Abstract: An omnidirectional hydrophone using particles suspended in a liquid acoustically coupled to a conducting environment for detecting acoustic waves by providing scattering of internally generated electromagnetic radiation from particles driven by the acoustic waves.

Abstract: A high temperature method for the preparation of single and multiple epitaxial layers of single-phase lead sulfide-selenide, [Pb].sub.a [S.sub.x Se.sub.1-x ].sub.1-a wherein x varies between one and zero, inclusive, and a=0.500.+-.0.003, deposited upon substrates of barium fluoride, BaF.sub.2, maintained in near thermodynamic equilibrium with concurrently sublimated lead alloy and chalcogenide sources. During preparation, the substrate is exposed to the vapor emanating from the single chimney of a two-zone, dual-chamber furnace, thereby providing an epilayer of uniform, and predetermined electrical and optical properties.

Abstract: The process of coating epitaxial films of lead chalcogenide materials with s.sub.2 S.sub.3 to insulate the films from the effects of oxygen upon exposure to air.

Abstract: A process and an apparatus using an inverse discrete Fourier transform for ynthesis of complex waveforms that have one or more sinusoidal components of arbitrary frequency, amplitude and phase. The component sinusoids are formed in segments of a predetermined period and modulated according to a preselected function. The modulation characteristic is compensated for by overlapped concatenation of adjacent segments.

Abstract: A detector for non-destructive sensing of binary information at a selected location along a domain wall of a thin magnetic film strip. Voltages are applied across a set of contacts arranged along the margin of the strip and the value of the voltage measured at an arranged, centered contact indicates the presence or absence of a Bloch line-crosstie pair at that location.

Abstract: An a.c. coupled, low-pass translating filter in which quadrature phases of n input signal spectrum are, in three successive balanced modulator stages driven by quadrature phases of externally generated carrier signals, alternately modulated-up and demodulated-down, and the sum of the remaining spectra is, in a final stage, demodulated below the cutoff frequency. Each stage terminates with a low-pass filter in which odd harmonics of the carrier frequencies and double frequencies generated in the second and final stages are eliminated.

Abstract: An underwater intrusion alarm system using an array of one or more remotely eployable, acoustic doppler detector probes. Each probe is a unitary submersible buoy formed by a pair of vertically coaxially and acoustically isolated, right cylindrical active transducer elements that are shielded from surface and bottom reflections. Transmitter and receiver circuits may be located either in the buoy with an external connection to conveniently located headphones and alarms or at a distant site with a fixed wire connection to the buoy transducer elements. A depth sensitive ancilliary mechanism regulates the submergence of the buoy in conformance with the rise and fall of the tide.

Abstract: A conformal electronically scanned antenna array system utilizing an inve Butler matrix in combination with directive antenna elements. The system provides a simple and inexpensive device for scanning an elemental array without the problems of output frequency shift or mutual coupling between antenna elements.

Abstract: A subprocessor and a method for a digital computer processing a special cs of programs wherein determination of the next processing program instruction address occurs simultaneously with execution of a preceding set of processing program instructions without incurring the delay inherent in performance of the intervening branch conditions.

Abstract: An electromagnetic intrusion sensor for detecting the presence of moving ects within a specified detection range by sensing the interaction between the moving objects and an electromagnetic field generated by the sensor.

Abstract: An electrical circuit for measuring the phase difference between a pair of nput signals by uniformly limiting selected properties of the waveforms describing the input signals and modulating an output signal in dependence upon the duration of contrariety between the unlimited properties of the input signals whereby error in the output signal due to "jitter" (i.e., abrupt, spurious variations in pulse amplitude or duration caused by superimposition of noise) is substantially eliminated. Various output means produce either a continuous wave analog signal or a digital bit signal in dependence upon the modulation of the output signal. Coupled ancillary circuitry monitors one input signal in comparison with the other input signal and provides an output signal signifying which input signal has a leading phase angle.

Abstract: A superheterojunction (SHJ) laser constructed from periodic structural semiconductor materials. The SHJ laser has approximately a thousand junctions which are planar and layered to provide gain in the plane of the layers. In addition, the device allows beam narrowing and beam steering of its output signal due to the multiple number of output sources with the ability to control the output phase of the combined sources.

Abstract: An isotropic antenna array formed by a plurality of adjoining stripline eents each having a two bit diode switched parallel feed path. Phase matching wavefronts emitted by groups of successively switched, adjacent antenna elements causes the antenna array to scan through space.

Abstract: The present invention provides within a ship, a passive electro-optic dev for providing a measurement of the range, together with a positively identifiable image of an approaching ship or object day or night on a CRT, with the range displayed digitally on the CRT. The rangefinder capability provides a substitute or supplement to radar or active-gated laser beam rangefinders for collision avoidance and station-keeping.

Abstract: A device to provide a ship's navigator with information day and night, as to the altitude of celestial bodies on a CRT display with digital display of the altitude and time on the CRT and/or LED read-out.