Abstract: The CAVITY REFERENCED ACOUSTO-OPTICAL LASER FREQUENCY STABILIZATION shown here locks the frequency of a laser 10 to that of a reference cavity 26. It frequency modulates the input 24 to the cavity 26 with an acouto-optical modulator 18 which operates on a sample 16 extracted from the output beam 14 of the laser 10 rather than on the output beam 14 itself. The cavity 26 can be tuned to any convenient frequency, and the operator is not limited to any specific reference absorption material. Since dithering is done on the sample 16 rather than on the output 14, no contamination of spectral purity takes place.

Abstract: Pyrotechnic removal of a radome cover may be accomplished by scoring longitudinal recesses 50, preferably at least four, on the inner surface 26 of the cover 18. Explosives cord 38, shaped to preferentially detonate outward, is placed in the recesses 50, and is backed with a backing 48 to prevent damage to the underlying radome 12. Annular explosive cord sections 40 and 42 are placed at the nose 28 and rear end 20 of the radome cover 18. A detonator 34 explodes all cords simultaneously.

Abstract: This invention relates to an induction velocity meter and more particularly to such a device having a highly accurate digital output signal which is of simplified construction and high reliability as compared with prior art devices.

Abstract: Low power tiltmeter electronics with compensation for bubble level fluid temperature include compensating methods both for temperature-induced conductivity changes and temperature-induced viscosity changes in the bubble level fluid of a tiltmeter. The conductivity changes are compensated for by comparing the difference between the tilt conductances with the average of the tilt conductances. The viscosity changes are compensated for with a critically damped bandpass filter and a thermistor filter.

Abstract: The low moving mass two axis gimbal shown here has a drive gimbal 10 and a payload gimbal 12 on a common central post 14. Each gimbal 10,12 has two axes 16,18,20,22. The rings 24,26 of the gimbals 12,14 are kept parallel to each other by three push rods 28,30,32, which are parallel to the post 14 and are joined to the rings 24,26 by universal joints 34,36,38,40,42,44. The distance between corresponding pivot points (46 and 52,48 and 54, and 50 and 56) is the same, and equals the distance from drive gimbal pivot 58 to payload gimbal pivot 60. In the drive gimbal 10, an X-axis motor 62 mounted on the central post 14 drives the X-axis 16, and a Y-axis motor 64 mounted on the X-axis 16 drives the Y-axis 18. Providing two small gimbal rings 24,26 instead of one large ring reduces the moving mass (rotational inertia) of the device, thereby producing quicker response times. Providing twin rings 24,26 also allow the device to fit within a narrower (although longer) volume than providing a single ring would.

Abstract: A method and apparatus are disclosed for manufacturing large Monolithic Microwave Integrated Circuit (MMIC) arrays. MMIC elements are manufactured on a substrate to form a MMIC module and first conductive vias are created in the substrate at locations corresponding to contact points for the MMIC. The MMIC module is then secured to a multi-layered ceramic backplate structure for physical rigidity and electrical interconnection. The MMIC module uses a conductive material, such as chrome, to fill or coat the vias to provide electrical contact with MMIC contact pads. Each layer of the multi-layered backplate structure has an electrical interconnection circuit or network formed thereon, and conductive vias extending through the layer at locations corresponding to preselected vias in adjacent layers and electrical contacts for MMIC modules.

Abstract: The Dual Function Radar Receiver shown provides hardware commonality between detection and tracking modes. Four channels (56, 58, 60, 62) are provided, each of which searches a separate range bin during the detection mode. During the tracking mode, one channel (56) continues to search a range bin, while the second channel (58) servos the range bin to the range of the detected object. The third channel (60) processes the azimuthal difference signal (94), and the fourth channel processes the elevational difference signal (110).

Abstract: The removalbe radome cover shown here is suitable for protecting the radome at the nose of a high speed missile before the radar is turned on. An outer layer lies over, but is not bonded to, an inner layer, and is divided into longitudinal sheets by tear lines. When the radar is to be turned on, a pyrotechnic device at the nose of the radome drives a piston-operated cone forward. Knives on the outside of the cone start to tear the tear lines. The cone lifts the sheets from the inner layer. A spreader lies under each sheet and, rotated by the piston, spreads the sheet further from the inner layer. Air catches the sheets and tears then back to the base of the nose cone. A metal strip along the center of each sheet prevents it from disintegrating before being fully torn back, and provides an engaging surface for the spreader. Thus, only the inner layer will be presented to the radar after the radar is turned on.

Abstract: The present invention eliminates the release of vapors from an adhesive which bonds an organic multilayer substrate to a ceramic layer. Posts from the organic layer are plated up sufficiently high as to enter holes in the ceramic layer, but not completely penetrate through them. The holes may then be filled with solder, which both seals the holes against the escape of adhesive vapors and makes a good electrical contact with the post. A conductive pad may then be stenciled on top of the solder plug, and the chip or other electric component mounted to the pad. The hole is preferably plated with a conductive material prior to being filled with solder, so that solder may join the plating with the post. The solder plug is formed by forming a slurry of solder with alcohol, which is squeegeed into the holes and fused under pressure. A solder paste is then stenciled over the fused soldered power and is, itself, fused using the vapor phase.

Abstract: A passive ring resonator gyroscope comprising a single piece body having an integral first and second resonator cavity. The first resonator cavity contains a single frequency laser that provides a sharply tuned single frequency light source to the second resonator cavity. The single frequency light source is split to form first and second sources. The second resonator cavity is a passive high Q cavity with a closed second optical path. The two light sources are fed into the second resonator and propagate as CW and CCW beams within the second resonator. A first servo channel develops a first control signal to tune the frequency of the CW beam to a resonance peak. A second servo channel develops a second control signal to tune the CCW beam to its resonance peak. By converting both servo error outputs into frequency, the relative frequency difference between the CW and CCW beams are recorded as the frequency shift in response to the body rate rotation about the sensitive axis.

Abstract: A MEMORY TEST METHODOLOGY is disclosed. The memory is checkerboarded and divided into blocks, the cells of which are scrambled by a EEPROM. The memory is the assaulted. After each assault, one block (time-test) is tested in alternation with each of the other blocks (space-test) by reading each cell of the clock, comparing it with the checkerboard, and writing the opposite of the checkerboard to the cell. When this process has been completed for all blocks, it is repeated, this time writing the checkerboard to each cell. Failures are noted on a fast capture RAM. This cycle is repeated several times. The data is displayed, and the memory is assaulted again. It is re-checkerboarded immediately before the assault. Errors in the time test block are displayed separately from those in the space-test blocks, and both displays are repeated in the same format after each assault.

Abstract: A digital path length control for ring laser gyros comprises a square wave generator, a dither counter (driven by the generator with a quarter cycle delay, a dither DAC, a control counter, a control DAC, and a PZT driven by the two DACs. The PZT controls the path length of the ring laser gyro, and thus controls the intensity of the light in the gyro. A photodetector samples this light and produces an ac signal, which a voltage comparator compares with ground. The output of the comparator is XORed with the square wave, and the output of the XOR gate drives the control counter, strobed with a frequency at least twice that of the square wave. All signal processing is digital, and analog conversion is made only when interfacing the gyro.

Abstract: An alignment and path length control apparatus having a mirror housing having a base and a closed wall. The base has a mirrored external surface. The closed wall has a central axis. The closed wall is joined to the base at a base end of the closed wall by a flexible web. The closed wall extends above the base and terminates at a rim defining an aperture. The base has a central region coupled to the cylindrical wall. A post extends from the central region of the base within the cylindrical wall to a top end. A mirror axis extends from the mirrored external surface through the post. The central axis is substantially parallel to the mirror axis. An alignment transducer responds to a first alignment control signal by applying at least a first force between the post and the wall to deflect the mirror axis with respect to the central axis. A linear transducer responds to a linear displacement control signal by applying an axial force to the post to displace the central region longitudinally along the central axis.

Abstract: A passive ring resonator gyroscope comprising a single piece body having an integral first and second resonator cavity. The first resonator cavity contains a single frequency laser means to provide a sharply tuned single frequency light source to the second resonator cavity. The single frequency light source is sharply tuned and is split to form first and second sources. The second resonator cavity is a passive high Q cavity having a closed second optical path. The two light sources are fed to the second resonator and propagate as CW and CCW beams within the second resonator. A first servo tunes the frequency of the linear laser to the resonance peak of the CW beam in the second resonator. A second servo means is provided to shift the frequency of the CCW beam to its resonance peak. By converting both servo error outputs into frequency, the relative frequency difference between the CW and CCW beams are recorded as the frequency shift in response to the body rate rotation about the sensitive axis.

Abstract: A computer memory is transformed such that a data word to be sent to an address is transformed into a transformed data word, and the address to which it is to be sent is transformed to a transformed address. Such transformations are by inversion and permutation of the memory lines (address or data). The data transformation process depends on the address. The data inverse transformation process also depends on the address, but there is no address inverse transformation process. The invention may be used whenever it is desired to more nearly equalize the use of all the bits of the memory, or to impede unauthorized persons from extracting the virtual addresses and data from the transformed addresses and data.

Abstract: A freestanding visual aid is disclosed which includes instructional material displayed on multiple sufaces of a geometric object to allow the selective display of indicia representing information, on at least one of the surfaces, in a resting position of the geometric object. The indicia displayed by each face of the freestanding object is preferably related to one of a plurality of modes of operation of an apparatus or system with which the visual aid is used. Each surface, for example, may include an explanation of the key functions and command language applicable to a different computer program when the visual aid is used in connection with the operation of a computer or microprocessor system. The freestanding object allows immediate selection of the appropriate instructional information represented by the indicia on a given surface for the particular program employed by the computing system.

Abstract: A 3-D sonar image display takes two sonar signals from the same event, slightly displaced from one another in time, space, or both. Each signal is converted from audio to video, and is presented to a separate eye of the sonar operator. The coherent parts of the signal--those actually produced by the event--will be fused by the optical portions of the brain into a three-dimensional image. The noise portions of the signal will not be coherent, and will not produce a three-dimensional image.

Abstract: An aluminum foil has, sputtered upon it, a foil of tungsten, upon which a foil of gold is sputter deposited. The gold foil may be placed next to a gold substrate, and the three-foil combination bonded to the substrate with a stylus, upon which ultrasound is impressed, in the presence of a moderately elevated temperature. An aluminum region the size of the tip of the stylus is thus made available for an aluminum wire to be bonded to it, without any direct contact between the aluminum wire and the gold substrate.

Abstract: In-flight scale factor calibration of a ring laser gyro is encumbered by the dependence of scale factor on light beam intensity and by the susceptibility of the intensity monitor to decalibration. The monitor may be calibrated in flight by modulating the mirror alignment, the laser current, or both to modulate the intensity. The intensity modulation produces a modulation of the scale factor. The ratio of the amplitude of scale factor modulation to the amplitude of the measured intensity modulation should be the same in-flight as during factory calibration. If it is not, the intensity monitor is calibrated by multiplying its output by the change in the ratio, and the calibrated intensity measurement rather than the raw intensity measurement is used to determine the scale factor.

Abstract: A self-erecting tiltmeter includes a vertical seeking assembly suspended on a gimbals within a housing which contains a viscous fluid. Portions of the assembly outer surface spherically match corresponding portions the housing inner surface, leaving a gap or gaps across which the fluid may transfer tilts to the vertical seeking assembly. Different portions may have different radii or curvature. The fluid is sufficiently dense as to reduce the weight of the assembly on the gimbals. The vertical seeking assembly includes a conductivity difference bubble sensor assembly, signals from which are transmitted to the exterior of the housing through wires which pass through the pivots of the gimbals. An annulus of closed cell neoprene accommodates thermal expansion of the fluid.