Abstract: 4800 B/S full duplex operation of a frequency-multiplexing modem over the switched telephone network without cancellation is made possible by combining 900-baud, 32-state operation with a combination of analog filtering and raised cosine digital filtering and stop bit robbing.

Abstract: In a switchable impedance tester for measuring very small impedances, the effect of switch impedances is eliminated by connecting the test load between two switching transistors in their emitter-collector circuit, and driving them with operational amplifiers arranged to urge their inputs into equality. A test voltage source is connected across first inputs of the amplifiers, and the other inputs are connected between the respective transistors and the load. This produces an operational condition in which the voltage across the load is independent of the parameters of the switching transistors, i.e. the switching transistors appear to have zero impedance.

Abstract: Edge definition in FLIR images is improved by assigning to each pixel (X) the average intensity value of that 3.times.3 pixel sub-matrix (30a-30i) containing the pixel (X) which exhibits the smallest edge value. Apparatus for obtaining that intensity value in real time is disclosed. This process can be iteratively repeated on the same image, with each iteration creating more enhanced edges and greater area smoothing between edges.

Abstract: A cascadable seventeen-bit self-testing comparator (20) is produced on a twenty-four pin GAL.RTM. 39V18 generic array logic chip by so interconnecting the data pins (1-17) with the logic macro cells (24a-h, 26a-i), and configuring the macro cells, that any data applied to the pins is registered in the macro cells (24a-h, 26a-i) upon pulsing the clock (35), and any exact coincidence of subsequent data with the registered data causes one of the macro cells (26j) to generate a match-indicating output (61).

Abstract: The efficiency of a metal silicide infrared detector (10) in greatly enhanced by depositing on the substrate (14) a stack (30) of alternating metal silicide (12,24) and silicon layers (22). The metal silicide layers (12,24) are connected to each other and to a contact pad (20) in the substrate (14) by a metal silicide deposit (32) on one side of the stack (30) and the silicon layers (22) are connected to each other and to the substrate (14) by a silicon deposit (34) on another side of the stack (30). The stacking of layers is made possible by depositing the silicon layers (22) at a rate of 1 .ANG./sec or less in a vacuum of 10.sup.-9 torr or better at a temperature of about 250.degree. C.

Abstract: Process for increasing the density of an article. A coating containing boron nitride and carbon is applied to the article to form a coated article. The coated article is encapsulated. The encapsulated article is subjected to hot isostatic pressing. The coating reduces interaction between the article and the encapsulant during the hot isostatic pressing. The carbon is present in the coating in an amount up to about 30% by weight of the total boron nitride and carbon in said coating.

Abstract: A superior release coating for glass-encapsulated ceramic or ceramic composite bodies in hot isostatic pressing processes is obtained by mixing boron nitride with up to about 30% by weight of carbon.

Abstract: The angle of divergence of a laser beam (29) is controlled without significant variation of beam power by using a movable corner cube (18) to vary the length of the optical path of a noncollimated beam (12) so as to present a beam of varying diameter to a telescope lens (26). In a second aspect of the invention, the beam is made insensitive to vibration of the corner cube (18) by covering a portion of its beam-receiving face with a second reflector (32) which causes the beam to make a second pass through the corner cube (18) in a parallel but opposite direction therey cancelling any beam displacement caused by the vibration of the corner cube (18).

Abstract: The electronic simplicity of a rotating-telescope target acquisition device and the noise immunity and wide field of view of a non-rotating array device are combined in an assembly (10) using a rotating refractory telescope (21) on a gimbaled platform (28), and a combination reticle (38) and detector (34) on the same platform (28). The detector (34) is segmented (50) to detect the direction in which a target is substantially off the telescope's optical axis (32), and the detector (34) is also shielded (35) against any radiation coming from outside the optical path of the telescope (21). The reticle (38) also serves as the electrical connection (42,62) between the detector segments (40,50) and the contact pads (44,64) on the detector plate (36).

Abstract: The manufacture of monolithic HgCdTe detectors and Si circuitry in an IR focal plane array is achieved by forming a protective layer of SiO.sub.2 or SiN.sub.x on a silicon wafer containing silicon circuits, etching steep-wall recesses into the wafer, selectively depositing epitaxial single-crystal layers of GaAs, CdTe, and HgCdTe in the recesses fabricating HgCdTe IR arrays, and depositing appropriate insulating and conductive interconnection patterns to interconnect the Si devices with one another and the HgCdTe devices with the Si devices. Little or no GaAs, CdTe, and HgCdTe grows on the SiO.sub.2 or SiN.sub.x outside the recesses. Since material grown outside the recess is polycrystalline, it is easily chemomechanically removed.

Abstract: The encapsulation of ceramic preforms (10) for HIP processing is considerably simplified, and the use of standard laboratory glassware as encapsulation material is made possible, by placing non-sealed glass capsule parts (12, 14) around the preform (10) in the HIP pressure vessel (18), evacuating the vessel (18), heating the vessel (18) to a temperature at which the glass parts (12, 14) fuse together but do not collapse, and then pressurizing the vessel (18) and increasing the temperature therein as required for conventional HIP processing.

Abstract: A novel packaging system for VLSI circuits allows low-cost construction and maintenance of complex high density high-performance devices with low power requirements. The devices can be individually created by software means from a small selection of standardizable IC chips by disposing a plurality of chips in leadless chip carriers in a mosaic on a substrate, and configuring them by software to selectively communicate with other chips of the mosaic or even to individually change their operating function. The immediate juxtaposition of the chip carriers in the mosaic eliminates transmission line data skew, and also allows considerable savings in chip space and power requirements by dispensing with interconnection drivers, receivers and bonding pads.

Abstract: A novel packaging system for VLSI circuits allows low-cost construction and maintenance of complex high density high-performance devices with low power requirements. The devices can be individually created by software means from a small selection of standardizable IC chips by disposing a plurality of chips in leadless chip carriers in a mosaic on a substrate, and configuring them by software to selectively communicate with other chips of the mosaic or even to individually change their operating function. The immediate juxtaposition of the chip carriers in the mosaic eliminates transmission line data skew, and also allows considerable savings in chip space and power requirements by dispensing with interconnection drivers, receivers and bonding pads.

Abstract: Consolidation of active and passive detectors (26, 28, 34) on a single coldfinger (20) in a dewar (10) is made possible by interposing between the detectors (26, 28, 34) an electromagnetic interference shield (64, 68) which acts as a waveguide filter blocking any interfering frequencies. The waveguide is formed by a pair of spaced interleaved shields (64, 68), one of which (64) is associated with the dewar envelope and is externally grounded, and the other of which is associated with the coldfinger (20). Photons which penetrate through the waveguide (64, 68) are deflected to the outside of the dewar (10) by a flanged narcissus shield (40) surrounding the passive detector (34).

Abstract: A novel packaging system for VLSI circuits allows low-cost construction and maintenance of complex high density high-performance devices with low power requirements. The devices can be individually created by software means from a small selection of standardizable IC chips by disposing a plurality of chips in leadless chip carriers in a mosaic on a substrate, and configuring them by software to selectively communicate with other chips of the mosaic or even to individually change their operating function. The immediate juxtaposition of the chip carriers in the mosaic eliminates transmission line data skew, and also allows considerable savings in chip space and power requirements by dispensing with interconnection drivers, receivers and bonding pads.

Abstract: A novel packaging system for VLSI circuits allows low-cost construction and maintenance of complex high density high-performance devices with low power requirements. The devices can be individually created by software means from a small selection of standardizable IC chips by disposing a plurality of chips in leadless chip carriers in a mosaic on a substrate, and configuring them by software to selectively communicate with other chips of the mosaic or even to individually change their operating function. The immediate juxtaposition of the chip carriers in the mosaic eliminates transmission line data skew, and also allows considerable savings in chip space and power requirements by dispensing with interconnection drivers, receivers and bonding pads.

Abstract: The manufacture of monolithic HgCdTe detectors and Si circuitry in an IR focal plane array is achieved by forming a protective layer of SiO.sub.2 or SiN.sub.x on a silicon wafer containing silicon circuits, etching steep-wall recesses into the wafer, selectively depositing epitaxial single-crystal layers of GaAs, CdTe, and HgCdTe in the recesses fabricating HgCdTe IR arrays, and depositing appropriate insulating and conductive interconnection patterns to interconnect the Si devices with one another and the HgCdTe devices with the Si devices. Little or no GaAs, CdTe, and HgCdTe grows on the SiO.sub.2 or SiN.sub.x outside the recesses. Since material grown outside the recess is polycrystalline, it is easily chemomechanically removed.

Abstract: An inexpensive, reliable analog ramped-voltage timing device (34, 36, 38, 40, 44) can be used in a laser echo ranging device capable of resolution in the decimeter range by using a very steep ramp (42), and a flash A/D converter (50) to instantaneouly sample the ramped voltage upon receipt of the laser echo.

Abstract: A multi-spectral reticle projector coaxially projects two separate reticles at different wavelengths through a single aperture by using a lens system including a dichroic lens disposed coaxially between the two reticles. The visible light is reflected by the mirror and passes through the lens system twice, while the infrared light passes through the mirror and passes through the lens system once. At the output of the lens system, the two reticle images are superimposed, collinated and coaxial.

Abstract: An electromagnetic gun assembly includes a gun barrel, a projectile structure disposed within the gun barrel, and a plurality of bore rider members disposed between the projectile structure and the gun barrel. The bore rider members are dimensioned and arranged to maintain the projectile structure spaced-apart from the gun barrel, restrict lateral movement of the projectile structure relative to the gun barrel, accommodate ablative mass loss, and accommodate static and dynamic gun barrel expansion. Each bore rider member has a tapered shape that includes converging first and second surfaces, the first surface facing the gun barrel, the second surface facing the projectile structure, and the first and second surfaces converging in a direction opposite to a direction of acceleration in which the projectile structure is to be accelerated along the gun barrel.