Abstract: An electrical device package includes an aluminum header having a gold-coated sealing surface and an electrical device mounted within the boundary defined by the sealing surface. An annular gold-coated stainless steel seal ring registers with the sealing surface of the header. An annular bonding layer of a gold-tin alloy lies between, and registers with, the sealing surface of the aluminum header and the stainless steel seal ring. The electrical device is fastened to the header using an electrically and thermally conductive epoxy adhesive. A stainless steel cover has a flange which is welded to the seal ring to form a hermetically sealed package.

Abstract: Apparatus and method for providing an antenna feed (10) operative at different microwave frequency bands employ a circular waveguide (14) interconnecting an orthomode transducer (20) to a feed horn (16) thereby providing a feed (10) suitable for illuminating the reflector (54) of an antenna (12). The orthomode transducer provides for a coupling of waves in the first frequency band with both vertical and horizontally polarized waves. Included within the feed is a coupler assembly (26) of waves of the second frequency band operative via a sidewall of the circular waveguide. The coupler assembly includes plural identical coupling sections (28) each having a rectangular waveguide section contiguous and parallel to the circular waveguide with a row of apertures for coupling power into and out of the circular waveguide. Pairs of the coupling sections are disposed in orthogonal planes so as to introduce two linearly polarized waves which are perpendicular to each other.

Abstract: An integrated digital circuit is protected from reverse engineering by fabricating all transistors of like conductivity with a common size and geometric layout, providing a common layout for different logic cells, connecting doped circuit elements of like conductivity with electrically conductive doped implants in the substrate rather than metalized interconnections, and providing non-functional apparent interconnections that are interrupted by non-discernable channel stops so that all cells falsely appear to have a common interconnection scheme. The camouflage is enhanced by providing a uniform pattern of metal leads over the transistor array, with a uniform pattern of heavily doped implant taps from the transistors for connection to the leads; undesired tap-lead connections are blocked by channel stops.

Abstract: A method and apparatus for improving aim point accuracy in a programmable flight control missile includes a communication system for receiving at least one frame of imagery in a vision system mounted in a missile, predicting a subsequent frame content based on the content of the previous frame as a function of missile path height, missile velocity, and frame rate, and creating a residual image by determining the difference between a predicted subsequent frame content and actually received frame content. In the preferred embodiment, the residual image can be transferred at a high bit rate through a communication system into a controller at which location correction data can be generated and delivered to the communication system to the missile in flight. Preferably, the predicted subsequent video frame and the sensed subsequent frame content are centrally aligned before creating a residual image.

Abstract: A communication payload system for a satellite having a beam forming network, an amplifier associated with each output port of the beam forming network, and a plurality of hybrid matrices and a calibration pick-up antenna. Each hybrid matrix has a plurality of inputs connected to selected amplifiers and a corresponding number of outputs. One output of each hybrid matrix is connected to a power absorber adapted to function as an output calibration port producing a calibration sample and the remaining outputs connected to feed radiating elements. A calibration system applies power to selected output ports and calculates calibration corrections in response to the values of the calibration samples and the values of the power radiated by each feed radiating element which are applied to the beam forming network to maintain the calibration of the payload system.

Abstract: A phased array (20) and method for constructing the same are disclosed. The phased array (20) includes a superstructure (22) with cavities (40) therein. A cover plate (28) is mounted to the superstructure (22) and cooperates with the cavities (40) to form cavity style filters therebetween and to form a box-beam type superstructure. Ideally, the superstructure (22) is self supporting. Electronic modules (32) and amplifiers (33) are mounted to the superstructure (22). The method includes machining a block of material to form a webbed superstructure with cavities (40) therein. A cover plate (28) is mounted to the superstructure (22) over the cavities (40) to form cavity style filters. Amplifiers (32) and antenna elements (30) are then affixed to the superstructure (22) and cover plate (28). Ideally, the cover plate (28) is affixed to the superstructure (22) using an electrically conductive adhesive.

Abstract: The present invention relates to a subscriber unit in a wireless personal communications system (WPCS). In one embodiment, the subscriber unit includes a digital dataport for modemless communication of digital signals. Another preferred embodiment provides for a subscriber unit having a cable television transport module for modulating and demodulating signals over unused bandwidth available on cable television lines.

Abstract: Solar tabs are provided which have thermal emissivity and absorptivity properties designed to increase the attitude-control torques that can be generated with rotatable wings in a spacecraft. These increased torques enhance the ability to offset attitude-disturbance torques which typically tend to alter the attitude of a spacecraft from a desired attitude. The tabs include highly absorptive and nonemissive front faces, highly emissive back faces and a high thermal conductivity between the front faces and the back faces.

Abstract: A method and system for transmitting audio-associated text information in a multiple-channel transmission stream is disclosed herein. The method includes the steps of receiving text information associated with a song, formatting the information into song data, inserting the song data into a control data stream associated with an audio channel carrying a particular song, multiplexing the control data stream with a data stream associated with the song, transmitting the multiplexed data stream, receiving the control data stream, decoding the control data stream to obtain text associated with the song, and displaying the text. The method utilizes an existing control stream in the multiplexed transmission stream to forward text to a receiver. The receiver therefore requires no additional hardware to display the text on a connected video screen.

Abstract: A dual mode external DC power supply system for supplying DC power to an electronic device and which operates under the control of the electronic device is provided. The disclosed embodiment of the power supply system includes a first input adapted to receive an input signal of unregulated DC power, a second input adapted to receive a control signal from the electronic device, and an output adapted to provide either a constant voltage DC output signal or a constant current DC output signal depending on the magnitude of the control signal. The control signal also determines the level of constant current delivered to the electronic device when the system is operating in the constant current mode.

Abstract: A simple, low-cost deformation mechanism and method produces submicrometer increments of motion, to precisely stretch and compress fibers containing optical gratings in order to achieve a desired length and period. Such a "tunable" fiber can be used to, for example, produce an optical filter or to "match" two fiber lasers, thus enabling their use in a coherent detection system. Two beams, parallel to and opposing each other, are joined at two places. A screw is positioned between the beams such that a force is exerted on both beams simultaneously when the screw is rotated, deforming both beams. Motion reduction is provided by sharing the screw's movement between the two beams, and is further enhanced by making one beam thicker than the other. Two fibers are secured into grooves provided on one of the beams. By rotating the screw to increase or decrease the deformation, the fibers and their respective gratings are stretched or compressed.

Abstract: Complex additional feed-forward error sensor loops and error correction loops are replaced in a high-frequency multi-carrier signal amplifier system with simple signal predistortor structures. In addition, less costly error amplifiers are facilitated and system efficiency increased by the introduction of error predistortor structures.

Abstract: A microwave filter includes two resonant cylindrical cavities aligned in parallel along their longitudinal axes, with the cavities offset by one half the cavities' resonant wavelength with respect to one another. Signals to be filtered are coupled into a first, input, cavity through an input coupling and between the input cavity and a second, output, cavity through bridge and mainline couplings formed in a common cavity wall.

Abstract: A gimbal system includes a pair of stepper motors that drive respective drive trains of a differential drive assembly such as a differential gear assembly. Either the drive ratios or the step sizes for the two motors are offset from each other to provide four modes of operation, including modes for improved resolution and faster slew rate, and two intermediate modes with more balanced resolution and slew rate.

Abstract: A method and system for determining an actual location of a sense antenna associated with a phased array communications satellite. A plurality of calibration carrier signals are transmitted at known frequencies. Each of the plurality of calibration carrier signals are received at a second frequency and compared with each of the plurality of transmitted calibration carrier signals. The actual location of the sense antenna is determined based on the comparison between the known frequency and the second frequency. The phased array communications satellite then broadcasts communication signals based on the actual location of the sense antenna rather than a desired location of the sense antenna.

Abstract: A method of simultaneously performing a translational maneuver of a spacecraft by a thruster and dumping momentum from the spacecraft during a time period P. The method entails aligning the thruster along a thrust vector which is fixed during the time period P, wherein the thrust vector is aligned with the center of mass of the spacecraft at a time P/2, and firing the thruster throughout the time period P.

Abstract: The number of surface defects in semiconductor materials having a volatile species, particulary group-III nitride-based semiconductor devices, are reduced by first implanting species atoms into the semiconductor sample to fill some of the surface layer species vacancies created by growth and device fabrication processes, and then rapid thermal annealing the sample to repair broken bonds and crystalline defects and to move implanted species atoms from interstitial to substitutional sites. An optional third step deposits a dummy layer on the sample surface prior to implantation, making possible an implantation profile that places a higher density of species atoms in the surface layer than is attainable without the dummy layer and to inhibit species atoms from leaving the sample during high-temperature processing steps that follow.

Abstract: A holographic optical filter separates broadband electromagnetic radiation into spectral components corresponding to different spectral regions and then images this radiation onto pixels of a display. It includes two layers of holographic optical elements that are sensitive to each of these spectral regions. The holographic optical elements generally transmit radiation outside of their bandpass but can diffract radiation falling within it. The filter is well suited for display applications and can be used in either a reflective or transmissive mode.

Abstract: An erasable optical memory is provided by an erasable bistable photoactive chromophore that is covalently bonded to a polymer microsphere. An azobenzene chromophore that is bonded to the microsphere by an oxygen or NH replacement of chlorine, or a CH double bond to N, is preferred. An array of such microspheres is encoded by applying radiation at a resonant wavelength to induce a conformational change in the chromophores for selected microspheres, and the encoded pattern is read out by detecting changes in either absorption or fluorescence.

Abstract: An imaging system that can tolerate high intensity optical beams without a reduction in the system's field-of-view, comprises an imager, a fiber array positioned at the image plane of the imager, a sensor array positioned at the output end of the fiber array, a panel display positioned in proximity of the fiber array and an image processor for electronically processing the information from the sensor array.