last processing stage, a maximum oversampling factor required at the output from said penultimate processing stage is calculated; and
the optimum transposition characteristics and filter characteristics are determined enabling said maximum oversampling factor required at the output from said penultimate processing stage to be obtained;
the same reasoning is repeated until an earlier processing stage referred to as the xe2x80x9cfirstxe2x80x9d processing stage is obtained such that when said initial oversampling factor is applied thereto, then the oversampling factor at the output from said first processing stage is less than that previously calculated maximum required oversampling factor.
This prior stage makes it possible to optimize the filters of the various stages individually, starting with the last stage and working back towards the first.
Preferably, said preliminary stage also comprises a final step consisting in:
for the last or the last X processing stages where Xxe2x89xa71: retaining the optimum transposition and filter characteristics specific to each processing stage; and
for each of the L-X first processing stages, where L is the total number of processing stages and L-Xxe2x89xa72: replacing the optimum transposition of filter characteristics specific to each processing stage with common transposition of filter characteristics equal to those of the L-Xth processing stage.
It appears that from a certain stage (the L-Xth in the present notation) and going back to the first stage, the filtering is extremely simple to perform so there is little to be gained in terms of complexity by optimizing each filter stage individually. Under such circumstances, it is preferable to make the filter stages identical, thus making it possible to implement all of them using a single hardware cell.
The invention also provides a digital demodulator of the type comprising at least one single channel demodulation system, with each system including apparatus as specified above for filtering, decimating, and transposing into baseband.
Other characteristics and advantages of the invention appear on reading the following description of two preferred embodiments of the invention, given by way of non-limiting example and with reference to the accompanying drawings, in which:

Digital device and method for filtering, decimation and transposition into distributed baseband and corresponding digital modulator