Abstract: The environmentally protected module (16, 116, 216), which is qualifiable under military and space specifications, uses commercial and/or industrial grade electronic components (18, 20; 118, 120; 218, 220). The components are secured to and are electrically coupled together on a printed wiring board (24, 124, 224), through which thermally conductive vias (38, 138, 238) extend. The components are encapsulated in a thermally conductive and electrically insulative packaging material (25a, 25b; 125; 225, 229). Cooling or heating is provided by Peltier thermoelectric heat pump devices (32, 132, 232) coupled between an external heat sink/exchanger (35, 80; 135; 235) and the components.

Abstract: A gyroscope component (10) and its variations (10a, 10b and 10c) includes a spool (12, 12a) which supports a ring-shaped fiber optic gyroscope coil (14). The spool has a base (26, 26a) which is provided with a central hole (38, 38a). A perpendicularly extending tubular wall (28, 28a) extends from the base or a cover (16, 16a), and may directly contact the coil or be separated therefrom by a non-adhesive material (29) or a space (30). The cover covers the spools and, with the spool and the tubular wall, forms a ring-shaped enclosure. Each coil has a generally trapezoidal shape and comprises an optical fiber winding wound about an axis and having a cross-sectional configuration that approximates a 45.degree. right triangle whose hypotenuse is formed by the sloped sides to provide a side which is sloped with respect to its axis. Three components (10, 10", 10"') are positioned respectively about three orthogonally disposed axes to form an assembly (50) and are supported within and enclosed by a housing (52).

Abstract: To screen or test the electrical properties of HEMT-like wafers for their quality, the critical layer qualities of a wafer (16) are evaluated by measuring its conductivity (sigma or s) and mobility (mu or m) at upper and lower temperatures, which need only be sufficiently different as to remove uncertainties in the test data but, in practice, are room and liquid nitrogen temperatures. Novel equations show (1) that the crucial quality or merit factor (n.sub.s) the electron sheet density of two-dimensional electron gas (2DEG), can be determined by measuring the total layer conductivity (sigma or s) at the lower or liquid nitrogen temperature and mobility (mu or m) at the upper or room temperature and (2) by measuring overall layer effective mobility (mu or m) at both room and liquid nitrogen (the upper and lower) temperatures to provide a means to measure the value of the 2DEG density, n.sub.s which has better accuracy then where the temperature of mobility is only made at room temperature.

Abstract: A phase modulation control apparatus is taught in combination with an interferometer excited by a coherent light source providing a light beam to the interferometer having first and second optical paths. The interferometer senses a physical quantity such as pressure. The interferometer is coupled to provide an optical signal containing information providing a measure of the physical quantity via first and second interfering beams to a detector. The detector provides a composite output signal. The invention phase modulation control apparatus has a modulation means responsive to a modulating frequency signal and a phase modulation control signal to provide a frequency modulating factor signal for frequency modulating at least a portion of the light beam to provide a phase modulation between the first and second interfering beams at a carrier frequency. The composite output signal has at least four harmonic signals referenced to the carrier frequency.

Abstract: Disclosed herein is an Internal Anode System for Ring Laser Gyroscopes comprising at least one internal anode electrically connected, through an active gaseous medium, with a cathode to form a compact and shortened DC discharge pathway for a ring laser gyroscope. The internal anode comprises a conductive coating covering a taped end of the intersection of at least two passageways within a monolithic ring laser. The coated taped end of said passageways communicates with an external power source through an electrical feedthrough placed under and around a dielectric mirror substrate and seal. The gain-bore region within the cavity is narrowed and acts as the cavity aperture, increasing the available gain per unit length and relieving the fabrication tolerances.

Abstract: An electronically tuned dielectric resonator stabilized oscillator has a dielectric resonator that is fine tuned by an electronic method of tuning which includes a varactor coupled to a microstrip. This varactor microstrip transmission line is positioned below the dielectric resonator but above the plane in which a transmission line for the carrier frequency resides. By not placing the fine tuning microstrip line on the same plane as the main oscillator line, spurious oscillation between the fine tuning transmission line and the primary carrier wave resonator frequency line are minimized. Additionally, the fine tuning microstrip line is positioned orthogonal to the pathways along which the main signal transmission lines are coupled.

Abstract: This disclosure depicts a novel semiconductor device and the method of making it. A novel field effect transistor (FET) has a channel region which is heavily doped under the gate and between the gate and the source of the FET. The channel region between the gate and the drain is lightly doped. The FET is formed on a heavily doped semiconductor substrate. The method of making the novel FET comprises providing a mask layer over a lightly doped channel region and forming openings in the mask layer such that a portion of the mask is located at the gate location and has a predetermined width and height.

Abstract: An improvement to an existing crossed-field amplifier is shown which includes the replacement of an existing thermionic emitter with a larger platinum emitter. The platinum emitter is cooled from a surface opposite to the surface upon which a high voltage is applied to permit the form of the existing crossed-field amplifier to be maintained.

Abstract: A ring laser gyro is shown having a mirror designed for maximum reflectivity of parallel and perpendicularly polarized light at a frequency slightly greater or less than the frequency of the laser. In this configuration, the reflection of the preferred perpendicularly polarized light is reduced but slightly, while the reflection of the less desirable parallel polarized light is reduced significantly.

Abstract: The application describes digital signal processing of radar video signals to provide an optimum display. Three interacting components of the system are further described in detail: a global mean estimating circuit, a statistical analyzer circuit, and a dynamic range compression circuit. The global mean estimating circuit determines the mean of the amplitude distribution of video signals over a wide section of the display as opposed to a local mean of signals. A local mean of signals is the mean of the amplitude distribution of video signals occurring in the near vicinity of a point on the display. The statistical analyzer circuit evaluates the amplitude distribution of video signal samples and controls the gain of the signal path so that the variance of the sampled amplitude distribution follows the variance of a model distribution. The dynamic range compression circuit functions to compress the range of amplitude distribution in a manner to provide maximum information from the display.

Abstract: A circuit is shown which utilizes signals transmitted from global positioning system satellites to create change in phase signals. The change in phase signals are measured over a predetermined time interval, one second, and stored. The stored signals are applied to a Kalman filter and back to the storage unit so that each one second time interval includes the information from all previous time intervals. This accumulated information is referred to as accumulated Delta-Range information which permits a more rapid determination of position by the circuit.

Abstract: A method for manufacturing a sub-micron length Schottky barrier gate electrode. A wafer is coated with a first photoresist layer, which is exposed and developed to leave a substantially vertical line of photoresist having a sub-micron thickness. A dielectric layer is then deposited and the line of photoresist lifted off, leaving a dielectric coating layer with a sub-micron opening atop the wafer. The dielectric layer provides a mask for subsequent etching and metallization steps.

Abstract: An improved electron gun is shown with a cathode having a smooth, concaved surface and a grooved pattern therein which matches, and is aligned with, the pattern of a shadow grid placed immediately before the cathode surface so that the outer, larger radius of curvature of the shadow grid closest to the cathode is substantially identical and concentric with the radius of curvature of the smooth, concave cathode surface. Beyond the shadow grid is a control grid which controls the flow of electrons emitted from the cathode toward an anode. The grooves which form the pattern within the cathode surface have tapered side walls and rounded outer and inner corners to improve the flow of emitted electrons and facilitate manufacture.

Abstract: A tunable, coaxial-vacuum magnetron is shown having a cathode surrounded by an anode within a surrounding evacuated anode cavity. Located between the cathode-anode interaction space and an output from the anode cavity is a tuning mechanism which includes a single symmetrical ceramic tuning rod that is adjusted along its axis into and out of the anode cavity. The adjustment mechanism includes a tuning nut rotatably mounted in a tuning housing which turns to move a threaded shaft along the axis thereof. Separating the threaded shaft from the anode cavity is a bellows attached to the tuning housing and to which is attached the symmetrical tuning rod for sealing the vacuum cavity.

Abstract: A ring laser gyroscope is described having two counterpropagating primary modes and one or more secondary laser modes having a component c cos .omega. t to produce a dithering effect which reduces or eliminates the lock-in range of the primary modes. The ratio of c to .omega. is controlled to minimize J.sub.o (c/.omega.) wherein J.sub.o is the Bessel Function of the first kind of zero order. In one embodiment, cavity length control circuitry is adjusted to detune the cavity length to allow two secondary opposing modes of angular frequency separation .omega. to be generated within laser gain medium in the cavity while two primary counterpropagating modes operate well above threshold. Another embodiment has an external laser beam source for generating two secondary waves, at two light frequencies separated by an angular frequency .omega., which are introduced into the ring laser path through a partially transmitting mirror which forms one of the corners of the ring laser closed loop path.

Abstract: A nuclear magnetic resonance (NMR) cell for use in a gyro is shown which is maintained at a predetermined temperature, established by testing. Testing of each cell is conducted by heating the cell within a gyro to a series of temperatures and plotting the gyro bias (degrees/time) for each temperature within the series. At one temperature the magnitude of gyro bias will no longer increase but will start to decrease. This temperature turning point is the temperature at which the NMR cell should be maintained for zero temperature sensitivity of the gyro.

Abstract: There is disclosed a nuclear magnetic alignment device for use in a nuclear magnetic resonance gyroscope and the like. One embodiment includes a container for gas having a layer of rubidium hydride on its inner surface. The container comprising a spherical portion and a tip portion, is rotationally symmetric about an axis of symmetry. Enclosed within the container is a nuclear moment gas having a nuclear electric quadrupole moment, such as xenon-131, and an optically pumpable substance, such as rubidium. A portion of the rubidium is a vapor. The remainder is a condensed pellet which is deposited in the tip of the container such that the pellet is also rotationally symmetric about the axis of symmetry of the container. A layer of rubidium hydride is deposited on the inner surface of the container.

Abstract: There is disclosed a weapon sight for night time use having an image intensifier tube and an illuminated aiming dot. A front lens forms an image of a dimly lit scene onto the input surface of an image intensifier tube. A resulting intensified image is displayed at an output surface of the tube. A rear lens then projects this image to a viewer. A light source illuminates an aiming dot which is optically relayed by a beam combiner mirror through the rear lens to the viewer so that the images of the aiming dot and scene are superimposed. Mechanical means are provided for moving the aiming dot in elevation and windage.In a specific embodiment of the invention, the light source is a light emitting diode (LED) which illuminates an input end of a short length of fine diameter optical fiber, the output end of which forms the aiming dot. Alternatively, the aiming dot can be a small aperture within an opaque disk mounted adjacent the LED.

Abstract: A coupled cavity traveling wave tube is disclosed which includes a plurality of pole piece members and hollow spacer members which are alternately arrayed to define a plurality of cavities. The pole piece members each has a central aperture and a coupling slot through which microwave energy is coupled between adjacent cavities. The tube includes a plurality of first loss elements each of which is positioned in both of two respective adjacent cavities, with each of the first loss elements having its first end in contact with the front face of a respective one of the alternate pole piece members, its central portion pass through an aperture in the next intervening pole piece member in which it is coupled to the coupling slot in that pole piece member, and its second end in contact with the rear face of the next alternate pole piece member.

Abstract: A coupler for wavelength multiplexing or demultiplexing of multimode optical signals in optical circuits. Light introduced through an input/output surface at one end of a planar optical waveguide formed within a glass substrate propagates to a convexly curved second end of the waveguide on which is contiguously mounted a flexible, reflective diffraction grating. The light is diffracted by the diffraction grating and focussed by the curved end back onto the first end of the waveguide.In a multiplexer (beam combiner) embodiment, a plurality of optical signal sources, each having a different wavelength component, is aligned along the first end of the waveguide so that light propagating from each of the sources travels through the waveguide to the reflective diffraction grating, is diffracted by the grating and then brought to a common focus at the first end. An optical fiber abutting the first end is positioned at the common focus to receive the combined beams.