Abstract: An assembly of simultaneously transmitted electrically generated signals is disclosed, which contains a subset of binary spreading-code sequences that are members of a larger set of binary spreading-code sequences available to a particular node of a multi-node communication network. All sequences in the set of spreading-code sequences available to the particular node of the network can be generated by the same configuration of two linear-feedback binary shift registers, where feedback taps of the two linear-feedback binary shift registers correspond to primative polynomials of the same degree over GF(2), the field of two elements.

Abstract: A photoconductive detector (3) comprises a single continuous photoconductive strip consisting of two interleaved photoconductive spiral paths (1, 2) separated by much thinner gaps (5, 6). The two spiral paths (1, 2) have the same central point (19). The detector (3) is substantially planar and has the overall shape of roughly a circle (10). A circular band (4) of incident radiation (16) crosses the gaps (5, 6) in a nearly parallel fashion, rather than nearly perpendicularly as in the prior art, lessening unwanted modulations of the detected signal. The terminal (11) to terminal (12) resistance of the detector (3) is increased to the point where, when the photodetector (3) is made of the preferred HgCdTe, simple thermo-electric coolers are sufficient to enable use of the detector (3) as an infrared detector (3) in a heat-seeking missile (17).

Abstract: An adaptive beamformer and signal processor for sonar and other signal receptor arrays, in which beamforming is accomplished by correlation feedback loops providing matched weighting across the array. To constrain the adaptive beamformer thus comprised against cancellation of useful signals from a particular angular region, which normally is the beam mainlobe or boresight region, one or more spatial notch filters are interposed within the correlation feedback loops for preventing signal suppression within such angular region.

Abstract: An intermediate frequency sidelobe canceller of the kind including a cancellation loop and switch means for sampling and holding correlation weights present in the loop, affording enhanced cancellation and reduced loop lock-on time. This capability is achieved by provision of means for control of the sample-hold switch means so as to limit duration of the sampling interval to an optimum value substantially shorter than the loop stabilization time. Such shorter sampling interval may be either of fixed duration or adaptively controlled in response to one or more loop operating parameters.

Abstract: A built-in-test capability is provided for determining the integrity of an optical fiber connecting: (a) an optical firing unit having a primary light source emitting a first wavelength, a test light source emitting a second wavelength different from the first wavelength, a mechanism both for coupling light from the light sources to the optical fiber and also for coupling the return light to a filter/detector; and (b) an optically initiated device which is coupled to a second end of the optical fiber. The apparatus includes a photoluminescent material disposed at a junction of the optically initiated device and the optical-fiber-second-end. This photoluminescence material photoluminesces at a third wavelength (when exposed to the test light source), and the light travels through the optical fiber and, when detected indicates optical fiber continuity.

Abstract: Design forms are disclosed for infrared imaging systems that can operate at hyper-hemispherical fields of view (e.g., up to 270.degree.) and at wide relative apertures (e.g., up to f/0.7) to produce images having low distortion--typically no more than 20% greater than the distortion resulting when the image size is proportional to the field angle.

Abstract: To develop a design form for a Cassegrain-type telescope with spherical primary and secondary mirrors, which is well-corrected for chromatic aberration as well as for geometrical aberrations including spherical aberration, coma and astigmatism, the designer begins with a "starting design form" for a conventional Cassegrain-type telescope with spherical primary and secondary mirrors, and then modifies the "starting design form" by:(a) positioning lens elements of a corrector lens group along an optic axis inside the front focal plane of the spherical primary mirror, where the lens elements of the corrector lens group are made of optical materials that enable a desired degree of correction for chromatic aberration to be achieved;(b) providing a reflective coating on a central portion of the back surface of the rear-most lens element of the corrector lens group, which replaces the secondary mirror of the "starting design form" and becomes the secondary mirror of the telescope;(c) locating the entrance pupil of t

Abstract: In an optical system comprising a pair of rigid (e.g., glass) lens elements 11 and 12 mounted coaxially within a hollow cylindrical housing 10 so as to define a gap therebetween, a liquid (which functions as a liquid lens element 13) is contained within the gap. The rigid lens elements 11 and 12 are bonded to corresponding interior surface portions of the cylindrical housing 10 by means of an adhesive material that also functions as a sealant to prevent leakage of liquid from the gap. The adhesive sealant material preferably consists of a fluorosilicone sealant marketed by Dow Corning Corporation of Midland, Mich. under the trademark DOW CORNING X5-8738.

Abstract: Design forms are disclosed for 5X and 10X laser beam expanders whose lens elements consist only of plastic and liquid optical materials, which provide diffraction-limited performance without refocussing over a wavelength range from 0.4 micron to 0.8 micron.

Abstract: A method and apparatus for electrically generating sets of binary spreading-code sequences for use in a multi-node communication network are disclosed. A method for assigning disjoint sets of binary spreading-code sequences to different nodes of such a network is also disclosed. Each set of binary spreading-code sequences consists of multiple sequences, which are generated using two binary shift registers. The sequences can be generated simultaneously, or sequence segments can be generated sequentially. To generate sequences simultaneously, the contents of multiple pairs of stages of two linear-feedback binary shift registers are combined by modulo-2 addition, where each pair of stages consists of one stage from each of the two binary shift registers.

Abstract: In a lens assembly for a telescope objective that comprises liquid lens elements contained between adjacent glass lens elements, each glass lens element is adhesively bonded to an interior surface of a corresponding cylindrical mounting ring by a sealant that is impervious to the liquid lens elements. The sealant is a proprietary fluorosilicone compound marketed as "DOW CORNING X5-8738". The cylindrical mounting rings (with the corresponding glass lens elements bonded thereto) are coaxially aligned so that planar end surfaces of adjacent mounting rings adjoin each other. Compressible O-rings made of Viton.RTM. are received in annular grooves formed on one end surface of each pair of adjoining end surfaces of adjacent mounting rings. Adjacent mounting rings are secured to each other to provide three-point mounting contact between adjacent mounting rings so as to obtain precise axial alignment of the glass lens elements.

Abstract: Design forms are disclosed for wide-field infrared imaging systems characterized by a large ratio of entrance aperture to focal length, where the limiting aperture stop is located in the converging image space.

Abstract: In an optical system comprising a pair of rigid (e.g., glass) lens elements 11 and 12 mounted coaxially within a hollow cylindrical housing 10 so as to define a gap therebetween, a liquid (which functions as a liquid lens element 13) is contained within the gap. The rigid lens elements 11 and 12 are bonded to corresponding interior surface portions of the cylindrical housing 10 by means of an adhesive material that also functions as a sealant to prevent leakage of liquid from the gap. The adhesive sealant material preferably consists of a fluorosilicone sealant marketed by Dow Corning Corporation of Midland, Mich. under the trademark DOW CORNING X5-8738.

Abstract: A large aperture microlens array assembly has at least two arrays of microlenses with individual unit cell trains optically interconnecting individual microlenses in one array with related individual microlenses in another array. In each unit cell train the light entering an entrance pupil of a microlens in one array is transmitted through the exit surface of a related microlens of the other array to provide a collimated output through the exit. One array may be moved with respect to the other array for scanning a field of regard.

Abstract: Design forms are disclosed for 5.times. and 10.times. laser beam expanders whose lens elements consist of glass and liquid optical materials, which provide diffraction-limited performance without refocussing over a wavelength range from 0.4 micron to 0.8 micron.

Abstract: Design forms are disclosed for 5X and 10X laser beam expanders whose lens elements consist only of plastic and liquid optical materials, which provide diffraction-limited performance without refocussing over a wavelength range from 0.4 micron to 0.8 micron.

Abstract: Integrally formed grid structures made of composite graphite-epoxy material are disclosed in which graphite fibers extend three-dimensionally in at least three different directions.

Abstract: A grid structure with sinuous interstices comprises intersecting grid sections having undulate surfaces. The intersecting grid sections of the grid structure are made of a composite material consisting of fibers (e.g., graphite fibers) embedded in a matrix (e.g., epoxy resin).

Abstract: A path analyzer for determining if a specified path is blocked by a given solid obstacle in three dimensional space. A programmable comparator converts path endpoints into first and second map signals, wherein each map signal indicates whether the corresponding path endpoint's position on predefined X, Y and Z coordinate axes is above, below or within a range of coordinate values associated with a specified obstacle. The specified obstacle is modelled as a rectangular parallelepiped, regardless of the actual shape of the obstacle. A first high speed decoder uses these map signals to make an initial determination as to whether the specified path is blocked, not blocked, or may be blocked by the specified obstacle. Whenever the first decoder determines that the path may be blocked, a second decoder determines the minimum number of additional computations needed to resolve whether the specified path is blocked.

Abstract: Optimized design forms are provided for glass-liquid lens triplets for use as telescope objectives having reduced secondary spectrum. Each lens triplet comprises an abnormal-dispersion liquid lens element contained between two normal-dispersion glass lens elements. The glass lens elements are made of readily available and relatively inexpensive optical glasses. The liquid lens element in each lens triplet consists of a commercially available viscous supercooled liquid of abnormal dispersion, which is transparent to optical radiation at visible wavelengths without freezing at temperatures in a range from about -50.degree. C. to about 50.degree. C.