Abstract: An acceleration responsive switch includes a material that changes from a high viscosity to a low viscosity when subjected to acceleration forces. The material's change in viscosity causes the switch to change from one state to another.

Abstract: An OFDM frequency/timing recovery circuit provides accurate recovery of both sub-carrier frequency and symbol timing information from a single OFDM symbol. Accuracy may be further enhanced in demanding applications by utilizing two OFDM symbols. A unique frequency/timing recovery symbol is used that is an OFDM symbol.

Abstract: A sequential color scanner capable of generating both two and three dimensional moving color images has only one x- and y-deflection channel. The system includes first, second, and third optical signal generators for generating a first, second, and third optical signal, respectively. Each optical signal is characterized one of the three primary colors. The first, second, and third light signals are blue, green, and red, although not necessarily in that order. The first optical signal is generated along an optical axis. First and second beam combiners direct the second and third optical signals, respectively, along the optical axis. A first optical deflector deflects the optical signals in a first plane, and a second optical deflector for deflecting the optical signals in a second plane that is orthogonal to the first plane. First, second, and third modulators modulate the intensity of the first, second, and third optical signals, respectfully.

Abstract: A method for communicating with a decreased probability of detection by an unintended listening party uses frequency hopping and two substantially identical linearly polarized antennas whose polarization vector is synchronized to frequency. Synchronization of polarization with frequency is accomplished through specifically designed conductor-backed spiral antennas. For these conductor-backed spiral antennas, a change in frequency is synchronized to a change in the polarization vector of the communication signal. Since the receiving station will be programmed to alter its reception frequencies in accordance with those being transmitted, the second spiral antenna will automatically change its polarization upon making these frequency changes. A rapid change of polarization increases the difficulty in detecting and intercepting the communication by parties for whom the message was not intended.

Abstract: A laser communications link provides a downlink laser beam having a wavelength suitable for transmission through water transmitted from an aircraft or satellite to a submerged vehicle. An uplink laser beam having a wavelength that is visually undetectable is conducted through the water from the submerged vehicle by an optical fiber and radiated from the optical fiber at the surface of the water to the aircraft or satellite.

Abstract: An active sonar system with improved noise-limited performance in littoral regions with reverberation. This invention solves the active sonar comb-waveform power-limitation problem by introducing for the first time a system employing a new comb waveform herein denominated the triplet-pair comb waveform. Ambient noise-limited performance of the system of this invention is superior to that of systems employing other Doppler-sensitive waveforms such as the geometric comb waveform. Reverberation-limited performance of the system of this invention is slightly inferior to that of systems employing other Doppler-sensitive waveforms but this invention eliminates much of the range ambiguity problems seen with other non-comb waveforms.

Abstract: An eye activity monitor of the present invention integrates multiple eye activity parameters and applies them to alertness models to determine the onset of operator fatigue or drowsiness in real time.

Abstract: A matched pair circulator antenna isolation circuit provides isolation between an antenna and one or more receivers and transmitters and may also be applied to other RF devices. A portion of the transmit signal is extracted by a first RF circulator and divided into two phase-inverted signals. The first phase-inverted signal is coupled through a first directional coupler to cancel most of the transmit signal present in the receive signal. The second phase-inverted signal is coupled through a second directional coupler to cancel remaining transmit signal in the output of the first directional coupler. The output of the second directional coupler is coupled to the input of the receiver.

Abstract: A radar target simulator outputs multiple video and timing signals for a selected radar type from a single computer bus card slot. Several targets including cluster targets may be simulated at conveniently selectable signal-to-noise ratios. Multiple radar types may be simulated concurrently using additional bus card slots in a single desktop computer.

Abstract: An interactive overlay for displaying 3-D data of the present invention provides a method for analyzing 3-D data by superimposing an adjustable, semi-transparent bounding surface on a display of the 3-D data. The bounding surface makes visually apparent nulls on the 3-D data surface that fall below the selected value of the bounding surface. The bounding surface also provides a visual reference for estimating relative magnitudes.

Abstract: A method for making electrical contacts and junctions in silicon carbide that concurrently incorporates and activates dopants from a gaseous ambient. The low temperature processing of the present invention prevents the formation of crystalline defects during annealing and preserves the quantitative chemical properties of the silicon carbide. Improved activation of dopants incorporated in a silicon carbide sample is provided for making the electrical contacts and junctions.

Abstract: A human oriented object programming system provides an interactive and dynamic process for the incremental building of computer programs which facilitates the development of complex computer programs such as operating systems and large applications with graphic user interfaces (GUIs). The program is modeled as a collection of units called components. A component represents a single compilable language element such as a class or a function. The three major functionality are the database, the compiler and the build mechanism. The database stores the components and properties. The compiler, along with compiling the source code of a property, is responsible for calculating the dependencies associated with a component. The build mechanism uses properties of components along with the compiler generated dependencies to correctly and efficiently sequence the compilation of components during a build process.

Abstract: A self-aligning air bearing suited to stabilize a rotary structure having a height greater than the width of the structure. A substantially round sleeve is located in a central chamber formed between a mated top and bottom race. An air gland mounted within the sleeve is disposed to receive a journal shaft fixed to the rotary structure, forming an air bearing interface between the shaft and gland when pressurized air is introduced. The sleeve is free within the central chamber to move and align with the axis of rotation of the rotary structure when the air enters the gland but may then be locked into its adopted alignment. The air bearing is particularly useful for supporting a distal end of an extended rotary apparatus in a system for writing servopatterns to the disk surfaces within a plurality of aligned head-disk assemblies (HDAs).

Abstract: An intelligent disk drive includes a controller which embeds user data address information into error correction code check symbols written to the data storage disk. The address information is not written to disk, but address errors are detected by decoding the error correction code check symbols during read operations. Disk space is saved while maintaining robust address error detection.

Abstract: A format for embedded servo track identification fields in rotating disk data storage units such as magnetic disk drives. The present invention uses the concept of tri-bits (i.e., three code bits per logical bit) to encode track identification information in servo wedges of embedded servo disk drive systems. More specifically, two particular sets (and their equivalents) of tri-bit codes have been discovered to have optimum characteristics for providing a phase coherent encoding of a Gray code that is simple to translate into straight binary code. The properties of such tri-bit encoding limit error propagation to a single bit, which allows for very reliable track identification during movement of a head transducer across tracks (i.e., "seeks"). A full range of Gray scale codes is available since more than two consecutive logical "0"s can be reliably decoded when encoded using such tri-bits.

Abstract: A disk drive head disk assembly having a compact configuration includes an actuator assembly with an E-block mounted to a base plate through a three point mounting system. The second ridges in a generally cylindrical opening and includes means for forcing a mounting post against the first and second ridges. The E-block has a flex cable mounting surface and wedge: shape extension adapted to receive a portion of said flex cable forming an oblique angle with the flex cable mounting surface. A flex circuit is attached to the base plate and includes a ribbon-like flex cable and an L-shaped member adapted to receive the flex cable with snap-on clamps adapted for mounting the flex cable to the E-block.

Abstract: A magnetic memory disk storage system has a pair of storage disks rotatably mounted in a housing. A head actuator assembly is pivotably mounted adjacent to the storage disks and includes a plurality of load beam assemblies for placing read/write heads adjacent to the disk surfaces. Each of the load beam assemblies has a load beam, a magnetic recording slider adjacent an outboard end of the load beam, an actuator arm welded to the inboard end of the load beam and two alignment ears on the actuator arm. A pivot bearing assembly extends through pivot holes through the load beam assemblies for pivotable support of the head actuator assembly. The load beam assemblies are clamped together with the alignment ears on all of the load beam assemblies being in alignment. A torque washer next to the nut which clamps the parts on the bearing assembly includes a hole for resisting torque and preventing twisting of the load beam assemblies.

Abstract: A rotating-shaft hydrodynamic bearing assembly adapted for use in a rotating disk data store. The bearing assembly combines a plurality of spaced-apart radial journal bearings with a two-faced axial thrust plate to provide stiffness against runout at high rotational velocities. Fluid pressure is controlled on both sides of every fluid dement by bounding all radial fluid bearing layers and the dual thrust bearing layers with circumferential undercuts coupled to ambient pressure through a plurality of fluid-filled passages in the rotating shaft. Outward-biased surface-relief patterns are disposed in both axial thrust bearing layers to increase hydrostatic pressure and prevent cavitation in the non-bearing thrust-plate peripheral layer. The fluid bearing layers are disposed in a continuous pressure-controlled fluid film sealed at both ends by surface tension, thereby eliminating sources of air-bubble entrapment.

Abstract: A disk drive for use with an embedded head positioning servo system is disclosed. The disk drive includes a disk on the surface of which spaced-apart servo bursts are prerecorded in servo sectors. Successive servo bursts are read by a read/write head which produces oscillating signals having variable magnitude peaks. A timing circuit provides a timing signal, synchronized with the occurrence of the servo sectors, which defines, in time, a servo signal window, during which time a servo burst is being read by the read/write head. A detector circuit measures the magnitudes of each of the peak signals of a servo burst occurring in the servo timing window. The median peak value for a burst is stored, a next burst is detected and measured and the median peak value for that burst is stored. By comparing the median peak magnitudes of successive servo bursts, a servo error signal for use in correcting any error in head position relative to a desired track centerline is produced.