Abstract: A sine wave synthesis controller circuit intended to be utilized in conjunction with a digitally-controlled neutral-point clamped inverter to produce a sinusoidal waveform from a direct current source. The controller circuit is configured so that it provides separate positive and negative control signals to the neutral-point clamped inverter's logic controller. These signals direct the modulation a sinusoidal waveform in response to a reference sine wave, the instantaneous voltage output by the neutral-point clamped inverter, as well as positive and negative reference voltages input to the controller.

Abstract: A digital demodulator utilizes voltage to frequency converters, digital counters and a computer to combine demodulation and analog to digital conversion into one step, therefore providing for in-phase and quadrature demodulation of amplitude modulated double sideband suppressed carrier signals. Accleration sinusoidal signals and phase reference pulses are input to a voltage to frequency converter and counter board which interfaces to a computer where the signals are demodulated using a digital demodulation scheme.

Abstract: A display system for enabling a pilot in an aircraft to simultaneously view an image of selected display information and a scene external to the aircraft during low visibility conditions, such as the night-time, is provided. An image intensifier tube is mounted on the side of a pilot's helmet, preferably a Helmet Display system, so that the image sensed coincides with the pilot's field of view. The image intensifier tube intensifies light from the external scene and outputs voltages representative of the scene to a converter. The output voltage is converted to a video signal having a format which is compatible to the display system in use. A Combining Circuit combines the compatible video signal with video signals from other display sources, such as instrumentation panel displays. The combined electrical signals are input to a display driver which drives the display system to cause the selected display information to be superimposed on the external scene viewed by the pilot.

Abstract: A gyro having a liquid hydrostatic bearing includes an integral liquid hydrostatic suspended pendulum arrangement which senses the direction of the gravity vector of the gyro housing. The configuration described provides close coupling of the hydrostatically suspended pendulum arrangement, which is in effect a level sensor, and the gyro input axis, the same being essential to precise gyrocompassing applications.

Abstract: A planer contact grid array connector features a selectively ceramic coated metal substrate in combination with ceramic thick film and/or multi-layer thin film circuitry and contacts of various configurations which may be affixed to or incorporated in mating connector halves. Planer contact array connectors of the type described have coaxial connection features, increased power handling capability and improved means for effecting gas-tight contact between mating connector halves. Additionally, the connectors are more reliable, lighter and more rugged than currently available connectors and have the capability of incorporating integral ceramic thick film components such as capacitors and resistors for filtering, impedance control and signal/power conditioning, as the case may be.

Abstract: A ring laser gyro is configured in accordance with a model whereby a closed line integral is evaluated along the optical path of the gyro so that reducing the integral by configuring the plasma discharge path of the gyro reduces the sensitivity of the gyro to magnetic effects.

Abstract: In systems requiring multiple identical digital correlators the original m-bit counter for each correlator can be replaced by an n-bit multi-channel counter. The most significant bit of each n-bit counter is sampled every 2.sup.n-1 clock cycles and the results are stored in dual port memory. Stored input counter samples are converted into a series of binary words which are multiplexed to one of two signal outputs. The dual port memory allows current samples from the input counters to be written on port A, while previously written samples are time multiplexed and read to the output counters on port B. This design not only reduces the number of parts needed for counters but also the buffers needed for so many counters to appear on the same computer bus. In addition, the maximum delay between the sampling of any correlator is greatly reduced.

Abstract: Means for compensating for threshold voltage shifts of Metal Oxide Semiconductor Field Effect Transistors (MOS FETs) of a Large Scale Integrated Circuit device (LSI), where the threshold voltage shifts are induced by radiation dosage. The FETs are formed in a relatively thin layer of silicon on an insulator film supported by a substrate. The compensating means includes a pair of sensor FETs formed integrally with the LSI device, an operational amplifier and a back gate formed opposite the channel regions of the FETs of the LSI device. The sensor FETs develop an output voltage that is applied as one input to the operational amplifier. A reference voltage, equal to the sensor output voltage prior to exposure to radiation, is applied as a second input to the operational amplifier. The amplifier output is applied to the back gate. The sensor output voltage changes as a result of radiation dosage.

Abstract: An inertial measurement instrument including a gyroscope and accelerometer utilizes fiber optics to measure gyro rates and accelerations in two orthogonal axes. Bender beam fiber optic transducers are mounted on a rotating shaft and signals representative of force effects on the bending beams are provided at the rotor in an optical format. The signals are then optically transmitted to the stator thereby eliminating the need for slip rings and the like.

Abstract: A diagnostic tool based on a hybrid knowledge representation of a system under test is disclosed. Data collected from the system during its operation is compared to an event based representation of the system which comprises a plurality of predefined events. An event is recognized when the collected data matches the event's critical parameter. The recognized event is analyzed and an associated set of ambiguity group effects, which specify components to be re-ranked in an ambiguity group according to an associated ranking effect. Additonally, a symptom-fault model and a failure model can be analyzed to determine symptom-fault relationships and failure modes which are applicable to the system operation. Each applicable symptom-fault relationship and failure mode is also associated with a set of ambiguity group effects which rerank the ambiguity group. A structural model is analyzed starting with the components in the ambiguity group having the greatest probability of failure.

Abstract: A processing system using a number of distributed associative (content addressable) memory modules each connected through a sending device to a common serial communication bus. The memory modules are concurrently accessible by a central receiver. Data accessed from each memory module is compressed according to content induced transaction overlap (CITO) format, and the compressed data is serially communicated to the receiver according to a CITO protocol.

Abstract: A simple mechanism for a CITO communication channel with a possibility to use variable length messages which combines different control functions; bootstrapping, synchronization, and interrupts is disclosed. The mechanism introduces and maintains synchronization of the CITO communication channel by actively interrupting and restarting the transmission process.

Abstract: A high frequency amplifying device comprises a field effect transistor-bipolar transistor darlington pair. Such a device combines the main desirable features of both field effect transistors and bipolar transistors, therefore, having a high input impedance that is typical of FETs and a high transconductance (or high current gain) which is typical of bipolar transistors.

Abstract: A method for monitoring a phased array antenna system to determine the existence of faulty components in the system and the location of such components in the system. More particularly, the invention relates to a Butler matrix-fed circular phased array antenna system wherein an individual one of the plurality of columns of the array which is faulty can be identified by comparison of a measured amplitude value to a predetermined level.

Abstract: An airborne wind shear detection radar includes a transmitter for transmitting successive radar beams into airspace in front of an aircraft and a receiver for receiving reflected signals. The radar analyzes the received reflected signals in the frequency domain to determine if a wind shear condition exists in the airspace in front of the aircraft.

Abstract: A method for making a lateral bipolar transistor using SOI technology. A base mask is formed on the surface of a silicon island and its sidewalls coated with a layer of silicon dioxide. After local oxidization of the silicon island, emitter and collector regions are implanted using the base mask and the silicon dioxide deposited on the sidewalls of the base mask as a mask. The base mask is then removed and a shallow base contact region is implanted in the base region previously shielded by the base mask. The remaining silicon dioxide deposited on the sidewalls of the base mask form vertical spacers which are used as a self-aligned mask for forming silicide contacts on the emitter, collector and base contact regions. These remaining silicon dioxide vertical spacers physically separate emitter-base and base collector junctions from the highly doped base contact area and electrically isolate the silicide contacts.

Abstract: A miniature two degree of freedom fluid bearing angular rate sensor used primarily for tactical applications includes a spherical hydrodynamic fluid bearing rotor, a permanent magnet motor/torquer, and an optical pick-off, all of which are arranged to provide two axes of rate information in a small package. The individual components can be pre-assembled as sub-assemblies, and individually stocked and tested for final assembly.

Abstract: A digital blanker for scanned displays is provided which turns off the electron beam on a Cathode Ray Tube whenever the beam is in a pre-defined area on the screen. A high speed analog to digital converter is utilized to digitize the position of either a raster or randomly scanned CRT beam. Once the beam position is digitized, the resulting number is used as an address to an EPROM. The data in the EPROM is coded to cause the CRT beam to be blanked if the beam is positioned in the predefined area where blanking is required.

Abstract: A generator having a bearing retaining stator includes a housing, a shaft, a rotor, a stator and a bearing. The rotor is connected to the shaft and the stator is inductively coupled to the rotor. The bearing supports the shaft in the housing and is retained in place by the housing and the stator.

Abstract: Method and apparatus for performing system monitoring and diagnostics is disclosed. In performing system monitoring, data is acquired from the system under test and compared to an event model. The event model comprises a database having event records which pre-define events which can occur. Each event record includes a state vector dependency which lists the events which must occur prior to the pre-defined event occurring and one or more critical parameters defining the data which must occur during the system's performance for the event to have occurred. Event recognition is performed by comparing each event record to acquired operational data and to events already recognized. Associated with each event record in the database is an intelligent data acquisition action which defines an action to be taken as a result of the event record being recognized. These actions can modify the performance of the system being monitored or the acquisition of data.