Abstract: A thermally conductive wedgelock having improved thermal conductivity is used to secure a circuit card assembly in a card guide slot formed in a housing of an electronics package. The circuit card assembly has a thermal mounting plate that is used to secure the assembly in the slot. The thermally conductive wedgelock secures the circuit card assembly in the housing and conductively couples heat from the circuit card assembly to the housing by way of the card guide slot. The wedgelock provides a secondary heat path to the card guide slot to housing in addition to the primary heat path through the thermal mounting plate. Apparatus is provide for expanding the wedgelock in the card guide slot to secure the circuit card assembly therein. The thermally conductive wedgelock may be made of copper or other metal having high thermal conductivity. The wedgelock preferably comprises two tapered wedges, and has a guide that prevents rotation between the adjacent wedges.

Abstract: A low voltage analog front end (AFE) includes a differential transistor pair which converts an input voltage, typically A.C.-coupled to the pair's control inputs, to a differential current. Impedance networks connected to each transistor's control input are joined together at a common node, and a current source is connected to the node which causes DC bias currents to be mirrored through the pair's current circuits, so that the AFE's differential output current comprises a differential current produced by the pair in response to an input voltage and superimposed on the DC bias currents. The current source preferably generates mirrored currents which are larger than its reference current to linearize the pair's response and to provide the AFE with a wide dynamic range. An input to the AFE sees a low impedance which is about equal to the sum of the impedance networks, which can be resistive or complex as needed.

Abstract: A current steering circuit diverts bias current from a differential current summing amplifier's front end when the differential input exceeds a safe threshold level, thus preventing the amplifier's output stage from being overdriven. Diverting the front end's bias currents also turns off transistors within the amplifier's front end and thus protects the front end from damage which may otherwise result from excessive input signals.

Abstract: Mixer structures are described which include a current mirror for insertion of trickle currents to an input differential amplifier and an output interface for coupling an output differential amplifier to an output port. The current mirror trickle currents improve the mixer's conversion gain and third-order intercept point and the current mirror introduces them without introducing spurious signals. The output interface couples mixer currents to the output port while isolating the output port from power-supply spurious signals.

Abstract: An amplifier includes an amplifying circuit and bias current circuit. The bias current circuit includes a beta matching circuit which employs a temperature compensated current reference to develop a bias current for the amplifying circuit. The beta matching circuit is connected to track the current gains of transistors within the amplifying circuit and to thereby provide a temperature compensated bias current to the amplifying circuit. The bias current maintains a fixed bias point regardless of temperature-induced, or other, variations of the current gains of the amplifying circuit's transistors.

Abstract: A cleaning system and method utilizing sonic whistle agitation to enhance the soil removal and mass transport capacity of the liquid carbon dioxide at low process temperatures. Sonic whistles are within a cleaning chamber, and liquid carbon dioxide is forced out of the sonic whistle jets to ultrasonically emulsify and disperse non-miscible liquids or insoluble solids, such as remove low solubility oils and greases, in the liquid carbon dioxide contained in the cleaning chamber. Cleaning is accomplished at temperatures between -68.degree. F. and 88.degree. F., and the temperature of the liquid carbon dioxide is typically below 32.degree. F.

Abstract: A multiple terminal selector switch for use with millimeter-wave signals has a layout of components enabling the switch to be constructed on a monolithic microwave integrated circuit (MMIC) chip while maintaining adequately low cross talk among ports of the switch to retain isolation among its ports. The circuitry includes a transmission line having multiple taps spaced apart by an integral number of half wavelengths of the signal, wherein the taps connect to separate ports via arms of the circuit. Each arm has an electronically switchable element for producing open or short circuits for connection and disconnection of a switch port from the transmission line. One primary tap of the transmission line is unswitched and connects with a further port from which, or to which, signals of the other ports are selectively switched.

Abstract: A low-noise, low-distortion clamping scheme includes a bootstrapped voltage clamp and an R.sub.gm current clamp that provide superior overdrive protection when used together in a Class-AB feedback amplifier. The bootstrapped voltage clamp includes a transistor that is connected to a circuit node to be clamped. The transistor's base is bootstrapped to the node to maintain a constant V.sub.be when not clamping, to reduce the adverse effects of the junction capacitance C.sub.je which would normally vary with the node voltage and distort the signal at the node. Two such clamps provide positive and negative voltage limiting. The R.sub.gm current clamp is used in the input stage of a Class-AB feedback amplifier to limit the current through the resistor R.sub.gm that interconnects the current inputs of two transconductance amplifiers whenever the voltage drop across R.sub.gm increases to an unacceptable level.

Abstract: A system and method that covertly provides in-flight target update data to a large number of missiles. The system and method covertly guides the missiles using a transponder located on a satellite that relays encoded target update data to receivers located on each of the missiles. The target update data is derived from intelligence data acquired by a remote sensing device. The target update data is typically transmitted to the missile launch site where it is encoded and transmitted to the transponder on the satellite. The encoding is preferably accomplished using direct sequence spread spectrum/code division multiple access (CDMA) encoding produced using unique seeds that are supplied to pseudo random code generators that uniquely encode the data to be transmitted to each missile. The receivers on each of the missiles have pseudo random code generators that are loaded with the unique seeds.

Abstract: A missile having an improved dome mounting arrangement, and a method for mounting a sapphire dome to a titanium missile turret that provides for minimum surface deformation and environmental sealing of the dome. A sealing material such as silicone rubber compound that is capable of enduring high temperatures attained during high speed missile flight is employed. The missile has a body with a nose and the dome mounting arrangement is attached to the nose. The dome mounting arrangement comprises a turret secured to the nose, the dome, and a retainer ring attached to the turret for securing the dome to the turret. An annular gap is formed between an outer surface of the dome and an inner surface of the retainer ring. The silicone rubber compound is disposed in the annular gap and cured to seal the dome. A plurality of shims may be disposed between the dome and the turret in a radial gap formed therebetween.

Abstract: A composite sensor includes at least one layer comprising a piezoelectric material such as a molecularly poled polymer material or a ceramic material having disposed therebetween a material which enhances the piezoelectric properties of the piezoelectric material. One pair of edges of said composite sensor are constrained from expanding in response to a force applied to the sensor.

Abstract: A rotary connector that transfers electrical power and signals using conductive metallic balls confined by a nonmetallic spacer and conductive conduits that are formed on two opposed metal-backed printed wiring boards. The rotary connector transfers electrical signals and power from a stationary printed wiring board to a moving printed wiring board by way of the conductive balls disposed in some or all openings of the conductive conduits. Nonconductive balls may be used in some of the openings. The use of a relatively large number of balls disposed in the openings of the nonmetallic spacer mechanically balance the connector. The connector is sealed and its interior contains nonconductive lubricant to lubricate the balls and conduits.

Abstract: Low-cost composite infrared windows that are transparent to long wave infrared radiation (8-12 microns) that provide sufficient strength and impact resistance for automotive-type environments, and the like. The windows may be used with night vision systems for automobiles, surveillance imaging systems, and other applications requiring low cost, long wave infrared windows. In one embodiment, the composite infrared window is a sandwich comprised of a polyethylene plastic film bonded with an acrylic adhesive to a relatively thin (0.015-0.040 inch) silicon substrate. The thin silicon substrate is mechanically stiff and low cost, and transmits in the 8-12 micron bandpass. The thin (0.001-0.007 inch) plastic film provides an exterior particle impact absorbing layer sufficient to enable the use of the window in automotive applications.

Abstract: A guidance system (30) for a missile comprising a sensor (20) mounted on the missile and having a fixed line-of-sight relative thereto. The body fixed sensor (20) provides a first signal representing frames of image data. A processor (40) identifies a target in the frames of image data and provides a second signal representative of the location of the centroid thereof. A conventional tracker (36) follows the target and provides a third signal representative of an aim point of the missile. A controller (44) then changes the velocity vector of the missile in response to the second and third signals. In a specific embodiment, the body fixed sensor (20) provides first and second frames of image data. The system (32, 34) subtracts the first and second frames of image data and ascertains a growth center of the target. The processor (40) compares the image growth center to the aim point and provides an error signal in response thereto.

Abstract: A wide angle large reflective unobscured system includes a primary reflective element for receiving a broad range of energy, a secondary reflective element for reflecting the energy from the primary reflective element to reimage a virtual entrance pupil at a real aperture stop. A beamsplitter element is provided for reflecting a first portion of the energy, such as visible energy, to a first tertiary reflective mirror, while transmitting a second portion of the energy, such as IR light, to a second tertiary reflector. Each tertiary reflector is capable of focusing the received energies to dual focal planes wherein a compact detector array assembly can convert the images to electronic signals.

Abstract: Optical apparatus that combines a plurality of separate optical functions into a single monolithic optical element. The the optical element comprises two or three optical functions, such as saturable absorption, retroreflection, and polarization rotation. The optical element comprises a body that is formed in the shape of a right-angle porro prism. The optical element is fabricated from a garnet material that combines the properties of high refractive index (greater than 1.414 to permit total internal reflection at a 45 degree incidence angle), saturable optical absorption (to provide Q-switching), and tolerance to high temperatures (to permit application of anti-reflection coatings). The optical element may be comprised of garnet materials such as yttrium aluminum garnet, gadolinium scandium gallium garnet, or gadolinium scandium aluminum garnet, for example. Doping the garnet materials with tetravalent chromium (Cr.sup.

Abstract: Apparatus and a method for generating a digital synthesized Gaussian noise-like waveform that may be used to modulate and demodulate communication data. The present invention uses a seed input that addresses a read only memory look-up table, for example, containing digital samples having Gaussian statistics. A sequence generator generates a pair of pseudo-random sequences in response to the seed input that address the read only memory to look up and output a pair of pseudo-random Gaussian samples that are used to generate the Gaussian noise-like waveform. A processor converts the pair of pseudo-random Gaussian samples into corresponding analog I and Q signals, and a modulator 33 modulates the analog I and Q signals to generate a modulated output signal having the Gaussian noise-like waveform.

Abstract: An electronic substrate is formed of a porous planar heat exchanger and an orifice plate overlying and thermally contacting the heat exchanger. The orifice plate has a plurality of apertures therethrough. An electronic device is mounted to the orifice plate. A coolant such as air or other gas is forced through the heat exchanger and the apertures of the orifice plate to remove heat that is generated by the electronic device. Preferably, at least two of the assemblies formed of the substrate and the mounted electronic device are mounted in a facing relationship to form a multichip module. A housing is provided to support the assemblies and to channel the flow of coolant through the substrates. Electrical interconnection between the components is provided by a peripheral ring with electrically conducting paths therethrough, which ring extends between the facing substrates.

Abstract: Safety discharge circuit and method, capable of protecting workers from electric shocks during maintenance of high voltage electrical systems. A high voltage electrical system is placed inside a grounded box having a cover, releasably connected to the box. The circuit uses an electronic device adapted to sense the removal of the cover from the box and disable the high voltage electrical system. The electronic device is connected to the cover at its input and to the high voltage electrical system at its output, and is preferably a semiconductor controlled rectifier having a gate at its input. The semiconductor controlled rectifier is in a reverse blocking state when the cover is connected to the box, and is latched in a forward conducting state when the cover is removed from the box. The connection from the gate of the semiconductor controlled rectifier to the cover is made through mounting screws, which hold the high voltage electrical system connected to the cover.

Abstract: A solid-state power processor circuit and method is used to supply power to generate a discharge in a corona discharge pollutant destruction apparatus. The circuit uses field effect transistors (FETs) and integrated circuit devices based upon metal oxide semiconductor field effect transistor (MOSFET) technology to amplify low-voltage pulse signals to high voltage levels. A resonator in the power processor circuit generates sinusoidal oscillation from the high voltage pulses, and provides the high-voltage, high-frequency electrical power necessary for corona discharge.