Abstract: An adjustable mounting tray for installation of an aircraft gyroscopic and/or inertial reference apparatus, comprises, a baseplate member mounted so that it is substantially level in roll and pitch on the equipment shelf or rack of a levelled aircraft. A top plate or tray member is pivotally mounted on the baseplate for azimuthal adjustment thereon. The aircraft is pitched up or down and the top plate rotated in azimuth to remove any roll/yaw cross-axis coupling thereby assuring precision longitudinal axis alignment.

Abstract: A harmonic locking ring having a predetermined number of spaced holes centered on a major and minor circumference. Said holes fit over pins in concentric parts thereby locking parts together in desired positions within very close tolerances.

Abstract: An optical waveguide apparatus provides for single-mode and multimode switching or modulation of light wave energy with reduced bias voltages. Optical channels are formed in a crystal substrate by depositing film stripes thereon to cause stress-induced changes in the relative refractive index. Coupling or switching of light waves between the channels is provided by applying a bias which is of reversed polarity at adjacent film stripes, thereby augmenting or diminishing the stress in individual channels. By allowing operation with close spacing of the electrodes and using the enhancement in refractive index change of the stressed substrate in combination with the applied bias, the required control voltage is substantially reduced.

Abstract: A data compressor compresses an input stream of data character signals by storing in a string table strings of data character signals encountered in the input stream. The compressor searches the input stream to determine the longest match to a stored string. Each stored string comprises a prefix string and an extension character where the extension character is the last character in the string and the prefix string comprises all but the extension character. Each string has a code signal associated therewith and a string is stored in the string table by, at least implicitly, storing the code signal for the string, the code signal for the string prefix and the extension character. When the longest match between the input data character stream and the stored strings is determined, the code signal for the longest match is transmitted as the compressed code signal for the encountered string of characters and an extension string is stored in the string table.

Abstract: A surface acoustic wave processor capable of performing convolution, correlation, time expansion/compression, and time reversal utilizes the nonlinear interaction between two input surface waves to generate a third surface wave. Phase matching for the third surface wave to perform an integration function is provided by a fan multistrip coupler (FMSC) which appropriately alters the velocity of an electric field pattern transferred from one track of the FMSC to a second track thereof.

Abstract: Light from an external source is collimated, polarized, passed through a voltage dependent quarterwave plate and onto an elasto-optic sensor which serves to retard the light passing therethrough as a function of the external stress being measured. Light emanating from the sensor is divided into components at .+-.45.degree. to the applied stress axis. These components are coupled through optical fibers to photodetectors and the resulting electrical signals are applied to difference amplifier. The amplifier output is used to control a second light source whose output via an optical fiber is converted to a voltage suitable to drive the voltage dependent quarterwave plate in a negative feedback fashion such that the wave retardations resulting from the applied stress and nulled out. The power necessary to drive the voltage dependent quarterwave plate is used as a measure of the applied stress.

Abstract: An address sequencer utilizes binary words generated by Exclusive-OR addition of Gray code words to linear code words to produce a sequence of computer or memory addresses such that the addresses whose indices lie within a selected range of the index of a particular address are a predetermined Hamming distance from that address, whereby the possibility of recent data being overwritten is reduced.

Abstract: Superconductive integrated logic gate circuits of the magnetically controlled type incorporating Josephson tunnel junctions utilize a superconductive layer that forms a base electrode for Josephson junction devices on the integrated circuit, a ground plane, and magnetic control lines. A layer of super-conductive material superposed on a barrier layer provides inductive loops connected to junction counterelectrodes and coupled to the magnetic control lines. By patterning the control lines in the same plane as the ground plane-base electrode layer, two layers, an insulating layer and a super-conductive layer, can be eliminated from the prior art structure of a 1:2:1 magnetically controlled logic gate interferometer. A preferred embodiment utilizing an all refractory superconductor-barrier-superconductor trilayer patterned by local anodization is also described. Processes for manufacturing the embodiments of the invention are disclosed.

Abstract: Stroke display apparatus generates symbols or characters on a display screen and permits dynamic rotation or translation of those characters without placing a computation burden on the host processor. The characters are represented as a series of connected line segments, or blank segments, each having a characteristic direction or vector angle. Each of the line segments are generated by successively adding incremental .DELTA.x and .DELTA.y steps to an x,y position until the desired length is achieved. The character is rotated by adding a predetermined offset angle to each characteristic vector angle and then by converting the rotated vector angle into incremental .DELTA.x and .DELTA.y steps. Character translation is accomplished by including an extra, typically blanked, line segment command before the character is drawn.

Abstract: A flat panel display in which photoresistive dividers on a first substrate are coupled to the leads of an optical display on a second substrate, such as an electroluminescent panel, by means of elastomeric connectors for coupling the photoresistor conductive leads to corresponding leads of the optical display means.

Abstract: A rotary variable differential transformer has coil windings at an angle with respect to the longitudinal axis of the transformer and a core rotatable about this axis with end faces cut at projected angles therewith such that a rotation of the core varies the coupling between the primary and secondary windings. Amplitude and phase variations at the secondary windings are measurements of core rotation.

Abstract: A ternary magnetic recording system wherein groups of binary input digits are transformed into corresponding groups of ternary recording code symbols utilizing a hierarchical code substitution system in which the longest valid group in the code is encoded. The code substitution system provides retention of the advantageous properties of a prior ternary recording system while significantly enhancing the automatic gain control utilized in amplitude discrimination between two of the ternary recording symbols. Anomalous detection of chained doublets is also obviated. Data recovery is effected by decoding apparatus utilizing an eight bit addressable ROM addressed with a twelve bit ternary word.

Abstract: An approach to hover control system for a helicopter in which a constant deceleration is commanded at an initial approach speed and then the actual deceleration as a time function of the airspeed from the initial airspeed to a second airspeed is measured. Based on these measures, the total deceleration time to approach to a hover condition can be predicted accurately after which the commanded deceleration is removed.

Abstract: A compact apparatus for transmitting and receiving multiple sonar beams utilizes an acoustic lens to direct plane waves incident in desired directions to collimating lenses for presentation in phase to electroacoustic transducers having planar surfaces. The electroacoustic transducers emit sound waves which are transformed by the lenses into plane waves emergent in the desired directions.

Abstract: An apparatus for rapidly starting and stopping a conical scan antenna beam in which a feed rotating about a centerline provides a non-conical scan antenna beam during a search mode. When a target is detected a solenoid moves an actuator pin which displaces one end of the feed from the centerline providing a conical scan antenna beam for target tracking.

Abstract: An angular measuring system consisting of one or more sensors that transmit angular measurements to a central control unit where numerical readout of any selected sensor is provided. A threshold can be preset at individual sensors or the control unit for an allowable angular deviation, beyond which a warning device is actuated. The circuitry permits locating the sensors remotely from the console and provides precision and stability of operation. Low power consumption permits extended operating periods with internal batteries. False alarms are minimized by incorporating a hysteresis loop in the threshold detection circuitry.

Abstract: A thin film passive integrated optical waveguide is formed in a lithium tantalate substrate by proton exchange in a benzoic acid bath. Annealing the substrate provides increased waveguide depth and stabilizes the refractive index. Optical components are formed by proton exchange of the masked substrate after formation of a planar waveguide.

Abstract: An apparatus for color and brightness correction for a multi-gun color CRT display, providing compensation for variation in phosphor efficiency with cathode energization and for color tracking between guns. The brightness correction circuit is required to respond only to essentially DC changes, while a color selection circuit responds at a video rate. In a preferred digital embodiment, brightness and color tracking correction factors are stored in memory dedicated to a particular CRT, and addressed in response to input from a reference brightness level selected by an operator. A color selection decoder having stored in a second memory relative brightness characteristics of each color phosphor as a function of the hue commanded converts an input binary command to an analog output, which is combined with the brightness and color tracking correction factor to determine the resulting cathode energization for each color gun.

Abstract: In superconductive integrated circuit a semiconductor substrate is used in combination with normal resistors formed by degenerate doping of the substrate in selected regions. Doping is preferably performed by planar diffusion or ion implantation. Application of the invention to fabrication of a Josephson Atto-Weber gate by forming a normal resistor intermediate the junctions is also disclosed.

Abstract: A quaternary saturated digital magnetic recording system for enhancing information entropy provides an effective bit density increase of 100% or more over the MFM code. In the simplest implementation, groups of two input binary bits are mapped into one data cell, preferably into four combinations of long or short breaks and positive or negative polarity, with the break optionally centralized within the data cell for self-clocking. A system for reproducing the recorded information provides a peak detector, responsive to the recorded signal, coupled to pulse polarity and break width detector circuitry, with an internally synchronized clock, for remapping the recorded data into binary format.