Abstract: Josephson junction integrated circuits of the current injection type and magnetically controlled type utilize a superconductive layer that forms both Josephson junction electrode for the Josephson junction devices on the integrated circuit as well as a ground plane for the integrated circuit. Large area Josephson junctions are utilized for effecting contact to lower superconductive layers and islands are formed in superconductive layers to provide isolation between the groundplane function and the Josephson junction electrode function as well as to effect crossovers. A superconductor-barrier-superconductor trilayer patterned by local anodization is also utilized with additional layers formed thereover. Methods of manufacturing the embodiments of the invention are disclosed.

Abstract: Superconductive tunnel junctions are manufactured with precise junction areas by defining a narrow-line junction of precise width utilizing a narrow-line mask of precise width and thereafter applying a second narrow-line mask of precise width at an angle to the narrow-line junction to define a junction area with dimensions precisely controlled by the widths of the narrow-line masks. "Edge lithography" is preferably utilized to provide the narrow-line masks.

Abstract: A mechanism for aiding the insertion and extraction of an avionics electronic chassis having a plurality of electrical connectors on to a mounting tray with a corresponding plurality of mating electrical connectors. Levered camming hooks on the chassis, matched with fixed keeper pins on the tray are rotated by a rotary, torque limiting knob and screw arrangement to engage the keeper pins and thereafter pivot thereon. Upon insertion, rotation of the knob applies a limited translational force between the electrical connectors sufficient to effect a full mating of the connectors but insufficient to cause any damage to the connectors should there be any misalignment therebetween. The mechanism has a very short longitudinal profile in its extracted position thereby rendering it useful in restricted spaces. The mechanism further conveniently provides a carrying handle for the chassis.

Abstract: A measure of the enroute weight of an aircraft is continuously provided by determining the zero fuel weight during takeoff, adding the weight of total fuel as measured by fuel quantity sensors, interrupting the latter measure and holding its then current value whenever the fuel quantity sensors may be in error, such as when the aircraft is not level or during aircraft accelerations, and during this time computing the rate of change of aircraft weight as a function of aerodynamic and engine parameters and subtracting the time integral of this computed value from the held fuel quantity sensor value. Upon the aircraft resuming level, unaccelerated flight, the integrator is reset and the sensed fuel quantity measure restored.

Abstract: A bi-directional driver system for an electrical load operable in response to two independent logic command signals provides a means for selecting the direction of current flow in the load when driven by the external command. A bridge circuit employs inputs to dual transistor switches operating in the saturated mode in series with the electrical load, cooperating with common emitter transistor linear amplifiers and diodes, and biased by the input logic signal so as to drive the load current in a predetermined direction. The circuit provides protection from undesired power supply current surges when logic command signals are applied to both inputs, and from transients due to failure of a saturated transistor switch at one input to cease conducting before the application of a command signal to the second input. Embodiments for inductive loads and annunciator lamps are described.

Abstract: An altitude preselect apparatus for use with or incorporation into an automatic flight control system combines the incremental altitude signal from a pneumatic encoding altimeter with a vertical speed computation to generate a smooth, continuous instantaneous altitude signal. A vertical speed reference signal is generated to control the vertical flight path of the aircraft when the instantaneous altitude reaches a prescribed proximity to a desired flying altitude which is manually selected by the pilot. The apparatus initiates a capture sequence to hold the aircraft at the desired altitude once it is reached.

Abstract: The takeoff weight of an aircraft is computed from measures of the thrust of the engines and the forward acceleration of the aircraft detected over a time period when such acceleration is at a maximum following brake release on the runway. A major variable that must be considered is the coefficient of rolling friction of the landing gear of the particular aircraft involved and other factors inducing ground roll drag. The present invention calculated this variable as a function of engine thrust and manifest weight for each takeoff of the aircraft and updates weighted filter values thereof for use during subsequent takeoffs. For each takeoff, therefore, and average value of rolling friction is used to calculate takeoff weight, which average value becomes more nearly the actual value for the existing condition of the landing gear.

Abstract: A superconducting tunnel junction device having superconductive electrodes has a non-homogeneous barrier layer of amorphous semiconductive material, wherein when the central region is deposited in the presence of a gaseous atmosphere containing hydrogen there obtains a reduced density of localized states in the central region of the barrier so as to minimize leakage currents, resulting in improved current-voltage characteristics approximating an ideal tunnel junction device. The low leakage currents improve margins of Josephson logic circuits over tunneling barriers using uniformly deposited hydrogenated silicon with niobium electrodes, and increase the sensitivity of S-I-S microwave and millimeter wave length detectors and mixers. In a preferred embodiment, superconductive electrodes of niobium are conjoined with a tri-layer barrier using pure silicon adjoining the electrodes and a core of hydrogenated amorphous silicon. V.sub.

Abstract: A cruise speed control apparatus in an aircraft performance management system wherein target Mach command is supplied to the engine automatic throttle controls to establish an engine thrust to overcome and equate to the aircraft nominal drag characteristics at that commanded Mach speed and simultaneously the difference between the actual Mach number speed and the target Mach command speed is supplied to the automatic pilot pitch axis control to cause the aircraft to maintain the commanded Mach speed through change in pitch attitude and altitude. The integral of any altitude standoff is used to adjust required thrust to achieve the commanded Mach target and reduce the standoff to zero. If necessary, filtered altitude error may be used to provide dynamic damping of the throttle control loop and compensation for long term degradation in the aircraft's drag characteristic with time is provided by measuring the drag degradation ratio and adjusting the target Mach command in accordance therewith.

Abstract: An apparatus and method for measuring the height of a liquid above a reference level in which short pulses of subnanosecond duration are coupled to a dual-mode transmission line immersed in a liquid to propagate thereon in a plurality of modes. A surface wave propagating on the outer conductor is reflected from the surface of the liquid, and coaxial-mode propagating within the transmission line is reflected from the reference level. These reflected pulses propagate back along the transmission line, coupled to a receiver for detection, the detected pulses processed to determine the liquid height above a reference level.

Abstract: A signal processor for detecting the presence of two signals whose over-all phase or frequency is related by a known rational number. The first signal of frequency .omega.M is raised to the N.sup.th power, while the second signal of frequency .omega.N is raised to the M.sup.th power. The two raised signals are then correlated, energy detected, and compared against a predetermined threshold to provide an indication when both signals are present. By utilizing the known frequency relationship between the two signals the processor yields enhanced detection performance over that achievable by detection of each signal separately.

Abstract: The invention is an integrated pick-off, torquer, and reference signal generator system for a two-degree-of-freedom flexure-suspended free-rotor gyroscope and a miniature gyroscope incorporating such an integrated system. The three gyroscopic functions are combined within apparatus including a single coil assembly using a radially permanent magnetized ring located on the gyroscope rotor wheel, with a plurality of pick-off coils mounted compactly with respect to the instrument case and each partially inserted in an air gap provided at the gyroscope rotor wheel periphery. The spacial flux magnitude variation around the rotor wheel in the air gap generates an alternating current in each pick-off coil as the rotor spins. The difference in the voltages induced in diametrically opposed pick-off coils provides an output pick-off signal, while the sum of the signals induced in all coils provides an alternating phase reference voltage.

Abstract: Speed control apparatus for use in an aircraft performance management system of the type wherein a target Mach number command is supplied to the aircraft pitch controls to attain the target Mach and is simultaneously supplied to the aircraft throttles to capture a computed engine pressure ratio (EPR) or fan speed (N.sub.1), said apparatus being operative during maximum thrust climbs and minimum thrust descents upon an abrupt step function target Mach number command wherein said step function command is converted to a ramp command, the slope of which is directly proportional to the existing thrust-minus-drag conditions of the aircraft and inversely proportional to its existing weight, thus ensuring a proper division between aircraft acceleration and rate of climb or aircraft deceleration and rate of descent.

Abstract: A rigid capacitor plate for use in a capacitive pressure transducer of the type having a flexible diaphragm with a concave central portion serving as a pressure responsive capacitor plate, said rigid plate being supported on and spaced from said diaphragm by a plurality of small cross-sectional area pedestals.

Abstract: An incoming signal is tested for the presence or onset of a frequency shift keyed (FSK) signal which alternates at a known rate between two unknown frequencies separated by a known frequency shift. The incoming signal is time delayed an odd multiple of the keying period and the delayed signal is multiplied by the incoming signal to produce sum and difference frequencies when the FSK signal is present. The difference frequency is selected by filtration and multiplied by a time delayed version of itself to produce a steady phase signal. The steady phase signal is extracted by filtration, demodulated and integrated to produce a useable detector signal for comparison with a threshold level.

Abstract: An artificial horizon display generator determines either sky shading or ground shading in real time as each pixel of a raster display is generated. Transition line parameters are specified by host processor, whereupon the display generator computes whether the raster line currently being generated will intersect the horizon boundary line, and if so, at what X-Y transition point. Pixels generated prior to the transition point are of the initial shading; pixels generated subsequent to the transition point are of the opposite shading.

Abstract: A saturated flux equivalent to three amplitude level recording is attained by recording two levels by conventional saturation of the medium and the third level by writing a high frequency which erases old data and is read back as a zero level due to limited playback or read frequency response.

Abstract: A stability augmentation system utilizing a limited authority series actuator has an adaptive washout circuit which automatically reduces the effective washout system washout time constant as a function of attitude error or series actuator displacement. For small errors and for disturbances due to gusting winds, the system washout time constants are slow, thus providing good stability. For large errors the circuit smoothly reduces the time constants to keep the series actuators from saturating.

Abstract: The vector generator comprises X and Y digital-to-analog converters providing X and Y deflection voltages to a cathode ray tube display. X and Y digital accumulators provide respective inputs to the X and Y digital-to-analog converters. The word lengths of the accumulators are wider than those of the digital-to-analog converters and the digital-to-analog converters derive their inputs from the most significant digits of the accumulators. X rate and Y rate signals proportional to the sine and cosine of the vector angle are applied as inputs to the respective accumulators which accumulate the rate signals with the present contents of the accumulators so as to generate linearly changing X and Y deflection signals. The vector angle is adjusted by changing the ratio of the sine to cosine inputs to the accumulators and the vector speed is controlled by increasing and decreasing the sine and cosine signals but maintaining the ratio therebetween the same.

Abstract: A quartz crystal vibrating diaphragm pressure sensor includes a primary quartz crystal body having a diaphragm formed therein and electrodes on each side of the diaphragm for piezoelectrically exciting thickness shear mode oscillations of said diaphragm, said oscillations varying in frequency in accordance with variations in fluid pressures applied to the surfaces of said diaphragm. A second identical or substantially identical diaphragm similarly excited but exposed to a constant pressure provides a reference frequency for providing precision difference frequency pressure measurement and for inherently compensating for ambient conditions affecting both diaphragms.