Abstract: A method of fabricating light emitting diodes to prevent degradation caused y thermally induced stress. A voltage is applied across the chip to cause it to bend to a prestressed condition while it is being soldered to the header. The biasing voltage applied is continued until after the heat is removed and the solder cooled leaving the diode in the prestressed condition.

Abstract: A sampled speech compression and expansion system, for two-dimensional prssing of speech or other type of audio signal, comprises transmit/encode apparatus and receive/decode apparatus.The transmit/encode apparatus comprises a low-pass filter, adapted to receive an input signal, for passing through low-frequency analog signals. A converter is connected to the low-pass filter for converting the analog signal into a digital signal. A buffer memory, whose input is connected to the converting means, stores the digitized signals.A correlator, having inputs from the A/D converter and the buffer memory, correlates the digital signal received directly from the converter with a delayed signal from the buffer memory. An "interval-select" circuit, whose input is connected to the output of the correlator, uses the autocorrelation value as a basis for comparison with subsequent peaks in the correlation value which are greater than a specified fraction of the autocorrelation value.

Abstract: An improved normally off insulated gate field-effect transistor capable of peration at frequencies in excess of 1 GHz wherein the substrate is a semi-insulating semiconductor. The substrate may be Fe or Cr doped InP or Fe or Cr-doped GaAs. Contacts for the source and drain electrodes are realized by forming n.sup.+ contacts for the n-channel device and p.sup.+ contacts for the p-channel device. Au-Sn will form n.sup.+ contacts while Au-Zn will form p.sup.+ contacts.

Abstract: A means for placing freshly mixed concrete on the ocean floor at great des. A pipeline is grossly positioned by a ship whereas the position of the submerged end is controlled by guide wires, water jets, props, etc. The discharge device at the end of the pipeline includes a slip joint, a tank flooded with seawater to maintain the pipe end submerged a certain distance in the concrete, and an expansion chamber where the velocity of the concrete being discharged is reduced. Deflector means at the pipe end directs the concrete laterally and negates the vertical lift component of the discharging concrete.

Abstract: A charge-coupled device (CCD) analog and digital correlator comprises identical modules, each of which is a simple analog CCD correlator with digital input and output. Circuits are included:(1) for injecting charges proportional to the voltage sequences s(n) and r(n), where s(n) refers to the input signal, and r(n) relates to a reference signal, against which the input signal is correlated;(2) for non-destructively sensing and tapping each sample s(n) and r(n);(3) for forming the summation s(n)+r(n);(4) and finally for squaring s(n), r(n), and [s(n)+r(n)] in simple, floating gate MOSFET amplifiers. The amplifiers operate in their saturation region, and have outputs proportional to s.sup.2 (n), r.sup.2 (n), and [s(n)+r(n)].sup.2, which are then fed into a differential amplifier to produce s(n)r(n).

Abstract: An apparatus is described for converting the carrier frequency of a moduld signal sampled from the output of an RF transmitter. The conversion provides a replica of the modulated signal at a predetermined center frequency without regard to the selection of a transmitter channel or to the modulation technique used. The replica is presented to a demodulator which provides an information signal suitable for monitoring the quality of modulation of the transmitted signal.

Abstract: A filter replaces the oxygen canister of an oxygen breathing apparatus and the air flow path is modified to provide a realistic simulation for training personnel in the use of closed circuit breathing units.

Abstract: Precise concentric alignment of the coolant, plasma and sample gas tubes d in conventional ICPs is an operationally important factor often achieved by fused arrangements which effectively preclude dismountability for maintenance and repair. Spacer rings slip-fitted into the coolant and plasma passages provide support for the concentric arrangement and also permit dismountability. Each ring is slotted to direct coolant and plasma gases and improve their intended functions. One ring spans the plasma tube and has a number of vertically-directed peripheral slots producing a laminar plasma gas flow. The other ring spans the coolant passage and has a pair of threads cut at spaced intervals to spiral the coolant gas and improve its heat transfer function. A separable base member supports the concentric lower ends of the tubes.

Abstract: A dynamic parachute four-line release simulator device which allows aircren to practice the steps necessary to assure a safe parachute descent and landing following emergency aircraft egress. The device is suspended at a desired height adjacent a raised platform, and is constructed of a cross-braced metal ring having parachute suspension lines connected thereto via bungee cords and eye bolts; a parachute riser assembly, which serves as an attachment point for aircrewmen trainees, is connected to the suspension lines via metal connector links.

Abstract: Supercorroding magnesium alloys that operate like galvanic cells and react apidly and predictably with seawater to produce heat and hydrogen gas. The alloys are formed by a mechanical process that bonds magnesium and noble metal powder particles together in a strong electrical and mechanical bond. The alloy powders can be compacted and sintered to form barstock, etc., suitable for making self-destructing corroding links.

Abstract: Apparatus for following the sun using the sun's radiant energy to heat a fluid-containing sensor to create a pressure which is used to rotate the apparatus against a spring force provided by an expansion bellows. The sunlight is permitted to strike the sensor only for certain angles of incidence to the apparatus so that the fluid pressure and the spring force rotate the apparatus to a predetermined position relative to the angle of incidence. In one embodiment, sunlight passing through a filter including several parallel plates which allow passage of sunlight having a predetermined angle of incidence relative to the filter is focused on the sensor. A reflector focuses sunlight on the sensor to reposition the apparatus to the desired position when the apparatus is incorrectly positioned because the sun has been obscured by clouds. In two alternative embodiments, a fresnel lens and a parabolic reflector, respectively, focus sunlight having a predetermined angle of incidence onto the sensor.

Abstract: An angle servo preamplifier for use in the tracking antenna servo drive sem of a precision tracking radar system. The angle servo preamplifier processes tracking error signals indicative of tracking antenna pointing errors with respect to a target. The preamplifier is comprised of an input differential amplifier stage, a phase control stage, a sample and hold stage and a power amplifier stage. In addition, interfacing circuitry is included for coupling the preamplifier to the azimuth/secant correction system of the tracking radar system. The sample and hold stage includes "deglitching" circuitry for suppressing sampling/switching transients. And, to accommodate a bipolar tracking error signal while utilizing a single voltage supply, the power amplifier stage performs d.c. level translation.

Abstract: A charge coupled device signal output summing circuit is disclosed for prding a video data signal to a scan laser projector system which projects an optical image on a 360.degree. wide angle display screen. The charge coupled device signal output summing circuit comprises a linear image sensor which senses the light received from the optical image and produces a pair of output signals, each of which has a plurality of video data components. The video data components of the pair of output signals are then summed by a unique combination of buffers, analog switches, capacitors, a video amplifier, and adder to produce the video data signal.

Abstract: An improved method of liquid phase epitaxial growth of III-V compound on an nP substrate by growing the epitaxial layer in an atmosphere of H.sub.2 with 10.sup.-5 to 10.sup.-4 mole fraction PH.sub.3.

Abstract: A single or multilayer optical interference filter and method of forming filter by ion implantation. One or more layers of nitrogen ions are implanted into a single crystal silicon with the crystal at a temperature of from about 600.degree. C. to about 1000.degree. C. The implanted ions create a buried layer(s) of silicon nitride (Si.sub.3 N.sub.4) whose refractive index is substantially different from that of silicon (Si) such that appreciable multiple reflection of incident light occurs between the buried layer(s) and the front surface. The resulting interference maxima and minima in transmitted or reflected light which occur at well-defined positions in wavelength may be controlled both in amplitude and wavelength position. The ions may be implanted in layers at different depths to produce a "thin film" interference filter.

Abstract: A nickel-titanium composition alloy connector capable of having a memorized hape is provided that will mechanically splice very thin optical fibers by the application of heat in a self-aligning orientation that achieves maximum coupling efficiency, and which method can be utilized in field installations.

Abstract: A search apparatus is provided for an aircraft. The search apparatus includes a transparent observation chamber and a plurality of bulkheads which divide the chamber into at least two compartments. A cradle is mounted within each compartment for supporting a bird with the head of the bird facing outwardly with respect to the chamber. A peck key is mounted in each chamber in proximity to the outward end of the cradle, and a tray is provided for containing food for the bird. A device is mounted within each compartment for sliding the tray inwardly or outwardly, the outward position being adapted to present food to the bird and the inward position being adapted to withdraw food from the bird. Indicators may be connected to the peck keys for indicating which bird in a chamber has visual contact with an object, and a control device may be provided for selectively actuating the food trays for the inward and outward movements.

Abstract: A pulsed laser emits laser energy by dissociative excitation of metal dihalide and cyclic recombination. A metal dihalide selected from subgroup II-B of the periodic table of elements is contained within an elongate sealed enclosure. Two elongate electrodes having external terminals are supported in parallel relationship within the enclosure, forming a gap parallel to the principal axis of the enclosure. A source of pulsed electric power is connected to the terminals of the two electrodes, producing repetitive transverse electric discharges across the gap. An inert buffer gas is included within the enclosure for aiding electric discharge uniformity, to provide vibrational relaxation of the lasing medium in its electronic states and to participate in the dissociative excitation process. The buffer gas is one of several mixtures of discrete percentages of neon and nitrogen.

Abstract: 1. A method for detecting and differentiating between containers of submed junk and explosive-filled mines in demolition operations, comprising the steps of subjecting an unknown submerged container under surveillance to a gamma radiation source, traversing said submerged container with said source along a standard diagnostic path, detecting the changes in intensity of the radiation penetrating the submerged container, and recording the variations of intensity of said radiation penetrating the submerged container along said path to obtain a density signature of said submerged container and contents enabling a positive identification of said unknown submerged container by comparison of its density signature with density signatures of known containers.

Abstract: A drive mechanism is provided particularly suitable for use in ambulators ving a mobile platform that transports a paraplegic in a standing position, the unique drive mechanism enabling the platform to be of a minimum size with a very low center of gravity, and being movable about three axes to provide maximum maneuverability and access to confined spaces.