Abstract: In a SIMD architecture having a two dimensional array of processing elements, where a controller broadcasts instructions to all processing elements in the array, a dynamically reconfigurable switching means useful to connect four of the processing elements in the array into a group in accordance with either the broadcast instruction of the controller or a special communication instruction held in one processing element of the group, the switch includes at least one dataline connected to each processing element in the group. A multiplexer is connected to each data line and to the controller and to a configuration register. It is adapted to load the special communication instruction from the one processing element in the group into a configuration register and to operate in accord with either the broadcast instruction from the controller or the contents of the configuration register to select one of the four data lines as a source of data and applying the data therefrom to a source output port.

Abstract: The present invention provides a method of performing statistical classification that can resolve conflict in independent sources of information, thereby creating a robust statistical classifier that has superior performance to classifiers currently available. Additionally, the present invention is automatically trainable, yielding improved classification performance. The present invention may be embodied in a method of statistically classifying events or objects, including the steps of gathering sets of information representative of features of an object or event; creating basic probability assignments based on said sets of information; determining a coarse information set from said sets of information; performing coarsening on said sets of information; performing linear superposition on each feature; and combining all features to reach a conclusion.

Abstract: A system for distributing first and second television signals of diverse modulation formats to a number of locations in a multiple-dwelling unit includes first and second antennas for receiving, at the multiple-dwelling unit, respective first and second received television signals having respective first and second, different modulation formats. The system also includes first and second transmodulators for transmodulating the first and second received television signals, respectively, to develop first and second transmodulated signals, respectively. A combiner or diplexer combines the first and second transmodulated signals into a combined signal, and a distributing network distributes the combined signal to each of a plurality of locations. A diplexer at a particular location selected from the number of locations separates the combined signal to recover the first and second transmodulated signals.

Abstract: A process is provided for fabricating MODFET's in group III nitride compound semiconductors. The process precedes isolation of the MODFET structure with the use of e-beam lithography to define very narrow (e.g., .about.0.25 micrometer) gates which enhance transistor microwave cut-off frequency. Because these compound semiconductors resist chemical etchants, isolation is accomplished by etching with reactive ions to form an isolation mesa having a vertical mesa sidewall. To improve breakdown, the mesa sidewall is covered with a passivation layer prior to deposition of a gate feed that contacts the gate. To reduce parasitic gate capacitance, the gate feed is spaced from a narrow edge of the transistor's two-dimensional electron gas.

Abstract: A low profile, low cost receiver/transmitter system includes a planar waveguide-to-microstrip adapter, a dielectric loaded waveguide fed slot array antenna, and a downconverter all formed on a single dielectric substrate made of polytetrafluoroethylene. The waveguide antenna includes a set of slots disposed in a surface thereof to receive/transmit a microwave/millimeter wave signal. The waveguide-to-stripline adapter is connected to the waveguide antenna and includes a taper section attached to a microstrip line. The taper section, which may be linear or may follow some other more complex taper function such as a Chebyshev function, adapts a signal propagating within the waveguide antenna to the microstrip line or vise versa.

Abstract: A micro-dimensional coupling conductor with a shape that is customized for a particular electronic device. A fabrication method is used in which the physical dimensions of the conductor are precisely controlled with photolithographic techniques, resulting in a conductor that is more precisely tuned to the operating frequency of the device. The conductor is fabricated on an SiO.sub.2 substrate using vacuum deposition techniques. After fabrication, the conductor is separated from the SiO.sub.2 substrate by dissolving the SiO.sub.2. Alternatively, the conductor may be fabricated on a Teflon.TM. substrate. The use of a Teflon substrate allows a user to remove the conductor from the substrate by applying a small mechanical force to the conductor.

Abstract: A contactless system for imaging an acoustic source within a workpiece directs a preferably annular optical probe beam pattern onto the vibrating workpiece surface, with the vibrationally modulated beam then detected by an array of preferably non-steady-state photo-emf detectors arranged in a similar pattern. The probe beam is scanned over the vibrating surface, either mechanically or through an electronically simulated phased array scheme. Time gating is used to suppress unwanted side-lobes when the individual detector outputs are summed over an appreciable waveband. A self-calibration scheme is also preferably used that provides a quantitative as well as qualitative output. A calibration modulation is imposed on at least one of the probe and reference beams, with the calibration modulation later removed at a post-detector stage and used to normalize the acoustic modulation output.

Abstract: An apparatus for providing uniform light intensity is disclosed. The apparatus consists of a number of wires arranged diagonally and horizontally on a frame. The horizontal wires are arranged with variable vertical spacing to create eight different zones of light attenuation transmission. The apparatus is designed such that the zones having the highest light attenuation are placed in front of the most intense light from a source and the zones having the lowest light attenuation are placed in front of the least intense light from the source. By matching the zones of the apparatus to the intensity pattern of the light source a uniform light source is created.

Abstract: A contactless system for imaging an acoustic source within a workpiece directs a preferably annular optical probe beam pattern onto the vibrating workpiece surface, with the vibrationally modulated beam then detected by an array of preferably non-steady-state photo-emf detectors arranged in a similar pattern. The probe beam is scanned over the vibrating surface, either mechanically or through an electronically simulated phased array scheme. Time gating is used to suppress unwanted side-lobes when the individual detector outputs are summed over an appreciable waveband. A self-calibration scheme is also preferably used that provides a quantitative as well as qualitative output. A calibration modulation is imposed on at least one of the probe and reference beams, with the calibration modulation later removed at a post-detector stage and used to normalize the acoustic modulation output.

Abstract: A method for stripping photoresist used as an etch mask in carbon based reactive ion etching includes flood exposing a patterned photoresist with a light and cyclically exposing the photoresist with an oxygen plasma in between the carbon based plasma. The step of cyclically exposing occurs after the step of flood exposing. The step of flood exposing includes the step of decomposing photosensitive compounds in the photoresist, while the step of cyclically exposing includes the step of cyclically removing layers of the photoresist.

Abstract: An improved liquid crystal display cell (34) comprising two substrates (108, 124) spaced apart and containing a quantity of liquid crystal mixture (18) therebetween, in which the substrates have facing surfaces (108', 124') coated with a continuous, electrically conducting material (38, 36), is provided with an array of spacer pads (40) at a pre-selected distance apart from each other, having a pre-selected height to maintain a given spacing between the substrates, and having a pre-selected cross-section that avoids substantial interference with the display properties of the liquid crystal display cell.

Abstract: A low cost highly integrated method of fabricating a heat sink on the backside of a power semiconductor device maintains device performance, improves thermal transfer, and enables reliable planar connections without having to dice the wafer or package the discrete device-heat sink assembly. An etch stop layer is formed between the wafer and the frontside power devices to protect them during backside processing and to reduce the contact resistance between the device and its heat sink. The heat sinks are formed by thinning, patterning and then plating the wafer in such a manner that the devices can be released without dicing. The heat sinks are preferably oversized so that a vacuum tool can grasp the heat sink from above without damaging the device and then compression bond the heat sink onto a planar microstrip circuit assembly, which is designed and packaged to facilitate easy replacement of failed devices.

Abstract: Methods for the design and fabrication of micro-electro-mechanical switches are disclosed. Two different switch designs with three different switch fabrication techniques are presented for a total of six switch structures. Each switch has a multiple-layer armature with a suspended biasing electrode and a conducting transmission line affixed to the structural layer of the armature. A conducting dimple is connected to the conducting line to provide a reliable region of contact for the switch. The switch is fabricated using silicon nitride as the armature structural layer and silicon dioxide as the sacrificial layer supporting the armature during fabrication. Hydrofluoric acid is used to remove the silicon dioxide layer with post-processing in a critical point dryer to increase yield.

Abstract: A highly uniform, planar and high speed JHEMT-HBT MMIC is fabricated using a single growth process. A multi-layer structure including a composite emitter-channel layer, a base-gate layer and a collector layer is grown on a substrate. The composite emitter-channel layer includes a sub-emitter/channel layer that reduces the access resistance to the HBT's emitter and the JHEMT's channel, thereby improving the HBT's high frequency performance and increasing the JHEMT's current gain. The multi-layer structure is then patterned and metallized to form an HBT collector contact, planar HBT base and JHEMT gate contacts, and planar HBT emitter and JHEMT source and drain contacts.

Abstract: A method of growing a p-type doped Group II-VI semiconductor film includes the steps of forming a lattice comprising a Group II material and a Group VI material wherein a cation-rich condition is established at a surface of the lattice. The method further includes the steps of generating an elemental Group V flux by evaporating an elemental Group V material and providing the elemental Group V flux to a Group VI sublattice of the lattice.

Abstract: A display includes a plurality of light-emitting devices arranged as a matrix of pixels and an addressing circuit coupled to each respective light-emitting device. The addressing circuit includes a plurality of micromachined electromechanical (MEM) switches operable to control the plurality of light-emitting devices. Each MEM switch includes a cantilever beam and a control electrode spaced therefrom to deflect the cantilever beam electrostatically in order to close or open the switch.

Abstract: A satellite-based communications system operating at high data rates includes a plurality of satellites each having uplink and downlink antennas for transmitting and receiving a plurality of signals utilizing a plurality of spot beams to and from a plurality of coverage areas at a predetermined range of frequencies. The system also includes a plurality of user terminals for transmitting and receiving signals to and from the plurality of communications satellites at the predetermined range of frequencies and at one of the first plurality of data rates. Each of the user terminals having a steerable antenna for tracking relative movement of each of the user terminals with respect to each of the plurality of communications satellites and for tracking movement of each of the plurality of communications satellites in order to maintain communications with the plurality of communications satellites.

Abstract: A combined test fixture and spatial-power-combined amplifier includes a base, a first waveguide mounting flange engaged to said base, a second waveguide mounting flange engaged to said base, a waveguide input fixed to said first flange, a waveguide output fixed to said second flange, an amplifier array disposed between said first flange and second flange, said array comprising a plurality of semiconductors for amplifying a signal, and a spacer for spacing apart said semiconductors. A plurality of amplifier cards constitute the array, with the cards being disposed in various arrangements which include a linearly stacked arrangement and radially stacked arrangement. The first and second waveguide mounting flanges are constructed to slide along the base to enable the amplifier array to be easily changed.

Abstract: A coordinatable system of geosynchronous (24-hour), inclined, and slightly elliptical satellite orbits enables spectrum re-use by forming "highways" of moving "slots" in the latitudes above and below the geostationary (GSO) belt worldwide. Each of a plurality of repeating ground tracks is shared by multiple satellite orbits (and thus slots). These are phased to achieve minimum specified angular separation from other slots using the same frequencies. Ground track (and thus orbital) parameters are chosen to realize specified shapes and are located at specified longitudes of symmetry to maximize the total number of slots. Consideration is given to specified constraints on service area coverage, elevation angle, and time coverage.

Abstract: An object-based image/video coding algorithm that encodes arbitrary shaped objects using LOTs defined on rectangular and L-shaped regions. The regions of support of the blocks in the L-shaped regions are extended to form tapered overlapping regions that meet at the object's exterior and concave corners. The overlapping regions taper to the corners with a slope having a magnitude .delta./.epsilon., where .delta. and .epsilon. are the amounts of overlap between the blocks. This allows the basis and tapered window functions to be defined in the L-shaped region and specifically in the tapered overlapping regions in a manner that maintains the orthogonality of the basis functions while providing a smooth transition at the edges.