Abstract: Improved unvoiced speech performance in low-rate multi-pulse coders is achieved by employing a multi-pulse architecture that is simple in implementation but with an output quality comparable to code excited linear predictive (CELP) coding. A hybrid architecture is provided in which a stochastic excitation model that is used during unvoiced speech is also capable of modeling voiced speech by use of random codebook excitation. A modified method for calculating the gain during stochastic excitation is also provided.

Abstract: A power supply includes a dc-to-dc converter with an integral boost power supply for maintaining the effective converter input voltage within a predetermined steady-state range, even if the input voltage to the power supply exhibits substantial voltage transients. In one preferred embodiment, the boost power supply comprises a boost transformer and a rectifier, and the converter comprises two parallel-coupled resonant converter modules, each including either a half-bridge or full-bridge connection of switching devices and a resonant circuit. The primary winding of the boost transformer is coupled between the junctions joining the switching devices of the resonant converter bridges. When the power supply input voltage is outside the steady-state voltage range, the boost power supply is activated by phase shift control of the voltage across the primary winding of the boost transformer.

Abstract: Laser drilling and real-time sensing and control of hole depth by the provision of magnetic field jack-up coils located around or to the side of a laser beam, in a stream of ionized plasma, and the coils are connected to a depth detector and comparator to halt laser drilling at a desired depth.

Abstract: A transmitter location searching system produces fast, stable and accurate results in a multipath transmission environment by geometrically partitioning the monitored area into a plurality of cells and finding the optima of a total cost function at the centers of the cells. The original three-dimensional optimization problem is thus reduced to a one-dimensional problem. Based on this calculation, the cell providing the smallest cost is chosen as a new candidate cell which is divided into smaller cells and the minimum costs are calculated for each of these smaller cells. The cell that provides the smallest cost is chosen as the center of another new candidate cell. The process is iterated until a dimension of a new candidate cell is smaller than a predetermined threshold. By reducing the dimensions of each cell by a factor of two at each iteration, the algorithm converges rapidly.

Abstract: Selected scintillator materials provided in transparent block form for use in systems such as CT scanning systems employ a garnet host material for an activator ion which provides the desired luminescence. The garnet host material preferably includes gadolinium as one of its components in order to provide a transparent host material in bar form which has a high x-ray stopping power (where the radiation to be detected is x-ray radiation). Chromium, cerium and neodymium are preferred activator materials.

Abstract: The invention is directed to an automated, real-time, rule-based reasoning with uncertainty system and method for practicing same. The system has a three layer structure comprising of representation, inference and control layers. Rule firings and conclusions are computed in the inference layer in a manner to propagate uncertainty information through the system in accordance with predetermined formulas designated by the control layer. Rule structures and conclusions and uncertainty information associated therewith are represented to the user in the representation layer. The control layer includes a planning mechanism which determines the fastest plan for reaching the conclusion and generates prioritized alternate plans which, if time permits, will be executed in accordance with their respective priorities.

Abstract: A refrigerator apparatus is provided having a cabinet with a freezer compartment and a fresh food compartment. A refrigeration system is included having a first expansion valve, a first evaporator situated in the freezer compartment, a first and second compressor, a condenser, a second expansion valve, and a second evaporator situated in the fresh food compartment all connected together in that order and in series in a refrigerant flow relationship. First and second fans are provided in the freezer and fresh food compartments, respectively. A servovalve is connected between the first evaporator and the first compressor for reducing refrigerant flow through the first evaporator when activated. A first thermostatic controller situated in the freezer compartment causes operation of the compressors and fans when a selected temperature in the freezer is exceeded. A second thermostatic controller situated in the fresh food compartment causes operation of the servovalve when a predetermined value is reached.

Abstract: A microprocessor-based relay system is used in combination with relay contactors and a control circuit therefor to protect an electric motor from overload currents in addition to phase faults, ground faults, load losses, and load jams. The microprocessor is provided with a data base comprising thermal characteristics of the motor during heating and cooling. The heating data comprise current versus time curves stored as a look-up table for which each data point represents a thermal limit, i.e., the maximum time the motor is permitted to operate at a particular current level. The cooling data comprise motor cooling rates. Phase currents are sampled at preselected fixed time intervals during a predetermined period thereof, and an average motor current value is calculated therefrom. A thermal sum, which is initialized at zero upon first starting the motor, is adjusted depending on the average motor current value relative to a predetermined overload current value.

Abstract: A starting circuit for an electrodeless HID lamp provides a two-stage resonant starting signal to a gas probe starter of the type comprising a starting chamber which contains a relatively low-pressure gas and is attached to the outer wall of the arc tube. The starting circuit comprises a resonant LC circuit of variable impedance including the series combination of a variable inductance and the parasitic capacitance between the gas probe starter and the excitation coil. In operation, the resonant circuit is tuned to a predetermined value so that, upon application of an RF signal to the excitation coil, resonant operation of the starting circuit results in the application of a sufficiently high starting voltage to the starting chamber to ignite a low-current glow discharge therein. Once the glow discharge is ignited, the starting circuit is retuned to ensure that a sufficiently high starting voltage is capacitively coupled to the arc tube to ionize the arc tube fill and initiate an arc discharge therein.

Abstract: A reactant particulate mixture comprised of Bi.sub.2 CaSr.sub.2 Cu.sub.2 O.sub.8.+-.x where x ranges from 0 to 0.5, Ca.sub.2 CuO.sub.3, cupric oxide and lead oxide is formulated and reacted to produce superconductive Bi.sub.2-y Pb.sub.y Ca.sub.2 Sr.sub.2 Cu.sub.3 O.sub.10.+-.z where y ranges from 0.1 to 0.5 and z ranges from zero to less than 1.

Abstract: The linearity and dynamic range of a photodetector system is enhanced by providing real time cancellation of condition-dependent quiescent output signals from the photosensitive devices by provision of a condition-dependent output signal monitoring device which drives the input section of a current mirror having output sections connected to the active photosensitive devices to zero out the condition-dependent quiescent output signals of those photosensitive devices during system operation. Multiple output sections may be run from a single input section of the current mirror.

Abstract: A particulate mixture comprised of Bi.sub.2 CaSr.sub.2 Cu.sub.2 O.sub.8.+-.x where x ranges from 0 to 0.5, Ca.sub.2 CuO.sub.3, cupric oxide and lead oxide, wherein the Bi.sub.2 CaSr.sub.2 Cu.sub.2 O.sub.8.+-.x crystals are oriented with their c-axis at least sufficiently parallel to each other so as not to differ significantly from a common direction, is initially reacted producing an intermediate swollen partially reacted product which is pressed to remove the swelling and then sintered to produce a superconductive Bi.sub.2 yPb.sub.y Ca.sub.2 Sr.sub.2 Cu.sub.3 O.sub.10.+-.z body where y ranges from 0.1 to 0.5 and z ranges from zero to less than 1.

Abstract: A microporous plug is provided which serves to seal a vessel so as to prevent the bulk flow of gases through an outlet. The pores of said microporous plug are sized so as to permit the transport of gases to and from the vessel interior by Knudsen diffusion. In preferred embodiments, the pores of the plug are sized so as to release helium from the interior of a vessel and restrict the transport of carbon dioxide into the vessel from the surrounding atmosphere by Knudsen diffusion. Such embodiments are particularly useful on Mars where the helium is transported into an environment of higher pressure. In other embodiments, the microporous plug is used in conjunction with an absorber positioned within the vessel to react with atmospheric gases that pass through the plug, such as carbon dioxide. Also provided are radioisotope thermoelectric generators that incorporate a microporous plug and optionally an absorber.

Abstract: A Wiegand-effect shaft position sensor is excited by an alternating magnetic field generated by stationary magnets or solenoids interacting with a high-strength, toothed wheel that is fixed to the rotor. A set of three stationary poles are situated proximate to the rotor and are connected together by a yoke. The magnets or solenoids are mounted in the outside poles of the set of three stationary poles. The central stationary pole contains a Wiegand-effect device. In operation, a flux reversal in the Wiegand-effect device occurs at twice the frequency at which the poles of the toothed wheel pass the stationary poles, resulting in the generation of sharp voltage pulses indicative of rotor position.

Abstract: A protective coating of suitable composition and thickness is applied to the inner surface of the arc tube of a high-intensity, metal halide discharge lamp in order to avoid a substantial loss of the metallic component of the metal halide fill and hence a substantial buildup of free halogen, thereby extending the useful life of the lamp. A preferred lamp structure includes a fused silica arc tube with a silicon coating. The silicon coating is preferably applied to the arc tube using a chemical vapor deposition process.

Abstract: A method for soldering a lead to a pad having a solder plate formed thereon is described. In one embodiment of the method, a tape is disposed between the lead and a laser source, and the method includes the steps of aligning the lead with the solder plated pad, transmitting a beam from the laser source through the tape and to a location where a solder joint is to be formed, and the beam heating the solder plate thereby causing reflow of the solder plate to form a solder joint.

Abstract: An optical fiber coupler for coupling a high power laser beam delivered by an incoming fiber into multiple outgoing fibers is disclosed. The beam emitted from the incoming fiber is collimated and split into multiple split beam portions for injection into the respective multiple outgoing fibers. Each split beam portion is shaped for injection into its respective outgoing fiber in accordance with specific beam injection criteria.

Abstract: An improved reluctance motor with reduced windage losses and reduced internal rotor stresses is proposed. The reluctance motor is constructed with continuous, non-magnetic supported members in the interpolar spaces of the salient pole rotor. End plates may be added to the rotor which are attached to the support members creating a "cage" structure which supports the rotor. In addition, the rotor through shaft may be eliminated by providing stub shafts on the cage end plates to transmit torque from the rotor. Various methods of constructing the rotor of the invention are also described.

Abstract: A method is provided for making certain hydroxy-terminated arylene ethers useful as spacers in liquid crystalline polyesters. There is initially formed a dicarbonyl adduct from a dihydroxyaromatic compound, such as hydroquinone and a haloarylcarbonyl compound. The adduct formed is oxidized to the corresponding diester. Hydrolysis of the diester provides the hydroxy-terminated arylene ether.

Abstract: To achieve a large reduction in the amount of computer time in limited-angle computerized tomography, the reconstructed image is decomposed into two partial images reconstructed from available scan data and missing scan data. Because the former is unchanged during the interative image reconstruction procedure, it is reconstructed from the measured projections only once at the beginning of the iterations and used repeatedly. The composite image formed by summing the two partial images is corrected by the a priori information about the object. The improved partial image due to missing projections is calculated and again summed with the partial image due to measured projections and corrected. These steps are iteratively repeated until a test for convergence yields a final image. A limited-angle x-ray CT system utilizes the projection space version of the iterative transform algorithm.