The present invention relates to a multiple differential demodulator using a weighting value. The multiple differential demodulator according to the present invention includes a weighting value generator for integrating a real part and an imaginary part of a value acquired by multiplying one of a plurality of differentiated reception signals by a conjugated value of a differentiated PN code signal corresponding to a preset symbol, and determining the greater of the integrated real and integrated imaginary parts to apply a predetermined weighting value to the greater value, where the PN code signal is differentiated in the same fashion as the differentiated reception signals.

1. Field of the Invention
The present invention relates to a multiple differential demodulator used in a wireless communication system such as a WPAN and sensor network. More particularly, the invention relates to a multiple differential demodulator which does not employ square operations conducted by a correlator of a noncoherent detector in a conventional multiple differential noncoherent demodulator but applies a weighting value to the greater value of either a real part or an imaginary part to decrease phase offsets, thereby eliminating square loss.
2. Description of the Related Art
The term "ubiquitous" has been proposed recently to refer to a communication environment in which one can connect to a network at any time, any place. In addition, there have been active researches on small-scale wireless communication systems such as a Wireless Local Area Network (WLAN), Wireless Personal Area Network (WPAN), sensor network, Radio Frequency Identification (RFID), and the like rather than large-scale communication networks such as a cellular network.
Among these communication systems in particular, WPAN and sensor network require ultra-small size, low power consumption, and low price in addition to communication performance. Therefore, high-performance and expensive components used in the existing cellular communication systems or WLAN systems are hardly employed in the small-scale wireless communication systems including the WPAN and sensor network. However, if low-price components are adopted to lower the costs, frequency or phase offsets can occur, which requires a solution.
Therefore, there have been researches on a demodulator that performs well in a communication system with large frequency or phase offsets.
FIG. 1 is a block diagram illustrating a conventional multiple differential noncoherent demodulator proposed to compensate for frequency or phase offsets.
Referring to FIG. 1, the conventional multiple differential noncoherent demodulator 20 includes a multiple differentiator 21 for multi-delaying an I/Q signal outputted from an IF end 10 of a receiver to differentiate the signal, a plurality of noncoherent detectors 22 (only one is illustrated) for computing the correlations between the differentiated reception signals outputted from the multiple differentiator 21 and PN codes corresponding respectively to 16 symbols, and a maximum value selector 23 for comparing output results of the plurality of noncoherent detectors 22 to detect the maximum correlation value and determining a symbol of the PN code having the maximum correlation value as the symbol of the reception signal.
The conventional multiple differential noncoherent demodulator 20 can be described in greater detail as follows. An RF reception signal is frequency-converted into an IF signal at an RF end (not shown) of a receiver, separated and converted into a baseband I/Q signal by a mixer of the IF end 10. Then, the signal is sampled by an analogue/digital converter A/D and inputted into a demodulator 20 as a digital signal. The reception signal r(k) (k represents a sequence of a received packet) is a complex signal, where a real part is represented by "real{r(k)}" and an imaginary part by "imag{r(k)}."
Thereafter, demodulation is executed on the digitized baseband signal, real{r(k)} and imag{r(k)}. First, the multiple differentiator 21 in the demodulator 20 complex-multiplies the digital signal (the signal received before the predetermined delay times) delayed by predetermined delay times 1Tc, 2Tc and 3Tc by a current reception signal to acquire differentiated values. FIG. 2 shows blocks of the multiple differentiator 21 in detail. The multiple differentiator 21 delays the signal r(k) received at the IF end 10 (FIG. 1) by delayers 211 to 213 having a plurality of predetermined delay times, e.g. Tc, 2Tc and3Tc, and conjugates the delayed signals by conjugators 214 to 216. Then, each of the multipliers 217 to 219 multiplies the reception signal r(k) by the delayed conjugated signals to output differentiated signals. Thus, a plurality of differentiated signals Dr,Tc(k), Dr,2Tc(k) and Dr,3Tc(k) delayed by different delay times are outputted from the multiple differentiator 21. Given that the signal r(k) received at the multiple differentiator 21 is represented as in Equation 1, the output signal of the multiple differentiator 21 can be represented as in Equation 2.r(k)=s(k)ej2πΔfk   Equation 1
                                                                                D                  r                                                                  (                  k                  )                                            =                                                                            r                                                        (                    k                    )                                                                                r                                                              (                                              k                        -                        N                                            )                                                        *                                                                                =                                                                            s                                                        (                    k                    )                                                                                ⅇ                                      j2πΔ                                                                                fk                                                                                s                                                              (                                              k                        -                        N                                            )                                                        *                                                                  ⅇ                                                            -                      j2πΔ                                                                                f                                                                    (                                                  k                          -                          N                                                )                                                                                =                                                                            s                                                        (                    k                    )                                                                                s                                                              (                                              k                        -                        N                                            )                                                        *                                                                  ⅇ                                      j2πΔ                                                                                fN                                                                                =                                                                            s                                                        (                    k                    )                                                                                s                                                              (                                              k                        -                        N                                            )                                                        *                                                                  (                                                            cos                                                                                2                                            πΔ                                                                                fN                                        +                                          j                                                                                sin                                                                                2                                            πΔ                                                                                fN                                                        )                                                                                Equation                                                  2
In above Equations 1 and 2, s(k) is a transmission signal, i.e., a PN code of a symbol corresponding to the reception signal. Examining Equation 1, the reception signal r(k) includes channel distortion of ej2πΔfk in addition to the transmission signal s(k) (the PN code of the symbol), and the demodulator functions to restore the signal s(k) from the reception signal r(k). Here, Δfk is a value representing frequency offsets and ΔfN is a value representing phase offsets obtained from differentiating Δfk.
A plurality of noncoherent detectors 22 (FIG. 1) correlate the signals outputted from the multiple differentiator 21 with differentiated PN code signals of symbols to output correlation results. This process is described with reference to FIGS. 3 and 4.
FIG. 3 is a detailed block diagram of a noncoherent detector. As shown in FIG. 3, the noncoherent detector 22 (FIG. 1) includes first to third correlators 221 to 223 and a summer 224. The first to third correlators 221 to 223 complex-conjugate the differentiated signals by the delay times Tc, 2Tc and 3Tc with PN code signals differentiated (by each delay time) in the same fashion as the differentiated signals. The summer 224 sums output values from the first to third correlators 221 to 223 to output a correlation value Ei with the corresponding symbol, where i is a constant at least 0 and up to 15, referring to the corresponding symbol.
The first to third correlators 221 to 223 complex-multiply each of the plurality of differentiated signals Dr,Tc(k), Dr,2Tc(k) and Dr,3Tc(k) outputted from the multiple differentiator 21 (FIG. 1) by PN code differentiated signals Ds,Tc(k), Ds,2Tc(k) and Ds,3Tc(k) (also referred to as differentiated PN codes). The PN code differentiated signals are differentiated in the same fashion as the differentiated signals. One of the correlators is shown in greater detail in FIG. 4. FIG. 4 is a detailed block diagram of the first correlator 221, which has an identical structure with the second correlator 222 and the third correlator 223. As shown in FIG. 4, the correlator 221 includes first to fourth multipliers 241 to 244, an adder 245, a subtractor 246, two integrators 247 and 248, two square operators 249 and 250, and another adder 251. Each of the first to fourth multipliers 241 to 244 distinguishes the differentiated signal Dr,Tc(k) and the differentiated signal of the PN code Ds,Tc(k) into a real part and an imaginary part, and conducts multiplication between the real parts/imaginary parts or between the real and imaginary parts. The adder 245 adds output values of the first and second multipliers 241 and 242, and the subtractor 246 calculates difference between output values of the third and fourth multipliers 243 and 244. The two integrators 247 and 248 respectively integrate the output values of the adder 245 and the subtractor 246 for one symbol period. The two square operators 249 and 250 respectively square output values from the two integrators 247 and 248. Another adder 251 adds output values of the two square operators 249 and 250 to output a correlation result ETc.
When the differentiated signals and the differentiated PN code signals are complex-multiplied, four multiplication results are obtained from the first to fourth multipliers 241 to 244. Afterwards, the multiplication results are integrated by the integrators 247 and 248. Then, the real part and the imaginary part are squared respectively. The final results are added together to obtain the correlation result ETc.
The correlation results ETc, E2Tc and E3Tc for each delay time outputted from the first to third correlators 221 to 223 having the structure and operation described above (FIG. 3) are summed by the summer 224 (FIG. 3) to acquire a correlation value Ei between the reception signal and the symbol. The correlation value Ei outputted from the noncoherent detector 22 (FIG. 1) can be expressed as in Equation 3 below.
                    Ei        =                              ∑                          j              =              0                        3                                                                                                        ∑                                      K                    =                    N                                    K                                                                  [                                                                                D                        r                                                                                (                        k                        )                                                                                D                          s                                                                                (                          k                          )                                                                    *                                                        ]                                                                    2                                              Equation                                                  3
In above Equation 3, N represents a delay time and K represents the number of samples in a symbol period.
Then, the maximum value selector 23 (FIG. 1) compares the correlation values outputted from the plurality of noncoherent detectors 22 (FIG. 1) operated as described above to detect the maximum value, and determines the symbol value corresponding to the PN code with the maximum value as the demodulation value of the reception signal r(k).
According to the conventional multiple differential noncoherent demodulator having the configuration as described above, as the reception signal r(k) is converted to a differentiated reception signal (differentiated value of the reception signal) Dr(k), phase offsets remain as seen in Equation 2. Thus, the correlators of the noncoherent detector execute square operations to sum the squared values in order to compensate for the phase offsets. However, due to these square operations, a signal including noise is squared to result in square loss, thereby degrading transmission performance.

Multiple differential demodulator using weighting value


A loopback connector system for testing token ring components such as routers or interface assemblies with requiring that the component to be tested be connected into the local area network (LAN). The connector permits the component to be tested to be isolated from the LAN, permitting the integrity of the component to be tested without regard to the integrity of lobe cables or other devices on the ring, and without degrading network performance. The connector system includes two different multi-pin connector types, a DB9 and an RJ45 connector, used to connect into the network, separated by a short two-pair cable. Resistors used to simulate the network loading on the component are connected between appropriate pins, with the resistors being shared between the two types of connectors.

This invention relates to token ring local area networks, and more particularly to a means for diagnosing the integrity of a particular hardware component without connecting the component into the network.
One local area network ("LAN") architecture is the Token Ring topology local area network at 4- and 16-Mbit/second. IEEE 802.5 is an IEEE local area network standard that closely follows the token ring standard, and currently supports 4-Mbit/second token ring networks. IEEE 802.5 is described in "Token Ring Access Method and Physical Layer Specifications," ISBN 1-55937-012-2, IEEE Std. 802.5-1989 (ANSI), IEEE, 345 E. 47th Street, New York, N.Y. 11017. Token ring and IEEE 802.5 topologies connect computer systems in a local environment.
In order to test hardware components connected into a token ring or IEEE 802.5 LAN, one must also consider lobe cables connecting the components, other devices on the ring, and the risk of degrading the network performance while performing the testing. It has been necessary in the past to supply a "known good" lobe cable and a "known good"0 Token Ring Multi-Station Access Unit (MsAU) with no other nodes attached to achieve adequate troubleshooting capability. The MsAu is a passive device which includes a relay set, and receives power to operate the relays from node devices inserted into the ring.
It would therefore represent an advance in the art to provide a means for diagnosing the integrity of a particular hardware component for a token ring LAN without connecting the component into the network.

Token ring test simulation method and device


There is disclosed a camera having a first imaging medium which acquires subject image data from a subject light flux transmitted through a photographing lens; an optical path branching member which is disposed in an image pickup optical path of the first imaging medium to branch an optical path of the subject light flux; a primary image forming surface on which the subject light flux branched by the optical path branching member forms an image; and a second imaging medium which picks up the subject image formed on the primary image forming surface. When the present camera satisfies at least one of a plurality of optical conditions, the amount of shading of the light flux guided to the second imaging medium is reduced.

1. Field of the Invention
The present invention relates to a camera including a plurality of imaging mediums (image sensors (CCD, CMOS), films or the like) to which an incoming light flux from a subject (an incoming subject light flux) is guided.
2. Description of the Related Art
Cameras including a plurality of imaging mediums to which an incoming subject light flux is guided have heretofore been known. Examples of the plurality of imaging mediums include one for photographing a subject and one for monitoring a subject image before photographing. These cameras branch or refract a subject light flux incoming from a photographing lens system to guide the fluxes to the plurality of imaging mediums by use of optical systems such as a quick return mirror, a half mirror and a prism.
As this type of camera, there are proposed cameras described in, for example, Jpn. Pat. Appln. KOKAI Publication Nos. 9-5866 and 2000-165730 described later.
In the camera described in Jpn. Pat. Appln. KOKAI Publication No. 9-5866, a light flux incoming from a subject and transmitted through a photographing lens is divided by a half mirror (an optical path branching member) disposed midway in an optical path for photographing by film so that another optical path is formed in a direction different from that of the film. Moreover, a mirror or a prism (an optical path refracting member) is disposed in the optical path branched in the direction different from that of the film to bend the light flux, and an image sensor is disposed in the bent optical path.
In the camera described in Jpn. Pat. Appln. KOKAI Publication No. 2000-165730, a quick return mirror (a first optical path change member) is disposed midway in an optical path for picking up a light flux incoming from a subject and transmitted through a photographing lens to a first image sensor so that the optical path can also be switched in a direction different from that of the first image sensor. Moreover, in the optical path switched to the direction different from that of the first image sensor, a movable mirror (a second optical path change member) is disposed which can switch the direction of the optical path between the direction of a second image sensor and that of an optical finder. In the optical paths switched by the second optical path change member, the second image sensor and the optical finder are provided, respectively.


Mobile terminals have the problem of large packet loss during movement because the mobile terminal has no opportunity to detect movement and generate a new care-of address until a new router advertisement is received, and also cannot register the position in the home agent. The present invention is characterized in including a means to automatically collect network information on access router devices in the vicinity of a particular access router device, and a means to send information in the router advertisement including information on at least one or more adjacent access router devices. The mobile terminal selects an access router device to become the next movement destination, and the most essential characteristic is a means to register the position information beforehand in the home agent.

In recent years, many intensive studies have been made on IP (Internet Protocol) for mobile communication networks.
The IETF (Internet Engineering Task Force) is proceeding with efforts to standardize Mobile IPv6 specifications. The essential elements comprising a Mobile IPv6 network are a mobile node (hereafter expressed as MN), a home agent (hereafter expressed as HA), a correspondent node (hereafter expressed as CN), and an access router (hereafter expressed as AR).
The basic operation of Mobile IPv6 is described next. An IP address (home address, hereafter expressed as HoA) that does not change even if the MN has moved, is assigned to the MN1. Therefore, an application that starts up on the MN can continue running without stopping even if the MN is moving. A network possessing a network prefix identical to the HoA is called a home network. When the MN moves to a network (host network) other than the home network, it acquires an IP address that conforms to the communication protocol within that host network. This IP address is called the Care of Address (hereafter expressed as CoA).
The MN receives a router advertisement (RA) sent periodically from the AR located in the host network. If the network prefix detected at this time that is different from the HoA, then this signifies movement has been detected and a CoA is then generated. The MN that detected movement sends to the HA, a position registration message (Binding Update: BU) requesting the relay of a packet for an MN destination sent to the home network. The HA that received the binding update creates a binding cache to link the MN home address with the care of address (CoA). The HA afterwards sends a position registration reply message (Binding Ack: BA) to the MN, and broadcasts a packet acquisition message (Gratuitous Neighbor Advertisement: G-NA) as a proxy for receiving the packet addressed to the MN moving in the host network. The CN is the communication correspondent node (other communication party) for the MN. The CN sends a packet addressed to the HoA of the MN. The HA receives as a proxy, the HoA addressed packet for the MN. The HA searches the Binding Cache and acquires a CoA corresponding to the HoA for the MN. The HA attaches (encapsulates) an IP header for the CoA that matches the original received packet and sends that packet. The MN removes (decapsulates) the encapsulated header of the CoA. The CN can then receive the packet sent addressed to the HoA of the MN, which is the original packet.
However, in the technology of the related art the MN cannot identify movement of the mobile terminal until a router advertisement is received from the AR installed within the host network at the movement destination. The packet from the CN cannot be received during this time, because a new CoA cannot be generated and position registration messages (binding updates) cannot be exchanged due to failure to identify movement of the mobile terminal.    [Non-patent document 1] D. Johnson et. al. "Mobility Support in IPv6", IETF 2003,    http://www.ietf.org/internet-drafts/draft-ietf-MobileIP-IPv 6-24.txt

Communication system, server, router, and mobile communications terminal

Hitachi Communication Technologies, Ltd.


The present invention provides a method for mapping a netlist of an integrated circuit to a design. The method includes steps as follows. Chaos algorithm is used to obtain most favorable places in the design for cells from the netlist. Kuhn's algorithm is utilized to assign each cell of the netlist a cell in a template so that, for each cell of the netlist, its place in the template is as close as possible to its place obtained by the chaos algorithm. Simulating annealing optimization technique is applied to reduce a sum of wire length of the design.

Platform-based IC (integrated circuit) design is a powerful concept for coping with the increased pressure on time-to-market, design and manufacturing costs encountered in the current IC market. A platform is a large-scale, high-complexity semiconductor device that includes one or more of the following elements: (1) memory; (2) a customizable array of transistors; (3) an IP (intellectual property) block; (4) a processor, e.g., an ESP (embedded standard product); (5) an embedded programmable logic block; and (6) interconnect. RapidChip™ developed by LSI Logic Corp. is an instance of a platform. The basic idea behind the platform-based design is to avoid designing and manufacturing a chip from scratch. Some portion of the chip's architecture is predefined for a specific type of application. Through extensive design reuse, the platform-based design may provide faster time-to-market and reduced design cost.
Under a platform approach, there are two distinct steps entailed in creating a final end-user product: a prefabrication step and a customization step. In a prefabrication step, a slice is built on a wafer. A slice is a pre-manufactured chip in which all silicon layers have been built, leaving the metal layers or top metal layers to be completed with the customer's unique IP. For example, RapidSlice™ developed by LSI Logic Corp. is an instance of a slice. One or more slices may be built on a single wafer. It is understood that a slice may include one or more bottom metal layers or may include no metal layers at all. In a preferred embodiment of the prefabrication step, portions of the metal layers are pre-specified to implement the pre-defined blocks of the platform and the diffusion processes are carried out in a wafer fab. The base characteristics, in terms of the IP, the processors, the memory, the interconnect, the programmable logic and the customizable transistor array, are all pre-placed in the design and pre-diffused in the slice. However, a slice is still fully decoupled because the customer has not yet introduced the function into the slice. In a customization step, the customer-designed function is merged with the pre-defined blocks and the metal layers (or late-metal components) are laid down, which couple the elements that make up the slice built in the wafer fab, and the customizable transistor array is configured and given its characteristic function. In other embodiments, early-metal steps may be part of the pre-fabricated slice to reduce the time and cost of the customization step, resulting in a platform which is more coupled and specific. It is understood that a prefabrication step and a customization step may be performed in different foundries. For example, a slice may be manufactured in one foundry. Later, in a customization step, the slice may be pulled from inventory and metalized, which gives the slice its final product characteristics in a different foundry.
A slice such as RapidSlice™ may contain several RRAMs (Reconfigurable RAMs, or Redundant RAMs, or RapidSlice™ RAMs). Each RRAM is a set of memories of the same type that are placed compactly. RRAMs include built-in testing and self-repairing components and include a set of tools for mapping arbitrary customer memories (logical memories) to the memories from the matrix (physical memories). All RRAM memory ports are ports of customer memories. Ports of memories from the matrix are invisible from outside a RRAM. Thus, from the customer's point of view a RRAM is a set of customer memories.
A netlist describes the connectivity of an IC design. The problem of mapping a netlist to a design, which includes cells with predefined locations, often rises up during the development of chips based on the RapidChip™ technology, and/or FPGA. RapidChip™ technology uses RRAM cells that include pre-diffused internal memories and R-Cells. An R-Cell is a 5 transistor element configured by metal. In order to implement a customer memory mapped to RRAM, the memory may be represented as a tiling netlist of R-Cells and internal RRAM memories. Each memory of the tiling netlist may have already been assigned to the internal memory of RRAM. Therefore, what is needed is to map R-Cells of the netlist to the pre-diffused R-Cells of the RRAM.
Consider a set (called a template design or template) T of cells and pins with predefined locations in RRAM. T has no wires. Let N be a netlist such that it has cell types that are instantiated in T only. All the input and output pins of the netlist N are assigned to predefined pins of T. In order to obtain a design that implements the netlist N, pins of cells of T need be connected to pins of T that correspond to the pins of N by wires. Since the total wire length is an important consideration in IC design, thus, it is desirable to provide a solution with the sum of wire length being as minimal as possible.

Method and system for mapping netlist of integrated circuit to design


Provided is a multi-channel optical module and a manufacturing method of the same. The optical module includes a base block having a cavity on one edge of the base block; a substrate arranged on the other side of the base block that faces the cavity; an integrated circuit (IC) chip mounted on the substrate; a platform arranged in the cavity; electrical contacts connected to the IC chip, wherein the electrical contacts are formed on the platform; an optical device array block arranged in the platform, wherein the optical device array block is connected to the electrical contacts; a plurality of optical fiber cores aligned with the optical device array block; and an optical fiber array block fixing the plurality of optical fiber cores, wherein the optical fiber array block is bonded to the platform and to the optical device array block and is fixed in the cavity.

The present invention disclosed herein relates to an optical communication system and a manufacturing system of the same, and more particularly, to a multi-channel optical module and a manufacturing method of the same that enable multi-channel light transmission and light reception for data transmission.
Recently, an active optical cable (AOC) such as a High-Definition Multimedia Interface (HDMI), a Display Port, a Digital Visual Interface (DVI), etc., needs four or more channels that may collect four or more wavelengths in an optical fiber so as to transmit A/V data.
Moreover, an electrical connection reveals a limit in a coupling system such as general chip to chip, board to board, board to system, and system to system and thus a demand for a multi-channel optical module for transmitting massive data so as to replace it continues to increase.
A general multi-channel optical module may include a fiber block to which many precise molding products having special shapes and guide pins are attached. In the case of the molding products, a lot of time and costs are consumed for accurate tolerance control in relevant processes, and in particular, if a single mode fiber of which a core size is about 8 um is used, there is a limitation in that the final tolerance between the fiber and an optical device needs to be controlled to be within several micrometers.
Another multi-channel optical module has a structure in which an optical device array block having a lens module that includes a mirror for converting an optical path by 90 degrees is optically coupled to optical fiber arrays. The alignment process between the optical fiber and the mirror, the mirror and the lens, or the lens and the optical device is necessarily required. Thus, the general multi-channel optical module has limitations in that the optical coupling efficiency between the final optical fiber and the optical device is not good, and many parts such as a mirror, a lens, a support tool, and a spacer for securing a space for optical coupling are used.
Another multi-channel optical module may include a fiber array block that includes guide holes and guide pins on a silicon wafer. When an optical device is passively connected to an optical fiber, a through hole needs to be formed in the correct position on a silicon wafer. The multi-channel optical module has drawbacks that it is very difficult to manufacture guide pins and a fiber array block including the guide pins and reliability is low because a crack may appear on a silicon mount due to contact with the guide pins. Moreover, the multi-channel optical module has a drawback that electrical performance decreases due to electrical crosstalk between electrical contacts of adjacent channels, which becomes more serious as a transmission rate increases.

Multi-channel optical module and manufacturing method of the same

ELECTRONICS AND TELECOMMUNICATIONS RESEARCH INSTITUTE


In a device and a method for operating a driven axle in a machine tool, in particular in an injection-molding machine, at least two different drives are coupled to form a common effective drive, wherein the performance and energy consumption data for each drive are stored in the form of characteristic values or characteristic curves. To use the effective drive as optimally as possible in terms of energy, it is proposed to determine the performance requirement for the driven axle, to determine the particular operational combination of the different drives that requires the least expenditure of energy based on the determined performance requirement and to drive the drives with the determined particular operational combination.

The present invention pertains to a method for operating a driven axle in a machine tool, in particular an injection molding machine, wherein at least two different drives are coupled into a common effective drive, as well as to a device for operating a driven axle in a machine tool.
Machine tools such as, among other things, injection molding machines typically feature several driven axles that in some instances have very high and different load ranges. In an injection molding machine, for example, the injection process, i.e., the process, in which the molten material is conveyed into the cavity of the tool, is the process with the most variable requirement. In this case, an extreme speed range and pressure range needs to be controlled depending on the respective application. Injection speeds from a few tenths of a millimeter per second up to 1 meter per second are required. With respect to the load range, the requirements may lie between less than 100 bar and more than 2,000 bar. On extreme examination, the performance requirement therefore varies by up to a factor of 20,000. If this broad scope of applications should be covered with today's conventional drive arrangements, the power cannot be made available in an energetically optimal fashion, at least not in all applications. For example, high peak powers can only be made available directly by a hydraulic pump (e.g., variable displacement or fixed displacement pump) up to a certain power limit. Beginning at a certain power limit, an intermediate storage is required (e.g., by means of a hydraulic accumulator) and the power is then obtained from such a storage.

Method and device for operating a driven axle in a machine tool


A motor vehicle audio system having an audio signal receiver, an amplifier connected thereto via a fiber optic cable and a loudspeaker. A separate amplifier is provided for low audio signals. The amplifier is provided with a substantially higher line voltage when compared with the other audio frequency amplifiers.

The invention relates to a motor vehicle audio system comprising an audio signal receiver, at least one amplifier connected thereto by way of an optical waveguide, and a loudspeaker.
A system of this type is known from European Patent Document EP 0 027 043 B (corresponding U.S. Pat. No. 4,282,605). Such an audio system is operated by means of an operating voltage which is equal to the normal onboard power supply voltage of preferably 12 volt. In the case of loudspeakers with a resistance of 8Ω, particularly in the case of powerful amplifiers, a distortion factor occurs which is also clearly noticeable acoustically and which impairs the listening enjoyment. If, on the other hand, a higher operating voltage is to be used for the amplifiers in order to avoid the harmonic distortion, the interferences, which necessarily occur in the onboard power supply and which also occur on the supply lines of the amplifiers, result in clearly audible clicks and plops.
It is an object of the invention to provide an audio system of the initially mentioned type which permits an undisturbed listening enjoyment.
The invention achieves this object by providing an audio system of the type referred to above, wherein a separate amplifier is supplied with a significantly higher operating voltage than the at least one amplifier for other audio frequencies.
The invention provides a separation of the audio signals of the bass range and a separate amplification therefor. The high operating voltage is used only for supplying the separate amplifier. In addition, the use of two independent amplifiers can also be provided for the medium/high frequency range.
The amplifier of the bass range receives a supply voltage of preferably 42 volt, while the medium/high frequency range is supplied with, for example, 12 volt.
Occurring electric interferences do not affect the bass range because they have significantly higher frequencies. The use of a supply voltage of 42 V therefore results in a high power yield in the low-bass range while simultaneously acoustic interferences cannot be perceived. In contrast, such a high power yield is not required for the medium/high frequency range. The use of amplifiers with 12V permits a sufficient power yield. The power required for the medium/high frequency range can and will clearly be lower than for the bass range.
The invention will be further explained by means of the drawing.

Bayerische Motoren Werke Aktiengesellschaft


A reduced coefficient of thermal expansion and an increased resistance to thermal shock in cordierite-containing ceramic articles is achieved by contacting such articles with water either in a liquid or gaseous state. It is particularly desirable for such treatment to reduce the coefficient of thermal expansion of the article by at least 1.times.10.sup.-7 .degree. C..sup.-1, measured between 25.degree. and 800.degree. C., during the contacting. This treatment can be used in conjunction with extruded honeycomb structures conventionally used as diesel particle filters and supports for catalysts which treat automotive exhaust gases.

Automobile exhaust gases are conventionally purified with a catalyst supported on a ceramic body able to withstand high temperatures. The preferred catalyst support structure is a honeycomb configuration which includes a multiplicity of unobstructed parallel channels sized to permit gas flow and bounded by thin ceramic walls. The channels may have any configuration and dimensions provided gases can freely pass through them without being plugged by entrained particulate material. Examples of such preferred structures include the thin-walled ceramic honeycomb structures described in U.S. Pat. No. 3,790,654 to Bagley and in U.S. Pat. No. 3,112,184 to Hollenbach.
Ceramic honeycomb catalyst supports are exposed to high temperatures resulting from contact with hot exhaust gases and from the catalytic oxidation of uncombusted hydrocarbons and carbon monoxide contained in the exhaust gas. In addition, such supports must withstand rapid temperature increases and decreases when the automobile engine is started and stopped. Such operating conditions require the ceramic honeycomb catalyst support to have a high thermal shock resistance, a property generally inversely proportional to the coefficient of thermal expansion.
Generally similar ceramic structures are used as diesel engine particulate filters. In such applications, ceramic honeycomb filters are fitted to diesel engine exhaust systems for removal of particulates from the high temperature diesel engine exhaust gases. Examples of diesel engine particulate filters are disclosed in U.S. Pat. No. 4,329,162 to Pitcher, Jr. and U.S. Pat. No. 4,415,344 to Frost et al. Again, the ceramic materials utilized in such applications must have a high thermal shock resistance and a low coefficient of thermal expansion.
Cordierite (2MgO.multidot.2Al.sub.2 O.sub.2 .multidot.5SiO.sub.2) is known to display a very low thermal expansion over a wide range of temperature. In substantial amounts, cordierite gives a ceramic body excellent thermal shock resistance when subjected to rapid and severe changes in temperature. This property has caused cordierite to find widespread use as a catalyst support for automotive catalytic converters and as diesel engine particulate filters. Despite the low average coefficient of thermal expansion of corderite crystals, the need further to reduce this value in ceramic articles remains a desired objective.
U.S. Pat. No. 3,885,977 to Lachman et al. ("Lachman") forms an extruded, honeycomb carrier having thin walls extending between its ends, and comprising a mixture of clay, talc, and alumina which react during firing to form cordierite. Because of the orientation imparted to the clay and talc platelets during extrusion, the cordierite grains that develop during firing have a preferred orientation, with the cordierite crystallographic c-axes tending to lie in the plane of the walls and the a-axes tending to lie perpendicular to the plane of the walls, assuming that the cordierite is of the hexagonal variety. The thermal expansion of cordierite is known to be low, even negative, in the direction of the crystallographic c-axis and relatively high in the direction of the a-axis. As a result, a low coefficient of thermal expansion in the direction parallel to the walls and a higher coefficient of thermal expansion transverse to the walls is achieved. The low coefficient of thermal expansion aspect of the present invention is able to impart thermal shock resistance to the body as a whole. By contrast, the effect of the transversely-extending high coefficient of thermal expansion regions is minimal, because any expansion in such directions is accommodated by internal spaces in the honeycomb.
Cordierite bodies produced in accordance with Lachman are generally formed as elongate logs and then cut into shorter pieces after firing. To limit dust generation, water at a temperature of 5.degree. to 18.degree. C. is sprayed on the log during cutting. After cutting, the short pieces are washed and become fully saturated with water as they pass beneath a water curtain with the water being at a temperature of 5.degree. to 18.degree. C. A few minutes later, the washed pieces are blasted with air to remove water from their exterior and channels; some moisture, however, remains absorbed within the cordierite walls. A few minutes after air blasting, the pieces enter a drier, operating at temperatures in excess of 190.degree. C. After 17 minutes of drying, the pieces are removed from the dryer in a completely dry state. From cutting through drying, water remains in contact with the cordierite body for about 20 minutes. This treatment has little effect on the body's coefficient of thermal expansion.
In U.S. Pat. No. 3,958,058 to Elmer, cordierite with an ultra-low thermal expansion coefficient and a high thermal shock resistance is obtained by treating it with a strong mineral acid. The acid is said to remove Al.sub.2 O.sub.3 and MgO, while the low expansion values are partly attributable to microcracks in the leached material. It has been elsewhere recognized that the internal stresses in highly anisotropic crystalline cordierite ceramics lead to microcracking. Despite its ability to reduce a cordierite article's coefficient of thermal expansion, this acid treatment has not received wide acceptance, because it requires specialized handling systems for the acid, it chemically modifies the cordierite product by removal of Al.sub.2 O.sub.3 and MgO, and it can cause large reductions in mechanical strength.
U.S. Pat. No. 3,979,216 to Fritsch, Jr. et al. relates to the production of synthetic cordierite ceramics having thermal expansions below 1100 ppm in the temperature range of 25.degree.-800.degree. C. and 15 to 150 micrometer microcracks. This product is prepared by mixing talc, clay, and alumina, consolidating this mixture as a green body, heating at 150.degree. C. per hour to a temperature of 1350.degree. to 1425.degree. C., holding at this elevated temperature for 0.5 to 10 hours, and cooling to below 1000.degree. C. at a rate of -150.degree. C. per hour. Thermal expansion is said to be dependent upon maintaining a low glass content in the body.
U.S. Pat. No. 4,869,944 to Harada et al. relates to a cordierite honeycomb structural body formed by including high purity, non-crystalline silica in a mixture of talc, kaolin, and alumina. As a result, crystals with their c-axes preferentially oriented in the plane of the walls are formed. Structural microcracking occurs to the same degree regardless of whether or not high purity, non-crystalline silica is incorporated in the mixture; however, the use of silica causes more microcracks to form along the crystallographic c-axis direction of the crystals in the domain structure. With such microcrack orientation, the article is able to absorb positive thermal expansion better and give the body a low coefficient of thermal expansion.


An improved device for removing used needles from reusable syringes is provided. The device may be operated using only one hand and requires a single downward force applied to the syringe body by the health care worker. At the lower end of the downward stroke, the collar of the needle has been twisted off the syringe body and is automatically deposited into the receptacle for used needles. The health care worker releases the force and the apparatus automatically resets itself to receive another used needle. The device has few parts and may be assembled easily.

Devices have been developed for removing needles from reusable syringes, commonly sold under the trademark VACUTAINER, without exposing the health care worker to infectious diseases such as AIDS, hepatitis or syphilis. However, several problems are associated with the presently available needle-removing devices: some needle-removing devices include numerous parts and are difficult to assemble and manufacture; other needle-removing devices include complicated gear systems or employ electric motors and are therefore too expensive to manufacture; some needle-removing devices are entirely manual and therefore are slow to operate; and other needle-removing devices are too complicated to operate, are prone to operator error and are not considered to be effective safety devices. What is needed is a needle-removing device that is dependable, contains few parts, is easy to manufacture and is also easy and safe to operate.
The need for devices to remove needles from reusable syringe bodies without requiring the health care worker to handle the needle arose in the advent of infectious diseases, such as hepatitis, syphilis nd more recently, AIDS, which subject health care workers to serious risks in the workplace. Simply put, a health care worker may contract a serious infectious disease if a dirty needle, just used on an infected patient, mistakenly pricks the worker's skin thereby resulting in direct contact of the infected patient's bodily fluids with the bodily fluids of the worker. The inherent risk to health care workers created a demand for a device for removing needles from syringe bodies without requiring manual handling of the used needles by the workers thereby avoiding many accidental needle pricks to the hands of the workers.
One type of needle-removing device includes a slot for inserting the needle. The slot grips the collar of the needle and the user then rotates the syringe thereby removing the needle from the syringe body. The needle drops downward into a container. When the container is full, the used needles are discarded.
The problem associated with this type of device is that it requires multiple hand movements by the user. The user must first insert the needle in a relatively small slot, engage the collar of the needle in the slot and thereafter twist the syringe body an appropriate number of turns to effectively remove the needle from the syringe body. Often, the collars of the needles will get caught in the slot and then the workers must remove the needle from the slot by hand or employ an additional instrument. Further, if the worker leaves the used needle disposed in the slot, the needle and bodily fluid remained exposed.
A second type of design includes a device where the needle is inserted into a hole or slot and an internal gear mechanism causes the needle and collar to be twisted off the syringe body. The problem associated with these types of design is that they require numerous parts to manufacture and are difficult to assemble. Many of these types of designs require multiple drive gears that are prone to failure. Further, these types of devices are also expensive to manufacture.
A third type of design includes an electric motor driven device that grabs the needle as it is inserted into a slot. The motor drives the gears which twist the needle off the syringe body. These devices are ineffective because it includes numerous parts and is therefore more expensive to manufacture. Further, the device must be located near an electric outlet.
Thus, there is a present need for an effective removing device that is easy to manufacture as well as easy to operate. The present invention satisfies this need by providing an effective needle-removing device that can be manufactured from as little as eight parts. The device is actuated by simple downward movement of the needle and syringe by the worker. The needle is automatically removed from the syringe body and ejected into a receptacle below the needle-removing device and away from the worker.


A sliding member includes a back metal layer and a sliding layer on the back metal layer. The sliding layer includes a synthetic resin matrix and graphite particles dispersed in the matrix in a volume ratio of 5-50% of that of the sliding layer. The graphite particles are composed of spheroidal and flake-like particles. The flake-like particles have a volume ratio of 10-40% of total graphite particles. The spheroidal particles have a cross-sectional structure with a plurality of AB planes of a graphite crystal laminated along a curved particle surface, from the surface toward a center direction. The flake-like graphite particles have a cross-sectional structure with the plurality of AB planes laminated in a thickness direction of the thin plate shape. The spheroidal particles have an average particle size of 3-50 μm, and the flake-like graphite particles have an average particle size of 1-25 μm.

A sliding member has been conventionally used, which includes a resin composition added with graphite flakes, as a solid lubricant, in a synthetic resin matrix (see JP-A-2005-089514). In general, natural graphite is classified to flake graphite, vein graphite, and amorphous graphite according to their properties. The vein graphite has the highest graphitization degree of 100%. The flake graphite has the graphitization degree of 99.9%, and the amorphous graphite has the low graphitization degree of 28%. Conventionally, the natural graphite of the vein or flake graphite having the high graphitization degree has been mechanically grinded to produce flake-like particles to be used as a solid lubricant of a sliding member.
The flake-like shaped graphite has a crystal structure including a large number of laminated AB planes (hexagonal net planes, or basal surfaces) where carbon atoms form a net structure regularly and extend in a planar shape, and defining a thickness in C-axis direction which is perpendicular to the AB plane. A bonding strength, by van der Waals force, is much weak between the laminated AB planes compared with an in-plane direction of the AB plane. Thus, shearing easily occurs between the AB planes. Accordingly, this graphite has a smaller thickness of the lamination in comparison with the extension of the AB plane, and thus the graphite generally has a thin plate shape. The flake-like graphite particles function as a solid lubricant since the shearing occurs between the AB planes when an external force is applied thereto.
In recent years, there is a problem that flake-like graphite particles break and drop off from a sliding member having a resin composition including the flake-like graphite particles, when a surface of the resin composition, which forms a sliding surface, is subjected to machining, since the flake-like graphite particles have a thin plate shape and are brittle. In the case, the sliding layer has a larger surface roughness, resulting in deterioration of seizure resistance. In order to solve the problem, WO 2012/074107, for example, proposes a sliding material including spherical natural graphite particles in a synthetic resin to improve a surface roughness after the machining.
The spherical graphite particles are produced by repeatedly applying a small load on the natural flake-like graphite particles as a raw material for bending them, and thereby granulating them to have a spherical shape (see WO 2012/137770 or JP-A-2008-024588).