Abstract: A mode-locked gallium arsenide crystal laser has a cavity length equal to one-half its principal noise resonance wavelength and an electrode overlying a portion of the crystal, the remaining portion being a self-aligned region diffused or implanted with impurities comprising saturable absorbing centers. An anti-reflective coating is placed on a crystal facet facing an external mirror defining one end of the laser cavity. The resulting laser has improved power, frequency and temporal stability.

Abstract: Circuitry is disclosed which generates signals which may be applied to subsequent processing circuitry, such as a display device. Applied signals having a first predetermined number of intensity levels are transformed by the circuitry into signals having a smaller predetermined number of intensity levels suitable for application to the display device. A histogram representing the number of occurrences of each particular intensity level in the first predetermined set of intensity levels is generated. This histogram is analyzed, and a plurality of peak intensity levels are selected for application to the display device. Mapping signals are generated which are determinative of which subsets of the remaining intensity levels are mapped into particular ones of the selected peak intensity levels. The mapping signals are then utilized to transform applied signals received during a subsequent time period into signals having the selected peak intensity levels.

Abstract: The specification describes a process and apparatus for pumping and removal of unwanted gases by effecting a chemical reaction between the gases and a highly reactive substance which is in the form of aerosol particles, to form a non-volatile, solid reaction product. In one embodiment of the invention, the reactive substance is initially provided in the form of a solid; the solid is heated to liquify it; and the liquid is forced through spray nozzles under high pressure to form the desired aerosol particles, which then react with the gas to be pumped.

Abstract: The charge coupled device focal zoom of the present invention is used in connection with a time delay and integration charge coupled device imager in which a plurality of detectors is scanned at an angular rate .omega. across a field of view subtended by a scanning angle .alpha., wherein output charge from the detector array is clocked through associated charge coupled device registers at a clock frequency f.sub.ccd in synchronism with the scanning motion. A video display receiving the signal from the charge coupled device register may zoom in on a small portion of the field of view subtended by a reduced angle .alpha./n. This is accomplished by restricting the scanning angle to the reduced angle .alpha./n and simultaneously reducing the CCD clocking frequency to f.sub.ccd /n and the scanning rate to .omega./n. The resolution of the image is enhanced because the sampling time T is increased while at the same time the synchronism between charge transfer and scanning movement is maintained for all values of n.

Abstract: Modulated signal levels in the range of 1 .mu.V, as is typical for radar returns, can be used to achieve a useful modulated optical signal that can be launched into a fiber optic waveguide for transmission to a remote location for signal processing. The device of the invention achieves such a conversion by suitably integrating a high gain bipolar transistor with an electroluminescent diode, such as a light emitting diode or diode laser, into a compact monolithic structure.In one structural configuration, the bipolar transistor comprises an emitter comprising a layer of doped n-(Al,Ga)As supported on a base comprising a layer of doped p-GaAs, in turn supported on a collector comprising a layer of undoped n-GaAs or n-(Al,Ga)As. The electroluminescent diode in this embodiment comprises a light-emitting diode formed by a p-n junction between the undoped n-GaAs or n-(Al,Ga)As layer and a supporting doped p-GaAs layer, in turn supported on a doped p.sup.+ -GaAs substrate.

Abstract: Disclosed is an improved optical waveguide and modulator and an ion implantation process for fabricating same. The process includes the step of implanting high energy protons in a suitable semiconductive substrate material, such as gallium arsenide, to form a semi-insulating wave guiding layer therein for efficiently sustaining light propagation. The relatively large difference between the refractive indices of the high resistivity proton implanted layer and of the underlying low resistivity substrate result in highly efficient coupling and modulation of light passing through the proton implanted layer. The letter is partly the result of the relatively high resistivity attainable by proton implantation and partly the result of the sharp profile of ion dosage versus proton implantation distance into the substrate.

Abstract: Disclosed herein is a process for growing II-IV semiconductor crystals which includes providing both a II-IV semiconductor source material and a crystal growth support member in a predetermined dynamic vacuum. This vacuum is sufficient to create a predetermined overpressure at the source material and simultaneously remove impurities therefrom. The temperature of the support member is initally raised to a predetermined level above the temperature of the source material to thereby prevent vapor transport between the two. Then, the temperature of the support member is lowered to a predetermined value below that of the source material to produce a disassociation of elemental gases from the source material and initiate controlled vapor transport of the elemental gases from the source material to the support member. In this manner, compound semiconductor crystals of high purity and stoichiometry are formed on the surface of the support member.

Abstract: Low friction pivot 10 has base 12 and pivot pin 16. Bands 22, 24, and 26 are secured to the base 12 on one end and half-wrapped around the cylindrical pivot pin 16 on the other end. The slot 18 in pin 16 is for receiving and clamping that end of the bands. The torque caused by the bent bands is equal so that in any rotative position there is no net torque applied to pin 16.

Abstract: Compositions capable of exothermic reaction in the condensed state are prepared by pressing a mixture of powders comprising a reactive metal such as titanium, boron carbide and, optionally, carbon (e.g., graphite and/or lampblack) and boron. With moderately fine particle size of boron carbide (about -400 mesh), sustainer compositions are formed. With considerably finer particle size of boron carbide (about -800 mesh), booster compositions are formed. A preferred composition consists essentially of about 67 to 79% titanium, about 13 to 30% boron carbide, up to about 10% carbon and up to about 10% boron.

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: 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: 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: 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: 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: Precisely curved, lightweight and low-cost reflectors for electromagnetic radiation are fabricated by use of a tool and a process in which a blank is planar stretched by uniformly applied isotropic and radially extending forces followed by deformation of the stretched blank to a precisely curved surface.

Abstract: A heat pipe (10) includes an evaporator (18) to which a heat generating device is coupled. A heat dissipating condenser 14 is coupled to the evaporator by a thermally insulating tube 46. A capillary is on the interior surfaces of the evaporator, the condenser and the thermally insulating tube. Both working fluid and inert gas are placed therein. Reservoirs (16) for receiving the inert gas are joined to the condenser. Both the condenser and the gas reservoirs are thermally secured to a heat sink (28); however there is a path of higher thermal conductivity between the reservoir and the heat sink than between the condenser and the heat sink.

Abstract: In the present invention, a novel magnetic circuit maximizes the electrical power generated upon manual actuation of a push-button switch while minimizing the required weight of the magnetic materials. In particular, the magnetic circuit of the power supply of the present invention includes the following magnetic materials: an unmagnetized core (comprising iron) around which a coil is wound, the coil being connected to supply power to the transmitter; a permanent magnet (comprising iron having a permanent magnetic moment) mounted on a vibrating reed, at least one pole of the permanent magnet facing at least one end of the core. Actuation of the push-button switch induces oscillatory motion of the reed and of the permanent magnet. An advantage of this novel magnetic circuit is that, in at least one embodiment, the oscillatory motion of the permanent magnet causes a complete flux reversal through the coil during each cycle of the mechanical oscillation of the reed, a significant advantage.