Abstract: A method of compressing a block of time series data involves sorting the data by variable name, separating the series of time values from the series of variable values, and performing data extraction and/or compression independently on the series of time values and on the series of variable values. The reduced volume of data is then written to a database. In a preferred embodiment, the time series of data represents data generated from a computer simulation of an integrated circuit. In order to efficiently compress the time series data, individual blocks of time series data representing a particular time range are sorted by variable name, with each variable name having associated time values and variable values. The time values and variable values are separated into two distinct data sets, and data compression is performed separately on the two distinct data sets. The compressed information related to each individual variable is then stored in individual variable blocks.

Abstract: A projection monitor and a method of displaying an output image on a viewing screen of the monitor utilize a number of reconfigurable holographic optical elements (HOEs), allowing the components of the monitor to be physically arranged in a compact configuration. The reconfigurable HOEs may be designed to perform simple optical functions that are commonly associated with traditional optical devices, such as those performed by lenses, prisms and mirrors. However, the reconfigurable HOEs are also designed to perform sophisticated optical manipulations, such as varying the light intensity with respect to a specific direction. Each reconfigurable HOE includes a hologram that is sandwiched between two electrode layers. The hologram is a holographic photopolymeric film that has been combined with liquid crystal. The hologram has an optical property that changes in response to an applied electrical field.

Abstract: A current-limit circuit and a method of limiting current supplied to a load through a power transistor utilize a control transistor that is selectively activated to a conducting state to limit the current conducted through the power transistor in response to a predefined condition. The predefined condition may be a short-circuit condition or an over-current condition. The configuration and operation of the control transistor are such that, when the control transistor is in a conducting state, the current conducted through the power transistor is limited by the structural ratio of the two transistors. However, during normal operating conditions when the control transistor is deactivated to a non-conducting state, the control transistor does not degrade the performance of the power transistor. In a first embodiment, the current-limit circuit is configured to provide protection from a short-circuit condition.

Abstract: A full duplex speakerphone system and a method of detecting a valid near-end talker component within an outgoing signal utilize a near-talker estimator that produces a near-talker energy estimate using a spectrum analysis. The near-talker energy estimate is indicative of the amount of the valid near-end talker component within the outgoing signal. Depending on the near-talker energy estimate, the system may attenuate the outgoing signal and/or incoming signal and adjust the filter process executed by an adaptive filter of the system in order to provide a clear voice communication between connected parties. In the preferred embodiment, the near-talker estimator operates with at least one processing unit to sample the outgoing signal that has been filtered, or “cancelled,” of echo by an acoustic echo canceller of the system.

Abstract: A method and apparatus for managing simulation results involves identifying distinct transactions in a group of simulation results so that the simulation results can be stored and viewed on a transaction basis instead of as a single continuous block of simulation results. A transaction is defined as a specific sequence of transitions on a selection or grouping of signals over a period of time where the signal activity has some higher level operational meaning. Simulation results are recorded on a transaction basis by storing standard simulation results information along with transaction-specific data elements, including the name of the transaction, the start time of the transaction, the end time of the transaction, and the interface on which the transaction takes place. Additional transaction-specific data elements may include parent and child relationships and predecessor and successor relationships between transactions.

Abstract: A method of managing latency in a system for tracking movement of an object includes providing a request-and-response mechanism for transferring tracking data across a communications link. In one embodiment, the object for which movement is to be tracked is a human head and the system is a virtual reality system. Packets of the tracking data may be generated using a conventional sensor processing technology, but the packets are transferred via the communications link to an image processing capability, such as that of a host computer. The packets are generated at a fixed sample rate that is asynchronous with respect to the processing requirements of the host computer. When the host computer is available for fresh tracking data, a packet-transfer request is transmitted to the source of the packet. Latency can be reduced by enabling the source of the packets to anticipate reception of a packet-transfer request.

Abstract: A method and system for monitoring and controlling network access includes non-intrusively monitoring network traffic and assembling data packets that are specific to individual node-to-node transmissions in order to manage network access both inside and outside of a network. A rules base is generated to apply at either or both of the connection time and the time subsequent to connection. With regard to a particular node-to-node transmission, the data packets are assembled to identify the source and destination nodes, as well as contextual information (i.e., ISO Layer 7 information). The access rules are applied in a sequential order to determine whether the transmission is a restricted transmission. The rules are maintained in a single rules base for the entire network and are distributed to each monitoring node. Any of the protocols in the suite of TCP/IP protocols can be managed.

Abstract: A circuit and a method for comparing an input voltage to an internally generated reference voltage utilize a bias network to make the voltage comparison. The bias network is preferably configured to generate a proportional-to-absolute-temperature (PTAT) reference voltage, which is used for the voltage comparison. Although the circuit can be implemented to operate in a number of applications, the circuit is particularly useful in a current sensing application. The circuit includes the bias network, a comparison current path and an output terminal. The comparison current path is configured to partially duplicate a current path of the bias network on which the reference voltage is generated. The comparison current path includes a current control element and an active transistor. Depending on the input voltage applied to the active transistor of the comparison current path, the output terminal is driven to generate either a high or a low comparison signal.

Abstract: A system and a method of displaying projected images on a projection screen of the system include one or more reconfigurable holographic optical elements (HOEs) in the screen to optically manipulate the projected images impinging on the screen. The reconfigurable HOEs may be configured to perform simple optical functions that are commonly associated with traditional optical devices, such as lenses, prisms and mirrors. However, the reconfigurable HOEs may also be configured to perform sophisticated optical manipulations, such as varying angular intensity of diffused light toward predefined viewing regions. Each reconfigurable HOE includes a hologram that is sandwiched between two electrode layers. The hologram is a holographic photopolymeric film that has been combined with liquid crystal. The hologram has an optical property that changes in response to an applied electrical field. The reconfigurable HOEs are utilized to control the diffusing characteristic of the projection screen.

Abstract: A solar control member utilizes a combination of layers that include spaced apart titanium nitride layers to selectively transmit a higher percentage of visible light than near infrared energy, with a low visible light reflection. The titanium nitride layers are spaced apart by a distance that promotes optical decoupling with respect to occurrence of constructive and destructive interference of visible light propagating between the two titanium nitride layers. In one embodiment, the titanium nitride layers are spaced apart by a laminating adhesive layer. In another embodiment, the titanium nitride layers are formed on opposite sides of a substrate. The ratio of transmission at the wavelength of 550 nm to transmission at the wavelength of 1500 is at least 1.25. Each titanium nitride layer is sputter deposited. Care is taken to ensure that each layer does not become too metallic and to ensure that excessive oxygen is not incorporated into the layer. Thus, the nitrogen flow rate and the linespeed are controlled.

Abstract: A projection system and a method of displaying a projected input image on a projection screen of the system utilize one or more reconfigurable holographic optical elements (HOEs) to optically manipulate propagating light in the system. The reconfigurable HOEs may be configured to perform simple optical functions that are commonly associated with traditional optical devices, such as lenses, prisms and mirrors. However, the reconfigurable HOEs may also be configured to perform sophisticated optical manipulations, such as varying the light intensity toward a specific direction and generating virtual (holographic) images. Each reconfigurable HOE includes a hologram that is sandwiched between two electrode layers. The hologram is a holographic photopolymeric film that has been combined with liquid crystal. The hologram has an optical property that changes in response to an applied electrical field.

Abstract: A method and apparatus for managing simulation results involve identifying errors within a group of simulation results so that the errors can be recorded into a database and viewed for analysis. In a preferred embodiment of the invention, distinct transactions within a group of simulation results are identified and recorded along with the identified errors. Recorded error-specific data and transaction-specific data are then utilized to graphically display the simulation results such that individual transactions identified within the simulation results are graphically distinct and such that errors occurring during a transaction are visually identified with the transaction. Recording and displaying error information and raising the level of abstraction of simulation results from cycles and signals to transactions enables easier simulation analysis and debugging.

Abstract: A system and a method for sensing the location of a remote object relative to a base object involve integrating inductive loop antennas with variable loop density into the base object and utilizing the antennas to transmit energy to and receive energy from an LC resonant circuit that is integrated into the remote object. The amplitude of a signal generated by the inductive loop antennas in response to energy received from the LC circuit identifies the location of the LC circuit relative to the antennas. Preferably, the sensing system is integrated into an electronic percussion instrument, where the keys of the instrument are formed with overlapping inductive loop antennas and the mallets used to activate the keys are formed with LC resonant circuits integrated into the mallet heads.

Abstract: An apparatus for latching an object, such as a payload for a space vehicle, includes an expandible latch which is shifted between a relaxed open condition and a flexed closed condition by actuation of a pair of temperature-responsive members, such as shaped memory alloy (SMA) coil springs. One of the two temperature-responsive members biases an actuator into a first position that allows the expandible latch to open. The other SMA member biases the actuator in the opposite position to close the expandible latch. Heating the appropriate SMA member causes the actuator to move from one position to the other position. In the preferred embodiment, no power is required to maintain the actuator in either position once the position has been established. For example, the actuator may have a rest position that allows the expandible latch to remain open when the two SMA members are cooled and allowed to reach an equilibrium condition with respect to applied force to the actuator.

Abstract: A head-mounted display system and a method of displaying scenes within the system include two or more reconfigurable holographic optical elements (HOEs) in a holographic diffuser of the system. The reconfigurable HOEs may be configured to perform simple optical functions that are commonly associated with traditional optical devices, such as lenses, prisms and mirrors. However, the reconfigurable HOEs may also be configured to perform sophisticated optical manipulations, such as optimally diffusing light with respect to intensity toward a predefined direction. Each reconfigurable HOE includes a hologram that is sandwiched between two electrode layers. The hologram is a holographic photopolymeric film that has been combined with liquid crystal. The hologram has an optical property that changes in response to an applied electrical field.

Abstract: A reflection control member includes a multilayer stack that is adhered to a substrate using a primer layer to promote adhesion. The multilayer stack includes pairs of layers in which the first layer is a grey metal and the second layer is a substantially transparent material. In the preferred embodiment, the grey metal is nickel chromium and the transparent layer is a silicon oxide. For each pair of layers, the grey metal is nearer to the surface of the substrate for which antireflection is a concern. The primer layer has a thickness of less than 50 angstroms. Although the primer layer is deposited in an essentially oxygen-free environment, it may oxidize following deposition.

Abstract: An autostereoscopic display system and a method of displaying a scene in a stereoscopic form on a screen of the system include two or more reconfigurable holographic optical element (HOE) stacks in the screen. The reconfigurable HOEs may be configured to perform simple optical functions that are commonly associated with traditional optical devices, such as lenses, prisms and mirrors. However, the reconfigurable HOEs may also be configured to perform sophisticated optical manipulations, such as optimally diffusing light with respect to light intensity toward a predefined viewing region. Each reconfigurable HOE includes a hologram that is sandwiched between two electrode layers. The hologram is a holographic photopolymeric film that has been combined with liquid crystal. The hologram has an optical property that changes in response to an applied electrical field.

Abstract: A diffractive display system and a method of collecting first order light beams from a diffractive display of the system utilize holographic optical elements (HOEs) to deflect one of two first order diffracted light beams that emerge from each diffracting pixel of the diffractive display, so that the first order diffracted light beams can be separated from the zeroth order light beams. The utilization of the HOEs allows the system to be implemented in a compact optical configuration, without sacrificing any portion of the first order diffracted light. In a first embodiment, the system includes three HOEs that have static diffracting properties that are optimized for red, green and blue lights. For each set of light beams from a diffracting pixel of the diffractive display, the HOEs are holographically configured to deflect only one of the two first order diffracted light beams, such that the deflected first order light beam propagates in the same direction as the other non-deflected first order light beam.

Abstract: A projection system and a method displaying a high resolution composite image on a projection screen include a number of reconfigurable holographic optical elements (HOEs) in the projection optics of the system. The reconfigurable HOEs of the projection optics allow the system to direct multiple image segments of the composite image that are projected from a single image source toward different regions of the projection screen to form the composite image on the screen. The image segments have a high resolution due to the fact that they have been magnified by a relatively small degree. Consequently, the displayed composite image formed by the image segments has an equally high resolution. Each reconfigurable HOE includes a hologram that is sandwiched between two electrode layers. The hologram is a holographic photopolymeric film that has been combined with liquid crystal. The hologram has an optical property that changes in response to an applied electrical field.

Abstract: An apparatus for controlling a drive mechanism of a panel display system includes a rotary member attached to a drive assembly, the rotary member having indicators located at known intervals that are detected to ensure that the drive assembly starts and stops at precise locations. In a preferred embodiment, the control system is applied to a panel display system that displays different scenes using an array of elongated three-sided display elements. The preferred control system includes an aluminum disk that is attached to rotate in connection with rotation of the drive assembly.