Abstract: This is a technique for extending the frequency range which employs in-phase and quadrature components of the signal coupled with non-uniform sampling to gain the advantages of a high sampling rate with only a small increase in the number of samples. By shifting the phase of the local oscillator by 90 degrees, a quadrature IF signal can be generated. Both in-phase and quadrature components are sampled and the samples are combined to form a complex signal. When this signal is transformed, only one alias is obtained per periodic repetition and the effective Nyquist frequency is doubled. Two sets of complex samples are then used with the slightly different sampling frequency. Each set is independently Fourier transformed and the frequency of the lowest aliases permits unambiguous determination of the signal frequency over a range far exceeding the Nyquist frequency.

Abstract: The RICTPD device is designed to protect integrated circuits with external leads on the sides of the case from electrical transients caused by lightning, switching inductive loads such as electrical motors, or other sources. The RICTPD is usually used when a particular IC is identified as most likely to fail in a system. The RICTPD comprises a casing which is slightly larger than the IC casing, and has metal legs in the form of springs which provide a friction fit on the legs of the IC. The inside top of the device case has a plurality of transient protection devices (TPDs) built in between a metal ground plane and the metal legs. A grounding strap is attached from a ground terminal which is part of the ground plane on the device to an available ground on the circuit board. The TPDs may consist of metal oxide varistors, surgectors or zener diodes made to be aligned with the IC legs and the ground plane of the device. The device may be installed over the IC by a press fit.

Abstract: The high voltage regulator employs a field effect transistor (FET) amplifier and a wide band frequency compensated RC voltage divider. The device comprises a FET amplifier used as a current source in a 20 KV power supply. The negative output of the supply is sensed by a voltage divider consisting of two resistors in parallel with two capacitors. The voltage divider output is applied to the non-inverting input of an operational amplifier whose reference is set to affect the linear operation of an inverting operational amplifier. A no load to full load and line regulation of 0.1% is provided to a microwave tube. For a 16-KV regulated output the inverting amplifier must have a dc operation point of 4 KV to accommodate a 20% storage capacitor voltage droop and a .+-.5% line change. At this level the inverting amplifier provides a swing of .+-.4 KV. This range allows for a large line voltage variation and storage capacitor voltage droop.

Abstract: The interface circuit passes data from a first unit running at one clock rate to a second unit running at another clock rate. READY leads from an In control circuuit to an Out control circuit are used to signal when a data word has been loaded by the first unit; and TAKEN leads from the Out control circuit to the In control circuit are used to signal when a data word has been received by the second unit. An anti-Metastable Flip-flop (AMF) is used with each READY lead and each TAKEN lead. Each AMF flip-flop comprises an input latch, an output latch, a decentration driver, and an oscillation suppressor. The decentration driver handles cases in which the output of the input latch is balanced and floating or balanced and driven by tugging the output of the input latch toward a logic 0 soon after an active edge of a signal on the flip-flop clock lead has caused the input latch to close.

Abstract: An automated, close-loop system for controlling the autoclave cure of fiber reinforced composites uses multiple expert systems hosted on different microprocessors running concurrently to control the cure process. This qualitative process controller uses sensory feedback to determine matrix material state-of-cure and then makes control decisions and executes control commands to the autoclave to attain desired material properties. The sensory information is interpreted and translated into a qualitative cure-state description by a system known as a parser hosted on a 68000 processor. The cure state description is then analyzed by the expert system known as the thinke hosted on another 68000 processor. The control decisions are determined using symbolic logic programmed as a rule-based paradigm generated from a human expert on the cure process. Once made, these control decisions are then posted to a blackboard hosted on an 80286 processor for execution by the autoclave feedback controller.

Abstract: This is a spread spectrum radio frequency (RF) communication system whose rpose is to "spread" the information bandwidth such that when it is de-spread any atmospheric interference (including jamming is spread rather than de-spread. A "low probability of exploitation" is obtained through the use of multiple modulations each of which creates a distinct spread spectrum symbol at the transmitter, and the reception of which requires a "match" condition at the receiver to determine the data bit state. The symbol sequence is known by the appropriate receivers and the collection of data bits forms a message.

Abstract: An analyzer recorder collects sonic boom information of supersonic aircraft and launch vehicles, for use to validate Environmental Impact Statements that contain supersonic aircraft activity. The device comprises a 16-bit microprocessor, a random access memory (RAM) storage, a data retrieval unit (DRU), and a microcomputer. It samples and captures in digital form any loud impulse noise from background noise. The unattended device can discern a sonic boom from the normal background noise and capture it in permanent solid RAM storage for later analysis. The RAM modules can then be transferred with the DRU and the information on the DRU transferred to the microcomputer. The microprocessor displays each recorded event, time of occurrence and summary information for all the stored data.

Abstract: This autofocus is a system for improving the image quality of an airborne Synthetic Aperture Radar (SAR), that is mechanized in the high-speed digital signal processors with some control capability from the operating console to perform on-line focusing, to provide a unique and superior focusing technique. It includes (a) selecting the range bins which contain the strongest signals; (b) forming the subapertures from the end pulses in the selected range bins and performing map correlations; (c) judging the quality of each map correlation by its associated discriminate and determining the best one; and (d) generating the correcting phasors based on the best correlation and correcting the radar data accordingly.

Abstract: The best features of narrowband and wideband signaling are merged to provide a simple and reliable multiple-access network. This is done by transmitting the header of the packet using narrowband signaling coupled with an associated channel access protocol such as carrier-sense multiple-access. The data portion of the packet is then sent as a spread-spectrum signal with a spreading sequence that is common to all nodes in the network. The narrowband headers allow easy monitoring of channel loading and busy nodes while acting as a synchronization aid to the wideband signal. The multiple-access capability of spread-spectrum signaling increases channel throughput dramatically over a conventional narrowband-only system, and the anti-multipath feature allows increased data transmission rates on a multipath-prone channel. Common spreading sequences simplify transceiver design and allow packet broadcasting on the network.

Abstract: This is a device for electromagnetic transient protection for integrated circuit boards in a convenient and easily customized package. The device comprises an array of transient protection devices (TPDs) made in the form of sleeves on hollow pins and installed in a fiberglass board. The board has a copper coating to conduct transients away from the pin of the IC. The array of TPDs on the fiberglass board corresponds to the leg spacing of the IC being protected. The device is soldered onto the circuit board and the IC is in turn plugged into it possibly using a friction fit or else it is soldered. An unwanted transient signal enters the device and the IC simultaneously from the circuit board land. The device sees the transient and changes from a high impedance "off" state to its low impedance"on" state and conducts the transient away from the IC. The other pins remain off unless transients are also present at these pins. The TPDs may comprise metal oxide varistors in tubular form, zener diodes or surgectors.

Abstract: An electrooptical sensor system directly measures the angle between two nearly parallel collimated laser beams. After focussing with a positive lens, the beams pass through a photoelastic modulator, a quarter wave retardation plate, and two polarizers. The beams then hit a lateral cell position sensor. Electrical signals from the lateral cell are processed with special electronics to yield a voltage which is proportional to the angular difference between the two beams. The sensor measures extremely small angles and operates at a high bandwidth. Its primary application is in the control of phased array optical telescopes.

Abstract: The receiver through an improved Prony method provides a measure of the frequencies, the angle of arrival (AOA) and the phase of signals at the receiver. The device comprises two antennas spaced a known distance apart. These antennas receive signals at different angles. Signals from the antennas are sent to delay lines. Each delay line experiences a different delay period. Signals are then sent to four correlator circuits whose outputs are analog signals which contain all the information required to solve for the frequencies and the angles of arrival of signals at the receiver. The signals are supplied to a digital processor where a mathematical method is used to solve for the frequencies, the phases and the angles of arrival of signals at the receiver.

Abstract: The controller is a logical network which, when interfaced with a mechanical system or an electromechanical system, will cause the output variable of the system to closely follow any command signal received. It comprises shift registers, memory banks, accumulators, arithmetic units and preferably no software. Universal Controller keeps the error between the output of the model and the output of the control system small, regardless of the transfer function of the controlled system by adjusting a number of gains in its internal feedback loop in accordance with that error. It therefore can be applied to an arbitrary electromechanical system without prior knowledge of its transfer function.

Abstract: The IFM receiver employs only two delay lines, thereby simplifying the IFM receiver design. The basic principle is to use two delay lines to provide fine frequency resolution, and at the same time cover a wide input bandwidth. The two delay line lengths must be relatively prime. The algorithm for achieving frequency resolution is based on the Chinese remainder theorem. That theorem states that if an unknown number X is divided by a with a remainder r.sub.1 and also divided by b with a remainder r.sub.2, where a and b are relatively prime numbers, the number X can be determined from a, b, r.sub.1, and r.sub.2 is X<ab.

Abstract: The Controller is a logical network which, when interfaced with a mechanical system or an electromechanical system, will cause the output variable of the system to closely follow any command signal received. It comprises shift registers, memory banks, accumulators, arithmetic units and preferably no software. The device works in two stages. In the first stage it identifies the unit-impulse response of the system piece-by-piece while using the accumulated information to control the system at the same time. In the second stage it continually readjusts the stored information at each clock pulse by comparing the observed output signal and the command signal, while generating the required control variable based on the updated information. Its operation incorporates a learning process which emulates a simple form of human intelligence.

Abstract: The QLIS images and quantifies low-level chemiluminescent reactions in an electromagnetic field. It is capable of real time nonperturbing measurement and simultaneous recording of many biochemical and chemical reactions such as luminescent immunoassays or enzyme assays. The system comprises image transfer optics, a low-light level digitizing camera with image intensifying microchannel plates, an image process or, and a control computer. The image transfer optics may be a fiber image guide with a bend, or a microscope, to take the light outside of the RF field. Output of the camera is transformed into a localized rate of cumulative digitalized data or enhanced video display or hard-copy images. The system may be used as a luminescent microdosimetry device for radiofrequency or microwave radiation, as a thermal dosimeter, or in the dosimetry of ultra-sound (sonoluminescence) or ionizing radiation.

Abstract: This technique involves digitally filtering data by determining the median of data values instead of mean or some other algebraic combination. It is unique in that the data used for the median calculation utilizes previous as well as the new data. This filter structure can be used in both time domain and spatial domain. Also, the filter size can easily be varied to permit adapting its size to system gain.

Abstract: To provide for improved uniformity of photoresist developing of silicon wafers, developer solution is injected via an inlet port through a set of holes in a surface in a chuck and distributed across the wafer thereby developing the wafer pattern. A second set of holes in the same surface of the chuck act as exhaust outlets for the used developer. An end point detector is associated with an outlet duct. This design provides great uniformity potential since it is a single wafer system, and the holes and fluid flows can be adjusted as needed. Also, this design requires minimum developer volume which means end point detection can take place using the waste developer at the outlet. Test such as optical density or color, PH or normality, density, or others can detect photoresist content in effluent to determine completion.

Abstract: A crossover for microwave electromagnetic radiation is constructed in a planar configuration for the transference of all of the power of a wave in a first transmission line to a wave in a second transmission line. The crossover is formed of two pairs of cross arms wherein, in each pair, the arms are spaced apart by an electrical length of ninety degrees along the first and the second transmission lines, and couple power of the waves between the first and second transmission lines with an introduction of a quarature phase relationship. The impedance presented to a wave of a cross arm is less than the corresponding impedance of the first and the second transmission lines by a factor of the square root of two to inhibit the generation of relections at junctions between a cross arm and the first or the second transmission line. Each junction provides for a diversion of one-half the power of the wave from the first or the second transmission line to a cross arm.

Abstract: A dual-beam amplitude-modulated laser transmitter/receiver suitable for laser-radar applications is scalable to high powers because there is no active modulator element that the laser beam passes through. The transceiver comprises a laser source with two separate independent laser optical cavities. Each laser cavity is similar, but each operates at its own frequency. Signals from the two cavities are superimposed at a combining beam splitter to form two transmitter output beams with each combined beam intensity modulated at the laser difference frequency. The output consists of two beams separated in elevation and with equal beam powers from each laser cavity the intensity modulation is 100%. Each beam has its own homodyne detector and separate local oscillator. Thus, each beam path is considered to be a distinct homodyne transceiver. If the frequency of one of the laser sources is changed in time, an AM/FM/CW output suitable for absolute range measurements and fine doppler is generated.