Abstract: The angular and/or spectral bandwidth of a holographic lens assembly can be widened to accomodate highly diverging and/or wide spectral bandwidth illumination sources, respectively. Each lens in the lens assembly is comprised of a plurality of angularly customized holograms (an angularly customized hologram set). Each of the individual holograms in an angularly customized hologram set has an acceptance angle range that is centered on a discrete peak acceptance angle. The separation between the holograms' peak acceptance angles is chosen so that the acceptance angle ranges of the individual holograms overlap. The resulting cumulative acceptance angle range of each angularly customized hologram set provides a holographic lens assembly that has a wider angular bandwidth than prior holographic lenses.

Abstract: Methods and systems for encoding an audio signal into a bit stream, and for recreating the audio signal from the bit stream are disclosed. In an embodiment of an encoder, a first encoder (10) symbolically encodes a substantially vocal audio signal to form a first encoded signal. A second encoder (12) symbolically encodes a substantially nonvocal audio signal to form a second encoded signal. A multiplexer (14) multiplexes the first encoded signal and the second encoded signal to form the bit stream. In an embodiment of a decoder, a demultiplexer (80) extracts an encoded vocal signal and an encoded nonvocal signal from the bit stream. A first decoder (82) forms a decoded vocal signal based upon the encoded vocal signal. A second decoder (84) forms a decoded nonvocal signal based upon the encoded nonvocal signal. A mixer (86) combines the decoded vocal signal with the decoded nonvocal signal to form the audio signal.

Abstract: A diamond matrix metallic mesh suppresses RF energy, and particularly side lobe energy, in a phased array antenna, while passing main beam energy. The metal mesh emulates the structure of the bond segments joining the carbon atoms in a diamond structure. The wire diamond lattice structure is placed above an array of radiating elements to absorb side lobe energy. The wire lattice structure is fabricated through use of complementary forms which compress a wire into a required unit shape. Many unit shaped wires are placed in a form which hold the wires in the proper position. Other unit shaped wires are rotated 90 degrees and attached in place to the held wires. Additional unit shaped wires are added to form the basic interlocking cube structure of the diamond lattice.

Abstract: A light source system (10) for collecting and directing light. The light source system (10) includes light cubes (12) including an enclosure (22) substantially surrounding a light emitter (26). The enclosure includes a body (22) enclosing a cavity (24). A plurality of light pipes (32) are disposed to extend through the body into the interior of the cavity, so that the light pipes (32) carry light from inside to outside the cavity. By utilizing a plurality of these light cubes (12), the intensity of light can be controlled by combining light from a plurality of such light sources into a combiner unit (16) which combines the light from all of these sources into a single path. The intensity of light in the combiner output can be controlled by selectively turning on or off one or more of the light sources. The present invention thereby provides a high intensity light source which is rugged and easy to manufacture at low cost. The modular design provides built in redundancy and light intensity control.

Abstract: An aviator's helmet-mounted display includes a visor/combiner module (14) which is configured for use with an essentially standard aviator's flight helmet (12). The helmet-mounted display also includes a conformal image source and relay optics (ISRO) module (30) which is removably attachable to the aviator's helmet. This ISRO module (30) projects an image inwardly from outside the visor/combiner module through a transparent window portion (44) thereof and out and inner surface (48) of an angulated transparent viewing portion (18,20) of the visor/combiner module (14). The image is focused at infinity and is partially reflected from the inner surface (48) to an eye (50) of the aviator so that the image is superimposed on the aviator's view of an outside scene viewed through the viewing portion (18,20).

Abstract: A method of providing accurate elevation data from three or more complex SAR images. A SAR vehicle is operated to produce a number of SAR images at different grazing angles. The present method provides precise elevation maps derived from the SAR images. In a multiple channel variant of the present invention, more than two antennas collect SAR data from various grazing angles, increasing sensitivity while resolving the ambiguity problem in a mathematically optimum manner. A multiple pass variant of the present invention collects data from more than two passes, and from various grazing angles (interferometric "baselines"). The multiple pass approach and associated processing preserves the high sensitivity of the long-baseline available from dual pass IFSAR while resolving the ambiguity problem in a mathematically optimum manner. Accuracy and ambiguity resolution are improved with each additional pass or channel. The method processes raw SAR data to produce a plurality of complex images therefrom.

Abstract: A surface-emitting laser system includes a laser that emits a vertically divergent beam generally parallel to the substrate on which it is formed, and a turning mirror in the path of the beam that extends up from the substrate to a level well above the laser height. The extended mirror area reflects a greater portion of the beam than prior planar designs, increasing the output efficiency and providing a smoother beam pattern. One fabrication method employs a masking and ion beam milling technique that uses an accumulation of redeposited material to form the additional mirror area, with a thick mask layer that is later removed guiding the redeposition. An alternate fabrication method involves epitaxial growth of an additional layer of material above the conventional laser epilayers, with the additional layer subsequently removed from the laser region but retained in the mirror region.

Abstract: A ceramic sensor comprising a thin film of Cu.sub.x Mn.sub.3-x O.sub.4 is provided that quantitatively measures the partial pressure of CO and hydrocarbon gases in a flowing system. The sensor is specific to both CO and hydrocarbon gases and is negligibly affected by the presence of the common automobile exhaust vapors NO and H.sub.2 O, within the operational temperature range from about 250.degree. to 450.degree. C. The CO/hydrocarbon sensor of the invention has other applications, such as monitoring CO and hydrocarbon levels in laboratories, mines, and industrial smoke stacks, and may be used in environments up to about 700.degree. C.

Abstract: A liquid carbon dioxide dry cleaning system that employs a rotating basket inside a dry cleaning vessel that is powered by hydraulic flow. The present invention is particularly useful as a dry cleaning system that uses liquid carbon dioxide as the cleaning agent. The dry cleaning system has a pressurized vessel containing a liquid carbon dioxide bath. The basket is disposed in the vessel and has a plurality of openings around its periphery. A plurality of roller bearings are disposed between the basket and the vessel that allow it to rotate within the vessel. A plurality of manifolds are disposed between the vessel and the basket that have nozzles that produce jets of liquid carbon dioxide that agitate the garments. The nozzles are aligned with the plurality of openings in the basket. A pump is coupled between the manifolds and the vessel for circulating the liquid carbon dioxide to produce the jets that clean the garments and rotate the basket.

Abstract: Methods and systems for stabilizing satellite spin about an intermediate inertia axis (Z) are disclosed. A set of gyros (22) sense the X component and the Y component of the angular velocity of the satellite body. A single degree of freedom momentum wheel (26) has a fixed transverse orientation with respect to the intermediate axis in order to store momentum. In one embodiment, the momentum wheel (26) is oriented to store momentum parallel to the Y axis. A tachometer (30) senses the rotation rate of the momentum wheel (26). A processor (24) forms a control signal representative of a control torque to be applied to the momentum wheel (26). The control torque is based upon the X component and the Y component of angular velocity of the satellite, and the angular velocity of the momentum wheel (26).

Abstract: A plurality of biphase modulators (42) each modulate a sinusoidal radio frequency signal based upon a corresponding one of a plurality of bits contained in a time-dependent data word. The biphase modulators (42) form a plurality of biphase modulated signals which are communicated to a summing network (40). The summing network (40) contains a plurality of attenuators (44) which attenuate the modulated signals to form a plurality of attenuated signals. The summing network (40) combines the attenuated signals to form a radio frequency signal.

Abstract: Bonding of expanded polymeric parts together to produce lost foam molds suitable for casting metallic details is accomplished by applying a non-aqueous, adhesive-free coating comprising a polar, highly dielectric component contained in a liquid vehicle to the interfacing surface of at least one of the parts to be joined. The interfacing surfaces of the parts to be joined are held in contact while the assembly is irradiated with high frequency electromagnetic energy. This energy enables the coating to dielectrically heat the mated expanded polymeric parts until a bond is effected by melting the polymeric parts and inducing expansion of the parts into one another.

Abstract: A spacecraft includes a spacecraft element, such as a deployable antenna, and a black paint on the spacecraft element. The paint has a composition of 100 parts by weight of a methyl phenyl silicone-based polymer, and from about 1.35 to about 3.5 parts by weight of an electrically conductive carbon pigment having a porous, sponge-like structure. The paint is applied by mixing these constituents with a solvent such as naphtha or xylene in an amount sufficient to permit the paint to be applied by a selected technique such as brushing or spraying.

Abstract: A method of operating a liquid crystal display, and a liquid crystal display constructed to operate in accordance with the method. The liquid crystal display has a plurality of display pixels, and the method comprises the steps of (a) operating a first switch (S1) for storing a charge on a storage capacitance (C1), the charge having a magnitude selected so as to cause a desired degree of polarization of a region (pixel) of liquid crystal material; (b) operating a second switch (S2) so as to conductively couple the stored charge to the region of liquid crystal material, thereby storing a charge on a capacitance (C2) that is associated with the region of liquid crystal material; and (c) operating a third switch (S3) so as to discharge the storage capacitance and the capacitance that is associated with the region of liquid crystal material.

Abstract: An epitaxial structure and method of manufacture for a field-effect transistor capable of low-noise and power applications. Preferably, the epitaxial structure includes an N-type barrier layer comprising a wide-gap semiconductor material having the formula Al.sub.1-y Ga.sub.y P.sub.0.71+z Sb.sub.0.29-z.

Abstract: A micro-dimensional coupling conductor with a shape that is customized for a particular electronic device. A fabrication method is used in which the physical dimensions of the conductor are precisely controlled with photolithographic techniques, resulting in a conductor that is more precisely tuned to the operating frequency of the device. The conductor is fabricated on an SiO.sub.2 substrate using vacuum deposition or electroplating techniques. After fabrication, the conductor is separated from the SiO.sub.2 substrate by dissolving the SiO.sub.2. Alternatively, the conductor may be fabricated on a Teflon.TM. substrate. The use of a Teflon substrate allows a user to remove the conductor from the substrate by applying a small mechanical force to the conductor.

Abstract: A DAC converts a sequence of digital codewords into an approximately piecewise linear analog waveform that follows rising and falling edges between plateau levels. The DAC processes, in parallel, each bit of the codewords to produce component waveforms that are weighted according to their bits significance and summed together to produce the piecewise linear analog waveform. Waveform shaping circuits control the rise and fall times of each component waveform so that the analog waveform's rising and falling edges settle to within a desired error bound of a linear output ramp whose slope is a function of the difference between successive codewords and the rise or fall times. The rise and fall times are preferably approximately the same. Limiting switches control the plateau levels of the component waveforms so that the analog waveform's plateaus settle to within the desired error bound of the ideal values represented by the codewords.

Abstract: A die is disclosed for applying radial force to an eccentric workpiece. The die includes a set of faces that are each inclined from an orthogonal relationship with a different radial plane of the workpiece by an offset angle. The die also includes wedges that are positioned on the faces. They each have a jaw surface and a slide surface that are inclined from a parallel relationship with each other by a wedge angle that equals the offset angle of their respective face. The wedges can move over the faces to abut the workpiece along each of a plurality of transverse planes. In each of these planes, their movement can accommodate the workpiece's eccentricity in that plane. In addition, each jaw surface abuts the workpiece in a tangential relationship.

Abstract: A corona source suitable for use in vehicle ignition systems uses a conductive coil that receives an RF input at one end and has a corona discharge site at the other end, with a reference electrode capacitively coupled to the coil. The pitch and the length of the coil are selected to produce a corona discharge in response to an RF input signal at a predetermined frequency and voltage, through quarter wavelength resonation. Either the new resonant coil or other corona discharge devices can be used to remediate fluid-borne wastes by initiating and sustaining RF corona discharges within the fluid. The pulses used to initiate the corona discharge preferably have alternating positive and negative components, with high initial voltages on the positive components to initiate the discharge, followed by lower positive voltage levels to sustain the discharge. Unipolar pulses, preferably with progressively decreasing voltage levels, can also be used.

Abstract: A high frequency microwave integrated circuit assembly (14,20) includes a fragile monolithic microwave integrated circuit (MMIC) chip (22) mounted in an MMIC subassembly (20) that is completely assembled, tested and burned in independent of the main high frequency microwave integrated circuit assembly and is mechanically attached to the main assembly by a captivation screw (100). The MMIC chip (22) is bonded to an uppermost tier (30) of a multi-tier spaced pedestal (26) and is received within an aperture (46) within a slave board (44) that itself is mounted and bonded to a lower tier (28) of the pedestal (26). The main integrated circuit assembly is formed with a rectangular opening (84) in an upper portion of its substrate to non-rotationally receive the rectangular slave board and a slightly larger internally threaded circular hole (94) in a lower portion of the main assembly substrate that threadedly receive the captivation screw (100).