Abstract: A single bit bandpass analog-to-digital converter has an analog summer, an analog bandpass filter, a single bit quantizer, and a single bit digital-to-analog converter connected in a loop. An input signal to the single bit filter is applied to a plus input terminal of the summer, and the output of the digital-to-analog converter is applied to a minus input terminal of the summer. The output signal from the single bit filter is taken from the output of the quantizer. The bandpass filter is preferably driven by a digital clock running at the same frequency as the quantizer and the digital-to-analog converter. This architecture reduces quantization noise within the passband at the possible expense of increasing it outside the passband. The passband is centered precisely on one-quarter of the clock frequency.

Abstract: A method for the densification of a shaped nickel base single crystal alloy article utilizing a pre-HIP, a hot isostatic pressing (HIP) step, and post-HIP solution heat treatment to enhance removal of casting porosity in a finished article.

Abstract: A temperature-responsive actuator for a sealing assembly comprises first and second annular members each having a camming surface for engagement with one another, the first and second annular members being positioned against each other so that they are nested and together exhibit a height "h" at ambient temperatures, the first annular member having a coefficient of thermal contraction less than the coefficient of thermal contraction of the second annular member so that when the thermal actuator is subjected to temperatures less than ambient temperatures, the first and second annular members contract different amounts such that the "effective" height of the actuator becomes "h+.tangle-solidup.h".

Abstract: A resonator produces a signal which is processed by being digitized and demodulated. The processed signal is applied to a filter having three sections. The first is a lowpass filter, the second is a decimator, and the third is an equalizer filter. The lowpass filter filters out the high frequency components which would be aliased by the decimator. The equalizer filter performs whatever processing as is appropriate for the measurement which is sought. A second or subsequent equalizer filter may be driven by the first. The lowpass filter and the equalizer filters all have the same architecture of allpass filters, weighting elements, and adders. The weights applied to the weighting elements vary to perform the varied purposes of the various filters. The filtered signal is applied to a display, such as a human operator, or a device (such as an auto-pilot) either in or out of a feedback loop, or both.

Abstract: In a skywave communication setting, a number of independent measurement techniques can be employed simultaneously and their results combined to yield a metric representative of the channel quality during a particular reception. This sample can then be combined with previous samples taken using the same frequency (or same frequency hop set in a frequency hopping system) to serve as a basis for selecting the best operating frequencies.

Abstract: An alerting process is presented that uses the steps of first receiving at least a first signal from a signal source for a predetermined short interval. The first signal is analyzed over the predetermined short interval to obtain the spectral energy of the first signal within contiguous incremental frequency bands that extend over the frequency spectrum of interest. The energy value obtained for each incremental frequency band is then stored as a short term integrated value in a memory at an address location corresponding to the incremental frequency. Successive short term integrated values are then integrated over a predetermined long term interval to obtain a long term integrated value for each respective incremental frequency band. Each short term integrated value is then divided by the corresponding long term integrated value to obtain an enhanced STI frequency value for each incremental frequency band.

Abstract: Copper alloy rocket engine combustion chamber linings have been found to deteriorate when exposed to cyclic reducing/oxidizing (redox) environments which are a consequence of the combustion process. This deterioration, known as blanching, can be characterized by increased roughness and bum through sites in the wall of the combustion chamber lining and can seriously reduce the operational lifetime of the combustion chamber. The blanching problem can be significantly reduced by depositing a thin layer of Cu-30.sup.v /.sub.o Cr (a copper matrix with 30.+-.10 volume percent of chromium) on the inside wall of the combustion chamber. The microstructure of the Cu-30.sup.v /.sub.o Cr coating consists of finely distributed chromium (Cr) particles in a copper (Cu) matrix. When exposed to an oxidizing environment at high temperatures, the coating forms a protective chromium scale which is stable in hydrogen atmospheres (e.g., substantially unreduced by high pressure hydrogen). The Cu-30.sup.v /.sub.

Abstract: An improved discrete media display apparatus and a method for quickly drawing high quality lines on discrete media displays where only pixels are rendered in the line drawing of a vector generator and then individual element intensities within a pixel are generated in response to predetermined pixel configuration and pixel distance and angle information from the desired line.

Abstract: An engine power enhancement/pollution control system which utilizes a vortex air separator. The invention comprises a compressor for receiving air from the environment and providing high pressure air output. The high pressure air output is cooled to partially liquefied air having a mass fraction of less than 30% liquid. A vortex air separation apparatus is provided for separating the partially liquefied air into gaseous nitrogen enriched air and liquid oxygen enriched air. The oxygen enriched air is introduced to an internal combustion engine, thereby enhancing the power of the engine and minimizing pollution thereof.

Abstract: A method for using a value of range rate observed by a receiver, such as a GPS receiver, to determine the coordinates of points on the surface of the earth from which this value of range rate would be observed. These coordinates are given in an earth-centered, earth-fixed (ECEF) coordinate system, and they form a locus of points of equal range rate. The coordinates of these points provide general estimates of the location of the receiver. By calculating multiple loci of points which intersect each other, a more precise determination of the location of the receiver may be made.

Abstract: A liquid hydrogen-liquid oxygen (LH.sub.2 -LOX) rocket engine system wherein a conventional oxidizer turbo pump is replaced with a jet pump--a jet oxidizer pump. Beneficial features of the jet oxidizer pump system, over a conventional oxidizer turbo pump system, include: 1) it does not require a complicated seal system, 2) it has no moving parts, and 3) it is lighter. All these features improve the operational reliability of the rocket engine while decreasing its manufacturing cost.

Abstract: A method and apparatus for a decision-directed timing recovery scheme to stabilize its equalizer positioning by centering equalizer taps is disclosed. First, the measure of equalizer positioning is calculated. The measure is then scaled to generate a timing bias signal. The timing bias signal is used to shift the timing phase of the equalizer input.

Abstract: Information often modulates an underlying carrier signal, thereby producing a modulated information signal 70. This same carrier signal is required, with a few modifications, to demodulate the modulated information signal. This required signal is called the demodulator reference signal. It must be complex, that is, it must contain separate in-phase and quadrature outputs. A degraded version 10 of this signal is often available with the correct frequency, but with the wrong phase and amplitude, and with a direct current (dc) offset. The present invention 68 produces a digital demodulator reference signal 38, 46 from the degraded signal 10. It eliminates dc offset with a dc blocker 18, adjusts amplitude with a scaler 14, adjusts phase with a first Hilbert transformer 20, multipliers 26 and 28 and summer 34, and produces in-phase and quadrature outputs with a second Hilbert transformer 36 cascaded with the first.

Abstract: A method and system for radio communications between mobile units and base stations geographically distributed through a substantial geographic area described. The system automatically finds and engages broadcast frequency for each geographic region. The engagement is confirmed at both the mobile unit and network so that both can begin data transmission and reception between each other as well as keep track of the status of one another. The system also verifies the correct base station has been engaged as well as automatically terminates communications once the mobile unit passes out of coverage for that base station.

Abstract: A debug port in accordance with the invention provides circuitry for enabling system (hardware and software) development within an inaccessible computer processor. In one embodiment, a debug port is incorporated within the internal logic of a single-chip, reduced instruction set signal processor referred to as the signal processor. A fully implemented debug port is comprised of five interacting functional elements: debug bus unit (DBU), debug command unit (DCU), debug instruction Unit (DIU), debug inject/extract unit (DJU), and a debug flow unit (DFU). The DBU provides circuitry for buffering data received from the signal processor and other functional elements within the debug port as well as accepting data from an external source. The DBU provides for off-chip connections. The DCU provides circuitry for decoding and executing debug commands received by the debug port. The DIU provides circuitry to insert one or more instructions with, or without, data into the instruction stream of the signal processor.

Abstract: A hybrid circuit for coupling a modem to an external telephone line substantially compensates for and thereby cancels reflected echo. The hybrid includes a transformer coupled between the telephone line and the modem transceiver, which includes a transmitter and a receiver. A matching resistor connected between the transceiver transmitter and the transformer at a hybrid point presents a matching impedance to the telephone line impedance. A feedback network is implemented between the transceiver receiver and transmitter to feed back sufficient voltage into the receive line to cancel echo produced at the hybrid point.

Abstract: A modular product assembly platform which includes a multiple number of industrial robots or other similar assembly devices. The product assembly platform also includes a programmable controller system housed in a logic control cabinet, a vision control system housed in a vision control cabinet and a set of robot controllers which operate together to control the robots or assembly devices for performing product assembly tasks. The layout and configuration of the platform and the control equipment provide for convenience and flexibility in configuring and reconfiguring the assembly platform for different assembly procedures associated with different products.

Abstract: A virtual integrated software testbed for avionics is disclosed which allows avionics software to be developed on a host computer using a collection of computer programs running simultaneously as processes and synchronized by a central process. The software testbed disclosed uses separate synchronized processes, permits signals from an avionics device to be generated by a simulation running on the host computer or from actual equipment and data bus signals coming from and going to actual avionics hardware is connected to their virtual bus counterparts in the host computer on a real-time basis.

Abstract: An electro-optical sensor system for use in observing objects. A staring sensor is provided which includes a staring array of mid-wave infrared (IR) detectors for providing real-time observations of objects. A preprocessor system is connected to the staring sensor for providing temporal filtration of the real-time observations. A remote control is provided for controlling the temporal filtration.

Abstract: An anode wick for use with electrochemical fuel cells, in accordance with the invention, establishes a physical connection between a fuel cell's anode membrane surface and a liquid water reservoir. Wicking action substantially ensures the cell's anode surface is continually bathed in water. Two mechanical check valves are incorporated to effectively prevent mixing of gaseous hydrogen and oxygen gases in the event the fuel cell system's water tanks become over pressurized. This design can effectively eliminate the need for some of a conventional fuel cell system's pumps and/or compressors. Advantageously, the invention also reduces the overall weight and mechanical complexity of the fuel cell system, thereby improving system reliability.