Abstract: Techniques for interconnecting high-density, structures that include temperature sensitive materials such as piezoelectric ultrasonic transducer arrays, optical detector arrays, MEMS and the like to other structures (e.g., integrated circuits or mechanical assemblies) are disclosed.

Abstract: A method of forming sheets of superplastically formable material into a three dimensional article, the sheets being joined together along diffusion bonds to form discrete cells, at least one gas path being provided through the bond between cells. The sheets are heated to a temperature at which they exhibit superplastic properties and a gas injected between the sheets to expand the cells, the gas paths allowing the injected gas to pass from cell to cell. The edges of the gas paths are locally heated to change the microstructure of the sheets in the edge areas, which reduces the flow resistance of the edges under superplastic forming conditions and thereby reduces the propensity of the diffusion bonds bordering the gas transfer holes to peel apart under the forces of the inert gas exerted on the sheets at the gas transfer paths.

Abstract: A real-time, three dimensional, acoustical camera and a real-time, range-gated, intensified, electro-optical camera have substantially overlapping fields of view for co-registered imaging of underwater objects at close ranges. The system is typically mounted in an unmanned underwater vehicle but may be used in other fixed or mobile configurations. The coupled fields of view are steerable in an arc around at least one axis over a large field of regard with a servo-controlled rotating mirror system, while the vehicle or the target is moving or hovering. An automated target recognition system uses the multi-modality images to provide enhanced target recognition and/or autonomous operation in unmanned missions.

Abstract: A real-time multi-user detection (MUD) receiver processing simultaneous digitally modulated interferers and transmissions in the same frequency optimizing performance for heavily loaded and overloaded multiple access systems by implementing an iterative TurboMUD receiver using tree-pruning, including confidence ordering, power-ordering, and a voting procedure. On the first iteration, user indices are ordered according to received powers. On subsequent iterations, the voting system provides soft decisions or confidence values utilized as soft inputs to single-user decoders. Voting is computationally attractive and allows the bank of decoders to operate on soft values, improving performance and reducing the number of turboMUD iterations. The bank of soft output error correction decoders produces an improved set of soft decisions or confidence values corresponding to the channel bits transmitted by each interfering user.

Abstract: An SEU immune logic architecture includes a dual path logic gate coupled to a dual to single path converter. A first and a second logic element within the dual path logic gate are functionally and possibly structurally equivalent, and are coupled to receive input signals spanning redundant input signal sets. A given logic structure within the first logic element may receive specified input signals within a particular input signal set, while an analogous logic structure within the second logic element may receive corresponding input signals within the counterpart input signal set. A radiation induced transient pulse that affects one input signal may affect an output signal asserted by one logic structure; however, since the transient pulse doesn't affect a corresponding input signal applied to the analogous logic structure, the dual path logic gate may output at least one correctly valued signal when a transient pulse occurs.

Abstract: Bias error is reduced in a vibrating structure sensor having primary and secondary pick-offs separated by a fixed angular amount (45°) with respect to the vibrating structure by summing a proportion of the primary pick-off output signal into the secondary pick-off output signal or subtracting a proportion of the primary pick-off output signal from the secondary pick-off output signal effectively to reduce or increase the angular separation of the secondary pick-off from the primary driver by an amount sufficient to set the rate output signal from the vibrating structure to zero and thereby minimize bias error.

Abstract: A method and system for underwater detection of fully or partially buried objects such as sea mines and underwater cables, consisting of a mobile underwater platform configured with a real-time, three dimensional acoustical camera with a downward directed field of view used as an imaging interferometer, coordinated with a high-intensity, low frequency acoustical transmitter directed as to disturb the loose particulate or elastic matter comprising the seafloor within the field of view of the camera. The images recorded by the camera display the relative motion of the seafloor material before and after an acoustical pulse, in contrast to the lesser or no motion of submerged solid objects. Distinguishing man-made from natural objects is aided by recognizing geometric shapes apparent within the varying image density, not common in nature.

Abstract: A bolt with a partially threaded shank has a plurality of locking grooves located on the shank between the thread and its head. The bolt is inserted through a component stack and spacing washers and a stepped reaction washer such that at least half of the locking grooves are left exposed. A deformable frusto-conical locking ring is positioned on a nut having a circular receiving cavity on one end. The nut and locking ring are positioned on the thread of the bolt and tightened so that the locking ring is deformed from a frusto-conical shape to a substantially flat disc such that its bore diameter is reduced, thereby retaining it within one of the locking grooves. The outer diameter of the receiving cavity abuts the stepped reaction washer.

Abstract: A method for growing solid state laser crystal boules is disclosed that when made into laser rods do not need separate end caps attached to the laser rods. The crystal boule is grown as a single integral unit with three segments. Two segments, the end segments, are un-doped or non-laser active, and they flank a central segment of the boule that is doped with an active laser ion. A first end segment of the crystal boule is first grown from un-doped melt material in a first crucible by slowly withdrawing its growing end from the first melt. The boule is then transferred to a doped melt in a second crucible where its growing end is submersed therein to grow the doped, laser active central segment. The temperature of the melt in the second crucible is initially higher than the growing temperature of the first melt and causes the growing end of the boule to melt.

Abstract: Multi-pattern data retention testing and iterative change of measurement testing are used for the production of Known Good Dies. Multi-pattern data testing of a memory such as an SRAM comprises writing at Vdd, reduction of Vdd, restoration of Vdd, reading of the memory, and comparison of write patterns to read patterns to determine accuracy of data retention. Iterative or change of measurement testing involves repeated testing of a die to determine changes in Iddq, changes in multi-pattern data retention, or other changes in chip operating parameters. Defect activating test may be used in combination with change of measurement testing or with multi-pattern data retention testing.

Abstract: A single-event upset immune flip-flop circuit is disclosed. The single-event upset immune flip-flop circuit includes a first single-event upset immune latch and a second single-event upset immune latch. The first single-event upset immune latch has two inputs and two outputs. The second single-event upset immune latch also has two inputs and two outputs. The two inputs of the second single-event upset immune latch is connected to the two outputs of the first single-event upset immune latch. The state of the first single-event upset immune latch changes only when the signal polarities at both inputs of the first single-event upset immune latch are identical. Similarly, the state of the second single-event upset immune latch changes only when the signal polarities at both inputs of the second single-event upset immune latch are identical.

Abstract: An optical data transmission link with improved fiber utilization. VCSEL and detector elements are configured on an optical matrix array with allocated surface area footprints at standard industry pitch dimensions, the elements of alternate rows and columns being offset from centerline of their footprints in opposite directions so as to create a pattern of sets of two or four adjacent optical elements operating at a common or differential wavelengths. A connector provides offset alignment of the fiber bundle to the matrix array so as to align a single fiber of standard industry diameter equal to the pitch of the array, with the center of each multi-element set so the fiber core diameter spans all elements of the set. The required modification to standard commercial mask design and chip fabrication is within the scope of present fiber optic technology.

Abstract: An interference cancellation system for improved rejection of a signal coupled from a transmission antenna into a local receive antenna in the presence of local multipath. This interference cancellation system includes a frequency hopped radio adapted to operate in a dispersion environment. This frequency hopped radio has an instantaneously limited bandwidth communication channel operating over a substantially larger bandwidth. Transmission of a signal from the frequency hopped radio is via a directly coupled reference path and a received coupled path. A delay means is used for variably adjusting the phase slope delay of the signal in one path relative to the other path. The system employs an amplitude slope means for variably adjusting the amplitude slope of the signal in one path relative to the other path.

Abstract: A method for manufacturing a programmable chalcogenide fuse within a semiconductor device is disclosed. A resistor is initially formed on a substrate. Then, a chalcogenide fuse is formed on top of the resistor. Finally, a conductive layer is deposited on top of the chalcogenide fuse for providing electrical conduction to the chalcogenide fuse.

Abstract: A system is provided for detecting the presence of two or more acoustic sources or targets such as vehicles that are traveling between an array of unattended passive ground sensors, in which the sensors each include a phased-array microphone and processing to determine the bearing to the acoustic target. The bearings from pairs of these sensors are subtracted one from the other to provide a bearing line difference “delta” which is the indicator of the presence of an acoustic target close to the line between the two sensors of the pair. A tripwire threshold indicating the presence of a target is set when the absolute value of this bearing line difference “delta” is greater than, for instance, 150°, with the “delta” being 180° when the target is on the line between the two sensors.

Abstract: Meanderline loaded antennas having a wide bandwidth available for simultaneous or instantaneous use are disclosed. In one embodiment, the azimuthal angle of arrival associated with the antenna is provided by phase difference between signals at the RHCP and Vpol ports or by phase difference between signals at the LHCP and Vpol ports. In another embodiment, a quad meanderline loaded antenna is adapted to simultaneously provide four independent beams. Any beam direction can be synthesized by combining the independent beams.

Abstract: Methods and apparatuses for determining angular information from a target. A plurality of sensors on an image plane are used to obtain measured amplitude data. An azimuth and elevation may be estimated using this measured amplitude data. A residual error between the measured amplitude data and calibrated amplitude data may then be determined. The angular information corresponding to the azimuth and elevation at which the residual error is minimized may then be outputted as representing or corresponding to the angular information of the target.

Abstract: A method of fabricating a dense pixel array comprising the steps of: (a) printing a photoresist mask and applying said mask to a semiconductor material substrate to form a masked area and an unmasked area on said substrate; (b) applying a photoresist material layer to the unmasked area of the substrate, then applying a metal layer over the photoresist material layer and the substrate, and then applying a solvent to remove the photoresist material layer and said metal layer applied over said photoresist material layer to leave a plurality of metal layers superimposed over the unmasked area of the substrate; (c) removing the substrate to a depressed substrate surface between the metal layers formed in step (b) to form a plurality of pixels each having an upper metal layer; (d) superimposing an insulative layer over each of the metal layers formed in step (c); (e) forming a hole in at least one of the insulative layers formed in step (d) so as to expose the metal layer under the insulative layer; and (f) superim

Abstract: A whip antenna with switchable operative length provides seven band coverage from 30 to 90 MHZ. A coaxial choke section below a fixed upper antenna element is used for the highest frequency band. A series of four coaxial line sections are switchably coupled below the choke section to increase its operative length for operation in bands of successively lower frequency. One or more lumped constant non-coaxial transmission line sections are switchably coupled below the coaxial line sections for operation in the two lowest frequency bands. Dipole level gain is provided with low reflections loss. Increased height gain is provided by height of operative antenna elements employed at higher frequency bands.

Abstract: The invention provides an aircraft having a flight control system (20) comprising an aerodynamic lift generator, and a control system in use the lift provided by the lift generator. The lift control system in one embodiment uses a concentrated mass mounted within a longitudinal body of the aircraft, the concentrated mass comprising at least one existing aircraft function and/or system mounted on a support in a confined area. Bearings permit relative movement between the support for the concentrated mass and at least a portion of the lift generator. An actuator is provided for causing such relative movement whereby in use the center of aerodynamic lift and the center of gravity of the aircraft may be moved relative to one another for effecting flight control.