The present invention relates to an elevator control system, comprising a plurality of car position indicators and car indicators for displaying a current floor position information of a car; a plurality of hall call buttons and car traveling operating panels; a plurality of floor controllers and car controllers (or car controller group) for controlling an information signal's input/output of a floor or a car, as well as for storing a group identifying information and an individual identifying information; an elevator controller, a hall signal transmitting repeater and a car signal transmitting repeater for relaying an information signal among the controllers; and a plurality of serial communication lines.

1. Technical Field
The present invention relates to a technology to communicate several information in an elevator according to serial transmission methods. Particularly, an elevator control system which transmits the several information for the elevator driving state serially, comprises an elevator controller for controlling an elevator car driving state, a floor controller for controlling inpu/output signals generated from a plurality of floors, and the floor controllers installed in each floor in a building, and a plurality of car controllers for controlling input/output signals generated from in the car. Accordingly, using these devices, the communication efficiency and improvements of the communication reliability among the elevator controller, the floor controllers, and the car controllers can be maximized.
2. Description of the Background Art
In general, the conventional elevator system provided with a number of communication lines which are extended from an elevator machine room to each floor for transmitting a lighting signal of a responding lamp to a hall call signal generated at each floor in a building, and for transmitting the car position indicating signal to the indicator installed in the car.
However, as buildings become higher, and users of an elevator system require more sophisticated services about an elevator control and an indicating method, it was difficult to troubleshoot and repair parts(especially, interfaces between controllers).
To eliminate these disadvantages described above, there is a continued study for reducing numbers of lines installed and for introducing the compatibility of interfaces between the various controllers.
As one of the results of the above-mentioned studies, it is proposed that an elevator controller and a plurality of car controllers be linked together by a common cable, and the signals of respective controller are transmitted using serial transmission method by a microprocessor. However, such a system has a limited communication efficiency capable of handling an elevator system which has sophisticated functions and installed in skyscrapers.
FIG. 1 is a block diagram showing a conventional elevator signal transmission device. In FIG. 1, there are an elevator controller 1 for controlling overall elevator traveling operation upon receiving signals from floor controllers 3A-3C, a hall signal transmitting repeater 2 for sending signals transmitted from the floor controllers 3A-3C to said elevator controller, and for sending the received signals which the elevator controller 1 transmits to the floor controllers 3A-3C installed in each floor in a building via a common transmission line 6, the floor controllers 3A-3C for outputting a traveling information and a responding lamp signal to car position indicators 4A-4C and to hall call button devices 5A-5C received from the hall signal transmitting repeater 2, and for transmitting a call signal input via the call button devices 5A-5C to the hall signal transmitting repeater 2, the car position indicators 4A-4C for displaying a current traveling position of the elevator by receiving a traveling information from the floor controllers 3A-3C, and the floor call button devices 5A-5C for transmitting the call signals to the floor controllers in accordance with the waiting user request, and for displaying that the call signal is registered according to the control of the floor controllers.
FIG. 2 is a block diagram showing another example of a conventional signal transmission device in an elevator system. An elevator controller 1, a hall signal transmitting repeater 2, floor controllers 3A-3C, car position indicators 4A-4C, and hall call button devices 5A-5C are the same as in FIG. 1. In FIG. 2 the elevator system further comprises a car controller 7 for transmitting an output signal of car devices to the hall signal transmitting repeater 2 via the common transmission line 6, and for receiving the traveling information in the elevator from the hall signal transmitting repeater 2, a car indicator 8 for displaying the current traveling position and direction of the elevator by receiving the traveling information from the car controller in the elevator, and a car operating panel 9 for transmitting the generated call signal according to the user request in the car to the car controllers, and for lighting a corresponding floor button by receiving the driving state signal of the responding lamp accordingly. The operation of the signal transmission devices constructed as above will be described with reference to FIG. 3.
The signal transmission among the respective controllers in FIGS. 1, 2 is accomplished by the transmission data format illustrated in FIG. 3. The elevator controller 1, first of all, assigns the floor controller 3C of a first floor, and transmits floor output signals, such as a call responding signal, voice information signal, according to the responding signal received. Thereafter, the elevator controller 1 receives a floor input signal, such as the call button input signal, parking floor designating signal, floor controller check code, and so on from the floor controller 3C.
The elevator controller 1 also assigns the floor controller 3B on a second floor according to the operation described above, transmits the floor output signal, and then receives the floor input signal from the floor controller 3B again. In such ways described above, the elevator controller 1 is capable of successively communicating with the floor controller 3A on the top floor.
Referring back to FIG. 2, in the event that the car controller 7 is linked to the hall signal transmitting repeater 2 via a common transmission line, the elevator controller 1 transmits the output signal to car controller 7 by assigning the respective car controller 7. Thereafter, the elevator controller 1 receives the input signal from the car controller 7 so that the communication among these controllers are accomplished for data exchange.
Upon the completion of sending/receiving operation either between the elevator controller 1 and the car controller 7 or between the elevator controller 1 and the floor controllers 3A-3C for data exchange, respectively, the elevator controller 1 simultaneously transmits a common information of both the car controller 7 and the floor controllers 3A-3C.
The common information might comprise an indicator display information for displaying a current floor position of the car, a direction display lamp information for indicating the up/down traveling direction, a full-car lamp displaying information for indicating that the car passes without stopping since the car is full, a pause lamp information for indicating that the elevator car does not run in a predetermined period of time, and so on.
Upon the completion of the communication from the elevator controller 1 to either the plurality of floor controllers 3A-3C or the car controller 7 for exchange of the individual information and a common information, in other words, from the hall signal transmitting repeater 2 to both the plurality of floor controllers 3A-3C and the car controller 7 in the manner as described above, the various indicator units installed at the floor controllers 3A-3C and the car controller 7, received the corresponding signal to display extra information, such as a weather forecast, a stock market information, an advertising information and so on, in the case of having visual or audible display information units.
In summary, FIG. 3 illustrates the process comprising a first period of time set at will according to the building floor number at which the hall signal transmitting repeater 2 transmits the individual information after assigning successively the respective remote controllers, in other words, the floor controllers 3A-3C and the car controller 7, a second period of transmitting the common information to the remote controllers, and a third period of transmitting various information in accordance with a visual and an audible information process devices. This process is finished as one period, accomplished by repeating above 3 transmission periods.
Since the sending/receiving operation of the individual information for the corresponding floor is performed by assigning the respective devices of each floor during the first period of time, a problem of which the transmission period becomes longer might be partially solved, a constant answering time is guaranteed for taking it granted that the transmission device is slow, and the extra information except the elevator control information can be also transmitted.
After the elevator controller assigns the respective floor controllers, it can detect the failure of the corresponding floor controllers when exchanging the individual information during the first period of time, and after the predetermined period of time has passed, it can service normally in the elevator controller when the failure of the corresponding floor controllers is repaired as in Korean Patent No. 96-12682.
It is natural that the information via the transmission line increases in case that a building becomes higher, devices installed in the elevator system are more various, and the devices which process various kinds of information use the one transmission line. In this case, although the transmission speed should be quick to transmit a lot of information during a predetermined period of time, it is desirable that the transmission speed is slow properly to improve the reliability of communication.
However, in the event that the signal is transmitted by using the conventional communication method as described above even though the building becomes higher, and the elevator runs express, a sending/receiving time of the first period of time is longer in proportion to the number of building floors, the sending/receiving period of time is always assigned to the devices in the elevator system, and actually do not generate the input signals in the process of sending/receiving the individual information on the respective system by designating successively devices of the respective system as well. Accordingly, there are shortcomings that a transmitting time is delayed when the signals are generated in each floor or an indicating time for displaying the driving state of the elevator is delayed because a designation time of the second period of time and the third period of time is assigned late, and it takes much time relatively when the plurality of floor controllers check the failure at every predetermined period of time. These shortcomings are more serious in case of an express elevator.


There is described an aerodynamic surface drive mechanism (20) containing at least a drive combination (50, 50′), each drive combination (50, 50′) comprising a fixed element (21) associated to a fixed aircraft structure and a first mobile component (22) connected pivotably by a first end to the fixed element (21) by way of an articulation axis (E) and associated to an actuator (30) by an opposite end, the aerodynamic surface drive mechanism (20) further comprises a second mobile component (23) rotationally associated to the first mobile component (22) by way of primary swivel joints (24, 24′) linearly disposed along a vertical axis (Y) and rotationally connected to the aerodynamic surface (40) by way of secondary swivel joints (25, 25′) linearly disposed along a horizontal axis (Z); the first mobile component (22) and the second mobile component (23) simultaneously moving the aerodynamic surface (40) linearly and rotatively by means of the actuator (30) and of the primary swivel joints (24, 24′) and secondary swivel joints (25, 25′).

Various types of drive mechanisms and aerodynamic surface support, especially the flaps of aircraft wings, are known in the state of the art.
In this sense, mechanisms of the "simple hinge" kind are used for driving aerodynamic surfaces such as, for instance, the flaps, when they are driven and moved in the perpendicular direction to the trailing edges of the wings (movement Chordwise).
When it is desirable to move the flaps in a direction parallel to the flight direction (Streamwise movement), other mechanisms are known and used such as, for instance, the "roller track", "combined hinges", "four-bar" mechanism, among others.
However, these already known aerodynamic surface drive mechanisms present flaws, such as the lack of robustness, localized wear and tear and high number of parts in the case of the "roller track" mechanism, impossibility of driving in a Streamwise movement when the "simple hinge" mechanism is used.
The movement of the flaps in a direction parallel to the flight direction (Streamwise movement) is often preferred because it diminishes drag compared to the movement of the flaps in a direction perpendicular to the trailing edges of the wings (Chordwise movement). However, the sweeping of the aircraft wings, required by the high speed of the modern jets, requires an aerodynamic surface drive mechanism such as flaps that enable the "Fowler" movement when the flap is driven. The "Fowler" movement is characterized by an initial horizontal movement, followed by a rotation.
Thus, further in relation to drive mechanisms already known in the state of the art, document U.S. Pat. No. 4,448,375 refers to a device for trailing flaps formed by a four-bar mechanism with the use of "swing-link" and rotary actuators to perform the "Fowler" movement when the flap is driven. The drawback of using "swing-link" in this movement lies in the increase of loads in the mechanism combination and flap panel when it is slanted on the plane transversal to the aircraft. Additionally, the "swing-link" provides a greater degree of freedom, whereby introducing more leeway in the flap mechanism, adversely affecting the robustness of the combination.
The "Layout" document published in Mechanical Design of High Lift Systems for High Aspect Ratio Swept Wings (Rudolph, P.—NASA 1998) illustrated in FIG. 1 shows a flap drive mechanism that uses, as indicated in the drawing, the principle of the "simple hinge", with a rotary actuator and "swing-link". Although this mechanism enables the flaps to be driven streamwise, this movement is made by way of the rotary actuator 1 fixed to the structure of the aircraft, in this case a wing, a spherical joint 2 disposed on the flap and a rod 3 acting as "swing-link" which is a rod privotable at its ends, between the mechanism and the flap, used to transfer loads exclusively in the direction parallel to the axis formed by these ends.
One objective of the present invention is to provide a robust mechanism, that is, without problematic elements such as rails or "swing-link" for driving aerodynamic surfaces moving them in a direction parallel to the flight direction (Streamwise movement).


A zoom lens comprises, in order from the object end to the image end, a positive power first lens group, a negative power second lens group, a negative power third lens group, a positive power fourth lens group and a positive power fifth lens group. The second lens group is axially movable to vary the focal length of the zoom lens, and the fifth lens group is axially movable to correct a change in position of an image formed by the zoom lens caused during zooming and a change in position of an image formed by the zoom lens due to a change in object distance. The zoom lens satisfies at least the following condition: EQU 0.8<F.sub.4 /(F*Z1.sup./2)<4.0. where F is the focal length of the overall zoom lens at the wide angle end position, F.sub.4 is the focal length of the fourth lens group of the zoom lens and Z is the zoom ratio of the zoom lens.

1. Field of the Invention
This invention relates to an imageforming optical lens for cameras having an image pickup device such as a charge coupled device (CCD) and an image pickup tube or cameras using a photographic film, and, more particularly, to a inner-focusing type of zoom lens system for a video camera and a television camera.
2. Description of Related Art
Typically, a popular inner-focusing type of zoom lens comprises four lens groups, namely, in order from the object end to the image end, a positive power first lens group, a negative power second lens group axially movable to vary the focal length of the zoom lens, a positive power third lens group, and a positive power fourth lens group axially movable to focus the zoom lens and correct a change in position of an image due to zooming. While such a inner-focusing type zoom lens is compact, which is essential for quick focusing, it causes a significant change of aberration during focusing
Because the inner-focusing type zoom lens is designed with intention to be installed to single imaging plate type of video camera which generally has a short back focal distance for nonprofessional use, various constraints are imposed on structure and size in the case the inner-focusing type zoom lens is installed to a multi-imaging plate type of video camera, which are always undesirable.


The present invention is directed to a process for the production of polymethylene polyphenyl polyisocyanates by phosgenating the corresponding polyamines in solution in an inert organic solvent, removing excess phosgene, and stripping the solvent. The improvement resides in adding at least 0.02 parts by weight of reducing agent per 150 parts by weight of polyamine to the polyamines at any time prior to the stripping step.

Processes for the production of polymethylene polyphenyl polyamines and phosgenation of such polyamines to produce the corresponding polyisocyanates are well known in the art (see, e.g., U.S. Pat. Nos. 3,253,031, 3,260,751, 3,277,139, 3,277,173, 3,362,979, 3,496,229, 3,517,062, 3,641,094, 3,912,600 and 4,259,526).
In general, the process of producing the polyisocyanates includes the steps of phosgenating the polyamines in solution in an organic solvent, removing excess phosgene and then stripping the inert solvent. Some effort has been expended in reducing the color of the resultant polyisocyanates. U.S. Pat. No. 4,465,639 describes the addition of water prior to the solvent stripping step to reduce the color. U.S. Pat. No. 4,792,624 describes a specific polyamine recycling step during the aniline/formaldehyde reaction to cause a reduction in color of the corresponding polyisocyanate.
Czechoslovakian Patent 154,431 describes a method isolating isomers of diaminodiphenylmethane using a water extraction process. The reference describes the use of deoxidized water in the extraction and suggests that reducing agents should be added to the water in order to minimize staining of the isolated diamine.

Color reduction of polymethylene polyphenyl polyisocyanates


The present invention refers to a printed three-dimensional optical component built up from layers of printing ink characterized in that the three-dimensional optical component comprises at least one foil between two consecutive layers. The present invention further relates to a corresponding manufacturing method.

The present invention relates to a printed three-dimensional optical component built up from layers of printing ink and a method for manufacturing such like optical component.
Printed optical components are known from the prior art, see for example WO 2010/091888 A1 and WO 2014/108364 A1. Producing three-dimensional optical components, in particular spectacle lenses, through an additive manufacturing scheme such as three-dimensional inkjet printing has several advantages. Currently, spectacle lenses are produced in a multi-step process from pre-manufactured lens blanks which are retrieved according to prescription and post-processed to yield the customized spectacle lenses that are fit into the spectacle frame by the optician. From lens blank to final spectacle lens, many handling steps and more than ten machine processing steps are necessary. Around 80% of the materials used are wasted in the cutting process, Even if some of this material can be re-used, providing spectacle lenses through the conventional subtractive manufacturing process is far from being sustainable. Three-dimensional inkjet printing allows manufacturing of spectacle lenses in a fast, one-step and sustainable way.
Correcting vision is, however, not the only requirement put on modern spectacle lenses. There is a desire for enhanced functionality of optical components, ranging from simple sun-blocking, polarization or colourization functions to augmented reality applications. Desirably, functionality of the optical components is responsive to ambient light conditions, user or sensor input as is the case in photochromic lenses, for example.
Implementing such functionality for printed optical components has been difficult to achieve so far, Colourization, for example, is achieved through a colour filter. In the case of printed optical components, the colour filter is provided by a layer of coloured printing ink. This, however, requires the use of low-viscosity printing inks, resulting in compromised colour density and evenness, leading to functional optical components of reduced quality.

Printed three-dimensional optical component with embedded functional foil and corresponding manufacturing method


A reception circuit that receives data by serial communication in a plurality of lanes and includes a plurality of error checking units each of which checks presence of an error in the received data, a plurality of memories each of which stores the received data, and a processing unit that reads the received data from the plurality of memories, and outputs a read data. The lanes include a redundant lane that transmits redundant data, the received data is stored in a first area of a plurality of areas included in each of the memories, and other received data received next to the received data is stored in a second area. When there is an error in any one of the pieces of received data stored in the respective first areas, the processing unit generates correct data using the redundant data stored in the first area, and outputs it.

When serial communication is performed between ports in a plurality of lanes, a transmission circuit of a connection source port divides transmission data into the number of lanes, and transmission of the divided pieces of data is performed in the lanes, respectively. A reception circuit of a connection destination port restores the pieces of data that are received in the lanes.
FIG. 1 is a configuration diagram of a conventional reception circuit.
FIG. 1 is the configuration diagram of the reception circuit that uses two lanes (a lane 0 and a lane 1).
A reception circuit 10 includes SERializer/DESerializer (SerDes) 11-i (i=0 to 1), cyclic redundancy check (CRC) checking units 12-i, dual port random access memories (RAM) 13-i, write pointers 14-i, and a read pointer 15.
The SerDes 11-i, the CRC checking units 12-i, the dual port RAM 13-i, and the write pointers 14-i process data of the lanes i.
The SerDes 11 is a circuit that performs interconverts between serial data and parallel data. In the reception circuit 10, the SerDes 11 converts the received serial data into parallel data.
The CRC checking unit 12 performs error checking of data using CRC.
The dual port RAM 13 is a storage device that stores data. The dual port RAM 13 writes data to a position that is indicated by a write pointer value, and reads data from a position that is indicated by a read pointer value.
The write pointer 14 transmits a write pointer value that indicates a writing position of data to the dual port RAM 13.
The read pointer 15 transmits a read pointer value that indicates a reading position of data to the dual port RAM 13. The read pointer 15 transmits a read pointer value to the dual port RAM 13 so that skews of the lanes are matched. Therefore, pieces of data in which skews are matched between the lanes are output from the dual port RAM 13.
In a conventional reception circuit, when any error is detected in the CRC checking unit for data that is received in the SerDes, the data becomes invalid, and write pointer value are different between the lane because a write pointer value stops in the middle.
Thus, conventionally, clear of a dual port RAM, a write pointer, and a read pointer is performed by reset, and transfer is performed again.
Conventionally, reset is performed at the time of occurrence of errors, and in a time period of the reset, reduction of performance is caused because regular transfer is not performed.    [Patent Document 1] Japanese Laid-Open Patent Publication No. 2002-223203    [Patent Document 2] Japanese Laid-Open Patent Publication No. 2002-7312

Reception circuit, information processing apparatus, and control method


A mark for position detection formed on a substrate has a first pattern disposed near the center of the mark and having periodicity in a Y-axis direction, and second patterns respectively disposed near both sides of the first pattern in an X-axis direction and each having periodicity in the X-axis direction. The position of the first pattern is detected by aligning the detection center of a detecting optical system, that is, the minimal aberration point of the detecting optical system, with the center of the first pattern. The positions of the second patterns are detected at respective points symmetric with respect to the minimal aberration point, and the detected values for the positions of the second patterns are averaged. An apparatus for detecting the mark for position detection detects the first and second patterns by image processing when the mark is in a stationary state.

The present invention relates to a mark for position detection and a mark detecting method and apparatus, and also relates to an exposure system. More particularly, the present invention relates to a mark for position detection formed on a plane surface of a substrate and a method and apparatus for detecting the mark, and also relates to an exposure system having the mark detecting apparatus as a device for detecting the position of the substrate. The mark for position detection according to the present invention is suitable for use in an exposure system to align a mask pattern and a photosensitive substrate in a photolithography process in which the substrate is exposed in accordance with the mask pattern to produce, for example, a semiconductor device.
In photolithography processes for producing micro devices, e.g. semiconductor devices, liquid-crystal display devices, image pickup devices (CCDs), or thin-film magnetic heads, a projection exposure system is used in which an image of a photomask or a reticle (hereinafter generally referred to as "reticle"), which has a transfer pattern formed thereon, is projected onto a substrate coated with a photosensitive material (photoresist), e.g. a wafer or a glass plate (hereinafter referred to as "wafer"), through a projection optical system.
In this type of projection exposure system, alignment of the reticle and the wafer must be carried out with high accuracy before exposure. To perform the alignment, the wafer has marks for position detection (alignment marks) formed (transferred by exposure) in a preceding photolithography process. By detecting the position of such an alignment mark, the position of the wafer (or a circuit pattern on the wafer) can be accurately detected.
The alignment marks on the wafer are entirely unnecessary for the operating characteristics of the completed micro device. Therefore, it is desirable that the size of the marks be as small as possible. Alignment marks are generally set in the boundary regions between micro devices, which are known as "street lines", i.e. "margins" for cutting the micro devices from each other after the completion of various processes. The street lines are belt-shaped regions each having a width of the order of from 70 to 90 micrometers. Therefore, the length of each shorter side of alignment marks is desirably not greater than 70 micrometers.
Some methods of detecting the position of a mark on a wafer have already been put to practical use. The mainstream of recent mark position detecting methods is an image detection method in which an optical mark image is detected, and the mark position is detected on the basis of the image intensity distribution.
Because the above-described alignment requires an extremely high degree of accuracy, the mainstream of conventional mark position detecting methods is such that marks (X mark and Y mark) are used exclusively for two orthogonal directions (X direction and Y direction), and the positions of these marks are successively measured. In general, line-and-space patterns having periodicity in the measuring directions have heretofore been used as the X and Y marks (marks for one-dimensional measurement).
FIGS. 8A and 8B show examples of the conventional marks for one-dimensional measurement. FIG. 8A shows a mark MX used for detection in the X direction. FIG. 8B shows a mark MY for detection in the Y direction. These marks MX and MY are used in a pair (there has been no specific restriction on the positional relationship between the two marks). In the conventional practice, position detection is first carried out with respect to one direction (X direction or Y direction) using one mark, and then position detection is carried out with respect to the other direction (Y direction or X direction) using the other mark.
As has been stated above, the length of each shorter side of these marks is demanded to be not greater than the street line width (in general, from 70 micrometers to 90 micrometers). Therefore, the widths of these marks in the non-detecting direction (Y direction for MX; X direction for MY) have generally been restricted to a length not greater than about 70 micrometers from the above restriction.
A mark detecting optical system for detecting the position of a mark as described above needs to be corrected for aberrations to an extremely high degree. The aberration correction includes not only the correction of aberrations due to errors in designing the optical system but also the correction of aberrations due to errors in machining, i.e. decentration of the lens and an error in the surface accuracy. In particular, errors in machining are difficult to eliminate completely. Therefore, after the assembly of the optical system, adjustment is made to minimize the residual aberrations at a specific "mark detecting position" (one point in the detecting area near the optical axis of the detecting optical system), thereby reducing the influence of the residual aberrations during the detection. Accordingly, if the position for detecting a mark deviates from the above-described minimal aberration point, a detection error due to the residual aberrations arises, and the mark detection accuracy degrades.
In the above-described conventional technique, the mark detection for position detection is carried out with respect to the X and Y directions separately from each other. Therefore, it takes a long time to detect the marks, and this causes the processing capacity (throughput) of the projection exposure system to be reduced unfavorably.
In view of the above-described circumstances, a conventional technique uses two-dimensional marks that enable simultaneous detection with respect to both the X and Y two-dimensional directions.
FIG. 9 shows one example of two-dimensional marks for detection in both the X and Y directions. A mark MG shown in FIG. 9 per se has periodicity in two-dimensional directions. However, as will be clear from FIG. 9, the size of the mark edge (boundary between black and white), which is effective for the position detection in each of the X and Y directions, relative to the mark area undesirably reduces to approximately a half of that of one-dimensional marks (MX and MY) because of the periodicity in the two-dimensional directions. Therefore, the mark area must be increased in order to obtain a detection accuracy equal to that in the case of the one-dimensional marks (MX and MY). However, if the mark area is increased, the length of one side (or shorter side) of the mark becomes greater than the street line width (e.g. 100 micrometers or more in the case of FIG. 9), and hence a part of the mark undesirably extends over the circuit pattern on the wafer. Accordingly, the restriction on the mark formation position increases unfavorably.
If a two-dimensional mark Mt as shown in FIG. 10 is used in which an X-direction one-dimensional detection mark portion Ma and a Y-direction one-dimensional detection mark portion Mb are disposed in a side-by-side relation to each other, the length of each shorter side of the mark can be made not greater than the street line width.
However, the mark Mt shown in FIG. 10 suffers from problems in terms of the detection accuracy. That is, the mark detecting optical system has been adjusted such that the residual aberrations are minimized at a specific "mark detecting position" (one point in the detecting area near the optical axis of the detecting optical system), as stated above. Therefore, if a detection mark portion for one direction, e.g. the Y-direction detection mark portion Mb (or the X-direction detection mark portion Ma), is disposed near the optical axis, the other mark portion Ma (or the mark portion Mb) for the other direction lies apart from the optical axis. Consequently, the detected value for the position of the latter mark portion Ma (or Mb) is adversely affected by the residual aberrations of the optical system when the position of the mark Mt is detected with respect to both the X and Y directions simultaneously. Consequently, detection errors increase unfavorably. (This problem will be described later in more detail to compare the present invention with the conventional technique in the description of the embodiments).

Mark for position detection, and mark detecting method and apparatus


An integrated search processor used in a modem for a spread spectrum communications system buffers receive samples and utilizes a time sliced transform processor operating on successive offsets from the buffer. The search processor autonomously steps through a search as configured by a microprocessor specified search parameter set, which can include the group of antennas to search over, the starting offset and width of the search window to search over, and the number of Walsh symbols to accumulate results at each offset. The search processor calculates the correlation energy at each offset, and presents a summary report of the best paths found in the search to use for demodulation element reassignment. The search is done in a linear fashion independent of the probability that a signal being searched for was transmitted at any given time.

I. Field of the Invention
II. Description of the Related Art
In a wireless telephone communication system such as cellular telephone systems, personal communications systems, and wireless local loop system, many users communicate over a wireless channel to connect to wireline telephone systems. Communication over the wireless channel can be one of a variety of multiple access techniques which facilitate a large number of users in a limited frequency spectrum. These multiple access techniques include time division multiple access (TDMA), frequency division multiple access (FDMA), and code division multiple access (CDMA). The CDMA technique has many advantages and an exemplary CDMA system is described in U.S. Pat. No. 4,901,307 issued Feb. 13, 1990 to K. Gilhousen et al., entitled "SPREAD SPECTRUM MULTIPLE ACCESS COMMUNICATION SYSTEM USING SATELLITE OR TERRESTRIAL REPEATERS," assigned to the assignee of the present invention and incorporated herein by reference.
In the just mentioned patent, a multiple access technique is disclosed where a large number of mobile telephone system users, each having a transceiver, communicate through satellite repeaters or terrestrial base stations using CDMA spread spectrum communication signals. In using CDMA communications, the frequency spectrum can be reused multiple times thus permitting an increase in system user capacity.
The CDMA modulation techniques disclosed in U.S. Pat. No. 4,901,307 offer many advantages over narrow band modulation techniques used in communication systems using satellite or terrestrial channels. The terrestrial channel poses special problems to any communication system particularly with respect to multipath signals. The use of CDMA techniques permits the special problems of the terrestrial channel to be overcome by mitigating the adverse effect of multipath, e.g. fading, while also exploiting the advantages thereof.
The CDMA techniques as disclosed in U.S. Pat. No. 4,901,307 contemplate the use of coherent modulation and demodulation for both directions of the link in remote unit-satellite communications. Accordingly, disclosed therein is the use of a pilot carrier signal as a coherent phase reference for the satellite-to-remote unit link and the base station-to-remote unit link. In the terrestrial cellular environment, however, the severity of multipath fading with the resulting phase disruption of the channel, as well as the power required to transmit a pilot carrier signal from the remote unit, precludes usage of coherent demodulation techniques for the remote unit-to-base station link. U.S. Pat. No. 5,103,459 entitled "SYSTEM AND METHOD FOR GENERATING SIGNAL WAVEFORMS IN A CDMA CELLULAR TELEPHONE SYSTEM", issued Jun. 25, 1990, assigned to the assignee of the present invention, the disclosure of which is incorporated by this reference, provides a means for overcoming the adverse effects of multipath in the remote unit-to-base station link by using noncoherent modulation and demodulation techniques.
In a CDMA cellular telephone system, the same frequency band can be used for communication in all base stations. At the base station receiver, separable multipath, such as a line of site path and another path reflecting off of a building, can be diversity combined for enhanced modem performance. The CDMA waveform properties that provide processing gain are also used to discriminate between signals that occupy the same frequency band. Furthermore, the high speed pseudonoise (PN) modulation allows many different propagation paths of the same signal to be separated, provided the difference in path delays exceeds the PN chip duration. If a PN chip rate of approximately 1 MHz is employed in a CDMA system, the full spread spectrum processing gain, equal to the ratio of the spread bandwidth to the system data rate, can be employed against paths having delays that differ by more than one microsecond. A one microsecond path delay differential corresponds to differential path distance of approximately 300 meters. The urban environment typically provides differential path delays in excess of one microsecond.
The multipath properties of the terrestrial channel produce at the receiver signals having traveled several distinct propagation paths. One characteristic of a multipath channel is the time spread introduced in a signal that is transmitted through the channel. For example, if an ideal impulse is transmitted over a multipath channel, the received signal appears as a stream of pulses. Another characteristic of the multipath channel is that each path through the channel may cause a different attenuation factor. For example, if an ideal impulse is transmitted over a multipath channel, each pulse of the received stream of pulses generally has a different signal strength than other received pulses. Yet another characteristic of the multipath channel is that each path through the channel may cause a different phase on the signal. For example, if an ideal impulse is transmitted over a multipath channel, each pulse of the received stream of pulses generally has a different phase than other received pulses.
In the radio channel, the multipath is created by reflection of the signal from obstacles in the environment, such as buildings, trees, cars, and people. In general the radio channel is a time varying multipath channel due to the relative motion of the structures that create the multipath. For example, if an ideal impulse is transmitted over the time varying multipath channel, the received stream of pulses would change in time location, attenuation, and phase as a function of the time that the ideal impulse was transmitted.
The multipath characteristic of a channel can result in signal fading. Fading is the result of the phasing characteristics of the multipath channel. A fade occurs when multipath vectors are added destructively, yielding a received signal that is smaller than either individual vector. For example, if a sine wave is transmitted through a multipath channel having two paths where the first path has an attenuation factor of X dB, a time delay of .delta. with a phase shift of .THETA. radians, and the second path has an attenuation factor of X dB, a time delay of .delta. with a phase shift of .THETA.+.pi. radians, no signal would be received at the output of the channel.
In narrow band modulation systems such as the analog FM modulation employed by conventional radio telephone systems, the existence of multiple paths in the radio channel results in severe multipath fading. As noted above with a wideband CDMA, however, the different paths may be discriminated in the demodulation process. This discrimination not only greatly reduces the severity of multipath fading but provides an advantage to the CDMA system.
Diversity is one approach for mitigating the deleterious effects of fading. It is therefore desirable that some form of diversity be provided which permits a system to reduce fading. Three major types of diversity exist: time diversity, frequency diversity, and space/path diversity.
Time diversity can best be obtained by the use of repetition, time interleaving, and error correction and detection coding which introduce redundancy. A system comprising the present invention may employ each of these techniques as a form of time diversity.
CDMA by its inherent wideband nature offers a form of frequency diversity by spreading the signal energy over a wide bandwidth. Therefore, frequency selective fading affects only a small part of the CDMA signal bandwidth.
Space and path diversity are obtained by providing multiple signal paths through simultaneous links from a remote unit through two or more base stations and by employing two or more spaced apart antenna elements at a single base station. Furthermore, path diversity may be obtained by exploiting the multipath environment through spread spectrum processing by allowing a signal arriving with different propagation delays to be received and processed separately as discussed above. Examples of path diversity are illustrated in U.S. Pat. No. 5,101,501 entitled "SOFT HANDOFF IN A CDMA CELLULAR TELEPHONE SYSTEM", issued Mar. 21, 1992 and U.S. Pat. No. 5,109,390 entitled "DIVERSITY RECEIVER IN A CDMA CELLULAR TELEPHONE SYSTEM", issued Apr. 28, 1992, both assigned to the assignee of the present invention.
The deleterious effects of fading can be further controlled to a certain extent in a CDMA system by controlling transmitter power. A system for base station and remote unit power control is disclosed in U.S. Pat. No. 5,056,109 entitled "METHOD AND APPARATUS FOR CONTROLLING TRANSMISSION POWER IN A CDMA CELLULAR MOBILE TELEPHONE SYSTEM", issued Oct. 8, 1991, also assigned to the assignee of the present invention.
The CDMA techniques as disclosed in U.S. Pat. No. 4,901,307 contemplate the use of relatively long PN sequences with each remote unit user being assigned a different PN sequence. The cross-correlation between different PN sequences and the autocorrelation of a PN sequence, for all time shifts other than zero, both have a nearly zero average value which allows the different user signals to be discriminated upon reception. (Autocorrelation and cross-correlation requires logical "0" take on a value of "1" and logical "1" take on a value of "-1" or a similar mapping in order that a zero average value be obtained.)
However, such PN signals are not orthogonal. Although the cross-correlation essentially averages to zero over the entire sequence length, for a short time interval, such as an information bit time, the cross-correlation is a random variable with a binomial distribution. As such, the signals interfere with each other in much the same way as they would if they were wide bandwidth Gaussian noise at the same power spectral density. Thus the other user signals, or mutual interference noise, ultimately limits the achievable capacity.
It is well known in the art that a set of n orthogonal binary sequences, each of length n, for n any power of 2 can be constructed, see Digital Communications with Space Applications, S. W. Golomb et al., Prentice-Hall, Inc., 1964, pp. 45-64. In fact, orthogonal binary sequence sets are also known for most lengths which are multiples of four and less than two hundred. One class of such sequences that is easy to generate is called the Walsh function, also known as Hadamard matrices.
A Walsh function of order n can be defined recursively as follows: ##EQU1## where W' denotes the logical complement of W, and W(1)=.vertline.0.vertline..
Thus, ##EQU2##
A Walsh symbol, sequence, or code is one of the rows of a Walsh function matrix. A Walsh function matrix of order n contains n sequences, each of length n Walsh chips. Each Walsh code has a corresponding Walsh index where the Walsh index refers to the number (1 through n) corresponding to the row in which a Walsh code is found. For example, for n=8 Walsh function matrix given above, the all zeroes row corresponds to
Walsh index 1 and the Walsh code 0, 0, 0, 0, 1, 1, 1, 1 corresponds to Walsh index 5.
A Walsh function matrix of order n (as well as other orthogonal functions of length n) has the property that over the interval of n bits, the cross-correlation between all the different sequences within the set is zero. This can be seen by noting that every sequence differs from every other sequence in exactly half of its bits. It should also be noted that there is always one sequence containing all zeroes and that all the other sequences contain half ones and half zeroes. The Walsh symbol which consists all logical zeros instead of half one's and zero's is called the Walsh zero symbol.
On the reverse link channel from the remote unit to the base station, no pilot signal exists to provide a phase reference. Therefore a method is needed to provide a high-quality link on a fading channel having a low Eb/No (energy per bit/noise power density). Walsh function modulation on the reverse link is a simple method of obtaining 64-ary modulation with coherence over the set of six code symbols mapped into the 64 Walsh codes. The characteristics of the terrestrial channel are such that the rate of change of phase is relatively slow. Therefore, by selecting a Walsh code duration which is short compared to the rate of change of phase on the channel, coherent demodulation over the length of one Walsh code is possible.
On the reverse link channel, the Walsh code is determined by the information being transmitted from the remote unit. For example, a three bit information symbol could be mapped into the eight sequences of W(8) given above. An "unmapping" of the Walsh encoded symbols into an estimate of the original information symbols may be accomplished in the receiver by a Fast Hadamard Transform (FHT). A preferred "unmapping" or selection process produces soft decision data which can be provided to a decoder for maximum likelihood decoding.
An FHT is used to perform the "unmapping" process. An FHT correlates the received sequence with each of the possible Walsh sequences. Selection circuitry is employed to select the most likely correlation value, which is scaled and provided as soft decision data.
A spread spectrum receiver of the diversity or "rake" receiver design comprises multiple data receivers to mitigate the effects of fading. Typically each data receiver is assigned to demodulate a signal which has traveled a different path, either through the use of multiple antennas or due to the multipath properties of the channel. In the demodulation of signals modulated according to an orthogonal signaling scheme, each data receiver correlates the received signal with each of the possible mapping values using an FHT. The FHT outputs of each data receiver are combined and selection circuitry then selects the most likely correlation value based on the largest combined FHT output to produce a demodulated soft decision symbol.
In the system described in the U.S. Pat. No. 5,103,459, the call signal begins as a 9600 bit per second information source which is then converted by a rate 1/3 forward error correction encoder to a 28,800 symbols per second output stream. These symbols are grouped 6 at a time to form 4800 Walsh symbols per second, each Walsh symbol selecting one of sixty-four orthogonal Walsh functions that are sixty-four Walsh chips in duration. The Walsh chips are modulated with a user-specific PN sequence generator. The user-specific PN modulated data is then split into two signals, one of which is modulated with an in-phase (I) channel PN sequence and one of which is modulated with a quadrature-phase (Q) channel PN sequence. Both the I channel modulation and the Q channel modulation provide four PN chips per Walsh chip with a 1.2288 MHz PN spreading rate. The I and the Q modulated data are Offset Quadrature Phase Shift Keying (OQPSK) combined for transmission.
In the CDMA cellular system described in the above-referenced U.S. Pat. No. 4,901,307, each base station provides coverage to a limited geographic area and links the remote units in its coverage area through a cellular system switch to the public switched telephone network (PSTN). When a remote unit moves to the coverage area of a new base station, the routing of that user's call is transferred to the new base station. The base station-to-remote unit signal transmission path is referred to as the forward link and the remote unit-to-base station signal transmission path is referred to as the reverse link.
As described above, the PN chip interval defines the minimum separation two paths must have in order to be combined. Before the distinct paths can be demodulated, the relative arrival times (or offsets) of the paths in the received signal must first be determined. The channel element modem performs this function by "searching" through a sequence of potential path offsets and measuring the energy received at each potential path offset. If the energy associated with a potential offset exceeds a certain threshold, a signal demodulation element may be assigned to that offset. The signal present at that path offset can then be summed with the contributions of other demodulation elements at their respective offsets. A method and apparatus of demodulation element assignment based on searcher demodulation element energy levels is disclosed in co-pending U.S. patent application Ser. No. 08/144,902 entitled "DEMODULATION ELEMENT ASSIGNMENT IN A SYSTEM CAPABLE OF RECEIVING MULTIPLE SIGNALS," filed Oct. 28, 1993, assigned to the assignee of the present invention. Such a diversity or rake receiver provides for a robust digital link, because all paths have to fade together before the combined signal is degraded.
FIG. 1 shows an exemplary set of signals from a single remote unit arriving at the base station. The vertical axis represents the power received on a decibel (dB) scale. The horizontal axis represents the delay in the arrival time of a signal due to multipath delays. The axis (not shown) going into the page represents a segment of time. Each signal spike in the common plane of the page has arrived at a common time but was transmitted by the remote unit at a different time. In a common plane, peaks to the right were transmitted at an earlier time by the remote unit than peaks to the left. For example, the left-most peak spike 2 corresponds to the most recently transmitted signal. Each signal spike 2-7 has traveled a different path and therefore exhibits a different time delay and a different amplitude response. The six different signal spikes represented by spikes 2-7 are representative of a severe multipath environment. Typical urban environments produce fewer usable paths. The noise floor of the system is represented by the peaks and dips having lower energy levels. The task of a searcher element is to identify the delay as measured by the horizontal axis of signal spikes 2-7 for potential demodulation element assignment. The task of the demodulation element is to demodulate a set of the multipath peaks for combination into a single output. It is also the task of the demodulation elements once assigned to a multipath peak to track that peak as it may move in time.
The horizontal axis can also be thought of as having units of PN offset. At any given time, the base station receives a variety of signals from a single remote unit, each of which has traveled a different path and may have a different delay than the others. The remote unit's signal is modulated by a PN sequence. A copy of the PN sequence is also generated at the base station. At the base station, each multipath signal is individually demodulated with a PN sequence code aligned to its timing. The horizontal axis coordinates can be thought of as corresponding to the PN sequence code offset which would be used to demodulate a signal at that coordinate.
Note that each of the multipath peaks varies in amplitude as a function of time as shown by the uneven ridge of each multipath peak. In the limited time shown, there are no major changes in the multipath peaks. Over a more extended time range, multipath peaks disappear and new paths are created as time progresses. The peaks can also slide to earlier or later offsets as the path distances change as the remote unit moves around in the coverage area of the base station. Each demodulation element tracks small variations in the signal assigned to it. The task of the searching process is to generate a log of the current multipath environment as received by the base station.
In a typical wireless telephone communication system, the remote unit transmitter may employ a vocoding system which encodes voice information in a variable rate format. For example, the data rate may be lowered due to pauses in the voice activity. The lower data rate reduces the level of interference to other users caused by the remote unit transmissions. At the receiver, or otherwise associated with the receiver, a vocoding system is employed for reconstructing the voice information. In addition to voice information, non-voice information alone or a mixture of the two may be transmitted by the remote unit.
A vocoder which is suited for application in this environment is described in copending U.S. patent application Ser. No. 08/363,170, entitled "VARIABLE RATE VOCODER," filed Dec. 23, 1994 and assigned to the assignee of the present invention. This vocoder produces from digital samples of the voice information encoded data at four different rates, e.g. approximately 8,000 bits per second (bps), 4,000 bps, 2,000 bps and 1,000 bps, based on voice activity during a 20 millisecond (ms) frame. Each frame of vocoder data is formatted with overhead bits as 9,600 bps, 4,800 bps, 2,400 bps, and 1,200 bps data frames. The highest rate data frame which corresponds to a 9,600 bps frame is referred to as a "full rate" frame; a 4,800 bps data frame is referred to as a "half rate" frame; a 2,400 bps data frame is referred to as a "quarter rate" frame; and a 1,200 bps data frame is referred to as an "eighth rate" frame. In neither the encoding process nor the frame formatting process is rate information included in the data. When the remote unit transmits data at less than full rate, the duty cycle of the remote units transmitted signal is the same as the data rate. For example, at quarter rate a signal is transmitted from the remote unit only one quarter of the time. During the other three quarters time, no signal is transmitted from the remote unit.
The remote unit includes a data burst randomizer. The data burst randomizer determines during which time periods the remote unit transmits and during which time periods it does not transmit given the data rate of the signal to be transmitted, a remote unit specific identifying number, and the time of day. When operating at less than full rate, the data burst randomizer within the remote unit pseudorandomly distributes the active time periods within the transmission burst. A corresponding data burst randomizer is also included in the base station such that the base station can recreate the pseudorandom distribution based on the time of day and the remote unit specific identifying number but the base station is unaware, a priori, of the data rate of the transmitted signal.
The eighth rate time periods determine a so called worthy group of time periods. A remote unit operating at quarter rate transmits during the worthy group time periods and another set of pseudorandomly distributed periods. A remote unit operating in half rate transmits during the quarter rate time periods and another set of pseudorandomly distributed periods. A remote unit operating in full rate transmits continually. In this way, regardless of the data rate of the transmitted signal, each time period corresponding to the worthy group is sure to correspond to a time when the corresponding remote unit is transmitting a signal. Further details on the data burst randomizer are described in copending U.S. patent application Ser. No. 08/291,647, entitled "DATA BURST RANDOMIZER," filed Aug. 16, 1994, and assigned to the assignee of the present invention.
To conserve system resources for actual data of voice transmissions, the remote unit does not transmit the rate for each frame. Therefore, the receiver must determine the rate at which the data was encoded and transmitted based on the received signal so that the receiver associated vocoder can properly reconstruct the voice information. A method of determining the rate at which burst data was encoded without receiving rate information from the transmitter is disclosed in co-pending U.S. patent Ser. No. 08/233,570, entitled "METHOD AND APPARATUS FOR DETERMINING DATA RATE OF TRANSMITTED VARIABLE RATE DATE IN A COMMUNICATIONS RECEIVER" filed Apr. 26, 1994, and assigned to the assignee of the present invention. The method of determining data rate disclosed in the above mentioned patent application is performed after the signal has been received and demodulated therefore the rate information is not available during the searching process.
At the base station, each individual remote unit signal must be identified from the ensemble of call signals received. A system and method for demodulating a remote unit signal received at a base station is described, for example, in U.S. Pat. No. 5,103,459. FIG. 2 is a block diagram of the base station equipment described in U.S. Pat. No. 5,103,459 for demodulating a reverse link remote unit signal.
A typical prior art base station comprises multiple independent searcher and demodulation elements. The searcher and demodulation elements are controlled by a microprocessor. In this exemplary embodiment, to maintain a high system capacity, each remote unit in the system does not transmit a pilot signal. The lack of a pilot signal on the reverse link increases the time needed to conduct a survey of all possible time offsets at which a remote unit signal may be received. Typically, a pilot signal is transmitted at a higher power than the traffic bearing signals thus increasing the signal to noise ratio of the received pilot signal as compared to the received traffic channel signals. In contrast, ideally each remote unit transmits a reverse link signal which arrives with a power level equal to the power level received from every other remote unit therefore having a low signal to noise ratio. Also, a pilot channel transmits a known sequence of data. Without the pilot signal, the searching process must examine all possibilities of what data may have been transmitted.
FIG. 2 shows an exemplary embodiment of a prior art base station. The base station of FIG. 2 has one or more antennas 12 receiving CDMA reverse link remote unit signals 14. Typically, an urban base station's coverage area is split into three sub-regions called sectors. With two antennas per sector, a typical base station has a total of six receive antennas. The received signals are down-converted to baseband by analog receiver 16 that quantizes the received signal I and Q channels and sends these digital values over signal lines 18 to channel element modem 20. A typical base station comprises multiple channel element modems like channel element modem 20 (not shown in FIG. 2). Each channel element modem 20 supports a single user. In the preferred embodiment, channel element modem 20 comprises four demodulation elements 22 and eight searchers 26. Microprocessor 34 controls the operation of demodulation elements 22 and searchers 26. The user PN code in each demodulation element 22 and searcher 26 is set to that of the remote unit assigned to that channel element modem 20. Microprocessor 34 steps searchers 26 through a set of offsets, called a search window, that is likely to contain multipath signal peaks suitable for assignment of demodulation elements 22. For each offset, searcher 26 reports the energy it finds at that offset to microprocessor 34. Demodulation elements 22 are then assigned by microprocessor 34 to the paths identified by searchers 26. Once one of demodulation elements 22 has locked onto the signal at its assigned offset, it then tracks that path on its own without supervision from microprocessor 34, until the path fades away or until it is assigned to a new path by microprocessor 34.
For the system of FIG. 2, each demodulation element 22 and searcher 26 contains one FHT processor 52 capable of performing one FHT transform during a time period equal to the period of a Walsh symbol. The FHT processor is slaved to "real time" in the sense that every Walsh symbol interval one value is input and one symbol value is output from the FHT. Therefore, to provide a rapid searching process, more than one searcher 26 must be used. Each of searchers 26 supplies back to microprocessor 34 the results of the search it performs. Microprocessor 34 tabulates these results for use in the assignment of demodulation elements 22 to the incoming signals.
In FIG. 2, the internal structure of only one demodulation element 22 is shown, but should be understood to apply to searchers 26 as well. Each demodulation element 22 or searcher 26 of the channel element modem has a corresponding I PN and Q PN sequence generator 36, 38 and the user-specific PN sequence generator 40 that is used to select a particular remote unit. User-specific PN sequence output 40 is XOR'd by XOR gates 42 and 44 with the output of I PN and Q PN sequence generators 36 and 38 to produce PN-I' and PN-Q' sequences that are provided to despreader 46. The timing reference of PN generators 36, 38, 40 is adjusted to the offset of the assigned signal, so that despreader 46 correlates the received I and Q channel antenna samples with the PN-I' and PN-Q' sequence consistent with the assigned signal offset. Four of the despreader outputs, corresponding to the four PN chips per Walsh chip, are summed to form a single Walsh chip by accumulators 48 and 50. The accumulated Walsh chip is then input into Fast Hadamard Transform (FHT) processor 52. When 64 chips corresponding to one Walsh symbol have been received, FHT processor 52 correlates the set of sixty-four Walsh chips with each of the sixty-four possible transmitted Walsh symbols and outputs a sixty-four entry matrix of soft decision data. The output of FHT processor 52 is then combined with those of other assigned demodulation elements by combiner 28. The output of combiner 28 is a "soft decision" demodulated symbol, weighted by the confidence that it correctly identifies the originally transmitted Walsh symbol. The soft decision data is then passed to forward error correction decoder 29 for further processing to recover the original call signal. This call signal is then sent through digital link 30, such as a T1 or E1 link, that routes the call to public switched telephone network (PSTN) 32.
Like each demodulation element 22, each searcher 26 contains a demodulation data path with an FHT processor capable of performing one FHT transform during a time period equal to the period of a Walsh symbol. Searcher 26 only differs from demodulation element 22 in how its output is used and in that it does not provide time tracking. For each offset processed, each searcher 26 finds the correlation energy at that offset by despreading the antenna samples, accumulating them into Walsh chips that are input to the FHT transform, performing the FHT transform and summing the maximum FHT output energy for each of the Walsh symbols for which the searcher dwells at an offset. The final sum is reported back to microprocessor 34. Generally each searcher 26 is stepped through the search window with the others as a group by microprocessor 34, each separated from its neighbor by half of a PN chip. In this way enough correlation energy exists at each maximum possible offset error of a quarter chip to ensure that a path is not missed because the searcher did not correlate with the exact offset of the path. After sequencing searchers 26 through the search window, microprocessor 34 evaluates the results reported back, looking for strong paths for demodulation elements assignment as described in above mentioned co-pending U.S. patent application Ser. No. 08/144,902.
The multipath environment is constantly changing as the remote unit and other reflective objects move about in the base station coverage area. The number of searches that must be performed is set by the need to find multipath quickly enough so that valid paths may be put to good use by the demodulation elements. On the other hand, the number of demodulation elements required is a function of the number of paths generally found to be usable at any point in time. To meet these needs, the system of FIG. 2 has two searchers 26 and one demodulation element 22 for each of four demodulator integrated circuits (IC's) used, for a total of four demodulation elements and eight searchers per channel element modem. Each of these twelve processing elements contains a complete demodulation data path, including the FHT processor which takes a relatively large, costly amount of area to implement on an integrated circuit. In addition to the four demodulator IC's the channel element modem also has a modulator IC and a forward error correction decoder IC for a total of 6 IC chips. A powerful and expensive microprocessor is needed to manage and coordinate the demodulation elements and the searchers. As implemented in FIG. 2, these circuits are completely independent and require the close guidance of microprocessor 34 to sequence through the correct offsets, and handle the FHT outputs. Every Walsh symbol microprocessor 34 receives an interrupt to process the FHT outputs. This interrupt rate alone necessitates use of a high powered microprocessor.
It would be advantageous if the six IC's required for a modem could be reduced to a single IC needing less microprocessor support, thereby reducing the direct IC cost and board-level production cost of the modem, and allowing migration to a lower cost microprocessor (or alternately a single high powered microprocessor supporting several channel element modems at once.) Just relying on shrinking feature sizes of the IC fabrication process and placing the six chips together on a single die is not enough. The fundamental architecture of the searcher needs to be redesigned for a truly cost effective single chip modem. From the discussion above, it should be apparent that there is a need for a signal receiving and processing apparatus that can demodulate a spread spectrum call signal at a lower cost and in a more architecturally efficient manner.
The present invention can use a set of real time searchers as described above or a single, integrated search processor that can quickly evaluate large numbers of offsets that potentially contain multipath of a received call signal.
The present invention is a method of searching for a multipath signal which is transmitted at an unknown variable rate and is subjected to power control.


Described are compositions and methods effective to improve the security obtainable for red phosphorescent inks printed, such as by ink jet printing. Specially designed polymeric chelating agents are water soluble and have a high chelating efficiency for lanthanide cations and are themselves strongly adsorbed on polymeric substrates, especially paper. The polymeric chelating agents comprise a polymer chain of either general formulae (1) or (2) containing pyridine-N-oxide, quinoline-N-oxide or isoquinoline-N oxide pendent ligand groups A, where m and n are independent integers in the range of from 1 to 10, and the number average molecular weight of the polymers lies in the range from 1×103 to 5×105:

It has been a common problem that water-based inks generally have poor water-fastness. Their solubility in water makes them effective as ink jet inks but this same property lessens their effectiveness in security systems.
While some red-luminescent inks provide particularly effective security features and it would be desirable to utilize them in ink jet printing devices, improvements are necessary to give them more fastness in the presence of water.
The art has provided a number of very interesting security inks based on lanthanide metal compounds and has developed a variety of security systems employing them. For example, In U.S. Pat. No. 5,837,042, Lent, et al., describe invisible fluorescent jet inks said to be suitable for producing security markings on documents and other articles. The jet ink compositions comprise a fluorescent colorant, an ink carrier, and optionally one or more binder resins. The markings are invisible to the unaided eye and are visible only when excited by ultraviolet light. The colorant comprises a rare earth metal and a chelating ligand, is excitable by ultraviolet light having a wavelength of from about 275 nm to about 400 nm, and fluoresces at a wavelength of from about 550 nm to about 700 nm, with the proviso that when the rare earth metal is europium, dysprosium, or terbium, the chelating ligand is not dibenzoylmethane. Also described is a method of identifying objects comprising providing a security marking as described above, exciting the marking and reading the fluorescent emission.
In another, U.S. Pat. No. 6,902,265, Critelli, et al., describe a method for printing high-information-density, machine-readable composite images. They teach printing machine-readable light-colored or invisible, but luminescent, postage-evidencing symbology and dark, other readable postage information, preferably in a single print operation, to provide large amounts of information without diminishing read rates. The resulting combination image can be printed independent of substrate material to enable the provision of a high information density without obscuring any one component. The postage-evidencing symbology is printed in large-format and can include redundant information within an IBI image or between an IBI and visible dark image for a variety of practical purposes. In a preferred form, the images are printed using conventional ink jet printers using water-based inks. In one embodiment of this type, the images are printed with a conventional two-cartridge color ink jet printer by printing postage-evidencing symbology with a single-color ink and printing the visible dark image as a composite dark color from a standard multi-color cartridge. Europium-containing inks can be utilized.
In U.S. Pat. No. 6,905,538 to Auslander, there are described water-based invisible red fluorescent inks provide machine-readable, inverse contrast invisible images and can be printed using conventional ink jet printers. The inks employ rare earth complexed ligand fluorophores having narrow excitation and emission spectra. In one embodiment the images are printed with an ink comprising water and a water-soluble organic fluorescent fluorophore, which when printed and dried on paper, is invisible to the eye and fluoresces in the green to infrared range, e.g., from about 550 to 1200 nm, when irradiated with short wave length UV radiation, e.g., from 230 nm to 280 nm. The highly specific excitation and emission rates, coupled with a high inverse contrast on papers of all colors, makes them particularly useful as ink jet inks for postal and other purposes.
In all of these and other cases of security inks, it is important that images printed with the inks retain their functionality if wetted by rain, spilled liquids or other common causes of wetness. Unfortunately, the factors which make inks easy to print with by ink jet printing, generally detract from the important property of water fastness.
There is a need for postal and security inks with strong fluorescent signals that can be printed by ink jet printing to produce images having a high degree of water fastness.

Red-luminescent ink jet printing compositions and methods for improved waterfastness

Abstract: In one aspect a polymeric chelate as described is produced in situ in an aqueous ink formulation and is subsequently printed onto a substrate and dried. In another, a substrate is pre-treated with a chelate as described and dried, and then subsequently printed with an aqueous solution of a fluorescent rare earth salt. In both cases, the result is a wet-fast, intensely luminescent print.


A needle having a shaft with a distal end defining a distal opening. The shaft has a longitudinal axis that extends through the distal opening and the distal opening has a projected area that is smaller than a cross-sectional area of a section of the shaft proximal to the distal end of the shaft. Also provided are methods of directly delivering a therapeutic agent to a target site using a Huber needle or pencil-point needle.

Needles have a wide variety of applications in the medical field. For instance, needles are used to delivery therapeutic agents, collect bodily fluids, and fill intravascular drug access devices. In many such applications, there is a desire to avoid or reduce damage to the site in which the needle is inserted. For example, intravascular drug access devices often include a chamber for holding a therapeutic agent and a pierceable rubber septum for receipt of a needle to either fill or empty the chamber. Repeated piercing of the septum with the needle can damage the septum leading to infusion of the septum fragments into the patient's vascular system or into any catheter or other device having access to the port, thereby occluding the port.
With respect to delivering a therapeutic agent to a target site in the body, particularly directly delivering a therapeutic agent to a target site, current injection needles have beveled open ends with Lancet point tips. Such open-ended needles have the potential to core tissue as the needles penetrate the tissue. In the case of directly delivering a therapeutic agent to a myocardial wall of the heart, since most myocardial direct injection procedures involve injecting a therapeutic agent into the left ventricle walls, the risk of tissue embolism into the left ventricular cavity exists.
Accordingly, there is a need for a needle that will prevent or minimize damage to the site in which the needle is inserted.


A computer tomography apparatus is disclosed wherein it is assured, given a migration of the focus out of a nominal position, that the radiation detector is always struck approximately centrally by the x-ray beam for the x-ray beams are provided at both ends of the radiation detector, which generate signals that are used to adjust the position of the primary radiation diaphragm, preferably an individual adjustment of the diaphragm plates, such that the x-ray beam always strikes the radiation detector approximately centrally.

Field of the Invention
The present invention is directed to a computer tomography apparatus of the type having a measuring unit composed of x-ray radiator and radiation detector which rotates around the system axis, as well as position detectors for the x-ray beam whose output signals cause the x-ray beam to be incident on the radiation detector approximately centrally.
Description of the Prior Art
In a computer tomography apparatus, the focus of the x-ray radiator can be slightly displaced given the rotation of the measuring unit, which can possibly result in the radiation detector no longer centrally intercepting by the x-ray beam. It is therefore known to provide a control circuit wherein position of one or both edges the x-ray beam is acquired with the assistance of position detectors and the x-ray radiator is adjusted such that the radiation detector is always approximately centrally struck by the x-ray beam. The adjustment of the x-ray radiator, however, involves considerable technological outlay because of the relatively large mass to be moved.

Computer tomography apparatus with compensation for focus migration by adjustment of diaphragm position


A method to equalize multiple-input multiple-output (MIMO) signals assigns a weight to the output of each receive chain in the MIMO system based on a first noise power value in each receive chain. A second noise power value can be computed using a difference between identical symbols from one or more weighted/un-weighted receive chain signals. Notably, the second noise power value includes thermal noise, phase noise, quantization noise, and distortion noise. The weighted outputs of the receive chains and the second noise power estimate may be used in an equalization calculation to recover the input signal.

1. Field of the Invention
Embodiments of this specification generally relate to wireless communication systems and more particularly to equalizing multiple-input multiple-output (MIMO) signals.
2. Description of the Related Art
Wireless communication systems may enable the transfer of data between a transmitter and multiple receivers. MIMO wireless communication systems may provide improved performance when compared to single-input-single-output systems. The improved performance may be provided by, in part, using multiple receivers to receive multiple transmitted signals. MIMO wireless communication systems may be governed, in part, by standards, such as IEEE standard (draft) 802.11n. Such standards may describe how a MIMO system receives and recovers a MIMO signal. In one embodiment, a MIMO system may be described by the equationy=H·x+n  (eq. 1)where H is a channel matrix (wherein computing the channel matrix H is well known in the art), x is a vector of input signals (hereinafter referred to as the x input signal), n is a vector of noise, and y is a vector of output signals.
A MIMO system may include multiple receivers configured to receive a MIMO signal. FIG. 1A illustrates a portion of an exemplary, prior art MIMO system 100 include "m" receive chains, wherein m is an integer equal to or greater than 2. In system 100, each receive chain 102 receives a MIMO signal via an antenna 101. Each receive chain 102 may produce a receive chain signal, denoted as yi in FIG. 1A. In general, a MIMO system may equalize the outputs of the multiple receive chains to recover the x input signal. One way to recover the x input signal in a MIMO system uses a Minimum Mean Square Error (MMSE) detector. The MMSE detector may be described by the equationx=(H*H+σ2I)−1H*·y  (eq. 2)where σ2 is a noise power value and I is the identity matrix. Oftentimes, recovering the x input signal may be referred to as equalizing y and (H*H+σ2I)−1H* may be referred to as the equalization coefficient. Equation 2 assumes that the noise power value is the same on all receive chains.
As shown in FIG. 1A, equalization may occur in an equalizer 103, which receives the output signal vectors y, from the multiple receive chains 102. However this approach has disadvantages. Specifically, if one or more of receive chains have relatively noisy receive chain signals (and therefore are of lower relative quality), and these receive chains signals are equally weighted with receive chains signals that have relatively lower amounts of noise (and are therefore of higher relative quality) during equalization, then the overall performance of the MIMO system is degraded because the equalized signal is of relatively lower quality.
As equation 2 above illustrates, a noise power value is typically required to recover the x input signal when using an MMSE detector. The noise power value may be determined by periodically measuring the receive power of a receive chain 102 during a quiet period, i.e. a period when no signals are being received. Because no signals are being received, the resulting measurement represents noise as seen by the receive chain 102. Typically, the receive power may be determined by examining the output of an analog front end, squaring that output, and then averaging the squares.
FIG. 1B illustrates an exemplary receive chain 102 including an analog front end 111 and a digital signal processing unit 115. Analog front end 111 includes a variable gain amplifier (VGA) 112, an analog to digital converter (ADC) 113, and an automatic gain controller (AGC) 114. Digital signal processing unit 115 includes a Fast Fourier Transform (FFT) unit 116. As shown, the input to VGA 112 may be provided by antenna 101. The output of VGA 112 may be provided to ADC 113. The output of ADC 113 may be provided to both AGC 114 and FFT unit 116. AGC 114 determines the gain of VGA 112 by examining, among other things, the output of ADC 113. The output of AGC 114 is provided to VGA 112. The output of FFT unit 116 produces the receive chain signal yi.
As described above, noise power value may be determined by measuring receive power during a quiet period. Such a measurement may be implemented using analog front end 111 of receive chain 110. For example, during a quiet period, the receive power may be determined by measuring, squaring, and averaging the outputs of ADC 113. Often, AGC 114 may set the gain of VGA 112 to a value such that the output of ADC 113 (and therefore the noise power value) is not limited by the upper or lower bounds of ADC 113.
Therefore, a noise power measurement may be associated with a particular VGA gain setting. As is well-known, a noise power measurement may be scaled using the VGA gain setting information to represent the noise power present at the input of the analog front end. This is often referred to as a root-mean-square (RMS) noise power value. Determining noise power in this way advantageously uses relatively smaller amounts of hardware and relatively smaller amounts of computation and in doing so produces a noise power value relatively quickly and is ready to use when receiving an actual receive chain signal.
Determining a noise power value in the above manner, however, has several disadvantages. A first disadvantage is that such a noise power value may not include several sources of noise. For example, although the method may capture thermal noise power, the method may not capture phase noise, quantization error, or distortion. This is because these other noise sources may be determined by measuring an actual receive chain signal in operation, not by measuring receive power during a quiet period.
A second disadvantage is that the accuracy of the noise power value may depend upon the linearity of the VGA. This is because the noise power value may be scaled in accordance with a gain setting within the VGA.
A third disadvantage is that the power measurement path (which includes the analog front end of a receive chain) may be different from the data path (which includes the analog front end and FFT unit of a receive chain). Although this may be overcome by scaling the determined noise power value by any signal gains or losses that may occur in the data path relative to the power measurement path, scaling is undesirable because it must be re-examined each time new hardware is developed (i.e. hardware may significantly affect the scaling factor).
Therefore, a noise power value determined in the manner described above may be inaccurate. As a result, the performance of MIMO equalizer 103 (FIG. 1A) receiving the multiple receive chain signals y, may be degraded.
Therefore, what is needed is a way to improve the recovery of input signals transmitted in a MIMO system, especially when one or more of the received MIMO signals may be relatively noisy.

MIMO equalization for wireless communication systems


Certain embodiments of the present invention provide functionalized nanoparticles and methods of use thereof. Certain embodiments provide nanoparticles functionalized with streptokinase. Certain embodiments of the present invention provide methods for treating a pathological fibrin associated disorder (e.g., cancer) in an animal.

Inefficient transport of drug delivery systems through tumor extracellular matrix (ECM) severely limits therapeutic efficacy. Tumors are characterized by the presence of a neo-vasculature that is underdeveloped and leaky. This leads to deposition of fibrin, a key ingredient of blood clot, within the tumor matrix (M. Schafer, S. Werner, Nat Rev Mol Cell Biol 9, 628 (2008)). The presence of fibrin is an important cause of elevated interstitial fluid pressure (IFP) in tumors (J. Ma, D. J. Waxman, Mol Cancer Ther 7, 3670 (2008)). Elevated IFP, in turn, results in increased resistance to convective transport of drug carriers in the tumor matrix and decreases the amount of drug reaching tumor cells (L. T. Baxter, R. K. Jain, Microvasc Res 37, 77 (1989)). This is especially true for central regions of the tumor, which are typically under-perfused. This is a critical problem because these poorly-perfused regions (which have low pH and low pO2) harbor the most aggressive and drug-resistant tumor cells.
Accordingly, there is a need for agents and methods that are useful for treating or preventing cancer. Additionally, there is a need for anti-cancer agents with improved therapeutic efficacy, e.g., improved transport of drug delivery systems through the ECM.

Functionalized nanoparticles and methods of use thereof


A gas treatment bottle comprises at least one gas dispenser (24;50) and has a distributor (25;51) intended to be fixed in a gas treatment bottle (10) in front of an inlet or outlet orifice (18;56). The distributor (25;51) has a head (26) which covers the orifice and has an openworked end wall (28) and an openworked side wall (30), typically inclined in the direction of the end wall (28) and surrounding it. The degree of openworking in the side wall (30) is greater than the degree of openworking in the end wall (28).

Bottles of this type contain, for example, adsorbent materials, in particular for separating nitrogen from air.
In bottles with vertical axial circulation, two orifices, for inlet or outlet, are arranged respectively in the lower part and in the upper part of the bottle. Depending on the period of the operating cycle of the installation, the lower or upper orifice lets gas into the bottle, whereas the opposite orifice lets it out.
The orifices are arranged along the axis of the bottle. Thus, the gas emerging from the inlet orifice should be distributed over the entire cross-section of the bottle in order to optimize the efficiency of the installation. The gas dispenser arranged in the bottle at the outlet of the orifice has the purpose of allowing a uniform distribution of the gas over this entire cross-section.

L'Air Liquide, Societe Anonyme Pour L'Etude et L'Exploitation des Procedes Georges Claude


A sheet supply apparatus includes a supply unit capable of loading a plurality of continuous sheets, a reading unit for reading sheet information that a continuous sheet has, and a control unit that, when the continuous sheet is loaded on the supply unit, enables the reading unit to read the sheet information in a first state and provides a notification to prompt an input of the sheet information in a second state, the first state being the state in which the reading of the sheet information by the reading unit is available, the second state being the state in which the reading of the sheet information by the reading unit is unavailable.

1. Field of the Invention
The present invention relates to a sheet supply apparatus for supplying a continuous sheet and to a printing apparatus.
2. Description of the Related Art
There is a printer known to print on a continuous sheet in a roll form (roll sheet) through an inkjet method. When having mounted a new roll sheet on a printer, a user would input the type of the roll sheet from an operating unit of the printer to associate the roll sheet with its type. The type of the roll sheet that has been input is used for succeeding image forming and convey controlling. When the roll sheet is removed from a mounting unit of the printer, a pattern (hereinafter referred to as barcode), which identifies the type of the sheet, is printed on the roll sheet at an end of the sheet (at the leading edge thereof) in order to retain the association between the roll sheet and its type. When the roll sheet with the barcode printed thereon is mounted on the mounting unit of the printer, the printer reads the barcode to set the type of the sheet automatically, eliminating a demand for the user to input the type of the roll sheet again.
A printer, disclosed in Japanese Patent Application Laid-Open No. 2010-264672, allows for replacing of a roll sheet unused for printing during the printing. When a roll sheet used for the printing is consumed, a replacement roll sheet is fed so that its barcode is read. If the type of the replacement roll sheet agrees with the type of the roll sheet used for the printing, the printing is continued. If the type of the replacement roll sheet disagrees with the type of the roll sheet used for the printing, the printing is suspended and an error is displayed.
The printer, described in Japanese Patent Application Laid-Open No. 2010-264672, allows a roll sheet to be mounted while another roll sheet is being printed. If, however, the type of the mounted roll sheet disagrees with the type of the roll sheet being printed, the printing operation is interrupted until the user mounts a roll sheet of the correct type.
If the mounted roll sheet lacks a barcode, or if its barcode is unreadable due to a stain or the like, it is problematic in that the type of the mounted roll sheet cannot be identified unless the user manually inputs information of the paper type. Furthermore, it is unknown whether or not the reading operation on the barcode of the mounted roll sheet has been executed until the roll sheet being printed is consumed and then the reading operation is attempted on the barcode. This leaves the printer unable to identify the type of the roll sheet if the user is away from the printer.

Sheet supply apparatus and printing apparatus


The present invention discloses a initializing and reconfiguring a network interface device connecting a client computer system to an external network. The network interface device is configured for the client system by automated procedures and protocols initiated from a remote server. Software programs within the network interface device provide transparent communication between the client computer system and services available on the external network. Similar software programs and a configuration database within the network interface device provide transparent communication between the client computer system and the remote server.

The present invention relates generally to the field of computer networks, and more particularly to a method of securely initializing and reconfiguring a network interface device.
The Internet is rapidly becoming an important source of information and electronic communication for users of computers in homes and businesses. A major problem associated with the Internet, however, is the difficulty faced by typical computer users in connecting their computers or local area networks to the Internet. A computer user desiring to connect to the Internet must make many critical decisions, such as which communication medium to use, which Internet Service Provider to subscribe to, how to secure their network interface, and which network services to utilize. Business managers in charge of local or wide area networks must also address questions related to the type and configuration of computer networks which are to be connected to the Internet, and other such external networks (referred to as xe2x80x98internetsxe2x80x99). Unlike installing a new telephone system, installing an external network connection requires an understanding of many different, and often confusing, communication protocols, network services, connection media, and computer network practices.
Connecting a computer network to an internet requires a service account and a data communication line to access the various networks that make up the internet. A dedicated Wide Area Network (WAN) connection to an internet is typically provided by a commercial Internet Service Provider (ISP). The ISP acts as the intermediary between the user and the network backbone servers which provide access to the various networks within the internet. Several different data communication lines are available to connect a computer or LAN to the internet. Common data communication lines include analog modems (14.4 Kbaud-56 Kbaud), ISDN (Integrated Services Digital Network), T1 lines, Fractional T1 lines, and several others.
Obtaining an internet connection typically requires the user to order an internet account and address block from an ISP, install the appropriate phone lines for the data communication medium (e.g., ISDN line, analog phone line), install the appropriate network interface device between the data communication port and the computer which will serve as the network gateway computer, and configure the network interface device for operation with the user""s LAN and in accordance with the network services provided by the ISP. Thus, the initial configuration of the network interface device must be performed by the computer user or LAN manager himself, and often requires extensive knowledge of network protocols, internet services, and LAN requirements. Initial configuration also often involves the entry of complex configuration parameters and options in a database or storage device by the LAN manager. Similarly, an upgrade or reconfiguration of the network interface device requires the user or LAN manager to obtain the upgrade information and perform the upgrade or reconfiguration operation himself. Because no internet services or data communication systems currently provides a comprehensive and reliable means of automatically configuring or updating a network interface connection to an internet, internet access remains a significant challenge to those who lack the requisite expertise or resources to undertake the task.
It is therefore desirable to provide a system for connecting a computer or client network to the internet with minimal user interaction. It is further desirable to provide a system for automatically upgrading or reconfiguring a network interface connection between a computer or client network and an internet.
The present invention discloses a method and apparatus for initializing, configuring, and upgrading a network interface between a client computer network and an external network.
According to one aspect of the present invention, a network interface device is provided to connect a client computer network to an external network. The network interface device is provided to the client user in an initially unconfigured state. The network interface device is configured for the client system by automated procedures and protocols initiated from a remote server. The remote server provides and maintains the client information in a secure database. The use of a secure database and automated procedures minimizes the amount of input required from the user. The network interface device contains application program interfaces which facilitate communication between the client computer system and services available on the external network. The network interface device also contains a configuration database which stores data and parameters related to the configuration of the network interface device. Through the use of the configuration database and the resident application program interfaces, the remote server is able to automatically upgrade or reconfigure the network interface device without user intervention.
Other features of the present invention will be apparent from the accompanying drawings and from the detailed description which follows.

Remote reconfiguration of a secure network interface