Abstract: Metal-coated optical fibers are often employed in high temperature optical communications applications. However, such optical fibers have been found to evidence a substantial decrease in optical transmission as a function of increased temperature. Optical fibers having a temperature-insensitive optical transmission are obtained by annealing a metal-coated optical fiber at a temperature at which optical transmission is substantially the same as that observed at room temperature. Aluminum-coated optical fibers annealed at 560.degree. C. evidence an optical transmission independent of temperature between about -200.degree. C. and at least about 560.degree. C.

Abstract: An electronic logic circuit utilized in conjunction with a scanning infrared detector to generate pulses which accurately indicate the precise location of the center of a preselected astronomical radiant body, such as the earth, notwithstanding a wide scanning frequency range with unknown initial value, and capable of rejecting undesirable input signals, is disclosed. The pulses are initially generated so as to conform the frequency of a generated signal to that of the signal applied from the infrared detector, thereby correcting the large initial signal frequency error. Both the conditions of an initially high and low frequency of oscillation of the generated signal relative to the applied signal are corrected. After such frequency correction has been rendered, signal phase correction is accomplished so as to negate the difference between the exact center of the signal applied from the infrared sensor and the trailing edge of the generated signal.

Abstract: The specification discloses a process for accurately aligning a chosen member with a focused beam of radiation or for aligning two chosen members with each other. A set of alignment marks having a predetermined spatial pattern is first provided on the surface of each member. Next, a detection signal is generated from the set of alignment marks, comprising a serial electronic signal as a function of time and containing serial information corresponding to the relative position of each mark in the set of alignment marks. Then, the detection signal is electronically processed to generate an alignment signal with a high signal-to-noise ratio. Next, the alignment signal is compared to a reference signal signifying a predetermined criterion of alignment, to generate an error signal which is indicative of the extent of misalignment.

Abstract: The invention includes a first switching transistor which is actuated by a logic signal. This switching transistor is disposed in a current path from the base of the power transistor. When this switch is actuated, the invention provides a large steady state base drive current superimposed with a base current peaking pulse from a current generator. The invention also includes a second switch which applies a reverse potential to the base of the switching transistor for fast turnoff. The specific embodiments disclose circuitry for regulating forward base drive current to minimize line voltage variations and component tolerances. An improved bipolar power transistor base drive circuit for switching regulator and DC to DC converter power supplies is disclosed.

Abstract: Apparatus for providing an amplified, phase-conjugated output beam. A nonlinear medium, gain medium, and output device are disposed along an optical path to form a ring resonator. An external laser source provides laser light to one end of the nonlinear medium which induces stimulated Brillouin scattering in the medium. Light provided by the gain medium at a first predetermined frequency is reflected from the acoustic waves traversing the nonlinear medium at a second predetermined frequency. The reflected light traverses the optical path through the gain medium and impinges upon the other end of the nonlinear medium, where it is further reflected from the acoustic waves. This reflected light is frequency shifted to the original predetermined frequency. A portion of the light at the predetermined frequency is coupled out of the resonator as an amplified phase-conjugated output beam by means of the output device. Alternatively, output beams at both the first and second predetermined frequencies may be provided.

Abstract: A method and associated means for producing simultaneous electrical representations of the electrical and acoustical (heart sound) activity of the heart, in which a pickup device and associated circuits produce a full wave rectified symmetrical heart sound signal annotated by pulses developed from the QRS wave of the electrocardiogram signal.The pickup device is designed to permit the direct (unbuffered) application of the pickup electrodes to the skin of the body and to provide a control of the associated circuits when not in contact with the body to shorten response times when the pickup device is placed in contact with the body.

Abstract: A source of microwave-frequency electromagnetic energy of a specific desired frequency is generated by a device that utilizes a filter network to absorb energy of unwanted frequencies and couples energy of the desired frequency into a tunable ridge waveguide. The filter network is designed into the DC bias conductor to increase oscillator efficiency.

Abstract: The specification discloses a process for converting the surface layer of a body of vitreous silica to the more stable crystalline form of silica known as cristobalite. The surface of the body of vitreous silica is exposed to a gas phase reactive atmosphere comprising atomic iodine at a predetermined elevated temperature for a predetermined period of time to convert the surface layer of the vitreous silica to polycrystalline cristobalite and thus passivate and enhance the stability of the treated surface. The disclosed process is particularly useful for forming improved crucibles, such as those used in crystal growth from a melt.

Abstract: A circuit is disclosed which provides overcurrent protection for switching regulator power supplies with soft start and soft turn OFF features. The invention includes first means for sensing the current through the switching transistor of the regulator and second means for providing a voltage signal to the switching transistor deactivation circuitry whenever the current through the switching transistor exceeds a predetermined threshold. In a specific embodiment, the current generator is provided by a transistor biased for nominal operation in its active mode. The means for sensing the current through the switching transistor is provided by a resistor the voltage drop across which provides the input voltage threshold to the bipolar transistor current generator. The current generated by the transistor causes a voltage to quickly develop across an RC network referenced to ground potential.

Abstract: A process of fabricating high density CMOS integrated circuits having conductively interconnected wells. The conductive interconnection is provided by a buried conductor formed in combination with channel stops encircling each of the wells and prior to the fabrication of FET active devices at the surface of the wells. The channel stops, as provided by the process, are automatically aligned with and spaced apart from the source and drain regions of their respective FETs.

Abstract: New nematic liquid crystal (LC) ester mixtures with relatively short average molecular lengths are made by including one or more binary sets of components which have identical, or nearly identical, molecular lengths. Undesirable solids solution phase effects are avoided by either utilizing appreciable asymmetry in the alkyl end groups or by combining LC esters of different classes.

Abstract: Apparatus for processing microwave signals at two predetermined frequencies. Signals at a first predetermined frequency are received or transmitted at one end (input port) of a microwave transmission line whose other end is utilized as a common output port for transmitting and receiving signals at both predetermined frequencies. A band rejection portion is provided which comprises first and second rejection resonators orthogonally disposed along the transmission line at two predetermined positions. A bandpass portion, comprised of a plurality of collinearly aligned bandpass resonators, is disposed at a third predetermined position along the transmission line. Signals at a second predetermined frequency are transmitted or received at a second input port which is part of the bandpass portion. All resonators are capacitively coupled together and to the transmission line.

Abstract: An adaptive comparator is provided which compares a signal from a horizon sensor of a satellite to a predetermined threshold to provide a signal indicative of the relative position of a celestial body with improved noise immunity. When the comparator receives a signal from the horizon sensor which exceeds the threshold, an output is provided which may be used to change the orientation of the spacecraft. The comparator includes circuitry for ascertaining the average of one or more of the most recent input pulses which exceeded the previous threshold. This average is then utilized to set a new or adapted threshold. The subsequent input signal is then compared to the adapted threshold and the recursive process continues.

Abstract: In the present invention, image processing is performed at speeds comparable to those achieved in parallel processing without requiring substantially more area on the substrate than that required in serial processing. In this invention, for an N.times.N processing kernel, N rows of image memory are processed in parallel through a plurality of N floating gate arrays of dimension N.times.N, N-1 of the data rows from the memory being recirculated through the N floating gate structures before being discarded. Each of the floating gate structures is offset from the adjacent floating gate structure by one row so that the data from memory need be recirculated only once.

Abstract: A full color high contrast image projection system with oil coupled dichroics and a single projection lens is disclosed. The invention includes a unitary optical tank in which a prepolarizer and dichroic separators are mounted in fixed alignment relative to a main polarizing prism. The prepolarizer acts on the incident light from a source to polarize the green light and reflect the S component out of the system. The red and blue components are transmitted unchanged. The main polarizer is mounted at a 90.degree. twist relative to the prepolarizer so that it reflects the green light to a first light valve via a first dichroic separator. The polarized red and blue components are transmitted to second and third light valves via a second dichroic separator. The light valves modulate the polarization state of incident light before returning it to the second beamsplitter. The second beamsplitter then recombines the individual beams into a single output beam.

Abstract: An improved line-of-sight commanded missile guidance system is provided which provides the operator of a missile system with the capability of hitting targets which would otherwise be obscured by darkness, smoke, aerosols or poor atmospheric visibility.The system includes a tracker equipped with an infrared sensor and means for periodically blinking a laser beacon which is mounted on the missile. The laser operates in a range in which it would be most visible under the above described atmospheric conditions. Blinking provides countermeasure resistance. The sensor provides electrical signals representing frames of data corresponding to the target scene. Alternate frames contain the beacon signature. Electronic circuitry is provided for subtracting successive frames to eliminate clutter and to then provide signals indicative of the position of the missile relative to the center of the field of view.

Abstract: 1. A system responsive to a composite signal including first signals in the presence of second signals and detecting the presence of said first signals with a selected threshold level ratio of signal voltage to noise voltage comprisingmeans for integrating the composite signal over selected intervals of time,means for comparing a selectable threshold level with the integrated signals,means for storing data to provide said threshold level,counting means responsive to the integrated signals exceeding the threshold level to accumulate a count thereof,constant selector means responsive to the count of said counting means to establish a proportion of the value of said stored data for changing said threshold level to maintain the selected threshold level ratio,and means responsive to said constant selector means for correcting the stored data after a selected number of said intervals of time.

Abstract: There is disclosed a metallic clad glass fiber optical waveguide suitable for use as a high-strength optical transmission line, e.g., for high capacity communications systems and for sensors operating at high temperature. At least two metallic claddings or coatings are formed on the glass waveguide structure, which comprises a core and glass cladding, by coating the glass fiber with at least one of the metallic coatings as it emerges from the furnace with a metal or alloy. The first metal or alloy employed is one that is substantially chemically inert with respect to the material comprising the glass fiber at the deposition temperature during coating of the metal or alloy onto the glass fiber. The second metallic coating may be of the same composition as the first, in order to repair pinholes or to increase the thickness.

Abstract: The specification discloses a low temperature process for forming an effective insulating layer of a selected oxide on the surface of a chosen conductive substrate. The oxide so formed has low pinhole density, good surface morphology, and good step coverage. In addition, the disclosed process simultaneously minimizes the deformation or restructuring of the surface of a temperature-sensitive conductive substrate, which would produce unwanted hillocks or spikes that degrade the insulating properties of the oxide. In accordance with the disclosed process, the substrate is exposed to a chosen vapor phase reactant in the presence of neutral, charge-free atomic oxygen to produce a reaction between the atomic oxygen and the vapor phase reactant to form the selected oxide, which deposits on the surface of the conductive substrate. Improved multilayer structures comprising multiple layers of conductive material separated by an oxide dielectric layer are formed by the disclosed process.

Abstract: An antenna pointing control system primarily useful for aiming and controlling a communications satellite directional antenna. The invention makes use of a ground based pilot station which transmits an up-link signal to the satellite, including frequency differentiated communication signals and command and control signals. The command and control signals are referred to as the beacon or pilot signal. The pilot signal is a triangular frequency modulation waveform. The communications signals and the pilot signal are received by a common directional antenna on the satellite. A microwave network coupled to a multiple feed horn assembly of the antenna and responsive to the pilot signal produces pilot signal components including a sum signal and east-west and north-south error signals indicative of the corresponding angular errors between the desired antenna pointing direction and the direction from the satellite to the pilot station.