Abstract: A high resolution room temperature infrared camera requires no cryogenic cooling and high vacuum packaging, normally though necessary for infrared target detection, by using a “blind” polycrystalline lead salt resistor in combination with a matched active polycrystalline lead salt photoresistor both maintained at room temperature to provide a differential output indicative of an IR generating target. As a result of the matched components, the differential output nulls out the dark current which is the result of the ambient at the camera. The high degree of linearity associated with polycrystalline photoresistors permits fabrication of a differential detector where dark current in the active element is nulled out by equal and opposite current flow in a non-optically active reference resistor.

Abstract: Two-photon absorption measurements are made at various points remote from monitoring apparatus by apparatus which includes two lasers that produce counter-propagating beams through the earth's atmosphere. The lasers are tuned such that the sum of the energies of the photons in each of the laser beams equals that associated with a predetermined transition of a gas in the earth's atmosphere. In one embodiment, a pulsed laser and a CW laser are used. The pulse from the pulsed laser propagates along the CW beam produced by the CW laser and overlaps the CW beam at positions determined by a range gating technique, which makes possible the measurement of the two photon absorption at the various positions of overlap or coincidence. In one embodiment, the subject apparatus is utilized for pollution monitoring, in which the frequencies of the lasers are tuned such that the energies of the photons from these lasers add up to a transition of a predetermined pollutant.

Abstract: An electromagnetic radiation detector system is disclosed which includes a detector of semiconductor material in the form of a superlattice having a plurality of layers of a first conductivity type spaced by alternate layers of a second conductivity type forming a layered structure having distinct natural energy band gap responsive to a narrow band of electromagnetic wavelengths, but which can be tuned by physical or electromagnetic devices to alter the band of wavelengths to which the detector responds. The system includes electrodes connecting the sensor to an output device.

Abstract: This invention is a thermoacoustic sonar system for detecting a target that is located at or beneath the surface of the water. The foregoing system comprises a laser or particle accelerator that is located above the water and a plurality of passive receivers that are located on or above the water. The laser produces a light beam whose amplitude is subsequently modulated or whose pulses are varied in time. A particle accelerator would produce a pulsed particle beam that varies in time. These modulated or varied pulses are focused or deflected to a small layer of water at the air/water interface so that the beam will be absorbed by the water causing the water to produce an acoustic signal that may propagate to a target where the acoustic signal will be reflected and possibly detected by one or more passive receivers.

Abstract: A meander line includes a electrically conductive plate, a plurality of transmission line sections supported with respect to the conductive plate, wherein the plurality of sections includes a first section located relatively closer and parallel to the conductive plate to have a relatively lower characteristic impedance with the conductive plate and a second section located parallel to and at a relatively greater distance from the conductive plate than the first section to have a relatively higher characteristic impedance with the conductive plate, and connector means for interconnecting the first and second sections and maintaining an impedance mismatch therebetween.

Abstract: Apparatus and method for fabricating a backside illuminated photodiode array is described which does not use epoxy, and therefore has better transmission characteristics. The method uses indium or other coldweldable metal to fasten the detectors to the transmissive substrate. Because the indium is opaque in the waveband of detector sensitivity, it also forms an optical mask for each detector element.

Abstract: A multi-color, multi-pulse laser target designator is disclosed in which the target is illuminated with pulses of preselected colors and interpulse spacings so as to uniquely identify the target. Inter-pulse spacing may be varied down to an arbitarily small spacing by virtue of the use of pulses of differing colors, thereby increasing countermeasure resistance due to the difficulty of a target detecting and duplicating inter-pulse spacing. Pulse elongation is provided in one embodiment to provide prolonged illumination of the target so as to permit increased homing accuracy for optically guided weapons.

Abstract: A context switching logic cell with public and context private data sharing for use in a context switching system. A context switching logic cell includes a programmable logic unit using configuration bits for implementing programmable logic functions for each context, a context memory for storing and providing results of context dependent logic operations, and carry logic. The context memory includes private registers, public registers and an active register. Each private register corresponds to a context and is addressable only within the corresponding context while public registers are addressable within all contexts and the active register stores results of logic operations for the current context. A context switching logic cell may include a data memory that is accessible within all contexts. The context switching logic cells may be arranged into a context switching logic array for use in a context switching system by level 1 buses and carry bit lines.

Abstract: An infrared radiation source is provided by directing combustion gases through a honeycomb mantle along the axis of symmetry thereof. The honeycomb mantle is formed of individual tubes disposed at an angle to the axis of symmetry of the mantle and is closed at the end away from the combustion gas input. The mantle may contain a structure to divert the combustion gases therein to aid in uniform heating.

Abstract: A bulk acoustic wave delay line is disclosed having a thin, amorphous metal substrate, and deposited on the first and second surface at each end of which is a very thin layer of a piezoelectric material. Positioned on each piezoelectric material layered area are a plurality of interleaved electrodes with a first portion of each plurality of electrodes being interconnected and a second portion of each plurality of electrodes being interconnected. The electrodes on the first and second surface at one end of said device are energized with electrical signals in a phased or un-phased manner to generate selected modes of pure Lamb waves in said substrate.

Abstract: Suppression of jamming from multiple sources is achieved by detecting the AM difference frequency produced by the beating of a desired signal and the smaller of the multiple jamming signal with the stronger jamming signal and applying same to one input of a single-sideband modulator while simultaneously applying the received signal (containing both the desired signal and the jamming signals) to the other input to the single-sideband modulator whereby the larger jamming signal is suppressed. The sum and difference outputs of the single-sideband modulator containing the upper and lower sidebands, respectively, of the desired signal plus the smaller jamming signal are each processed by a jamming cancellation circuit to suppress the smaller jamming signal and their outputs combined to receive the desired signal.

Abstract: A multi-color, multi-pulse laser operating at a number of wavelengths is provided with a like number of cavities to produce a like number of output pulses from a single pumping pulse. The spacing between the pulses is easily controlled by controlling the timing of Q-switches, each in a different cavity, so that information is imparted by the pulse spacing. In a two color embodiment, a beam splitting device is positioned along the longitudinal axis of the laser medium to produce two beams which are directed into different cavity resonators, each tuned to a different wavelength. Reflecting surfaces positioned at the end of each cavity redirect each beam back to the beam splitting device where the beams are spatially recombined and subsequently two pulses, one of one color and the other of the second color, are sequentially coupled out of the laser system.

Abstract: An apparatus and method reducing interference between multiple frequency modulated, FM, voice transmissions present in the same frequency bandwidth by receiving a radio signal which includes a first FM voice signal to be demodulated along with one or more additional FM voice signals which are present within a modulation bandwidth of the first FM voice signal, detecting the presence of a carrier frequency signal of the first FM signal and determining a lack of modulation of the detected carrier frequency signal by a voice signal, and squelching the received signal when the carrier signal is unmodulated.

Abstract: An antenna includes one or more conductive elements for acting as radiating antenna elements, and a slow wave meander line adapted to couple electrical signals between the conductive elements, wherein the meander line has an effective electrical length which affects the electrical length and operating characteristics of the antenna. The electrical length and operating mode of the antenna may be readily controlled.

Abstract: An apparatus and method are described for direction finding the source of emf emissions including a monotone signal by detecting the phase changes of the monotone signal during movement relative to the source. A software embodiment measures the amount of phase change.

Abstract: The present invention provides a method for producing single crystals of a group II-IV-V.sub.2 and group I-III-VI.sub.2 compounds by synthesizing compound material from its constituents and separately melting and refreezing the material in a transparent furnace while observing crystal growth.

Abstract: The present invention provides a radiant energy activated semiconductor control device having N+ ion implanted regions exposed to the radiant energy for switching purposes.

Abstract: A method for determining the time difference of arrival, tdoa, of signals from a cellular telephone, includes determining tdoas for a plurality of channels, averaging the tdoas from the channels, subtracting the average tdoa from the individual channel tdoas to determine residual channel tdoas and determining an overall residual tdoa from the residual channel tdoas. An apparatus and method for collecting cell phone transmission signals for performing tdoa calculations, includes receiving, digitizing and temporarily storing wideband transmission signals while monitoring a known reverse control channel for a predetermined cell phone number to be located, and permanently storing the delayed reverse control channel signal once the predetermined number is identified.

Abstract: This invention is a parachute array in which a plurality of hydrophones are attached to the skin of a planar or volumetric parachute or affixed to strings that are positioned around a planar or volumetric parachute. When the parachute is moved through water, the parachute will expand and provide the necessary tension forces to maintain and position the hydrophone array in a particular geometric orientation without the use of any rigid structural members.

Abstract: A method and apparatus for highlighting returns from optically augmented targets includes in one embodiment a receiver, a viewing device coupled to the receiver and first and second illuminators. The first illuminator is arranged on axis with the receiver and the second illuminator is placed off-axis therefrom. Means are provided for switching on alternately the illuminators such that returns of the first illuminator through retroreflection from high quality optical targets will enter the receiver, while retroreflection returns of the off-axis illuminator will not enter the receiver; therefore the retroreflected returns from high quality optical targets will appear to flicker when seen on the viewing device and thus be highlighted above the rest of the scene.