Abstract: A system for directing a receiving lobe of an adaptive antenna array toward an aircraft in flight includes an aircraft position vector calculator and an antenna weight vector generator. The aircraft position vector calculator receives aircraft position information from an aircraft tracking service and calculates, based upon the aircraft position information it receives, an aircraft position vector g. An antenna weight vector generator receives the aircraft position vector g from the aircraft position vector calculator and generates, based upon the aircraft position vector g, an antenna element weight vector w. The antenna weight vector w is applied to the elements of an adaptive antenna array to direct a receiving lobe of the array towards an aircraft in flight.

Abstract: A multiplexer for connecting a beamformer to a multi-row transducer array, where the transducer array has more electrically independent elements than the beamformer has channels, enables dynamic selection and beamforming control of multi-row apertures. The multiplexer allows the active aperture to be scanned along at least one axis of the array and allows the shape of the active aperture to be varied electronically. The multiplexer supports transmit and receive apertures appropriate for synthetic aperture beamforming. The multiplexer is designed so that each system beamformer channel may be connected to a single transducer element for near-field imaging and to a pair of adjacent transducer elements for far-field imaging.

Abstract: A circulating laser beam is generated in an oscillator having a gain medium. The laser beam is dumped from the oscillator to produce a laser beam pulse. The laser beam pulse is expanded and returned through the same gain medium for amplification thereof. The circulating laser beam and returning laser beam pulse travel in different paths through gain medium allowing the use of a small Pockels cell in the oscillator.

Abstract: A machine vane unit includes a first airfoil and a second airfoil located between and connected to a first flange and a second flange. The second airfoil includes a second leading portion located rearward of a first leading portion of the first airfoil relative to a direction of intended flow. The first flange and the second flange are configured to be connected to casing for a machine portion. The first airfoil and/or the second airfoil may include and/or have cast therein a hollow. The first airfoil and the second airfoil may be formed integrally.

Abstract: A method for simultaneous testing of individual components in multiple three phase inverters, each connected to a common source of direct current electric power and being coupled to supply power to a respective one of a plurality of three phase loads, involves the steps of monitoring the voltage applied to the inverters and the current at each output phase terminal while gating each switching device in each inverter momentarily into conduction in sequence from a first switching device in a first phase to a last switching device in a third phase until an input voltage drop or an output current is detected. In response to a detected voltage drop, the sequence of gating is interrupted and advanced forward to the next occurring phase. If phase current is detected in any phase during gating, the inverter generating the current is disabled.

Abstract: The number of simultaneous equations needed to find the location solution of an asset being tracked, such as a railcar, or, in the alternative, to improve the localization accuracy of any of several positioning methods used to track assets, is reduced by using a railway track database. Known railway track locations are used to constrain the railcar (i.e., asset) location solutions. This constraint makes the Cartesian coordinate location x, y and z values interdependent and reduces the number of simultaneous equations needed to find the location solution. Since all relevant railcars must be supported on railway tracks, and railway track locations and elevations throughout North America are available in a database, the number of satellite signals required is reduced. The railway track database represents a complex set of railway tracks.

Abstract: A current sensor for sensing alternating current in a current-carrying conductor includes a substantially C-shaped magnetic core having first and second ends with a gap therebetween. A current sensing element, which includes a microresonant element, is positioned proximate the gap between the first and second ends of the magnetic core such that the element oscillates when exposed to an alternating magnetic field. A biasing coil is attached to the micro-resonant element for carrying a bias current. The micro-resonant element resonates, or vibrates, at a standard oscillating frequency when no current is present in the biasing coil, and resonates at a modified oscillating frequency when current is present in both the biasing coil and the current-carrying conductor. The magnitude of current in the current-carrying conductor is determined as a multiple of the product of a ratio of the standard oscillating frequency and the modified oscillating frequency, and the bias current.

Abstract: An open superconductive magnet useful in magnetic resonance imaging (MRI) applications. The magnet has two spaced-apart assemblies and preferably has a "C" shape. Each assembly has: a vacuum enclosure having a longitudinal axis and surrounding a bore; a magnetizable pole piece located within the bore and outside the vacuum enclosure; and a superconductive main coil, a superconductive shielding coil, and a magnetizable ring positioned within the vacuum enclosure. There is no magnetizable solid path between the two pole pieces. Preferably, the ring is positioned longitudinally between the main and shielding coils.

Abstract: The present invention discloses a method and system for inspecting a surface of an object with laser ultrasound. In the present invention, the surface is scanned with a source laser emitting a laser beam at a plurality of scanning positions. The emitted laser beam generates surface or Lamb waves at the plurality of scanning positions and transmits the waves throughout the surface. The surface of the object is scanned with a detector laser emitting a laser beam onto the object surface at the plurality of scanning positions. Surface displacement produced by the waves reflected from the surface is detected with a detector at each scanning position. The detected displacement at each scanning position contains signals representing a laser ultrasound waveform data set corresponding to a two-dimensional surface region along the object. The laser ultrasound waveform data sets at each scanning position are processed with a synthetic aperture focusing technique in order to generate high resolution images.

Abstract: An array ultrasonic transducer precursor includes a body of piezoelectric material with a dielectric substrate bonded to a surface of the body. Circuit elements supported on the dielectric substrate include, in an active region, physically parallel signal conductors arranged in a pattern with spaces between adjacent ones of the conductors. Dicing saw cuts made in these spaces define individual circuit elements within the piezoelectric body. The circuit elements outside the active region include a set of resistive alignment elements in predetermined positions with reference to the pattern of signal conductors. The transducer precursor is mounted in a dicing saw fixture, and initial cuts made with the dicing saw remove portions of the resistive alignment elements. Locations of the initial cuts with reference to the resistive alignment elements are determined by measuring resistances of the resistive alignment elements after the initial cuts.

Abstract: A graphic workstation converts a polygonal model generated with computer aided design (CAD) software or volumetric data into a more compact polygon strip list having multiple strip sublists. The strip list, in addition to being more compactly stored, is displayed much more rapidly than conventional polygonal models since much of the redundant redrawing is eliminated. Shared point of adjacent polygons are eliminated. The strip list consists of a number of strip lists, each list having vertices of a first, or initial, polygon and subsequent vertices defining remaining portions of polygons to be `built onto` the polygon strip in the strip direction. Since this method of model storage and display is much more efficient, less powerful graphic workstation could be implemented in place of more powerful graphics workstations; or alternatively, existing graphics workstation would become faster and have more free memory available for other functions.

Abstract: RF tracking system employs a RF invasive device coupled to surgical tracking equipment for tracking the invasive device. An inductive coupling permits the device to be quickly coupled to, and decoupled from, the equipment. The coupling comprises an inducting coil which transmits a signal from the surgical tracking equipment to a communicating coil in the invasive device. The signal received by the communicating coil passes along leads to a tracked coil in a distal end of the invasive device. The tracked coil transmits the signal as RF energy which is received by the surgical tracking equipment which superimposes the position of the distal end of the invasive device on an X-ray image and displays it on a monitor A sterile shield is employed as a sterile barrier between the inducting coil and the equipment end of the invasive device to prevent contamination of the invasive device by the inducting coil.

Abstract: Apparatus for detecting defective conditions associated with a set of railway vehicle wheels and with a railtrack upon which a given railway vehicle travels comprises a rotation measurement unit for generating data indicative of rotational rate of the set of wheels; a motion sensor, such as an accelerometer or vibration sensor, for generating data indicative of motion along a vertical axis relative to the railtrack; and a data processor coupled to the motion sensor and to the rotation measurement unit for receiving the rotational rate and motion data. The data processor is designed for detecting, based on the received rotational rate and motion data, a defective condition associated with the wheel set and for detecting, based on the received motion data, a defective condition associated with the railtrack. The apparatus can be operatively combined with a mobile tracking unit for a vehicle tracking system.

Abstract: A permanent magnet rotor is shaped to optimize the flux distribution thereabout. In one embodiment, cut-outs in the rotor core between magnetic poles forces more of the magnetizing flux, i.e., that which would normally be distributed about the transition zone between the poles, into the main part of the poles, resulting in a substantially trapezoidal flux distribution that is substantially flat over approximately the central 120.degree. of each respective 180.degree. half-cycle thereof. In an alternative embodiment, the rotor core is shaped to be substantially square with rounded edges. Permanent magnet material is molded onto the square-shaped rotor core to form a plurality of magnetic poles such that the flux distribution about the rotor core is substantially sinusoidal.

Abstract: A digital radio receiver for synchronization of radiowave transmissions for digital and analog FM signals in TDMA systems such as cellular telephones uses a tangent type discriminator that minimizes the bit error rate. The digital discriminator employs A/D converter circuit that samples a received intermediate frequency (IF) signal, a sorter circuit that produces a predetermined number of samples to be used in the decoding, a sample and phase adjustment circuit that allows for a carrier phase adjustment and sample timing adjustment, a divider circuit that eliminates the need for a conventional limiter by causing a ratio of amplitudes to be processed instead of absolute signal amplitudes, an inverse tangent circuit that creates a decoded phase angle from the ratio, a delay circuit and a summer circuit that create a differential signal, a modulo-2.pi.

Abstract: An NMR system performs in vivo localized NMR spectroscopy. A two-dimensional selective RF excitation pulse is used to localize to a cylindrical region of interest, and either phase encoding or slice selective inversion is used to localize to a disk in the cylindrical region of interest. The two-dimensional selective RF excitation is performed in a series of pulse sequences rather than a single pulse sequence, and the resulting series of acquired NMR signals are summed together to substantially cancel signal conributions from outside the cylindrical region of interest.

Abstract: A scanning spectral-analysis micro-probe subsystem, for a surface imaging system, utilizes a micro-probe to detect the precise position of a point on a sample object surface having surface dimensions changing responsive to surface absorption of incident radiation from a modulated radiation source. The modulated incident radiation causes the sample region dimensions, in the vicinity of the micro-probe, to be modulated, so that the micro-probe detects this dimensional modulation, with a detected modulation strength directly proportional to the incident radiation absorption.

Abstract: A high power semiconductor rectifier is constructed so that the rectifier is normally off and can be switched on by applying a bias signal to a gate of a metal-insulator-semiconductor structure monolithically integrated with the rectifier in such a manner as to induce a conducting channel between the anode and cathode of the rectifier. The device has both forward and reverse blocking capability and a low forward voltage drop when in the conducting state. The device has a very high turn-off gain and both high dV/dt and di/dt capabilities.

Abstract: A method for enhancement of edge detail in fingerprint minutia first illuminates the finger with light passing through a polarizer in a first direction with respect to the polarization plane, for at least a portion of one rotation of the light source/polarizer about an optical axis generally perpendicular to the finger. The light reflected from the finger is converted to video data during at least a selected part of the rotation and the first set of video data is stored in a first storage means register. The illuminating, converting and storing steps are then repeated with light from a second direction, substantially orthogonal the first direction, illuminating the finger, and with a second set of video data, (for at least the same part of another rotation) being stored in a second register.

Abstract: An electric motor driven blade pitch varying system for the fan blades of an unducted fan type aircraft gas turbine engine utilizes permanent magnet alternating current motors located in the oil sump region of the engine. An alternator driven by the engine generates unregulated variable frequency, variable amplitude power which is rectified and placed on a DC bus. Controlled inverters convert the DC power on the bus to appropriate AC power for the motors. The system incorporates redundancy without significant weight penalty by providing alternators and motors dividing into two independent operating sections on common shafts. Separate electronic circuits are provided to supply power for each sectionalized motor or to rectify power from each alternator section. A common power bus may be used to couple the multiple motors and alternators. The common bus may alternatively receive power from tbe aircraft 400 Hz system or from on-board batteries.