Abstract: The improved diamond composite (10) exhibits increased oxidation resistance at elevated temperatures, as well as anti-reflective properties. The composite (10) includes a diamond (12), the surfaces (14) of which are protected by an adherent coating (16) consisting essentially of a layer (18) of hafnium carbide adhering and chemically bonded to the diamond (12), a layer (20) of hafnium oxy-carbide adhering and chemically bonded to the hafnium carbide layer (18) and an oxidation-resistant layer (22) of hafnium oxide adhering and chemically bonded to the hafnium oxy-carbide layer (20). Preferably, the coating (16) is sufficiently thin so that it or at least the hafnium oxide layer (22) thereof has about one-quarterwavelength thickness. The method of forming the composite (10) employs sputtering hafnium metal in an argon atmosphere, preferably at about 100.degree.

Abstract: A low noise frequency synthesizer 10 that uses uses frequency dividers 13, 15, at least one of which(divider 15) is incrementable and decrementable in half integer steps, and analog gain compensation in a phase/frequency detector 14 to achieve lower noise, lower spurious levels and faster switching speed than traditional methods of frequency synthesis. The key features of the present invention are its half integer dividers 13, 15 and the ability to adjust the phase detector gain to compensate the loop for varying divide numbers. The synthesizer 10 comprises two dividers 13, 15 that provide two reference frequency signals that are a function of an input signal and an output signal of the synthesizer 10. A voltage controlled oscillator (VCO) 18 provides the output signal (f.sub.O) of the frequency synthesizer 10. A phase/frequency detector 14 compares the reference frequency signals and provides a phase error output signal that drives the VCO 18.

Abstract: A multi-spectral seeker system for detecting radiation in the infrared (IR) band and a plurality of radio frequency (RF) bands suitable for use in a guided missile is disclosed. The IR and RF seekers are coaxially integrated on a single gimbaled platform and share a common aperture without significant performance degradation. In the preferred embodiment, the IR seeker uses a Cassegrainian reflector assembly with surfaces reflective to IR but transparent to RF signals. The first RF seeker uses a resonant dichroic reflector antenna which is transparent to RF signals at frequencies no closer than 0.5 octaves from the dichroic reflector system operating frequency. The second RF seeker may use any suitable RF antenna system although a planar-array of multi-mode spiral antennas or a standard flat plate slotted array are preferred. The second RF seeker may operate in an active, semi-active, or passive mode.

Abstract: A divider synchronization circuit (11) that provides faster settling to a new frequency in a phase-locked loop frequency synthesizer (10) that uses a programmable divider (16) and a phase detector (17). The circuit (11) is adapted to stop the divider (16) while its program is being changed, and then restart the divider (16) on command. The startup time of the divider (16) is automatically adjusted such that the divider output is in phase with a reference input to a phase detector (17). The outputs of the phase detector (17) are also blanked during the time period that the divider (16) is stopped. The circuit (11) reduces the time required for the phase locked-loop frequency synthesizer (10) to settle to its new frequency and phase when the frequency is changed. The timing of the divider startup eliminates the large phase transient that may occur when the divider startup timing is random, thus shortening the time that must be allowed for the synthesizer output to settle to its final phase.

Abstract: A coaxial cable conductor (20) comprises a center conductor (22) having a preselected longitudinal shape and a longitudinally split outer conductor (24). The split outer conductor (24) includes a first partial outer conductor (60) comprising a portion of the circumference of the outer conductor along its longitudinal length and a second partial outer conductor (62) comprising the remaining portion of the circumference of the outer conductor along its longitudinal length and mating with the first partial outer conductor (60) along two joints (64). The two partial outer conductors (60, 62) may be mechanically joined and sealed along the longitudinal joints against leakage of radio frequency energy, as by the application of a conductive coating along the joints. The center conductor (22) is supported within the outer conductor (24) by a plurality of electrically insulating dielectric supports (68), leaving an insulating air gap between the center conductor (22) and the outer conductor (24).

Abstract: An integrated circuit mask artwork generator (10) is disclosed which can define relationships between individual components and which is also independent of the technology chosen. An artwork library database (58) is provided which contains macros each macro being capable of generating artwork for one of the electrical components of the particular technology type. A device generator (18) is provided for defining the type of circuit to be executed and for executing the macro for that circuit independent of the component's particular technology type. A means for defining relationships between the circuits (16) is provided with the relationships specified desirable physical relationships between sets of related circuit components. In conjunction with the schematic this provides a schematic with relationship annotations (14).

Abstract: A control fin actuator (28) for a guided missile (20) includes a pressure actuator (40) having a slidable piston (44) inside a housing (42). Rolling diaphragm seals (50, 56) of the top piston face (46) and the bottom piston face (48) to the inside wall of the housing (42) divide the interior of the housing (42) into at least two chambers (54, 58). The rolling diaphragm seals (50, 56) eliminate sliding friction as the piston (44) moves within the housing. The two chambers (54, 58) are controllably pressurized to slide the piston (44) within the housing (42), thereby moving a push rod (78) attached to the piston (44) and extending out of the housing (42). The push rod (78) is connected to a missile control fin output shaft (24) by a taut band connector (80) that avoids backlash. A magnet (86) may be positioned adjacent to the push rod (78) to induce eddy currents in the push rod (78), thereby providing a damping force that increases with increasing rate of movement.

Abstract: A method and circuit for measuring direct and high duty factor current in a conductor (1) with minimal interference with the operation of a monitored circuit. Current flow in the conductor is magnetically sensed with a transformer T1 having a primary winding connected electrically in series with the conductor (1). The transformer T1 is driven into saturation during a first time interval and brought out of saturation during a second time interval. After the transformer T1 is brought out of saturation, an output signal is provided which is proportional to the flow of current in the conductor (1).

Abstract: A fixture for performing tensile tests on advanced materials at extremely high temperatures (greater than 2500 degrees fahrenheit). The fixture allows gripping a specimen without introducing thermal gradient in the specimen. It incorporates a self aligning feature while avoiding thermal stress problems inherent in using different materials at elevated temperatures.

Abstract: A missile (20) comprises a missile body (22) and a plurality of (typically four) body flaps (28) located around the circumference of the missile body (22). Each body flap (28) is independently pivotable to an extended position wherein the body flap (28) is pivoted outwardly from a pivot axis along the leading edge (34) of the body flap (28). The forward edge (34) of the body flap (28) is displaced outwardly from the body (22) of the missile (20) by a distance no less than a boundary layer thickness of the body (22) of the missile (22) at the maximum operating speed and altitude of the missile (20), and preferably about the boundary layer thickness, which thickness typically is about 1-3 inches for a high-velocity missile.

Abstract: A bidirectional optical fiber (12) amplifier suitable for use in a dual payout fiber-optic communication link (10) is disclosed herein. The inventive amplifier (12) is typically encasted in a shell or service loop, and is preferably connected between first and second optical fiber segments (18 and 20). The amplifier (12) includes a pump laser (102) for generating optical energy of a first wavelength. A wavelength selective optical coupler (82), in optical communication with the first fiber segment (18) and the pump laser (102), combines optical energy propagating through the first fiber segment (18) with the optical output of the pump laser (102). The amplifier (12) of the present invention further includes a doped optical fiber (114), optically connected between the wavelength selective optical coupler (82) and the second optical fiber segment (20), for amplifying optical energy within a predetermined wavelength spectrum passing therethrough.

Abstract: A multiple field of view sensor lens assembly suitable for inclusion in an infrared imaging system. The lens assembly includes a rotatable telescope 10 for providing first and second fields of view for the sensor, the first field of view being along a first axis thereof L and the second field of view being along a separate second axis T. A servo mechanism 30 is included for rotating the telescope 10 from a first orientation at which the first axis is aligned with the optical axis to a second orientation at which the second axis is aligned with the optical axis. In a preferred embodiment the inventive lens assembly is disposed to provide fields of view in opposing directions along the first axis L, and a third field along the second axis T.

Abstract: A gimbal mount for mounting a seeker for a large look angle comprises a base support frame for attachment to an airframe, a roll axis frame having a base and a pair of spaced apart forwardly positioned gimbal supports mounted for rotation about the roll axis of the frame, a pitch gimbal ring pivotally mounted on the roll axis frame for pivoting about a pitch axis, a yaw gimbal frame pivotally mounted for pivoting about a yaw axis on the pitch gimbal, a pitch drive motor and a yaw drive motor coaxially mounted directly on and coaxial of the roll axis frame, and a drive cable connecting the respective motors to the respective gimbals.

Abstract: A circuit arrangement to convert high voltage direct current energy into radio frequency energy that includes photoconductive switch means which is periodically closed by a pulsed light source, such as a laser, to generate the radio frequency energy. A segmented transmission line which includes a plurality of photoconductive switches positioned a half-wavelength apart that are closed simultaneously by the laser may be used to generate the radio frequency energy. The photoconductive switches may also be connected in parallel and closed by time delayed light pulses to generate the radio frequency energy. The pulses generated may also be used to excite a resonator circuit coupled to a load to increase the duration of the high frequency oscillation and to shape (filter) the resultant waveform. Other configurations utilizing photoconductive semiconductor discs and annular metal electrode configurations which may be closed by light pulses are also illustrated.

Abstract: A technique and apparatus for rearward launch of a missile. The inventive apparatus (10) includes a launch tube (12) in which the missile (14) is mounted with the forward end of the missile being mounted at the forward end (16) of the tube. The rearward end of the launch tube is sealed with a break-away material (18) prior to expulsion of the missile (14). An expulsion mechanism expels the missile in a rearward direction from the launch tube. The expulsion mechanism includes an airbag (20) and a pressurization mechanism (30). The airbag (20) includes a bra (22) for maintaining the orientation of the missile (14) during the expulsion thereof. The airbag (20) also includes a metallized enclosure (24) for sealing the launch tube (14) after the expulsion of the missile (14).

Abstract: Method and apparatus for making a filament winding amenable to inside payout and having squared-off ends providing optimal volumetric efficiency. The filament crossovers are distributed so as to reduce crossover stacking in one or a few places which can interfere with winding and payout from the finished winding. A base wire layer is wrapped onto a mandrel over which a guide is nestingly wound with adjacent guide wire turns spaced apart. The filament first layer is wound nesting in the guide wire spaces, and subsequent filament layers accordingly formed. Each crossing filament turn has an advance in a crossing region substantially aligned with a crossover region in the underlying layer and which in one embodiment is one-half the winding pitch.

Abstract: A method and apparatus for providing a switchable electromagnetic interference (EMI) barrier. The method protects an object against electromagnetic radiation, through the steps of: providing an object to be protected from electromagnetic radiation; placing a barrier sheet adjacent to the object, the sheet being opaque to radiation when exposed to light; directing the light against the sheet when a barrier to the radiation is desired; and extinguishing the light when passage of the radiation through the sheet is desired. One embodiment is a switchable electromagnetic radiation barrier system that includes a photoresistive sheet interposed between a source of electromagnetic radiation and an object to be protected from the radiation. This sheet is opaque to the radiation when exposed to light of a selected visible intensity range. A light source adjacent to this sheet directs the light against the sheet.

Abstract: In accordance with the teachings of the present invention, an enhanced performance opto-electric modulator (30 or 70) is provided herein which compensates for phase velocity mismatches between optical modulation and an RF electric signal. The modulator (30) includes an optical waveguide (38, 40) formed in a substrate (32) and coupled to an optical input (56). An RF waveguide (46, 48) is formed on the substrate (32) for applying an electric field (59) to a modulation region (50) adjacent the optical waveguide so as to modulate an optical signal. The substrate (32) has a ferroelectric domain which includes periodically inverted and non-inverted regions (54) and (52) which compensate for phase differences within the modulation region (50). In a preferred embodiment, the optical waveguide includes two substantially parallel optical waveguides (38) and (40) which have outputs combined to provide for an amplitude modulated (AM) optical output signal (60).

Abstract: A gimbal (22) with three critical dimensions is prepared by separately fabricating three components of the gimbal (22), and then joining the components on tooling. The steps of the method include fabricating a base ring platform (50) while maintaining a platform height critical dimension, and fabricating two brackets (56), while maintaining the bracket pivot bore height as a critical dimension. The gimbal (22) is completed by assembling the base ring platform (50) and the two brackets (56) on a tool base with an arbor extending between the pivot bores (26) on the brackets (56), while maintaining a bracket separation critical dimension, and rigidly fixing the two brackets (56) to the base ring platform (50) with locating pins (64). Three critical gimbal dimensions are thereby obtained, while reducing the cost and complexity of fabrication.

Abstract: The diameter of an optical fiber (36) moving past a measurement apparatus (20) is evaluated in a time of less than about 50 microseconds, permitting closely spaced individual measurements along the length of the optical fiber (36). The measurement apparatus (20) includes a number of discrete, stationary light sensors (22) arranged in a linear array (24), a light source (28) positioned to shine a beam of light (34) into the sensors (22) of the array (24), and a lens (38) that directs an enlarged image of the optical fiber (36) onto the array (24) of light sensors (22). The light sensors (22) each produce an output signal (26) responsive to the intensity of light reaching the sensor (22). The number of light sensors (22) having a signal below a threshold value at a selected moment is counted as a measure of the diameter of the portion of optical fiber (36) then lying between the light source (28) and the array of optical sensors (22).