Abstract: A thin film (at least one atomic layer to about 400 .ANG.) of nickel is electrolytically plated on top of electrolytically-plated gold electrodes in GaAs monolithic microwave integrated circuits (MMICs) without any additional photoresist masking step. The thin electrolytically-plated nickel film improves adhesion of a passivating dielectric layer (e.g., silicon dioxide, silicon nitride, and silicon oxynitride) formed on the electrolytically-plated gold electrodes. The electrolytically-plated nickel film can be removed locally to facilitate the fabrication of plated silver bumps (for off-chip electrical connections and thermal paths) on passivated flip chip MMICs.

Abstract: Mixer structures are described which include a current mirror for insertion of trickle currents to an input differential amplifier and an output interface for coupling an output differential amplifier to an output port. The current mirror trickle currents improve the mixer's conversion gain and third-order intercept point and the current mirror introduces them without introducing spurious signals. The output interface couples mixer currents to the output port while isolating the output port from power-supply spurious signals.

Abstract: A current steering circuit diverts bias current from a differential current summing amplifier's front end when the differential input exceeds a safe threshold level, thus preventing the amplifier's output stage from being overdriven. Diverting the front end's bias currents also turns off transistors within the amplifier's front end and thus protects the front end from damage which may otherwise result from excessive input signals.

Abstract: A low voltage analog front end (AFE) includes a differential transistor pair which converts an input voltage, typically A.C.-coupled to the pair's control inputs, to a differential current. Impedance networks connected to each transistor's control input are joined together at a common node, and a current source is connected to the node which causes DC bias currents to be mirrored through the pair's current circuits, so that the AFE's differential output current comprises a differential current produced by the pair in response to an input voltage and superimposed on the DC bias currents. The current source preferably generates mirrored currents which are larger than its reference current to linearize the pair's response and to provide the AFE with a wide dynamic range. An input to the AFE sees a low impedance which is about equal to the sum of the impedance networks, which can be resistive or complex as needed.

Abstract: An amplifier includes an amplifying circuit and bias current circuit. The bias current circuit includes a beta matching circuit which employs a temperature compensated current reference to develop a bias current for the amplifying circuit. The beta matching circuit is connected to track the current gains of transistors within the amplifying circuit and to thereby provide a temperature compensated bias current to the amplifying circuit. The bias current maintains a fixed bias point regardless of temperature-induced, or other, variations of the current gains of the amplifying circuit's transistors.

Abstract: A low-noise, low-distortion clamping scheme includes a bootstrapped voltage clamp and an R.sub.gm current clamp that provide superior overdrive protection when used together in a Class-AB feedback amplifier. The bootstrapped voltage clamp includes a transistor that is connected to a circuit node to be clamped. The transistor's base is bootstrapped to the node to maintain a constant V.sub.be when not clamping, to reduce the adverse effects of the junction capacitance C.sub.je which would normally vary with the node voltage and distort the signal at the node. Two such clamps provide positive and negative voltage limiting. The R.sub.gm current clamp is used in the input stage of a Class-AB feedback amplifier to limit the current through the resistor R.sub.gm that interconnects the current inputs of two transconductance amplifiers whenever the voltage drop across R.sub.gm increases to an unacceptable level.

Abstract: Low-cost composite infrared windows that are transparent to long wave infrared radiation (8-12 microns) that provide sufficient strength and impact resistance for automotive-type environments, and the like. The windows may be used with night vision systems for automobiles, surveillance imaging systems, and other applications requiring low cost, long wave infrared windows. In one embodiment, the composite infrared window is a sandwich comprised of a polyethylene plastic film bonded with an acrylic adhesive to a relatively thin (0.015-0.040 inch) silicon substrate. The thin silicon substrate is mechanically stiff and low cost, and transmits in the 8-12 micron bandpass. The thin (0.001-0.007 inch) plastic film provides an exterior particle impact absorbing layer sufficient to enable the use of the window in automotive applications.

Abstract: A wide angle large reflective unobscured system includes a primary reflective element for receiving a broad range of energy, a secondary reflective element for reflecting the energy from the primary reflective element to reimage a virtual entrance pupil at a real aperture stop. A beamsplitter element is provided for reflecting a first portion of the energy, such as visible energy, to a first tertiary reflective mirror, while transmitting a second portion of the energy, such as IR light, to a second tertiary reflector. Each tertiary reflector is capable of focusing the received energies to dual focal planes wherein a compact detector array assembly can convert the images to electronic signals.

Abstract: Apparatus and a method for generating a digital synthesized Gaussian noise-like waveform that may be used to modulate and demodulate communication data. The present invention uses a seed input that addresses a read only memory look-up table, for example, containing digital samples having Gaussian statistics. A sequence generator generates a pair of pseudo-random sequences in response to the seed input that address the read only memory to look up and output a pair of pseudo-random Gaussian samples that are used to generate the Gaussian noise-like waveform. A processor converts the pair of pseudo-random Gaussian samples into corresponding analog I and Q signals, and a modulator 33 modulates the analog I and Q signals to generate a modulated output signal having the Gaussian noise-like waveform.

Abstract: An adaptive feedforward vibration control system reduces vibrations at fundamental and harmonic frequencies of matched reciprocating pistons, such as back-to-back compressor pistons in Stirling cycle cryocooler, by driving the pistons with correction signals. The system is also applicable to reducing the vibrations generated by a pair of opposite expander and balancer pistons in a cryocooler. The correction signals are computed iteratively to increase their accuracy, and need only be updated relatively infrequently to adjust the pistons' motions, thereby enabling the use of a relatively slow microprocessor.

Abstract: Portable, lightweight, compact, eye-safe, battery-operated laser range finder and digital compass assembly, mountable onto a personal weapon or aiming device, to accurately measure distance, azimuth and elevation angle of a target and increase the accuracy and probability of the hit. The laser range finder and digital compass assembly has a laser transmitter for transmitting an output laser beam having a wavelength in the range of 1.0 to 1.1 microns, an OPO converter for converting the output laser beam to an eye-safe range between 1.5 and 2.

Abstract: An eyesafe laser system includes a Q-switch crystal formed of a semiconductor host material having noncentrosymmetric tetrahedral substitutional sites doped with transition metal ions in concentrations from about 0.001 to about 0.10 atomic percent, which functions as to be a saturable absorber of light at eyesafe wavelengths with a relatively long relaxation lifetime. Co.sup.2+ :ZnSe has been demonstrated to have advantageously high absorption cross section and advantageously high relaxation lifetime at both 1.54 .mu.m (Er:glass laser) and 1.6 .mu.m (Er:YAG laser). Other candidate host materials include other zinc chalcogenides, cadmium chalcogenides and zinc oxide.

Abstract: A plurality of sensor units are distributed over an area and communicate via a network with a central monitoring unit. The sensor units include sensor arrays that provide them with raw data in response to the presence of selected compounds in the ambient fluid. The raw sensor data is then processed to compute a local profile, which (a) illustrates a change in the compounds in the fluid from their normal state (change detection) , (b) indicates the presence and total concentration of foreign compounds in the fluid (presence detection), or (c) details the composition and concentrations of defined classes or individual species of compounds in the fluid (composition detection). The local profiles from the individual sensor units are then used to compute a spatial and temporal map for the compounds in the fluid.

Abstract: The wiring harness assembly of the present invention is an electrical and structural network which serves as a distribution system for the command/control signals and power of a comprehensive warfare system. The warfare system, which in worn by an individual soldier, contains multiple subsystems. The wiring harness assembly includes four distinct segments which allow each subsystem to communicate with a central microprocessor and with each other. The wiring harness assembly includes the Torso Segment which is partially embedded within the frame of an equipment carrier borne by the individual soldier. The embedded portion of the wiring harness assembly is protected from any harsh environment that may be encountered by the soldier. Other segments include the Integrated Helmet Assembly Subsystem Segment, the Weapon Subsystem Segment, and the Sensor Subsystem Segment which provide the electrical network for a variety of equipment options available to the soldier.

Abstract: An indoor air pollutant destruction apparatus destroys pollutants by a corona discharge that is generated by a rapidly oscillating electric field. Free electrons generated by the corona discharge produces ozone (O.sub.3), which effectively destroys volatile organic compounds (VOCs) and biological forms such as bacteria, fungi, viruses and spores. Fine particulate materials such as smoke and dust are charged by the corona discharge, and when they pass through the rapidly oscillating electric field, they coagulate to form larger particles which are then filtered out.

Abstract: An autostereoscopic display includes a projection system which generates a plurality of real images that represent different spatial views of an object and further includes a plurality of contiguous field lenses. From the real images, the field lenses form a plurality of exit pupils which are separated by one interpupillary distance. An observer can "walk around" the display and observe different stereoscopic views of the object by positioning his eyes at an adjacent pair of exit pupils.

Abstract: A method of replenishing liquid carbon dioxide solvent in a liquid carbon dioxide dry cleaning system or other dense phase carbon dioxide cleaning system. The method uses dry-ice or solid carbon dioxide, as a replenishing stock, thus reducing transportation, storage and handling costs. The method disposes solid carbon dioxide blocks in a cleaning chamber after a cleaning cycle. Liquid carbon dioxide solvent is boiled and is used to melt the solid carbon dioxide blocks. Liquid carbon dioxide solvent produced by melting the solid carbon dioxide blocks is pumped from the cleaning chamber into a storage tank to replenish the liquid carbon dioxide solvent.

Abstract: An improved eyepiece for an optical system. In general, the inventive eyepiece (10) includes a refractive element (16) and an optical arrangement for relaying the entrance pupil of the system to the refractive element. In a specific implementation, the optical arrangement includes a concave primary mirror (12) and a secondary mirror (14). The mirrors are mounted to communicate an image from the refractive element (16) to the entrance pupil (40). In the specific implementation, the refractive element (16) is one or more refractive lenses. The use of a reflective optical arrangement allows for the long eye relief. The placement of the entrance pupil close to the pupil of the lens allows for the use of a compact optical arrangement with high ratio of eye relief to effective focal length with a compact optical arrangement. The system affords minimal lateral chromatic aberration and good image quality.

Abstract: The present invention relates to an improved method and device for aiming and firing a rifle-mounted grenade launcher without having to approximate the range of a target and then manually adjust the position of subsequently fired grenades. The grenadier initiates the process by pointing the grenade launcher at the target. The range and azimuth of the target are determined by a microprocessor controlled laser range finder/digital compass combination. A ballistic solution is calculated by the microprocessor and the superelevation required to place the grenade on target is displayed on one of several video displays. The grenadier then uses the vertical angle measurement capability of the laser range finder/digital compass assembly to rotate the grenade launcher to the proper angle while maintaining the proper azimuth. The grenade is then fired on target.

Abstract: A head-mounted display device (10) offers light weight, a low center of gravity, and low moments of inertia about the azimuthal and elevational axes of head movement. The display device (10) employs an angulated beam splitter mirror (16) disposed between a user's (22) eye (20) and an inner combiner surface (18a) of a visor (28). A projector (36) is carried laterally of the user's eye with a low center of gravity and a position close to the horizontal axis of elevational movement of the head. This projector (36) includes an image source (12) and an compact light-weight relay optics module (14) along with a projection fold mirror (30) disposed at eye level and laterally of the beam splitter mirror (16) to project image light to the beam splitter mirror (16). The beam splitter mirror (16) reflects the light onto the inner surface (18a) of the combiner (18) for reflection back through the beam splitter mirror (16) and to the user's eye (20).