Abstract: An apparatus for isolating electronic devices from mechanical shock and thermal environments utilizes a metal outer protective shell surrounding the electronic device to be protected. Interposed between the protective shell and the electronic device are a thermal insulating layer, a layer of phase change material and a layer of mechanical shock absorbent material.

Abstract: A fiber optic rate sensor includes an arrangement for suppressing transient spikes in a signal corresponding to the phase difference between light traveling in clockwise and counterclockwise directions around a fiber optic coil. The arrangement is such that the signal having the transient spikes is clamped or switched at the times the spikes are active.

Abstract: A ground proximity warning system and a detector for aircraft having fixed or non-retractable landing gear which rather accurately detects a landing phase of flight in order to adjust the warning envelope to minimize nuisance warnings during such a phase of flight. In particular, the system monitors the flap position to provide an indication to the ground proximity warning system that the aircraft is either in an approach, cruise or landing phase of flight. Cams mounted to the air flaps system indicate a landing phase of flight when the approach flaps are configured for a normal landing, such as 16.degree.-18.degree. flaps or an approach phase of flight when the flaps are configured for a normal approach, for example, 5.degree.-7.degree. flaps. By providing a relatively accurate indication of the phase of flight for an aircraft with non-retractable landing gear, nuisance alarms will be virtually eliminated, while maximum protection is provided during all phases of flight.

Abstract: An information processing unit having a memory (16) storing a set of data elements in a data lattice structure. The memory is content-addressably searched by a pair of processors (12) and (14) controlling confronting traversals of the data lattice structure. A traversal controller (24) generates a search routine for the two processors (12) and (14) resulting in a natural two-way concurrency in their operation. A second memory (22) stores processing instructions and pointers used by the traversal controller (24) to generate the search routine. The processing instructions and pointers are extracted from the second memory under the control of processors (18) and (20). An interface processor (26) is connected to a communication link (28) connecting the information processing unit to utilization devices.

Abstract: A method for reaction bonding surfaces at low temperatures in which polished and cleaned surfaces are bombarded with a mixture of oxygen and fluorine ions to produce activated surfaces. The activated surfaces are then cleaned to remove particulates, then contacted at room temperature to affect a reaction bond therebetween. The bond energy of the reaction bonded surfaces increase with time at room temperature. The rate at which the bond energy of the reaction bonded surfaces increases may be enhanced by moderate heating at a low temperature below a temperature which would be detrimental to any part of the reaction bonded structure. A satisfactory bond energy for silicon wafers can be achieved in four hours at room temperature and in less than 10 minutes at 50.degree. C.

Abstract: A fluid pendulum arrangement is used for implementing fast initial erection of vertical gyros by maintaining the gyro wheel spin axis near vertical during the gyro "power-off" mode of operation. Fluid is contained in a lower fluid chamber section which is disposed below the rotational axes of the gyro inner and outer gimbals. The mass of the fluid in cooperation with the fluid chamber moment arm results in a gyro wheel pendulosity that is greater than the combined gyro component friction torques. Upon the "power-on" or gyro wheel spin up mode of operation, the fluid tends to migrate from the lower section of the chamber to an upper section thereof which is arranged relative to the gimbal rotational axes so that gyro wheel pendulosity is negligible. In one embodiment of the invention, the fluid chamber is an external "add-on" feature to the gyro wheel rotor and in another embodiment, the fluid chamber is integral with said rotor.

Abstract: An arrangement for obtaining flux rate information in a magnetic: circuit including passive means connected across a flux rate sensor for implementing control of said flux rate. The passive means being a tuned magnetic flux rate feedback sensing and control arrangement wherein impedance is tuned and the energy loss characteristic is adjustable. The selection of inductance and capacitance values provides tuning and the selection of resistance affects the energy loss characteristics.

Abstract: A vibrating beam force transducer is comprised of an oscillating sensing element having an output frequency indicative of the force applied to the sensing element. The sensing element has a variable electrical resistance which can vary in accordance with temperature fluctuations over the operating range of the transducer.A drive circuit utilizes an AC drive signal source that is electrically coupled to the sensing element to drive the sensing element at its resonant frequency which is a function of the force applied to the sensing element. The drive circuit has a DC compensation circuit that alters the electrical characteristics of the drive circuit in response to variations in the electrical resistance of the sensing element.

Abstract: A terrain clearance signal generator particularly usable with ground proximity warning systems provides a signal representative of terrain clearance when the radio altimeter signal is unreliable, such as in the case of excessive pitch or roll, out of track or other conditions resulting in invalid readings. The system monitors such conditions and takes a sample of the last valid radio altitude reading prior to sensing an invalid condition and, upon sensing an invalid condition, updates the sample utilizing barometric altitude signals or integrated barometric altitude rate or inertially-derived Z-velocity signals.

Abstract: A method of encapsulating temperature-sensitive electronic devices such as solid state memory devices used in aircraft for recording flight data and the like in a wax-like material having a high heat of fusion to establish a heat sink for protecting the device against intense heat resulting from fire includes the preparation of a wax "preform" under heat and pressure in a closed chamber for minimizing oxidation thereof and thereafter transferring the preform by the application of heat and pressure to move the material in a softened condition into a mold cavity supporting the memory devices and forming the material to encapsulate a printed circuit board, carrying memory devices to exclude air and protect the same from deleterious effects of intense heat.

Abstract: A method for enhancing the bond energy of reaction bonded surfaces in which polished (10) and cleaned surfaces (12) are bombarded with oxygen ions, fluorine ions or a mixture of oxygen and fluorine ions (14) to activate these surfaces. The activated surfaces are then cleaned to remove particulates (15) and then contacted (16) at room temperature to make a reaction bond therebetween. The reaction bond may be heated (18) to further increase the bond energy. The bond energy of oxygen ion bombarded surfaces can have two times the bond energy of surfaces subject to a conventional bonding process. The addition of fluorine ions to the oxygen ions used to activate the surfaces can further increase the bond energy between the contacted surfaces by at least another factor of 2.

Abstract: A method for selectively etching a semiconductor wafer in the presence of an electrochemical etchant wherein the electrical potential of the area that is selectively etched is automatically changed to a potential at which the etching is inhibited once the desired etching in the area is completed. The method is described with respect to making an electrode tip for a tunnel current sensing device.

Abstract: A synchronous generator start converter offers power conversion for performing multiple functions such as starting AC generators as a motor, charging batteries and also providing regulated DC output without degradation of input power quality. The converter utilizes common magnetic components and common semiconductor rectifiers within its three subcircuits. The three subcircuits include flyback converters, a square wave inverter and a field excitation controller.

Abstract: A circuit wherein a current sensing device is incorporated in an AC input line. An AC output is taken from the output of the current sensing device and from an other AC input line. Circuitry including a capacitor coupled bi-directional switching regulator and an energy storing capacitor adds current to or subtracts current from the instantaneous output load current. The arrangement is such that the AC output is equal to the AC input with no regulation effect. Substantially one hundred percent efficiency results when very little power factor correction is required.

Abstract: A circuit for relatively accurately measuring the capacitance of a pair of capacitive elements which may be part of an accelerometer. The circuit includes a drive circuit, a switching circuit, a pair of bridge capacitors and a detector circuit. The bridge capacitors and the capacitive elements are connected together to form a bridge. Common nodes between the capacitive elements and the bridge capacitors are interconnected together by the switching circuit in a first mode of operation to force a reference or null condition to enable the common nodes to discharge to a predetermined reference voltage. The common nodes are isolated from one another in a second mode of operation during which time the bridge is charged to a predetermined voltage by the drive circuit to enable the detector circuit connected to the common nodes to detect differences in voltage between each of the two common nodes.

Abstract: A digital phase modulation arrangement for a fiber optic angular rate sensor utilizes Pockels electro-optical effect operating in the transverse mode. Light travels around a fiber optic coil in clockwise and counterclockwise directions. An error signal corresponding to the phase difference between the clockwise and counterclockwise traveling light is applied to a digital processor which provides a plurality of logic bits. The logic bits are applied to voltage/phase transducers arranged on an integrated optics chip. The voltage/phase transducers are switched from an applied reference voltage to a particular voltage level to induce a phase change through Pockels electro-optical effect.

Abstract: A triaxial sensor substrate is adapted for use in measuring the acceleration and angular rate of a moving body along three orthogonal axes. The triaxial sensor substrate includes three individual sensors that are arranged in the plane of the substrate at an angle of 120 degrees with respect to one another. Each sensor is formed from two accelerometers having their sensing axes canted at an angle with respect to the plane of the substrate and further being directed in opposite directions. The rate sensing axes thus lie along three orthogonal axes. In order to reduce or eliminate angular acceleration sensitivity, a two substrate configuration may be used. Each substrate includes three accelerometers that are arranged in the plane of the substrate at an angle of 120 degrees with respect to one another. The sensing axes of the accelerometers of the first substrate are canted at an angle with respect to the plane of the first substrate toward the central portion thereof so that they lie along three skewed axes.

Abstract: A horizontal plan view and a vertical side view of a weather disturbance are combined into a single axonometric display to facilitate analysis of the disturbance. Desired azimuth and elevation angles for the center of the axonometric display and which of the four quadrants of the display to be emphasized are user selectable. Either the plan view or the side view can be separately displayed in the axonometric format and the axonometric display is user selectable with the conventional display being readily available.

Abstract: A pulse width modulated (PWM) power supply combines the advantages of pulse width modulator circuitry with linear circuitry to provide power supply operation over an extended input range with no dropout of power supply output and no adverse effect on a load. The PWM circuitry includes input voltage scalers, control logic, mode detectors, an inductor, a diode switch and a capacitor and the linear circuitry includes a transistor, transistor voltage scaling and gate driver logic.

Abstract: An arrangement using sensing coils for obtaining flux rate of change information in a magnetic circuit. The arrangement can be used for vibration attenuation in a magnetic forcer system. Active (electric powered) circuitry is used to implement closed loop control of flux rate. The control loop is "tuned" for attenuating a narrow range of vibration frequencies. The arrangement can be applied to magnetic forcer/suspension systems in which vibrations due to magnetic, mechanical/magnetic runouts, system mechanical resonances, or external vibration sources are present.