A method (200) for improving quality of output audio (126). The method can include detecting an output acoustic signal (128) and generating a receive audio signal (134) based, at least in part, on the detected output acoustic signal. A frequency domain representation (140) of the receive audio signal can be compared to a frequency domain representation (138) of a source audio signal (124) from which the output acoustic signal is generated. At least one distortion signal (142) in the receive audio signal can be identified, and the source audio signal can be selectively equalized to reduce an amplitude of the source audio signal at a frequency that correlates to the distortion signal.

1. Field of the Invention
The present invention generally relates to audio signal processing.
2. Background of the Invention
The design of high volume output audio transducers (e.g. loudspeakers) for small electronic devices is complicated. Small size restrictions in a mobile station, for example, typically limit the acoustic design to using only a very small output audio transducer. Nonetheless, high output audio levels are required to use the mobile station in speakerphone mode, which necessitates driving the output audio transducer with relatively high power. In this situation, it is not uncommon to have mechanical components within mobile station housing resonate due to vibration of the output audio transducer, which distorts the net sound being emanated by the mobile station.
In an attempt to minimize the effect of resonances, a designer of an electronic device may implement conventional equalization techniques to equalize audio output signals in order to reduce output audio volume at frequencies at which device components are known to resonate. However, the resonant frequencies of these components can vary from one device to another due to variations in manufacturing tolerances. Moreover, the resonant frequencies tend to shift over time due to components of the device loosening, grommets decaying, and general aging of the device. Thus, the use of conventional equalization techniques fails to insure long term acceptable sound quality from a small electronic device.

Dynamic distortion elimination for output audio


A piston velocity control and stability control system is provided for a combustion powered tool having a self contained combustion engine. The system includes a ring that may be adjusted relative to exit ports in a cylinder of the combustion engine. The ring includes openings which may be incrementally aligned between a completely exposed, and a substantially closed position relative to the exit ports. Displaced air volume within the cylinder exits through the exit ports as a piston advances down the cylinder, and the velocity of the piston will be greatest when the exit ports are completely exposed. User initiated reduction of the effective size of the exit ports by adjustment of the ring will reduce piston velocity as described per application. A nosepiece used to guide the driver blade and position the blade over a fastener is isolated from the cylinder so that the nosepiece remains stable relative to the workpiece upon combustion and until the driver blade strikes the fastener.

Portable combustion powered, or so-called IMPULSE.RTM. brand tools for use in driving fasteners into workpieces are described in commonly assigned patents to Nikolich U.S. Pat. No. Re. 32,452, and U.S. Pat. Nos. 4,552,162, 4,483,473, 4,483,474, 4,403,722, and 5,263,439, all of which are hereby incorporated herein by reference. Similar combustion powered nail and staple driving tools are also available commercially from ITW-Paslode of Lincolnshire, Ill. under the IMPULSE.RTM. brand.
Such tools incorporate a tool housing enclosing a small internal combustion engine. The engine is powered by a canister of pressurized fuel gas, also called a fuel cell. A battery-powered electronic power distribution unit produces the spark for ignition, and a fan located in the combustion chamber provides for both an efficient combustion within the chamber, and facilitates scavenging, including the exhaust of combustion by-products. The engine includes a reciprocating piston with an elongate, rigid driver blade disposed within a piston chamber of a cylinder body.
A valve sleeve is axially reciprocable about the cylinder and, through means of a linkage, moves to close the combustion chamber when a work contact element at the end of the linkage is pressed against a workpiece. This pressing action also triggers a fuel metering valve to introduce a predetermined volume of fuel gas into the closed combustion chamber.
Upon the pulling of a trigger switch, which causes the ignition of a charge of gas in the combustion chamber of the engine, the piston and driver blade are shot downward so as to impact a positioned fastener and drive it into the workpiece. As the piston is driven downward, a displacement volume enclosed in the piston chamber below the piston is forced to exit through one or more exit ports provided at the lower end of the cylinder. After impact, the piston then returns to its original, or "ready" position through differential gas pressures within the cylinder. Fasteners are fed magazine-style into the nosepiece, where they are held in a properly positioned orientation for receiving the impact of the driver blade.
Combustion powered tools may be contrasted from conventional powder activated technology (PAT) tools, which employ a gunpowder powered cartridge to propel a driving member to drive a fastener into a workpiece. PAT tools generate an explosion in a combustion chamber which creates high pressures for propelling the driving member at a high velocity toward the fastener. The relatively small volume of the combustion chamber and the explosive combustion combine to create a rapid acceleration of the driving member for the velocity required for achieving proper fastener driving. In contrast, combustion powered tools typically provide a much slower acceleration of the driving member. This is due to the relatively large size of the combustion chamber, and to the requirement of the preferred fuel to obtain atmospheric oxygen for combustion (the powder in PAT tools incorporates its own oxygen). Thus, in combustion powered tools, the combustion event is a relatively gradual process. Commercially available combustion powered tools have relatively short cylinder bodies, so that the driving member is incapable of achieving velocities which are comparable to those of PAT tools.
A high velocity combustion powered tool of the type described above and featuring an extended piston chamber or cylinder is the subject of a co-pending patent application serial number 08/536,854, filed Sep. 29, 1995. The extended cylinder increases the stroke of the piston, thereby allowing for increased piston velocity and transfer of power from the driver blade to the fastener. In one embodiment, the extended length also allows an operator to stand generally upright while driving fasteners which are at foot level.
A number of factors influence piston velocity, including piston diameter and stroke, but these factors are fixed by design in a particular tool. One way to vary the power of a combustion powered tool is by means of controlling the speed of the fan in the combustion chamber, as described in copending U.S. application Ser. No. 08/337,289, filed Nov. 10, 1994. A circuit is used to vary fan speed, and increased fan speed produces additional power. However, in most conventional combustion powered tools, the piston velocity is fixed by design.
In conventional combustion powered tools, the fixed piston velocity prevents an operator from controlling the driving depth of the fastener being driven into a particular type of workpiece or substrate. In addition, depending on the composition of the workpiece or substrate, the lack of velocity control may prevent an operator from obtaining a desired consistent driving depth. An identical driver blade velocity, when translated into a force applied to a fastener being driven into wood, for instance, will result in a different depth when applied to a fastener being driven into a steel beam. Such velocity will result in still another depth when applied to a fastener being driven into sheet metal being fastened to a roof truss. Thus, depending on the design of the tool, there may be insufficient power to properly drive a fastener into all desired workpieces.
An additional problem, limited primarily to the high velocity, extended cylinder tools, concerns stability of the tool during operation. The increased stroke of extended length combustion tools, used to increase both velocity and power transfer, also increases the delay between combustion and the driving of a fastener into the substrate. This increased delay can reduce the amount of control and applied power of the tool, because the tool recoils in reaction to the combustion, causing the tool nosepiece to move with respect to the workpiece before the fastener is actually driven. Drawbacks of such operation are misaligned or incompletely driven fasteners.

Velocity control and nosepiece stabilizer system for combustion powered tools


A system for measuring fluid flow through a plurality of holes in a part, such as an engine combustor part, comprises a hood, including a leak-resistant seal, the seal being capable of receiving or engaging an inner or outer side of the wall of the part; a pump or variable pressure blower coupled to the hood by a fluid flow line; a pressure sensor to measure pressure inside the hood; a controller coupled to the pump or blower to establish a predetermined pressure inside the hood in response to the pressure sensor, and a flow sensor in the fluid flow line to measure the fluid flow rate through the fluid flow line.

Inner or outer engine combustor liners are typically substantially circularly radially symmetrical. Furthermore, such combustor liners or parts for aircraft engines or gas turbines typically require a plurality of holes, often thousands, having a small diameter and being precisely placed to satisfy stringent fluid flow requirements desirable for satisfactory engine operation. One problem associated with the fluid flow requirements for such engine combustor parts is the capability to measure fluid flow in the relevant dynamic range of flows, given a predetermined pressure differential. More particularly, measuring the effect on the fluid flow of a misplaced or poorly formed hole in the part generally exceeds the capabilities of present fluid flow sensor technology, such as on the order of 0.030 lbs.mass/second for a row of holes or about 75 cubic feet per minute. Yet another problem is satisfactorily testing the part in a manner that addresses the large fluid or air flows associated with the operation of such an engine liner or part. Thus, large and costly flow test installations are frequently necessary for "full" flow testing of the combustor parts.
One approach to solving these problems has included performing random "spot checks" of hole diameters using gauge pins to assist in making adjustments to the drilling, usually performed by a laser beam, to fabricate or form the holes. A full flow test may then be performed on the finished part at a "flow" test installation or laboratory, as described above; however, this approach has several disadvantages. First, hole diameter checking using gauge pins is notoriously inexact, and furthermore may not provide a true indication of fluid flow. Likewise, such a technique fails to take into account hole taper, hole angle of orientation with respect to the part wall, or other possible hole fabrication anomalies other than hole size that may also affect flow. Furthermore, once the part is capable of being "fully" flow tested, modifications or corrections to the part are not feasible and the part must ultimately be scrapped if it does not perform within desired specifications. A need thus exists for an alternative method or apparatus to measure the fluid flow through holes in an engine combustor part or liner that satisfactorily overcomes these problems.


The invention relates to systems and methods of operating a wireless network including allocating and assigning frequency channels using a dynamic and distributed process. For example, a network node in an ad hoc wireless network will assign frequency channels to one or more of its transceivers based on at least one of a list of allowed frequency channels and a neighbor-frequency channel list.

Wireless communications between multiple devices or nodes within a network is becoming more and more prevalent. Currently, the nodes in most wireless multi-hop networks only contain a single transceiver, which only communicates over a single, preset frequency. This limits the maximum data capacity of the nodes and the network. Recent transceiver developments have resulted in transceivers that are cheaper and tunable over a wide frequency band. As a consequence, wireless network nodes can now be equipped with multiple transceivers and operate on multiple, tunable frequencies.
With the new capabilities provided by these tunable multi-transceiver network nodes, new frequency allocation methods are possible. One particular method, known as dynamic spectrum access, enables the assignment of operating frequencies to transceivers in real time, based on conditions of the surrounding network environment. This improved flexibility allows increased network capacity, both in terms of data transmission and number of nodes allowed, because the network can now more efficiently utilize the available spectrum.
To date, however, most dynamic frequency allocation methods are based on a centralized system, where a central computer decides how to allocate frequencies to a plurality of network nodes. This centralized system may lack knowledge of conditions local to particular network nodes, such as location and range, and the overhead involved in the centralized frequency assignments may impact network performance. This is exacerbated if the network contains mobile network nodes. Moreover, current dynamic frequency allocation methods do not consider the effect of non-cooperative nodes.

Distributed assignment of frequency channels to transceivers over dynamic spectrum


An apparatus for filling a hydrodynamics bearing with fluid. The apparatus includes a fill tube having first and second openings and a fluid reservoir having a reservoir opening. The first opening of the fill tube is aligned relative to a bearing channel opening for filling bearing channels. The second opening of the fill tube is selectively aligned relative to the fluid reservoir for filling bearing channels with fluid from the fluid reservoir via relative movement of the fill tube and fluid reservoir between a retracted position and a filling position. In the retracted position, the second opening of the fill tube is spaced from the reservoir and in the filling position, the second opening of the fill tube is immersed in the fluid reservoir to fill the bearing channels with fluid from the fluid reservoir.

The present invention relates to an apparatus and method for filling a hydrodynamics bearing with bearing fluid. In particular, the present invention relates to a method and apparatus for filling a hydrodynamics bearing of a spindle motor of a disc drive.
Disc drive memory storage systems include disc packs which include a plurality of stacked discs which are supported for co-rotation about a spindle shaft coupled to a base of the disc drive. A spindle is supported for rotation about the spindle shaft. A hub is rotationally coupled to the spindle to support a plurality of stacked discs for rotation.
Known disc drives include a ball bearing system for rotationally supporting the spindle relative to the spindle shaft. However, due to microscopic surface imperfections, such as rough or uneven operating surfaces, ball bearings impart vibrations to rotating discs. This vibration results in misalignment between the read and write transducers of a data head and the data tracks on the surface of the disc, thus affecting the performance and operation of the disc drive. In hard drives in portable computers, transportation of the hard drive may exaggerate the misalignment and cause damage to the ball bearings, due to vibrations and shock introduced during transport. Additionally, ball bearings are not easily sealable to smaller dimensions, thereby limiting the physical dimensions-of the disc drive.
Accordingly, hydrodynamics bearings are an alternative to ball bearing systems. In the case of hydrodynamics bearings, a fluid lubricant fills bearing channels defined between the spindle shaft and spindle to support the spindle for rotation about the spindle shaft. It is important to avoid the presence of any air bubbles within the bearing channels of the bearing. The absence of air bubbles will minimize the pressure buildup inside the motor due to drops in the ambient pressure and/or thermal expansion due to increased temperature. Pressure buildup can cause the bearing to leak hydrodynamics fluid. This absence of air bubbles helps eliminate hydrodynamics fluid leakage.
Hydrodynamics fluid leakage can cause contaminants to be expelled into the disc drive which can degrade disc performance. The loss of bearing fluid can also cause increase wear to the bearing surfaces of the spindle and the spindle shaft, leading to eventual failure of the bearing. Thus, it is desirable to provide an apparatus and method for filling bearing channels of a hydrodynamics bearing where air is evacuated from the bearing channels, which is efficient and cost effective and can operate without excessive human handling.

Method for filling a hydrodynamic bearing


A method including enabling a first user having a first user device to communicate with one or more second users having one or more second user devices via a network, wherein each user has a spatial position within a virtual space, such that, for each user within the virtual space, all other users within the virtual space have a relative spatial position; providing spatial audio data from the first user device to the one or more second user devices and receiving spatial audio data at the first user device from the one or more second user devices, such that each user is provided with audio from the other users in the respective relative spatial positions of the other users; and enabling a third user having a third user device to communicate with the first user and the one or more second users via the first user device.

Systems are known to enable a first user having a first user device to communicate with a second user having a second user device via a network (such as a mobile communications network and/or the Internet). Moreover, such systems can provide audio outputs such that each user is presented with audio from the other systems in a relative spatial position of said other users within a virtual space.

Use of local link to support transmission of spatial audio in a virtual environment


An apparatus and method of the present invention allows the digitally decoding of asynchronous communication signals and includes a sampling and storing circuit for sampling a digitally converted asynchronous communication signal and storing sampled signal values corresponding to negative edge signal values, positive edge signal values, and central signal values. A derivative calculating circuit is connected to the sampling of storing circuit for receiving at least negative edge signal values and positive edge signal values and calculating derivatives. A comparator circuit receives the calculated derivatives and compares the derivatives with the threshold based on the calculated negative derivative and produces negative output and positive output values used for determining a decoded output signal.

This invention relates to the field of asynchronous data communications, and more particularly, this invention relates to the field of decoding asynchronous digital data that is sent over a wire line, radio or fiber optic communication channel.
In the copending patent application Ser. No. 09/169,517, the problems of asynchronous communication systems and prior art methods for decoding were addressed. In that apparatus, the amplitude of a signal bit having negative and positive peak values was measured and a mid-bit reference computed. Changes in the base band signal peak excursions were tracked and the mid-bit reference was updated from the tracked changes of the base band signal excursions. To track thermal drifts and components aging, the positive and negative peak registers were periodically decremented and incremented, respectfully, at a rate several orders of magnitude slower than the ADC sample rate.
This apparatus addressed asynchronous communication systems that were commonly used where data was not time oriented and was sent in bursts and typically received in a burst receiver.
It is well known that in order to decode incoming data correctly, knowledge of the data amplitude should be ascertained in order to establish a reference within a communications receiver. Any receiver also should typically be capable of performing DC signal restoration during potentially long xe2x80x9cquietxe2x80x9d periods. An example of a xe2x80x9cquietxe2x80x9d period is shown in FIG. 1, where a frame of data has a stop bit, intermediate data (represented by the letter D) and a stop bit, followed by a two minute signal delay, followed by another frame of data with a start and stop bit and intermediate data (D).
Asynchronous digital data is often sent over a wire line, radio link, or fiber optic communication channel. In some prior art systems, analog implementations have been used for decoding the asynchronous signals. Typically, decoding circuits have been designed to take into consideration the length of a communication line or the link loss. In this type of system, the circuit will restore an analog signal to obtain a digital signal value and then make a decoding decision on the digital signal value. Typically, the circuit is designed based on knowledge of the difference in data amplitude coming into a communications receiver, such as in a fiber optic communications system.
In some prior art applications where the link distance is still known with certainty, the receiver could move even if the transmission distance and theoretical amount of attenuation is known. The link loss, however, would not be known and the signal strength could be variable. In some prior art asynchronous communication systems, designers typically would know the distance between a transmitter and receiver. For example, the communication line could be from room-to-room, or from city-to-city. Once this link distance is known, then the circuit is designed based on the theoretical amount of signal attenuation. There are often times when the amount of signal attenuation cannot be known in a communication line. Also DC signal restoration is difficult.
One of the key aspects of asynchronous data communication is the transmittal of packets or frames. Typically, a burst receiver may be used as mentioned before. In many prior art burst receivers, the receiver will lose its DC reference over a time pause in signal communication, which is why many communication systems use Manchester encoding or pseudo random number generation.
An example of one problem with DC signal restoration is comparing the difference between transmitting asynchronous data over three feet of cable between two computers in the same room, as compared to a longer distance system. In the asynchronous data communication system, if a logical 1 corresponds to five volts and a logical 0 corresponds to zero volts, there would be little problem in finding the midpoint reference or threshold when the data signal is transmitted through only three to five feet of cable. However, if the data signal is transmitted through 100 miles of cable, then the final attenuation would be great and the final signal could be about 100 millivolts. If the ideal threshold was set when only the three foot cable were used (i.e., a threshold of 2.5 volts), that threshold would be insufficient for the 100 mile transmission length and the threshold value would have to be lowered to about 50 millivolts. Thus, it is evident why the threshold in the most basic prior art asynchronous data communication system was set based on the transmission distance.
Some analog devices that are used for measuring the signal attenuation and setting a signal threshold in a receiver have been used with asynchronous data communications, but these systems do not accomplish high dynamic range burst mode asynchronous data decisions because of thermal drifts and parasitic effects of passive and active components.
Other common prior art methods have also been used to establish a signal reference in asynchronous data communication systems.
In a preamble system, several disposable data bits are sent prior to a data payload having the start bit to allow a decision circuit in the communications receiver to establish a signal reference. Thus, as soon as a start bit is transmitted, the circuitry has measured both zero and one logic levels and has set a threshold half-way between the zero and one logic levels.
In a second method known as xe2x80x9cavoidance of risk mode of operation,xe2x80x9d a continuous stream of data is sent with an even mix of ones and zeros by using a randomizing circuit. To avoid a long quiet period, which sometimes occurs such as a two minute delay as shown in FIG. 1, the data is multiplied by a pseudo random number in the transmitter to ensure the data stream is rich in data transitions. Thus, there will always be ones and zeros that are transmitted. Then the communications receiver circuitry decodes the pseudo random number and extracts the information.
In another method known as automatic gain control (AGC), a constant automatic gain control circuit controls the communications receiver gain. For example, if the transmission line is 100 miles long and there is a 100 millivolt threshold, then the signal will be amplified back to five volts. As a result, the system would use a 2.5 volt reference. However, there are time constants. If the system is quiet for extended periods, for example, about two minutes or some other time period, then the signal will decay and there is no signal information on which to make a gain or adjustment of the signal. Thus, the DC signal information is not present.
It is evident that the prior art methods are not adequate in some circumstances. For example, the preamble system reduces the data rate of the channel. As a result, in asynchronous data transmission, the preamble method prevents binary data transfer. Certain characters could be sent as a preamble and would, therefore, not be used for the information content. For example, if bits are sent to a communications receiver in order to synchronize that receiver, then no data information is sent. Thus, the preamble system requires a preamble and prevents binary data transfer. If binary data is transmitted, there could be no start bit. The preamble system would not know the difference between a binary data bit or preamble bit. There could also never be a xe2x80x9csyncxe2x80x9d word in the binary transmission because it would mistake it for a frame signal. In the xe2x80x9cavoidance of the first mode of operation,xe2x80x9d as noted before, a continuous transmission is required for randomized data. The automatic gain control system (AGC) solves the problem of amplitude fluctuations, but does not solve the problem of DC restoration. In an automatic gain control system, it is possible to correct the gain, but it cannot affect the DC reference point.
Although the apparatus disclosed in copending U.S. patent application Ser. No. 09/169,517 discloses a method and apparatus that decodes asynchronous data signals, that apparatus has not been found feasible with a signal having significant distortions, amplitude variations and DC offsets over a wide dynamic range, such as greater than 40 dB.
It is therefore an object of the present invention to provide an apparatus and method for decoding asynchronous data signals where the communication link contains unanticipated signal distortions that prevent reliable communication.
In accordance with the present invention, the apparatus digitally decodes asynchronous communication signals and includes a sampling and storing circuit for sampling a digitally converted asynchronous communication signal and storing sampled signal values corresponding to negative edge signal values, positive edge signal values and central signal values. A derivative calculating circuit is connected to the sampling and storing circuit for receiving at least negative edge signal values and positive edge signal values and calculating derivatives. A comparator circuit receives the calculated derivatives and compares the derivatives with a threshold based on a calculated negative derivative and produces negative output and positive output values used for determining a decoded alpha signal.
The derivative calculating circuit includes a plurality of subtraction circuits that receive sampled signal values to calculate a plurality of derivatives. A threshold control circuit is connected to the derivative calculating circuit and receives a derivative calculated from a maximum negative and positive edge signal value. A bit timer receives the negative output and positive output values and times operation of the sampling and storing circuit, derivative calculating circuit and comparator circuit. An automatic gain control circuit is connected to the threshold circuit for receiving compared values of previously stored and decoded output signals. A storage register stores samples of the decoded output signal and an output control circuit receives negative output and positive output values and produces decoded output signals.
A method of the present invention is also disclosed for digitally decoding asynchronous communication signals. A digitally converted asynchronous communication signal is sampled and a plurality of sampled signal values are stored corresponding to negative edge signal values, positive edge signal values and central signal values. The method further comprises the step of calculating derivatives based on sampled signal values and comparing the calculated derivatives for the threshold based on the calculated negative derivative. Negative output and positive output values are produced.

Apparatus and method for decoding asynchronous data using derivative calculation


In one embodiment, a system includes a TRILL-enabled network that includes a first physical routing bridge (RB) and a second physical RB, logic adapted for creating a virtual RB logically connected to the first and second physical RBs to form a vLAG group at an edge of the network, logic adapted for determining a first distribution tree linking the first physical RB to every other RB in the network in a non-repeating fashion, ending with the second physical RB, and logic adapted for determining a second distribution tree linking the second physical RB to every other RB in the network in a non-repeating fashion, ending with the first physical RB, wherein when a multicast packet is received by the virtual RB from one of the physical RBs, the multicast packet is distributed according to either the first or the second distribution tree thereby preventing looping.

The present invention relates to data center infrastructure and operation, and more particularly, this invention relates to enabling an extension of Virtual Link Aggregation (vLAG+) in a Transparent Interconnection of Lots of Links (TRILL)-based fabric network.
TRILL is a Layer-2 (L2) protocol which provides the ability to build a scalable Local Area Network (LAN) that is capable of replacing conventionally-used spanning-tree and other protocols. Details of the solution are described as part of the Internet Engineering Task Force (IETF) TRILL working group, found at http://datatracker.ietf.org/wg/trill/. A collection of entities called Routing Bridges (RBs) implement the TRILL protocol. RBs enhance some existing 802.1 bridges to function in a transparent manner. These RBs may either interoperate with or replace the functions of any existing 802.1 bridges.
In existing 802.1 bridge deployments, vLAG is a very popular LAG solution that allows a host, switch, or some other device to connect itself to two different 802.1 upstream bridges. The two upstream bridges work together to present a single LAG port instance so that the downstream devices do not perform any special tasks for the LAG to exist. The downstream devices work as though they are connected to two ports of a single bridge. In order to support this functionality, the two upstream bridges are connected through a link referred to as an Inter Switch Link (ISL). These two physical upstream bridges exchange information through the ISL. This solution supports an active-active scheme for all the VLANs carried on any LAG port.
However, when an existing 801.q bridge function is enhanced or replaced by a RB function, there are issues that occur that are not capable of being handled with conventional schemes that threaten to destroy the existing behavior of vLAG. The main issue is that when two RBs detect one another, one of the RBs asserts the Appointer Forwarder role. This mechanism elects only one of the RBs to be able to forward traffic for a given VLAN. This is not a desirable outcome because the active-active load balancing scheme for any given VLAN is broken when only one RB is forwarding all traffic. Load balancing is one of the main advantages of having vLAG span across multiple 801.q bridges, and with conventional techniques, it is not possible to take advantage of this load balancing.

Virtual link aggregation extension (VLAG+) enabled in a TRILL-based fabric network

International Business Machines Corporation


A paper feeding unit for a printing apparatus including conveyance and friction rollers conveying paper from a paper cassette to an image-transfer zone, the paper being urged against a frame, having a surface substantially parallel with the image-transferring zone, with one end of a spring mounted on the end of a cantilevered paper guide.

1. Field of the Invention
The present invention relates to printers. More particularly, the present invention relates to a paper feeding unit in a printer that reduces curling of the recording stock and maintains a gap between the printer head and the print media.
2. Discussion of Prior Art
Ink-jet printers, facsimiles, copy machines and like apparatuses employ printer heads. Referring to FIGS. 7-10, many printers include a head cartridge 1 containing ink used to form characters on print media, a carriage 2 that moves the head cartridge 1 along the print area, and a driving unit (not illustrated). The printer also includes a paper cassette 3 holding paper P, pickup rollers 4 for picking up paper, a paper sensor (not illustrated), conveyance rollers 5, aligning the leading edge of the paper and conveying it, and a registration sensor 6 controlling the conveyance rollers 5 and aligning the leading edge of the paper. A guide 7 conveys the paper, and a paper delivery roller 8 discharges the paper.
Once a print command is received by the printer from a host computer, the control unit of the printer directs the drive unit to operate. The pickup rollers 4 pick up the paper P one sheet at a time from the paper cassette 3 and deliver the sheets to the conveyance rollers 5 along the guide 7.
The registration sensor 6 converts a distance to the entrance to the conveyance rollers into time, and adds paper to be conveyed according to a value obtained by the conversion to let the paper be curled between the pickup rollers 4 and the conveyance rollers 5, aligning its leading edge. The conveyance rollers 5 deliver the paper to the printer front zone below a nozzle 1a of the cartridge 1. The cartridge 1 on the carriage 2 is translated according to a signal produced from a head driver, depositing ink particles on the paper to form characters thereon. Once the one-line printing is completed, the conveyance rollers 5 transfer the paper by a given length to complete the overall printing job, and the paper is output through the paper delivery roller 8, thus finishing one-cycle printing.
In the conventional ink-jet printer several problems may occur frequently when the paper P, picked up by the pickup rollers 4, is conveyed to a printing zone S. Referring to FIG. 9, a conveyance zone y exists between line k and the printing zone S. The paper, transferred by the conveyance force of the conveyance rollers 5, passes through the conveyance zone y into the printing zone S where characters are formed on the paper P by the cartridge 1. The characteristics of the paper P vary with the humidity and temperature of the room in which the printer is situated. The paper P must be used in a room with proper humidity and temperature to ensure good print quality. Improper temperature and humidity causes a paper curling problem in the conveyance zone y. The result of the paper curling problem is particularly acute after the paper moves into the printing zone y. In a room having improper temperature and humidity, the paper curls toward the printer or image-transferring head, which causes distorted images, smearing and other problems. Conventional printers typically do not have any mechanisms for preventing the paper curling problem. Therefore, printing sometimes is carried out on the paper having a portion elevated beyond a printing interval formed between the nozzle 1a of the cartridge 1 and a guide frame 11. During printing, some areas of the paper P gets close to the nozzle 1a of the cartridge 1, the interval between the paper P and the nozzle 1a being not constantly maintained, thus making the print quality inferior. In the worst case, the curled paper directly contacts the nozzle 1a of the cartridge 1 to make the nozzle 1a of the cartridge 1 unclean and deteriorating the overall print quality. In addition, the nozzle 1a of the cartridge 1 must be cleaned frequently. The paper curling problem also makes it difficult to introduce the leading edge of the paper between the paper delivery rollers 8, thus resulting in a paper jam.
The above demonstrates a need for a mechanism that reduces the potential image transfer and paper feed problems associated with paper curl.
U.S. Pat. No. 5,564,847 for Media Handling in an Ink-jet Printer Having Guide Ribs issued to Patrick et al., and also U.S. Pat. No. 5,527,123 for Media Handling in an Ink-jet Printer issued to Jackson et al., include an upper print media guide 118 having an extending portion 119 that terminates in a lower support edge 122 which contacts and supports paper 110 from above. A lower print media guide 126, downstream from the upper medium guide, includes an upwardly extending support edge 130. Although the medium 110 is shown maintaining a uniform spacing between it and a printer head 103, between the two dashed lines of FIG. 3, the lower support edge 122 and the upper support edge 130 actually urge the medium 110 to assume a humped, or non uniform, print area relative to the head 103.
U.S. Pat. No. 5,420,621 for Double Star Wheel for Post-printing Media Control in Inkjet Printing issued to Richtsmeier et al., referring to FIG. 1, includes a main drive roller 15 with idler roller 16 cooperating to maintain tension in the sheet 12. The device also includes a starwheel-type pinch wheel 28 which cooperates with an output driver roller 26 to maintain tension in the sheet and to control the position of the sheet relative to the printer head 22.

Paper feeding unit for apparatus using printer head


A pharmaceutical composition for the sustained release of human growth hormone from a polymer matrix is disclosed. The pharmaceutical composition comprises a biocompatible polymer, particles of metal cation-complexed human growth hormone wherein said particles are dispersed within the biocompatible polymer and an aqueous injection vehicle.

Human growth hormone (hGH) is a protein secreted by the pituitary gland and which can be produced by recombinant genetic engineering. hGH will cause growth in all bodily tissues which are capable of growth.
hGH is typically used to treat patients suffering from hypopituitary dwarfism. Currently, aqueous hGH is administered as a subcutaneous bolus three times a week, or once daily, to patients to maintain suitable serum levels of hGH. For patients chronically receiving hGH, the frequent injections result in patient compliance problems.
To resolve the problems associated with repetitive injections of aqueous hGH, attempts have been made to formulate controlled release devices containing higher doses of hGH than a bolus injection, encapsulated within a polymeric matrix wherein the hGH would be released in vivo over a period of about a week or more.
However, these controlled release devices often exhibited high initial bursts of hGH release and minimal hGH release thereafter. Further, due to the high concentration of hGH within these controlled release devices, the hGH molecules have tended to aggregate after several days to form aggregated hGH which is immunogenic in vivo and likely has reduced biological activity.
Therefore, a need exists for a means for sustaining the release of biologically active hGH in vivo without causing an immune system response over the release period of the hGH.
This invention relates to a composition, and methods of forming and using said composition, for the sustained release of biologically active, stabilized human growth hormone (hGH). The sustained release composition of this invention comprises a polymeric matrix of a biocompatible polymer and particles of biologically active, metal cation-stabilized hGH, wherein said particles are dispersed within the biocompatible polymer.
The method of the invention for forming a composition for the sustained release of hGH, includes dissolving a biocompatible polymer in a polymer solvent to form a polymer solution, dispersing particles of biologically active, stabilized hGH in the polymer solution, and then solidifying the polymer to form a polymeric matrix containing a dispersion of said hGH particles.
The method of using the sustained release composition of the present invention comprises providing a therapeutically effective blood level of biologically active, non-aggregated human growth hormone in a subject for a sustained period by administering to the subject a dose of said sustained release composition.
The advantages of this sustained release formulation for hGH include longer, more consistent in vivo blood levels of hGH, lower initial bursts of hGH, and increased therapeutic benefits by eliminating fluctuations in serum hGH levels. The advantages also include increased patient compliance and acceptance by reducing the required number of injections. The advantages further include the ability to use smaller amounts of hGH compared to bolus injection regimen because serum hGH levels are maintained closer to therapeutical thresholds.
The foregoing and other objects, features and advantages of the invention will be apparent from the following more particular description of preferred embodiments of the invention.
The human growth hormone (hGH) used in this invention is biologically active hGH in its molecular (monomeric or non-aggregated) form. Molecular hGH is typically non-immunogenic.
Aggregated hGH may induce an immune response resulting in antibodies formed against hGH. This may compromise the efficacy of long-term hGH therapy. Additionally, aggregated hGH may stimulate an auto-immune response to endogenous hGH.
A sustained release of biologically active, non-aggregated human growth hormone is a release which results in measurable serum levels of biologically active, monomeric hGH over a period longer than that obtained following direct administration of aqueous hGH. It is preferred that a sustained release be a release of hGH for a period of about a week or more, and more preferably for a period of about two weeks or more.
A sustained release of biologically active, non-aggregated hGH from a polymeric matrix can be continuous or non-continuous release with relatively constant or varying rates of release. The continuity of hGH released and level of hGH released can be established by using, inter alia, one or more types of polymer compositions, hGH loadings, and/or selection of excipients to produce the desired effect.
Stabilized (hGH) comprises biologically active, non-aggregated hGH which is complexed with at least one type of multivalent metal cation, having a valency of +2 or more, from a metal cation component. Stabilized hGH in the sustained release composition of the present invention is in particulate form.
Suitable multivalent metal cations include metal cations contained in biocompatible metal cation components. A metal cation component is biocompatible if the cation component is non-toxic to the recipient, in the quantities used, and also presents no significant deleterious or untoward effects on the recipient""s body, such as an immunological reaction at the injection site.
Typically, the molar ratio of metal cation component to hGH, for the metal cation stabilizing the hGH, is between about 4:1 to about 100:1 and more typically about 4:1 to about 10:1.
A preferred metal cation used to stabilize hGH is Zn+2. In a more preferred embodiment, the molar ratio of metal cation component, containing Zn+2 cations, to hGH is about 6:1.
The suitability of a metal cation for stabilizing hGH can be determined by one of ordinary skill in the art by performing a variety of stability indicating techniques such as polyacrylamide gel electrophoresis, isoelectric focusing, reverse phase chromatography, HPLC and potency tests on hGH lyophilized particles containing metal cations to determine the potency of the hGH after lyophilization and for the duration of release from microparticles. In stabilized hGH, the tendency of hGH to aggregate within a microparticle during hydration in vivo and/or to lose biological activity or potency due to hydration or due to the process of forming a sustained release composition, or due to the chemical characteristics of a sustained release composition, is reduced by complexing at least one type of metal cation with hGH prior to contacting the hGH with a polymer solution.
Stabilized hGH is typically stabilized against significant aggregation in vivo over the sustained release period. Significant aggregation is defined as an amount of aggregation resulting in aggregation of about 15% or more of the initial amount of encapsulated hGH monomer. Preferably, aggregation is maintained below about 5% of the initial dose of hGH monomer. More preferably, aggregation is maintained below about 2% of the initial dose.
The hGH in a hGH sustained release composition can also be mixed with other excipients, such as bulking agents or additional stabilizing agents, such as buffers to stabilize the hGH during lyophilization.
Bulking agents typically comprise inert materials. Suitable bulking agents are known to those skilled in the art.
A polymer, or polymeric matrix, suitable for the sustained release composition of the present invention, must be biocompatible. A polymer is biocompatible if the polymer, and any degradation products of the polymer, are non-toxic to the recipient and also present no significant deleterious or untoward effects on the recipient""s body, such as an immunological reaction at the injection site.
The polymer of the hGH sustained release composition must also be biodegradable. Biodegradable, as defined herein, means the composition will degrade or erode in vivo to form smaller chemical species. Degradation can result, for example, by enzymatic, chemical and physical processes.
Suitable biocompatible, biodegradable polymers include, for example, poly(lactides), poly(glycolides), poly(lactide-co-glycolides), poly(lactic acid)s, poly(glycolic acid)s, poly(lactic acid-co-glycolic acid)s, polycaprolactone, polycarbonates, polyesteramides, polyanhydrides, poly(amino acids), polyorthoesters, polycyanoacrylates, poly(p-dioxanone), poly(alkylene oxalate)s, biodegradable polyurethanes, blends and copolymers thereof.
Further, the terminal functionalities of the polymer can be modified. For example, polyesters can be blocked, unblocked or a blend of blocked and unblocked polymers. A blocked polymer is as classically defined in the art, specifically having blocked carboxyl end groups. Generally, the blocking group is derived from the initiator of the polymerization and is typically an alkyl group. An unblocked polymer is as classically defined in the art, specifically having free carboxyl end groups.
Acceptable molecular weights for polymers used in this invention can be determined by a person of ordinary skill in the art taking into consideration factors such as the desired polymer degradation rate, physical properties such as mechanical strength, and rate of dissolution of polymer in solvent. Typically, an acceptable range of molecular weights is of about 2,000 Daltons to about 2,000,000 Daltons. In a preferred embodiment, the polymer is a biodegradable polymer or copolymer. In a more preferred embodiment, the polymer is a poly(lactide-co-glycolide) (hereinafter xe2x80x9cPLGAxe2x80x9d) with a lactide:glycolide ratio of about 1:1 and a molecular weight of about 5,000 Daltons to about 70,000 Daltons. In an even more preferred embodiment, the molecular weight of the PLGA used in the present invention has a molecular weight of about 6,000 to about 31,000 Daltons.
The amount of hGH, which is contained in a dose of sustained release microparticles, or in an alternate sustained release device, containing biologically active, stabilized hGH particles is a therapeutically or prophylactically effective amount, which can be determined by a person of ordinary skill in the art taking into consideration factors such as body weight, condition to be treated, type of polymer used, and release rate from the polymer.
In one embodiment, an hGH sustained release composition contains from about 0.01% (w/w) to about 50% (w/w) of biologically active, stabilized hGH particles. The amount of such hGH particles used will vary depending upon the desired effect of the hGH, the planned release levels, the times at which hGH should be released, and the time span over which the hGH will be released. A preferred range of hGH particle loading is between about 0.1% (w/w) to about 30% (w/w) hGH particles. A more preferred range of hGH particle loading is between about 0.1% (w/w) to about 20% (w/w) hGH particles. The most preferred loading of the biologically active, stabilized hGH particles is about 15% (w/w).
In another embodiment, a hGH sustained release composition also contains a second metal cation component, which is not contained in the stabilized hGH particles, and which is dispersed within the polymer. The second metal cation component preferably contains the same species of metal cation, as is contained in the stabilized hGH. Alternately, the second metal cation component can contain one or more different species of metal cation.
The second metal cation component acts to modulate the release of the hGH from the polymeric matrix of the sustained release composition, such as by acting as a reservoir of metal cations to further lengthen the period of time over which the hGH is stabilized by a metal cation to enhance the stability of hGH in the composition.
A metal cation component used in modulating release typically contains at least one type of multivalent metal cation. Examples of second metal cation components suitable to modulate hGH release, include, or contain, for instance, Mg(OH)2, MgCO3 (such as 4.MgCO3Mg(OH)2.5H2O), ZnCO3 (such as 3Zn(OH)2.2ZnCO3), CaCO3, Zn3(C6H5O7)2, Mg(OAc)2, MgSO4, Zn(OAc)2, ZnSO4, ZnCl2, MgCl2 and Mg3 (C6H5O7)2. A suitable ratio of second metal cation component-to-polymer is between about 1:99 to about 1:2 by weight. The optimum ratio depends upon the polymer and the second metal cation component utilized.
A polymeric matrix containing a dispersed metal cation component to modulate the release of a biologically active agent from the polymeric matrix is further described in U.S. Pat. No. 5,656,297 to Bernstein et al., and co-pending PCT Patent Application PCT/US95/05511, the teachings of which are incorporated herein by reference in their entirety.
The hGH sustained release composition of this invention can be formed into many shapes such as a film, a pellet, a cylinder, a disc or a microparticle. A microparticle, as defined herein, comprises a polymeric component having a diameter of less than about one millimeter and having stabilized hGH particles dispersed therein. A microparticle can have a spherical, non-spherical or irregular shape. It is preferred that a microparticle be a microsphere. Typically, the microparticle will be of a size suitable for injection. A preferred size range for microparticles is from about 1 to about 180 microns in diameter.
In the method of this invention for forming a composition for the sustained release of biologically active, non-aggregated hGH, a suitable amount of particles of biologically active, stabilized hGH are dispersed in a polymer solution.
A suitable polymer solution contains between about 1% (w/w) and about 30% (w/w) of a suitable biocompatible polymer, wherein the biocompatible polymer is typically dissolved in a suitable polymer solvent. Preferably, a polymer solution contains about 2% (w/v) to about 20% (w/v) polymer. A polymer solution containing 5% to about 10% (w/w) polymer is most preferred.
A suitable polymer solvent, as defined herein, is solvent in which the polymer is soluble but in which the stabilized hGH particles are substantially insoluble and non-reactive. Examples of suitable polymer solvents include polar organic liquids, such as methylene chloride, chloroform, ethyl acetate and acetone.
To prepare biologically active, stabilized hGH particles, hGH is mixed in a suitable aqueous solvent with at least one suitable metal cation component under pH conditions suitable for forming a complex of metal cation and hGH. Typically, the complexed hGH will be in the form of a cloudy precipitate, which is suspended in the solvent. However, the complexed hGH can also be in solution. In an even more preferred embodiment, hGH is complexed with Zn+2.
Suitable pH conditions to form a complex of hGH typically include pH values between about 7.0 and about 7.4. Suitable pH conditions are typically achieved through use of an aqueous buffer, such as sodium bicarbonate, as the solvent.
Suitable solvents are those in which the hGH and the metal cation component are each at least slightly soluble, such as in an aqueous sodium bicarbonate buffer. For aqueous solvents, it is preferred that water used be either deionized water or water-for-injection (WFI).
It is understood that the hGH can be in a solid or a dissolved state, prior to being contacted with the metal cation component. It is also understood that the metal cation component can be in a solid or a dissolved state, prior to being contacted with the hGH. In a preferred embodiment, a buffered aqueous solution of hGH is mixed with an aqueous solution of the metal cation component.
Typically, the complexed hGH will be in the form of a cloudy precipitate, which is suspended in the solvent. However, the complexed hGH can also be in solution. In an even more preferred embodiment, hGH is complexed with Zn+2.
The complexed hGH is then dried, such as by lyophilization, to form a particulate of stabilized hGH. The complexed hGH, which is suspended or in solution, can be bulk lyophilized or can be divided into smaller volumes which are then lyophilized. In a preferred embodiment, the complexed hGH suspension is micronized, such as by use of an ultrasonic nozzle, and then lyophilized to form stabilized hGH particles. Acceptable means to lyophilize the complexed hGH mixture include those known in the art.
Preferably, particles of stabilized hGH are between about 1 to about 6 micrometers in diameter. The hGH particles can be fragmented separately, as described in co-pending U.S. patent application Ser. No. 08/006,682, filed Jan. 21, 1993, which describes a process for producing small particles of biologically active agents, which is incorporated herein in its entirety by reference. Alternately, the hGH particles can be fragmented after being added to a polymer solution, such as by means of an ultrasonic probe or ultrasonic nozzle.
In another embodiment, a second metal cation component, which is not contained in the stabilized hGH particles, is also dispersed within the polymer solution.
It is understood that a second metal cation component and stabilized hGH can be dispersed into a polymer solution sequentially, in reverse order, intermittently, separately or through concurrent additions. Alternately, a polymer, a second metal cation component and stabilized hGH and can be mixed into a polymer solvent sequentially, in reverse order, intermittently, separately or through concurrent additions.
The method for forming a composition for modulating the release of a biologically active agent from a biodegradable polymer is further described in U.S. Pat. No. 5,656,297 to Bernstein et al.
In this method, the polymer solvent is then solidified to form a polymeric matrix containing a dispersion of stabilized hGH particles.
One suitable method for forming an hGH sustained release composition from a polymer solution is the solvent evaporation method described in U.S. Pat. No. 3,737,337, issued to Schnoring et al., U.S. Pat. No. 3,523,906, issued to Vranchen et al., U.S. Pat. No. 3,691,090, issued to Kitajima et al., or U.S. Pat. No. 4,389,330, issued to Tice et al. Solvent evaporation is typically used as a method to form hGH sustained release microparticles.
In the solvent evaporation method, a polymer solution containing a stabilized hGH particle dispersion, is mixed in or agitated with a continuous phase, in which the polymer solvent is partially miscible, to form an emulsion. The continuous phase is usually an aqueous solvent. Emulsifiers are often included in the continuous phase to stabilize the emulsion. The polymer solvent is then evaporated over a period of several hours or more, thereby solidifying the polymer to form a polymeric matrix having a dispersion of stabilized hGH particles contained therein.
A preferred method for forming hGH sustained release microparticles from a polymer solution is described in U.S. Pat. No. 5,019,400, issued to Gombotz et al., and co-pending U.S. patent application Ser. No. 08/443,726, filed May 18, 1995, the teachings of which are incorporated herein by reference in their entirety. This method of microsphere formation, as compared to other methods, such as phase separation, additionally reduces the amount of hGH required to produce a sustained release composition with a specific hGH content.
In this method, the polymer solution, containing the stabilized hGH particle dispersion, is processed to create droplets, wherein at least a significant portion of the droplets contain polymer solution and the stabilized hGH particles. These droplets are then frozen by means suitable to form microparticles. Examples of means for processing the polymer solution dispersion to form droplets include directing the dispersion through an ultrasonic nozzle, pressure nozzle, Rayleigh jet, or by other known means for creating droplets from a solution.
Means suitable for freezing droplets to form microparticles include directing the droplets into or near a liquified gas, such as liquid argon and liquid nitrogen to form frozen microdroplets which are then separated from the liquid gas. The frozen microdroplets are then exposed to a liquid non-solvent, such as ethanol, or ethanol mixed with hexane or pentane.
The solvent in the frozen microdroplets is extracted as a solid and/or liquid into the non-solvent to form stabilized hGH containing nicroparticles. Mixing ethanol with other non-solvents, such as hexane or pentane, can increase the rate of solvent extraction, above that achieved by ethanol alone, from certain polymers, such as poly(lactide-co-glycolide) polymers.
A wide range of sizes of hGH sustained release microparticles can be made by varying the droplet size, for example, by changing the ultrasonic nozzle diameter. If very large microparticles are desired, the microparticles can be extruded through a syringe directly into the cold liquid. Increasing the viscosity of the polymer solution can also increase microparticle size. The size of the microparticles can be produced by this process, for example microparticles ranging from greater than about 1000 to about 1 micrometers in diameter. Yet another method of forming an hGH sustained release composition, from a polymer solution, includes film casting, such as in a mold, to form a film or a shape. For instance, after putting the polymer solution containing a dispersion of stabilized hGH particles into a mold, the polymer solvent is then removed by means known in the art, or the temperature of the polymer solution is reduced, until a film or shape, with a consistent dry weight, is obtained. Film casting of a polymer solution, containing a biologically active agent, is further described in U.S. Pat. No. 5,656,297 to Bernstein et al., the teachings of which are incorporated herein by reference in their entirety.
It is believed that the release of the hGH can occur by two different mechanisms. The hGH can be released by diffusion through aqueous filled channels generated in the polymeric matrix, such as by the dissolution of the hGH or by voids created by the removal of the polymer""s solvent during the synthesis of the sustained release composition.
A second mechanism is the release of hGH due to degradation of the polymer. The rate of degradation can be controlled by changing polymer properties that influence the rate of hydration of the polymer. These properties include, for instance, the ratio of different monomers, such as lactide and glycolide, comprising a polymer; the use of the L-isomer of a monomer instead of a racemic mixture; and the molecular weight of the polymer. These properties can affect hydrophilicity and crystallinity, which control the rate of hydration of the polymer. Hydrophilic excipients such as salts, carbohydrates and surfactants can also be incorporated to increase hydration and which can alter the rate of erosion of the polymer.
By altering the properties of the polymer, the contributions of diffusion and/or polymer degradation to hGH release can be controlled. For example, increasing the glycolide content of a poly(lactide-co-glycolide) polymer and decreasing the molecular weight of the polymer can enhance the hydrolysis of the polymer and thus, provides an increased hGH release from polymer erosion.
In addition, the rate of polymer hydrolysis is increased in non-neutral pH""s. Therefore, an acidic or a basic excipient can be added to the polymer solution, used to form the microsphere, to alter the polymer erosion rate.
The composition of this invention can be administered to a human, or other animal, by injection, implantation (e.g, subcutaneously, intramuscularly, intraperitoneally, intracranially, intravaginally and intradermally), administration to mucosal membranes (e.g., intranasally or by means of a suppository), or in situ delivery (e.g. by enema or aerosol spray) to provide the desired dosage of hGH based on the known parameters for treatment with hGH of the various medical conditions.

Composition for sustained release of human growth hormone


A flash memory device includes a memory cell array arranged in rows and columns; a pad configured to be supplied with a high voltage from the exterior during a stress test operation; a column decoder configured to select a part of the columns in response to column selection signals; and a column predecoder configured to generate the column selection signals in response to an all column selection signal and a column address. The column predecoder simultaneously drives the column selection signals with the high voltage from the pad when the all column selection signal is activated during the stress test operation.

1. Technical Field
This disclosure relates to semiconductor memory devices and more particularly, to a flash memory device that is capable of reducing a test time.
2. Description of the Related Art
A flash memory device is a highly integrated information storage device in which write and erase operations can be done on board. A flash memory cell includes one field effect transistor (FET) having a selection gate, a floating gate, a source, and a drain. Any variation of a threshold voltage of the flash memory cell results in a fluctuation of the amount of charges on a floating gate. This fluctuation represents information, which is stored in the flash memory cell. A flash memory device is classified as either a NAND flash memory device or a NOR flash memory device. NAND flash memory devices are typically used as mass data storage devices, and NOR flash memory devices are typically used as information storage devices for high speed data processing.
Generally, a NOR flash memory cell has two states—a programmed state and an erased state. When the NOR flash memory cell is programmed, residual electrons are trapped on a floating gate and a threshold voltage rises. Thus, drain-source current does not flow to a selected flash memory cell. The programmed state of the flash memory cell is referred to as logic "0". When the flash memory cell is erased, there are a small number of residual electrons on the floating gate and source-drain current flows to the flash memory cell. The erased state of the flash memory cell is referred to as logic "1".
FIG. 1 is a block/circuit diagram illustrating a conventional NOR flash memory device 100. Referring to FIG. 1, a NOR flash memory device 100 includes an address buffer 110, a row predecoder 120, a row decoder 130, a cell array 140, a column predecoder 150, a column decoder 160, and a sense amplifier 170. In the cell array 140, flash memory cells (not shown) are arranged at the intersections of wordlines WLi and bitlines BLi. The address buffer 110 receives an address signal ADDR from the outside so as to program or erase the flash memory cells and divides a row address RowAdd from a column address ColAdd by means of an output of the address buffer 110. The row predecoder 120 decodes the received row address RowAdd to generate a row selection signal RowSel. The row decoder 130 enables a predetermined wordline WLi in response to the row selection signal RowSel and drives the wordline WLi to a predetermined voltage level according to an operation mode of the flash memory device 100. In a program mode, the wordline WLi is driven to a voltage level of 10V. In an erase mode, the wordline WLi is driven to a voltage level of −10V. In a read mode, the wordline WLi is driven to a voltage level of 4.5V.
The column predecoder 150 decodes the received column address ColAdd to generate column selection signals ColSel1[m:0] and ColSel2[n:0]. The column decoder 160 selects a predetermined bitline BLi in response to the column selection signals ColSel1[m:0] and ColSel2[n:0] and connects a selected bitline BLi with the sense amplifier 170 through a data line DLj(j=0–3). For the convenience of description, 16 bitlines BLi (i=0–15) are described. A first column selection signal ColSel1[m:0] selects four bitlines (e.g., BL0, BL5, BL9, BL12) and a second column selection signal ColSel2[n:0] selects one (e.g., BL0) of the selected four bitlines to connect the selected one bitline with a data line (e.g., DL0).
FIG. 2 is a circuit diagram further illustrating the column predecoder 150 of FIG. 1. Referring to FIG. 2, the column predecoder 150 inputs column addresses ColAdd[3:0] to selectively generate first column selection signals ColSel1[3:0] and second column selection signals ColSel2[3:0]. The first and second column addresses ColAdd[0] and ColAdd[1] are decoded through a decoding block 200 to drive level shifters 202, 204, 206, and 208.
FIG. 3 is a circuit diagram illustrating the level shifters 202, 204, 206, and 208 of FIG. 2. Each of the level shifters 202, 204, 206, and 208 is structured as shown in FIG. 3 and generates a high voltage HV of about 10V as its output OUT in response to a low-level input signal IN. Four transistors in the column decoder 160 corresponding to the first column selection signals ColSel1[0], ColSel1[1], ColSel1[2], and ColSel1[3], respectively, are turned on when a high voltage HV appears as the output OUT of the level shifter 202, 204, 206, or 208, respectively. The third and fourth column addresses ColAdd[2] and ColAdd[3] generate second column selection signals ColSel2[0], ColSel2[1], ColSel2[2], and ColSel2[3] of high voltage HV through a decoding block 210 and level shifters 212, 214, 216, and 218. The second column selection signals ColSel2[0], ColSel2[1], ColSel2[2], and ColSel2[3] of high voltage HV select one of the four bitlines (BLi of FIG. 1). Each bitline BLi is coupled to one of the four transistors that are turned on by an activated first column selection signal ColSel1[0], ColSel1[1], ColSel1[2], or ColSel1[3]. In this way the selected signal is connected with a data line.
FIGS. 4A and 4B are cross-sectional diagrams illustrating the column selection transistors of FIG. 1 and where stresses occur in those transistors. When the flash memory device (100 of FIG. 1) is in the program mode, according to a programming type, a voltage of 5V is applied to a bitline of a selected memory cell and a voltage of 0V is applied to a bitline of an unselected memory cell.
The state of the bias of a transistor MF in a first group of transistors 161 (FIG. 1) coupled to the bitline of the unselected memory cell is described below with reference to FIG. 4A. A high voltage of about 10V is applied to a gate of the transistor MF by a first column selection signal ColSel1[0] that is coupled to the gate. A voltage of 0V is applied to a source of the transistor MF by a bitline BLO. Thus, a voltage of 10V is applied between the gate and the source of the transistor MF, and a voltage of 0V is applied to the data line DL0 of FIG. 1 that is coupled to the unselected memory cell.
The state of the bias of a transistor MS in a second group of transistors 162 (FIG. 1) is described below with reference to FIG. 4B. A high voltage of about 10V is applied to a gate of the transistor MS by a second column selection signal ColSel2[0] that is coupled to the gate of the transistor MS, and a voltage of 0V is applied to a drain of the transistor MS that is connected to the data line DL0. This state is maintained until the program is completed, which leads to increase gate oxide stress of the transistors MF and MS.
Furthermore, when the flash memory device (100 of FIG. 1) is in an erase mode, a voltage of about 9V is applied to a bulk that is coupled to a bitline. In this case, the first and second column selection signals ColSel1[m:0] and ColSel2[n:2] have a voltage of about 0V. Accordingly, a voltage of 0V is applied to the gates of the first group of the transistors 161 and a coupling voltage of 9V is applied to the sources thereof. As a result, gate oxide stress in the first group of transistors 161 occurs.
Over time, oxide stress from repeated program and erase operations may degrade the gate oxide layer to cause the transistor to malfunction. This contributes to faulty operation of the flash memory device. Accordingly, there is a need for a method of detecting a transistor error caused by the degradation of the gate oxide layer.
Since the first and second column selection signals ColSel1[m:0] and ColSel2[n:2] alternately apply a high voltage, it takes a long time to screen the transistor error by applying a stress to the first and second groups of the transistors in the column decoder (160 of FIG. 1). Furthermore, after a stress test, additional procedures such as reiteration of program and read operations must be performed to determine whether transistors in the column decoder have leakage paths caused by gate oxide deterioration and/or breakage. As a result, the test time that is required increases.
Embodiments of the invention address these and other disadvantages of the conventional art.

Flash memory device capable of reducing test time and test method thereof


A star coupler assembly includes an optical star coupler from which extend optical cables and a housing having a central grove accommodating the coupler. The optical cables are accommodated in a series of communicating groves of the housing and are held down therein by means of cable clips. The cables are led from the groves, between posts so that their end portions project through bores in side walls of the housing, whereby the end portions of the cables project from the housing side walls for connection to light transmitting or light sensitive devices at a site of use.

1. Field of the Invention
This invention relates to an assembly housing an optical star coupler. The invention also relates to a housing for the coupler. An optical star coupler is a device for transmitting light emitted by a selected optical cable of a first bundle of optical cables to each of the optical cables of a second bundle of optical cables.
2. Description of the Prior Art
Such star couplers are used, for example, in automotive vehicles, in optical instruments, for industrial automation, or for monitoring sensors in a machine, where it is required that a single light signal be transmitted to a plurality of light sensitive devices. Such a star coupler comprises an optical mixing rod having a bundle of optical cables optically and mechanically connected to each end of the mixing rod. Lengths of the cables extend from the bundles for connection to light emitting or light sensitive devices, as the case may be. Where an optical star coupler is being transported to its site of use, for example on the motor vehicle assembly line, there is a risk that the cables extending from the bundles may tangle, or become kinked, with a resulting loss of light when the coupler is in use.


An improved input circuit (9) for accepting a signal from a triboelectric probe (2). The circuitry provides gain, zero and probe contamination information which allows verification of said information without taking the probe and instrument off-line.

The measurement of gas with solid particles therein and certain fluids which behave similarly, is of importance in many industries, e.g. chemical processing, food handling, transport loading and unloading, filtration, aeronautics and combustion fuel feeds. The above referenced patents have provided significant improvements in this general technical field.
Current flow measuring systems electrically connect the triboelectric sensor probe through an ultra low noise cable. The signal connection is fed to a core impedance conversion circuit (converter). A conversion circuit will amplify the input signal, where for the purposes of this invention amplification is defined broadly as voltage amplification, current amplification, impedance amplification (reduction) or combinations thereof. An over voltage protector is installed at the probe, and a current limiting barrier resistor before the converter's summing junction provides intrinsic safety for the probe and cable allowing the probe to be installed in hazardous environments.
Electrical offsets and drifts are of concern in the various circuits, and arrangements disclosed in the above referenced patents are used to compensate for these offsets and drifts. Other circuit implementations known in the art way also be used. Also various filters and other conditioning circuits, known in the art, may be used for noise elimination or other desired effects.
One of the continuing limitations of instrumentation, when practically applied in the above fields, to perform the measurement and feedback control of flow has been contamination of the physical probe. Any conductive substances, e.g. acids or other electrolytes, contained in the materials whose flow is being measured, may eventually build up providing electrical leakage paths which give rise to measurement errors. Also system errors occur as sensitivity (gain) and system zero change due to inexact temperature compensation, drift and/or other causes.
Old methods to solve this contamination problem have involved disassembly and cleaning or purging of the probe on a routine basis, and system calibration or other external testing circuits are used to monitor or measure system gain and zero. Employing these methods involves taking the system off-line and having skilled technicians perform the work.
It is an object of this invention to provide a circuit means which detects and quantifies, with the system on-line, when the probe is contaminated and needs cleaning.
It is another object of this invention to monitor and measure system gain and system zero while the system is on-line.
Another object of this invention is to minimize system down time and make efficient use of a technician's time.
It is an object of this invention that the probe-contamination, gain or zero change detection circuitry does not unduly interfere with or otherwise compromise the efficacy of the triboelectric detection instrumentation.

On line triboelectric probe contamination detector


A method for designing a system on a target device is disclosed. A partition in the system with a plurality of instances from an extraction netlist is identified. Synthesis optimizations are performed on the partition to generate a synthesis optimization solution. The synthesis optimization solution is applied to the plurality of instances in the system.

Target devices such as field programmable gate arrays (FPGAs), structured application specific integrated circuits (ASICs), and ASICs are used to implement large systems that may include million of gates and megabits of embedded memory. The complexity of large systems often requires the use of electronic design automation (EDA) tools to create and optimize a design for the system onto physical target devices. Among the procedures performed by EDA tools in a computer aided design (CAD) flow are synthesis, placement, and routing. When designing large systems to be implemented on large target devices, EDA tools may require a large amount of time to perform these compilation procedures.
Although the design process is automated with EDA tools, generating a satisfactory system design may still be time consuming. It is an ongoing effort for EDA tool designers to shorten the runtime of its algorithms. By shortening the runtime of its algorithms, more flexibility may be offered to the system designer using the EDA tool and/or additional algorithms may be implemented in the EDA tool in order to further improve a system design.
In FPGA design, system designs are very structured in nature. It is not uncommon for a system design to include a plurality of subnetworks (subnets) that have common characteristics. Current EDA tools execute algorithms on a subnet regardless of whether an identical subnet had been previously processed. For system designs that include a large number of subnets having identical characteristics, this results in the consumption of a significant amount of time and computing resources for repetitive computations.

Method and apparatus for partitioning a synthesis netlist for compile time and quality of results improvement


An image recording apparatus includes: a carriage that carries a recording head capable of recording an image on a recording medium and reciprocates in a main scanning direction; a substantially box-shaped main frame having an open upper side and a pair of side plates extending in a sub-scanning direction orthogonal to the main scanning direction; and first and second guide members over which the carriage extends and by which the carriage is guided, the first and second guide members being disposed to be apart from each other by a predetermined distance in the sub-scanning direction, extended in the main scanning direction at the upper side of the main frame and fixed to the pair of side plates.

1. Field of the Invention
The present invention relates to an image recording apparatus of an ink-jet type or the like, and more particularly to a structure of a main frame to house a main part.
2. Description of the Related Art
A conventional image recording apparatus of an ink-jet type, a thermal-head type or the like is such that as disclosed in JP-A-11-246055 (see FIG. 1 and FIG. 5) or JP-A-2001-260475 (see FIGS. 1 to 4), cylindrical guide shafts to support a carriage carrying a recording head in such a manner that the carriage can reciprocate in a main scanning direction, a paper feed roller, a paper discharge roller, and the like are disposed in the inside of a box-type main frame made of a metal plate and fixed in a synthetic resin housing of the image recording apparatus. Both ends of these shafts are attached to right and left side plates of the main frame so as to be pivotally supported.
Besides, the structure is such that a paper feed cassette is housed at the lower side in the main frame to be capable of being pulled out and inserted, and after a sheet is transported to the lower surface of the recording head through the paper feed roller and a U-turn-shaped transporting passage and is recorded, the sheet is discharged to the front side of the housing.
Further, JP-A-2002-254746 (see FIG. 1 and FIG. 3) discloses that a pair of guide plates which support a carriage and can reciprocate it in a main scanning direction are integrally provided in a main frame.


The invention relates to a roll stand for rolling a product, in particular made of metal, comprising a pair of first rollers contacted by a pair of second rollers supporting the first rollers, wherein the first roller and the second rollers have an asymmetrical radius curve (CVC grind) relative to a center plane, wherein the radius curve of the first rollers is represented by a polynomial of the third or fifth order. In order to design the wedging of a second roller supporting a first roller such that optimal operating conditions are set, the invention proposes that the radius curve of the second roller is given by a polynomial of the third or fifth order, wherein special relationships are prescribed for the ratios between the coefficients.

The invention concerns a roll stand for rolling a product, especially a metal product, which has a pair of first rolls in contact with a pair of second rolls that support the first rolls, wherein the first rolls and the second rolls are provided with a radius curve (CVC cut) that is asymmetric relative to a center plane, wherein the radius curve of the first rolls is represented by a polynomial of third or fifth degree.
EP 1 307 302 B1 discloses a roll stand of this type. A polynomial curve of the specified type is provided as a radius curve in order to minimize the axial forces of the roll bearings, where suitable choice of the radius curve makes it possible to minimize horizontally acting torques without additional expense. The wedge component of the CVC work roll contour is of special importance. The configuration is carried out in such a way that the wedging of the work roll cut or work roll contour is optimized to avoid rotational torques or axial forces. The linear component of the polynomial (a1) is used as an optimization parameter for this. This makes it possible to prevent crossing of the rolls and to minimize the axial forces in the roll bearings.
In this regard, the solution according to the cited document EP 1 307 302 B1 is based on a profiling of the work rolls, which interact with cylindrical backup rolls. This is the focus of the optimization of the wedging of the work rolls. Efforts have been made to expand the adjustment range of the CVC system to further increase the strip profile-adjustment range. In this connection, in order to avoid high surface pressings between work been found, however, that to optimize the wedging of the CVC contour of the backup rolls, the same configuration as for the work rolls cannot be used if the aim is to achieve optimum conditions.

Roll stand for rolling a product, in particular made of metal


A rack has a plurality of LEDs arranged on the front surface thereof correspondingly to respective units. The rack is provided with an LED lighting circuit which lights these LEDs, on the back of a display section and an input section. The LED lighting circuit has an LED lighting control section and a memory. The LED lighting control section acquires correspondence relation information indicating correspondence between servers and apparatuses from the input section, and stores the information in the memory. When a server is selected, the LED lighting circuit lights some of the plurality of LEDs based on the correspondence relation information stored in the memory.

1. Field of the Invention
The present invention relates to a rack.
2. Description of the Related Art
There is provided a rack on which a plurality of apparatuses can be shelved. For example, a plurality of servers and a plurality of apparatuses to be connected to each server are shelved on this rack. This is to save space by shelving various electronic apparatuses on the rack.
The rack is adaptable to such a use as that a plurality of apparatuses having the same function are shelved and connected to different servers independently, and that a single apparatus is connected to a plurality of servers and the plurality of servers share the single apparatus.
When data stored in a server shelved on this type of rack is to be backed up or when the battery of a Uninterruptible Power Supply shelved on this type of rack is to be replaced with a new one, it is necessary to identify connective relations between servers and apparatuses.
However, it is impossible to identify connective relations between servers and apparatuses just by looking at the rack from its front. Therefore, in order to carry out the above kinds of works, the operator has to memorize the connective relations when he/she connects the apparatuses, or has to check the cable connections at the back of the rack when actually carrying out the works.
Meanwhile, there is proposed in, for example, Unexamined Japanese Patent Application KOKAI Publication No. H09-330184, an invention for use in a RAID (Redundant Arrays of Inexpensive Disks) system, which is capable of specifying the numbers, etc. assigned to disk devices or bodies of disks by lighting LEDs (Light Emitting Diodes) corresponding to the respective disk devices.
However, it is not always the case that each apparatus to be shelved on the rack has a display device for displaying the connective relation of the apparatus. Further, since each apparatus to be shelved on the rack is a finished product, it is impossible to attach a display element to each apparatus or to modify the circuit of each apparatus unlike the case of the above-mentioned system.


In assignment of radio channels to terminals for communication with a switching office, one of currently idle channels can be assigned to a calling terminal by use of a channel state memory in the office which memory stores channel numbers and terminal information currently using channels. The office further includes a terminal memory for storing the maximum number separately predetermined for each of fixed and mobile types of the terminals assignable to the channels. The calling terminal is rejected to be assigned with any idle channel when the maximum number is equal to the current number of terminals currently using channels which are same as the type of the calling terminal. In another aspect, the terminal memory further stores information that the fixed type has a priority. An idle channel is assigned to a calling one of fixed type terminals even when the maximum number for the fixed type is equal to or smaller than the current number. In other aspect, the channel state memory stores receiving signal strengths at terminals currently using the channels. When a calling is originated from one of fixed type terminals and when all of the channels are currently used, one of the mobile terminals using a specific channel at the lowest one of the receiving signal strengths is forced to release the specific channel, which channel is in turn assigned to the calling fixed type terminal.

This invention relates to a radio communication system comprises a switching office and a service area including therein stationary or fixed terminals and mobile terminals selectively communicating with the switching office through a plurality of radio channels, and in particular, to a channel assignment to a calling terminal in such a communication system.
In a known communication system of the type as described above, the switching office has a channel state memory having a table. The table comprises a channel number column having plurality of channel numbers, a channel state column representing using state of those channels, and a channel use column representing use of those channels. In more detail, in the channel state column, there is stored information whether those channels are currently idle or not, what terminal currently uses each of the channels and whether or not those channels are freely accessible by any one of terminals. The content in the column can be renewed. In the channel use column, there is previously stored that those channels are previously assigned to terminals, respectively. Usually, several, for example, three channels are previously assigned to three fixed terminals, while other channels are commonly and selectively used by mobile terminals.
The communication system has a control channel in addition to the radio channels for communication. The control channel is used for broadcasting the content in the channel state memory to all of the terminals. Therefore, the control channel is used for broadcasting assignment of one of common channels to a calling one of mobile terminals.
In the known communication system, since the fixed terminals are previously assigned with channels, it is impossible to freely increase the number of fixed terminals within the service area.
On the other hand, any one of the mobile terminals cannot use an idle one of the channels previously assigned to the fixed terminals. This is disadvantageous in the view point of the channel use efficiency.

Communication system having means for enabling channel assignment to calling terminal according to priority


A zoom lens system, in order from an object side to an image side, includes a first lens unit having positive optical power; a second lens unit having negative optical power; a third lens unit having positive optical power; a fourth lens unit having negative optical power, and a subsequent lens unit. The first lens unit includes a negative lens element and a positive lens element. In the zoom lens system, the conditions: 1.47<nd2<1.57 and 60<vd2<75 (nd2: a refractive index to a d-line of the positive lens element, vd2: an Abbe number to a d-line of the positive lens element) are satisfied.

1. Field
The present disclosure relates to zoom lens systems, interchangeable lens apparatuses, and camera systems.
2. Description of the Related Art
In recent years, interchangeable-lens type digital camera systems (also referred to simply as "camera systems", hereinafter) have been spreading rapidly. Such interchangeable-lens type digital camera systems realize: taking of high-sensitive and high-quality images; high-speed focusing and high-speed image processing after image taking; and easy replacement of an interchangeable lens apparatus in accordance with a desired scene. Meanwhile, an interchangeable lens apparatus having a zoom lens system that forms an optical image with variable magnification is popular because it allows free change of focal length without the necessity of lens replacement.
Zoom lens systems having excellent optical performance from a wide-angle limit to a telephoto limit have been desired as zoom lens systems to be used in interchangeable lens apparatuses. For example, various kinds of zoom lens systems have been proposed, each having a multiple-unit construction in which a positive lens unit is located closest to an object side.
Japanese Laid-Open Patent Publication No. 2011-232624 discloses an optical imaging system having a four-unit construction of positive, negative, positive, and negative, in which zooming is performed by moving the respective lens units from a wide-angle limit to a telephoto limit, and the first lens unit is composed of two lenses, a positive lens and a negative lens.
Japanese Laid-Open Patent Publication No. 2011-197471 discloses a zoom lens system having a six-unit construction of positive, negative, positive, negative, negative, and positive, in which zooming is performed by moving the second lens unit, the fourth lens unit, and the fifth lens unit from a wide-angle limit to a telephoto limit, and focusing is performed by moving the three lens units that are moved in zooming.
Japanese Patent No. 4802598 discloses an optical imaging system having a five-unit construction of positive, negative, positive, negative, and positive, in which zooming is performed by moving the respective lens units from a wide-angle limit to a telephoto limit, and the first lens unit is composed of two lenses, a positive lens and a negative lens.

Zoom lens system, interchangeable lens apparatus and camera system

PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO., LTD.


A computer graphics system is disclosed. The system is for modelling parametric objects having elliptical segments, which are defined as segments bounded by linear radial and elliptical tangential elements. The system includes a retrieval and display function for an object having elliptical segments which have boundary surfaces that intersect at vertices and which have a common origin. The system includes a calculation of the location of the vertices relative to the common origin and evaluates and discards invalid vertices. The system also calculates the boundary surfaces of individual elliptical segments, defined by valid vertices. Output is provided in the form of dimensionally accurate and geometrically undistorted digital models. In one embodiment the system is useful in designing elliptical elements for doors, windows and the like in an architectural drafting program.

It is a time consuming process to construct in 2D or in 3D space a graphical representation of an object which includes elliptical segments. Elliptical segments are segments bounded by linear radial elements and elliptical tangential elements. Linear radial elements are rectilinear elements that extend out from a common origin like spokes in a wheel. Elliptical tangential elements are curved elements whose curvature follows an elliptical path like a frame of an elliptical mirror. Elliptical segments may be part of complex elliptical designs for example used in architecture for door windows, windows or other applications.
At present, to generate an image incorporating elliptical segments requires that the segments be calculated and then drawn either on paper or on a computer. However, the image so created is specific to the attributes which are given (length, width, number of elements and the like), and cannot be used except with such attributes. Changing any value of the attributes of the segments such as number or width of linear radial elements, number, width or ellipticity of elliptical tangential elements usually requires redrawing the entire image of the elliptical segments.
To alleviate this problem computer graphics systems sometimes include a database with geometric data for a finite number of pre-constructed instances of objects with elliptical segments. The usability of such graphics systems remains limited to the selection of those instances which are stored in the database. Changing the total width or length of such a pre-constructed object typically will result in anamorphism which the user cannot correct. Such anamorphism, in the context of a computer graphics system for design, such as an architectural modelling program, is clearly unacceptable, because of the loss of dimensional accuracy and the geometric distortion which results.

Computer graphics system for modelling objects which include segments that are bounded by linear radial and elliptical tangential elements