Abstract: The automatic gain control loop has an automatic gain control loop filter generating a multi-bit gain control word in response to the power level of the output signal of the loop. A shifter circuit shifts the input data by selected number of bits under the control of selected most significant bits of the gain control word multiplying the power of the input signal. A multiplier circuit multiplies the shifted data output from the shifter circuit by predetermined multiplication factors under the control of the remaining bits of the gain control word. The shifting and adding of the input data under the control of the gain control word maintains the power level of the output signal within a predetermined range.

Abstract: An improved system (30) for measuring surface aberrations of concave cylindrical surfaces. In the illustrative embodiment, the invention includes a transmission flat (20), an interferometer (32), and a surface to be measured (28). The transmission flat (20) is a transparent disc that is placed between the interferometer (32) and the surface (28) to be measured. An electromagnetic wave (33,34,36,37) is generated by the interferometer (32), and is directed through the transmission flat (20). The wave (41) bounces off the surface (28) to be measured and is retro-reflected off a first surface (26) of the transmission flat. The electromagnetic wave (42) returns to the opposite side of the surface (28) under test. The wave (43) then bounces off the surface (28) under test and passes through the transmission flat (20). The wave (43) interferes with light (39) that is reflected from a reference surface (26) of transmission flat (20) on a first bounce.

Abstract: A unique photoresist process is provided which achieves clean and complete lift-off of a thin film layer such as a sputtered thin film formed on a photoresist which is formed above a semiconductor substrate. The process of the present invention relies on a reentrant photoresist profile which breaks the continuity of the thin film layer. Accordingly, the process of the present invention ensures a clean lift-off. The desired photoresist profile which breaks the continuity of the thin film layer can be obtained by a typical photoresist process preceded by an oxidation process that takes place on the surface of the semiconductor substrate. The oxidation process provides a thin native oxide layer with thickness ranging from about 30 to 50 .ANG.. No extra processing steps involving dielectric film deposition and etch are required to achieve clean lift-off. Nevertheless, the process of the present invention ensures the clean lift-off of the thin film layer.

Abstract: A rotary connector comprising first and second printed wiring boards that rotate relative to each other and that are electrically interconnected using spring loaded pogo-stick type contacts. The spring-loaded contacts are used to transfer electrical signals or power to metallized rings or contacts formed on the first printed wiring board. The spring-loaded pogo-stick type contacts are very rugged and provide for a rotary connector having long life.

Abstract: Production of precision reflective mirror surfaces on low cost, lightweight molded plastic substrates (10). The process involves making a master pattern (12) having a precision machined contoured surface (13) corresponding to the precision mirror surface desired on the plastic substrate. A release layer (14) and a reflective layer (17) are applied to the master pattern and then transferred to the molded plastic substrate (10), with a curable replication layer (18) therebetween preferably comprising a filler-reinforced polymer composition which is compatible with the polymeric substrate and has a low coefficient of thermal expansion (CTE) which closely matches the CTE of the substrate. The replication layer (20) is cured to replicate the precision of the surface (13) of the master pattern (12), which can be reused to produce a multiplicity of high precision molded plastic mirrors (21).

Abstract: A unique pulse forming network assembly designed for use with a laser flashlamp. The inventive assembly includes a planar printed circuit board (14) to which a plurality of electrical energy storage elements (L1, C1) are mounted. The energy storage elements (L1, C1) are mounted on one side of the primed circuit board (14) so that the electrical contacts thereof extend therethrough. The contacts are wave soldered to complete the assembly. In a specific embodiment, the planar mounting of the energy storage elements (L1, C1) is enabled by the substitution of a conventional relay (K1) with a field effect transistor (Q1). The FET selectively connects the energy storage elements (L1, C1) to an output terminal of the network to activate the flashlamp. In a more specific embodiment, at least one of the energy storage elements is a capacitor (C1) which is connected to the housing (16) by a flange (18).

Abstract: Multiple solid precursor bubblers are used to alleviate channeling effects caused by high carrying gas flow rates to provide for deposition of indium-based epitaxial materials in high-capacity MOCVD reactor systems. Precracking of precursor materials that exhibit higher dissociation temperatures using heated manifolds or heated susceptor, and rotation of individual wafers in a multi-wafer reactor chamber enhance thickness uniformity, surface morphology and electronic properties of deposited epitaxial layers.

Abstract: A modular array processor architecture (10) comprising a plurality of interconnected parallel processing node (11)s that each comprise a control processor (12), an arithmetic processor (13) having an input port (22) for receiving data from an external source that is to be processed, a node memory (14) that also comprises a portion of a distributed global memory, and a network interface (15) coupled between the control processor (12), the arithmetic processor (13), and the node memory (14). Data and control buses (17, 18) are coupled between the arithmetic processors (13) and network interfaces (14) of each of the processing nodes (11). Respective network interfaces (15) link each of the arithmetic processors (13), node memories (14) and control processors (12) together to provide for communication throughout the architecture (10) and permit each node to communicate with the node memories (14) of all other processing nodes (11).

Abstract: A tactile feedback switch actuator for an associated force-actuated switch has a key cap linked to a collapsible dome by an optical fiber, all of which are light-transmittable. The actuator is operated by manually applying an actuating force to the key cap which exceeds the modulus of collapse of the dome. In response, the dome reversibly collapses in a tactile snapping action against the underlying light-transmittable switch panel having pressure-sensitive contacts embedded therein to change the operative state of the switch. When the actuating force is withdrawn, the collapsible dome elastically returns to its uncollapsed condition, while the switch remains in its newly-actuated operative state. The actuator and associated switch are structurally integrated and aligned so that light-emitting pixels in an underlying electroluminescent panel provide visual feedback of the operative state of the switch.

Abstract: A high capacity radar plot display with low CPU loading. The display includes a display process (42) which controls a graphics window server (46) to render symbols on a display console by a "walking worm" animation. The current symbol plot as well as several symbol plot histories are sequentially displayed to render the animation. A plurality of color maps defining the colors of the current and plot histories are defined, with a clear color map to clear the display. The clear color map includes black (nonvisible) color for all the current and plot histories. The color map for the oldest plot history has a visible color assigned to the oldest history plot, with all other plot histories and the current plot still in black. Successive color maps for the remaining plot histories and the current plot, from the next oldest to the current plot, have progressively more plot histories in a visible color.

Abstract: A sensor is provided for detecting the presence of dielectric media, e.g., ice. The sensor includes a plurality of microstrip resonators which are positioned for electromagnetic coupling with a microstrip transmission line. The resonators produce amplitude minima in a radio-frequency signal that is carried over the transmission line. The resonance of the resonators changes in response to the addition of a dielectric coating. Each resonator can be configured with a different resonant frequency which serves as a signature that identifies the respective resonator's position. The sensor has a thin aerodynamic profile, can conform to nonplanar surfaces and its installation requires no intrusion into an aircraft skin.

Abstract: Contaminants are cleaned from the surface of a body in space by generating a substantially space-charge neutral reactive plasma, directing the plasma onto the contaminated surface at an energy below the surface sputtering energy (typically 20 eV), and reacting the plasma with the contaminants to remove them. A helicon wave plasma source is made light weight and compact enough for spacecraft use, with a plasma energy low enough to avoid damaging optical surfaces, by using permanent magnets to establish a static axial magnetic field, and a simple but novel rf antenna design. The antenna consists of a pair of spaced conductive rings which extend around the plasma tube, with conductive base and rf feed bars extending between the rings on diametrically opposite sides. The feed bar is interrupted to provide an rf input on opposite sides of the interruption. The antenna is preferably formed as an integral metal unit, with its rings rigidly supported by and integral with opposite ends of the base bar.

Abstract: A high-speed flywheel includes a composite rim supported for rotation about a central axis which is perpendicular to the plane of the rim. The rim includes at least a pair of rim portions or regions of differing elastic modulus in the circumferential direction of the material forming the rim. Moreover, a radially outer portion of the rim has a higher elastic modulus in the circumferential direction, while a radially inner portion of the rim has a lower elastic modulus in the circumferential direction. This variation of circumferential elastic modulus is achieved by a selected radial variation of the angle of the fiber reinforcement material relative to the circumferential direction of the rim. A result is that the radially inner portion of the rim transfers radial force to the outer portion, with a resulting lower radial stress in the radially inner portion of the flywheel rim. An improved speed of operation and greater energy storage for the flywheel is achieved.

Abstract: A pollutant destruction system connects a capacitive corona discharge chamber in a self-resonant circuit with an inductive element. Intermittent energizing signals are furnished from a power supply to induce corona discharges within the chamber, with the resonant circuit responding to the energizing signals by initiating additional corona discharges between energizing signals in a highly energy efficient operation. One or more discharge chambers can be provided in the resonant circuit, with each discharge chamber comprising a dielectric enclosure with a distributed electrode outside and an elongate electrode inside the enclosure. The inner electrode can extend either along the chamber axis, or along the inner chamber wall for better support and heat dissipation.

Abstract: Digital logic and a high resolution digital to analog converter are used to adequately digitize a magnetic signal that is subsequently processed by magnetic data processing algorithms. The high resolution digital to analog converter is directly incorporated in a feedback loop of a magnetometer sensor, an expensive precision analog to digital converter is replaced by a less expensive, lower power digital to analog converter. The circuit improvement provided by the present invention includes an analog low pass filter coupled to the sensor, a digital logic circuit coupled to the analog low pass filter for providing an output signal from the magnetometer and a feedback output signal, and the digital to analog converter coupled between the digital logic circuit and a feedback coil of the sensor for coupling the feedback output signal thereto.

Abstract: Boresighting apparatus that includes a multispectral reflective collimator combined with an adjustable rhomboid reflector that allows boresighting of any wavelength sighting, pointing, aiming or rangefinding device disposed on a small arms weapon. The boresighting apparatus comprises a housing and a small arms weapon adapter for securing the housing to small arms weapons having different calibers. An illuminated or heated target is disposed in the housing for selectively providing an image of an illuminated or heated target pattern. A power source is coupled to the target for providing power to selectively illuminate or heat the target. An adjustment mechanism is provided for incrementally adjusting the optical location of the target and thus the location of the target pattern. A mirror, such as an off-axis parabolic mirror, is disposed to reflect the image of the illuminated or heated target pattern along a visual optical path.

Abstract: A long-term thermally stable cryostat (40). The cryostat (40) pre-cools an incoming high-pressure gas, converts it to a cold liquid, contains the liquid, and cools an item by allowing the liquid to acquire heat from the item and boil into an exhaust gas, while maintaining an absolute pressure in the container to reduce thermal noise due to altitude-induced pressure changes. In specific embodiments, the cryostat (40) includes a hollow mandrel (52) disposed within a cooling volume (64) mounted within a dewar vacuum area (58). Pre-cooling fins (44) spiral around the hollow mandrel (52) within the cooling volume (64) and circulate an incoming high-pressure gas around the mandrel (52). A flow restrictor (60) receives the incoming gas from the pre-cooling fins (44) and releases it into the cooling volume (64), thereby converting the incoming gas into a cold liquid which can acquire heat from the item and boil into an exhaust gas.

Abstract: The invention is directed to the reduction of an electron beam transport problem during microwave generation in plasma-assisted microwave sources. A small, e.g., <200 gauss, secondary magnetic field is positioned in association with a slow-wave structure (SWS) of the sources to reduce the radial divergence of electron bunches in the sources' electron beams. The secondary magnetic field exerts radial forces on diverging electrons to supplement radial forces of a primary magnetic field and radial forces of an electrostatic field. The primary magnetic field is generated by electron movement in the electron beam and the electrostatic field is generated by ions which are created as the electron beam transits an ionizable gas in the plasma-assisted source. The addition of the secondary magnetic field can be implemented with a coil that is positioned to direct at least a portion of its magnetic field through a passage of the SWS.

Abstract: A method and system of attitude steering and momentum management for a spacecraft suitable over a wide range of orbit altitude and inclination parameters and a similar wide range of mission steering profiles is provided. The system utilizes two active momentum wheels positioned with their spin axes nominally coaligned on the spacecraft pitch axis. Each wheel is pivoted by jackscrew type mechanisms which allow the angular momentum to be tilted (e.g. within the range 0-45.degree. from the nominal alignment with respect to the spacecraft body). The spacecraft control processor generates wheel torque commands for the wheel speed electronics and jackscrew drive commands for the platform assemblies in order to adjust the speed and amount of tilt of the momentum wheels. The invention provides a two-momentum wheel array that allows use of either momentum bias steering or large angle zero-momentum steering and accommodates multiple orbit geometries and varying degrees of attitude steering agility.

Abstract: A high-speed flywheel includes a composite rim supported for rotation about a central axis which is perpendicular to the plane of the rim. The rim includes at least a pair of rim portions or regions of differing elastic modulus in the circumferential direction of the material forming the rim. Moreover, a radially outer portion of the rim has a higher elastic modulus in the circumferential direction, while a radially inner portion of the rim has a lower elastic modulus in the circumferential direction. This variation of circumferential elastic modulus is achieved by a selected radial variation of the angle of the fiber reinforcement material relative to the circumferential direction of the rim. A result is that the radially inner portion of the rim transfers radial force to the outer portion, with a resulting lower radial stress in the radially inner portion of the flywheel rim. An improved speed of operation and greater energy storage for the flywheel is achieved.