Abstract: A device and method for receiving a radio signal transmitted over a channel, selecting and deselecting an equalizer, and balancing processing in response to such selection. A radio frequency signal is received from a transmission channel into a receive path, and delay spread in the radio frequency signal is estimated using an analysis circuit. The analysis circuit also determines a threshold delay spread. In the event the estimated delay spread exceeds the threshold delay spread, an equalizer is selected, otherwise the equalizer is deselected. Similarly, in the event the estimated delay spread does not exceed the threshold delay spread, a high complexity processor is selected, otherwise a low complexity processor is selected. If the low complexity processor is selected, an output signal is generated using the low complexity processor, and if the high complexity processor is selected, the output signal is generated using the high complexity processor.

Abstract: A power converter for converting an input signal having an input DC voltage level to an output signal having a desired output DC voltage level. The power converter includes a switching converter having an input which receives the input signal and a floating differential output which includes a first output and a second output. The switching converter is operative to convert the input signal to an offset voltage equal to a difference between the desired output DC voltage level and the input DC voltage level. The offset voltage is generated across the first output and the second output of the floating differential output. The input signal is applied to the second output of the floating differential output to sum the input DC voltage level with the offset voltage and thereby produce the desired output voltage level at the first output.

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: An array of thick flared notch radiators, wherein the separation distance between adjacent pairs of flared notch sticks is set to be less than one-half wavelength at the highest frequency of concern. The separation distance suppresses the propagation of higher order modes along the length of the sticks, which would degrade the array performance. The separation distance is achieved by fabricating the sticks with an increased thickness, thereby reducing the stick-to-stick channel width.

Abstract: A technique for phase-up of array antennas of regularly spaced lattice orientation, without the use of a nearfield or farfield range. The technique uses mutual coupling and/or reflections to provide a signal from one element to its neighbors. This signal provides a reference to allow for elements to be phased with respect to each other. After the first stage of the process is completed, the array is phased-up into, at most, four interleaved lattices. These interleaved lattices are then phased with respect to each other, thus completing the phase-up process.

Abstract: A microwave horn antenna structure including a plurality of planar dielectric insulating layers stacked in laminar fashion so as to have a bottom layer and a top layer, respective similarly shaped conductive trace loops co-axially disposed on a plurality of contiguous ones of the insulating layers and of incrementally increasing size from a lowermost conductive trace loop an uppermost conductive trace loop, and a plurality of conductive vias extending through the planar dielectric layers for electrically interconnecting the respective conductive trace loops. Also disclosed is a flared notch antenna that includes a plurality of planar dielectric insulating layers stacked in laminar fashion, a slanted column of electrically interconnected conductive vias formed in a plurality of contiguous ones of the dielectric insulating layers and a second slanted column of electrically interconnected conductive vias formed in the contiguous ones of the dielectric insulating layers.

Abstract: A self-cooling Stirling cycle cooler (1). The cooler (1) includes a conduit (20) for transporting thermal energy from a first location to a second location. The conduit is a closed loop having first and second ends terminating in a first chamber (29). A pump (14) is mounted in the first chamber (29) for moving the heat energy therein from the first location to the second location. The pump (14) includes a piston (40) which reciprocates in the first chamber (29). A first valve (42) is provided for controlling the direction of a flow of fluid in the conduit (20) into the first chamber (29) and a second valve (46) for controlling the flow of the fluid in the conduit (20) out of the first chamber (29). In a Stirling cycle cooler, the balancer mass is used as the pump piston to facilitate the movement of fluid in the conduit. By utilizing the balancer mass of a Stirling cycle cooler, self-cooling is effected with minimal additional hardware, weight and cost.

Abstract: According to the present invention, light is provided to an elliptical optical surface (102) separating first and second homogeneous optical media (104), (106) that cause collimated light (108) originating in one of the media to be perfectly focussed either at a primary focus within the second medium or at a virtual focus within the first medium (110). For example, a collimated beam (510) is expanded by refraction in an immersion refractive confocal ellipsoid optic (502) having an input optical surface (504) and output optical surface (506). Further, the elliptical optical surface is used in combination with a second optical surface such that both surfaces share a common optic axis and are separated by an optically transmissive medium such as glass and spaced such that the optical focal points of both surfaces are common to create an immersion optical beam expander.

Abstract: A laser resonant cavity employs a dye sheet Q-switch disposed to receive the output of a laser and a Cr.sup.4+ :YAG Q-switch disposed adjacent the dye sheet Q-switch. Disadvantageous aspects of either Q-switch when used alone are eliminated, resulting in higher output energy and overall efficiency. A new Q-switch employing a dye sheet sandwiched between a pair of Cr.sup.4+ :YAG plates is also disclosed.

Abstract: A laser system includes a laser resonator cavity having a resonant axis and a lasing element within the laser resonator cavity. The lasing element emits, under stimulation, light at a wavelength of from about 0.95 to about 1.65 micrometers. There is a flash lamp which optically pumps the lasing element to emit light. A Q-switch crystal lies along the resonant axis within the laser resonator cavity. The Q-switch crystal is formed of a host material having a concentration of Co.sup.2+ ions therein, so as to be a saturable absorber of light of a wavelength of from about 0.95 to about 1.65 micrometers. The Q-switch crystal is preferably Co.sup.2+ -doped yttrium-scandium-gallium garnet or Co.sup.2+ -doped yttrium-aluminum garnet.

Abstract: An imaging system is attached to a satellite, the imaging system includes a transmitting segment which transmits a field of view of photonic radiation to a focal plane array imager. Displacements such as jitter and drift are capable of being applied to the imaging system, which can result in apparent movement of said field of view applied to the focal plane array imager. A stabilizing segment limits the apparent movement of the field of view detected by said focal plane array imager in two orthogonal sensed translational directions, and about a sensed rotary direction.

Abstract: A cryocooler system (20) includes a heat sink (24), such as a Stirling cycle heat engine having a cold cylinder sleeve (26) and a cold gas pocket region (32) within the cold cylinder sleeve (26). An adapter (36) is sealed to the cold cylinder sleeve (26) with a hermetic seal, such as a welded joint (38). A copper cold tip (28) has a first end (34) directly contacting the cold gas pocket region (32) within the cold cylinder sleeve (26). The periphery of the cold tip (28) is welded, preferably by frictional welding, to the adapter (36). The cold tip (28) thereby provides a hermetic seal to the end of the cold cylinder sleeve (26) to retain the working gas within the cold gas pocket region (32) and also to provide an unimpeded heat flow path to the cold gas pocket region (32).

Abstract: A dispersive optical element called a "grism" (50) which has characteristics of both a prism (56) and a grating (62). The grism (50) consists of a prism (56) with a grating (62) disposed adjacent to one surface of the prism (56). Light passing through the grism (50) is dispersed by both the prism (56) and the grating (62). The grating (62) may be attached to either the first or second surface of the prism (56) or may be simply adjacent to the prism (56). The grism (50) has dispersive characteristics such as resolving power that can be optimized in a very flexible manner by choice of both the grating (62) and prism (56) characteristics. For example, the grating (62) may be used to amplify the angular spread introduced by a prism (56). Also different diffractive orders of the grating (62) may be used simultaneously. The result is a device with a very flexible and improved dynamic range of its resolving power, which is particularly useful in applications such as spectrometers.

Abstract: A closed-loop missile tracking system (10) employs a missile (12) with a thermal beacon (22) and an optical beacon (24). A target designator (40) defines a boresight from a missile firing location, such as an aircraft, to a target. The closed-loop missile tracking system (10) employs a first tracker (48) and a second tracker (64) with a forward looking infrared (FLIR) sensor (52) to track the displacement of the optical beacon (22) and thermal beacon (24) from the boresight. The first tracker (48) generates a first set of azimuth and elevation error signals. The second tracker (64) further includes a video demultiplexing interface (70) which transforms serial multiplexed video signals, which are output by the FLIR sensor (52) and contain a field with M rows and L columns of pixels, into a demultiplexed parallel video signal. A video thermal tracker (VTT) (58) selects the N adjacent horizontal rows of pixels and generates a second set of azimuth and elevation error signals therefrom.

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).

Abstract: A Sigma Rho A/D converter (10) includes a transconductance element (R) having an input node for receiving an input voltage signal V.sub.in and an output node providing an analog current I.sub.in ; a charge integrator (12) having an input coupled to the output node, the charge integrator having feedback provided by an integrating capacitor C and an output node providing an output signal V.sub.o ; and a clocked voltage comparator (14) having an input coupled to V.sub.o for comparing V.sub.o to a reference potential. An output of the comparator updates in response to an occurrence of a first clock signal CLK1. A current sink (16) is switchably coupled to the output node of the transconductance element as a function of the logic state of the output of the comparator.

Abstract: A phase shifter that employs digital circuitry to achieve arbitrarily fine phase control of reference signals at frequencies extending to the Gigahertz region. The phase shifter includes a cascade of identical phase shift units that provide progressively finer phase control resolution over a full 360 degree range. The phase precision is set by the number of stages used.

Abstract: A dual frequency antenna and radome system, including a dual frequency antenna system for operation at a first, higher frequency band and at a second lower frequency band. The antenna system includes a first antenna operable at the first frequency band and a second antenna operable at the second frequency band. The first and second antenna systems are orthogonally polarized. A radome is tuned for dual frequency operation, and includes a dielectric wall having a thickness equal to one-half wavelength at a frequency in the first frequency band. The radome further includes a grid of monopole elements formed on a surface of the dielectric wall orthogonal to the first antenna to tune the radome to efficient operation at the second frequency band.

Abstract: A compact scanned antenna which includes a radiator, a rotatable tube and a line source. The radiator is formed by plating a shaped dielectric core. It generates an antenna beam at an output aperture in response to a microwave signal at an input port. The line source generates a radiation sheet which is directed across a signal plane to the input pot. The tube has a cylindrical wall which is positioned across the signal plane. As the tube rotates, refractive or diffractive transmission structures pass through the signal plane. The refractive structures include linear segments which refract the wavefront of the radiation sheet. Because the wavefront slope at the radiator's aperture is a function of the wavefront slope at its input port, the antenna beam is scanned. The linear contour segments have the same inclination but are not colinear. This arrangement reduces the thickness of the tube wall. Phase coherence is achieved by an appropriate radial spacing of adjacent ends of contour segments.

Abstract: A glass fiber laser system includes a laser resonator cavity having a resonant path and an erbium-doped glass fiber lasing element with an output of from about 1.5 to about 1.6 micrometers within the laser resonator cavity. A light source directed into an input end of the glass fiber lasing element optically pumps the lasing element to emit light. A passive Q-switch lies along the resonant path within the laser resonator cavity. The Q-switch is formed of a host material having a concentration of uranium ions therein, so as to be a saturable absorber of the light emitted by the lasing element. The Q-switch is preferably a uranium-doped fluoride crystal such as U:CaF.sub.2, U:SrF.sub.2, or U:BaF.sub.2.