Abstract: Digital logic and a high resolution digital to analog converter are used to adequately digitize a magnetic signal that is subsequently processed by magnetic data processing algorithms. The high resolution digital to analog converter is directly incorporated in a feedback loop of a magnetometer sensor, an expensive precision analog to digital converter is replaced by a less expensive, lower power digital to analog converter. The circuit improvement provided by the present invention includes an analog low pass filter coupled to the sensor, a digital logic circuit coupled to the analog low pass filter for providing an output signal from the magnetometer and a feedback output signal, and the digital to analog converter coupled between the digital logic circuit and a feedback coil of the sensor for coupling the feedback output signal thereto.

Abstract: An electro-optical target comprising an emissivity target and a controlled background source that has a temperature greater than, less than or equal to the temperature of the emissivity target. Appropriate adjustment of the temperatures of the emissivity target and heated controlled background source causes the "apparent" temperature of the emissivity target to be less than the specular ambient or background temperature, effectively emitting a negative temperature (delta T) relative to the background temperature produced by the controlled background source. It is useful to have an electro-optical target that emits a negative temperature (delta T) for minimum resolvable temperature testing of FLIR systems, for example, without cooling any of the components of the electro-optical target.

Abstract: A number of program modules (32,34,36) are sequentially controlled by a procedural user interface (PUI) 38 and an operating system (40) to perform tasks. Transfer of files or other data entities between the modules (32,34,36) and a storage (13) is seamlessly integrated by a sequential information integration service (SIIS) (50). For reading a file from the storage (13), a the PUI 38 or the operating system (40) generates a read command including a filename designation which can include a pathname, complete filename or wildcard characters. The read command can also include one or more arguments such as a user or group access code and an error message to display if the required file is not found. In an automatic mode, the service (50) automatically selects the most recent file corresponding to the filename designation and arguments, or displays the error message if a file meeting these criteria is not found.

Abstract: A light source system (10) for collecting and directing light. The light source system (10) includes light cubes (12) including an enclosure (22) substantially surrounding a light emitter (26). The enclosure includes a body (22) enclosing a cavity (24). A plurality of light pipes (32) are disposed to extend through the body into the interior of the cavity, so that the light pipes (32) carry light from inside to outside the cavity. By utilizing a plurality of these light cubes (12), the intensity of light can be controlled by combining light from a plurality of such light sources into a combiner unit (16) which combines the light from all of these sources into a single path. The intensity of light in the combiner output can be controlled by selectively turning on or off one or more of the light sources. The present invention thereby provides a high intensity light source which is rugged and easy to manufacture at low cost. The modular design provides built in redundancy and light intensity control.

Abstract: A DAC converts a sequence of digital codewords into an approximately piecewise linear analog waveform that follows rising and falling edges between plateau levels. The DAC processes, in parallel, each bit of the codewords to produce component waveforms that are weighted according to their bits significance and summed together to produce the piecewise linear analog waveform. Waveform shaping circuits control the rise and fall times of each component waveform so that the analog waveform's rising and falling edges settle to within a desired error bound of a linear output ramp whose slope is a function of the difference between successive codewords and the rise or fall times. The rise and fall times are preferably approximately the same. Limiting switches control the plateau levels of the component waveforms so that the analog waveform's plateaus settle to within the desired error bound of the ideal values represented by the codewords.

Abstract: Digital logic comprising a high speed analog to digital converter, a high speed analog to digital converter, a digital multiplier, and an infinite impulse response filter and decimation circuit are used to digitize a magnetic signal that is subsequently processed by magnetic data processing algorithms. The high resolution digital to analog converter is directly incorporated in a feedback loop of a magnetometer sensor, and an expensive precision analog to digital converter is replaced by a less expensive, lower power digital to analog converter. The improvement provided by the present invention includes a high speed analog to digital converter coupled between the oscillator and a first input of a multiplier, and a second analog to digital converter that is coupled between the sense coil of the sensor and a second input of the multiplier. The output of the multiplier is coupled to an infinite impulse response filter and decimation circuit that produces the digital output signal from the magnetometer.

Abstract: A transponder detection system for detecting the presence at a detection area of a vehicle on which the transponder is mounted. Two antenna arrays are located on opposite sides of the detection area, and have their boresights directed to the detection area. For each array, a sum and difference signal of signals received from the transponder are measured. The sum channel signal is used to establish whether a transmission has occurred, and the difference channel signal is used to isolate any transponder that is at the detection area.

Abstract: A FIM system integrates data from a plurality of interconnected local databases to provide users with access to a virtual database. The FIM includes a user interface for generating a global query to search the virtual database, a smart dictionary database (SDD) that contains configuration data, a data information manager (DIM) that decomposes the global query into local queries, and a plurality of local information managers (LIMs) that execute the local queries to search for and retrieve data from the enumerated databases. A filter generates a list of those local databases that contain information relevant to the global query. As a result, the DIM only generates local queries for the enumerated local databases. An input translator converts the global query into the respective local formats for the local databases so that the FIM provides true integration of heterogeneous databases.

Abstract: A linear systolic array of computation cells, each cell having several vector rotation stages. These stages are programmable to provide efficient implementation of a variety of matrix algorithms. All data movement between cells is via parameterized data packets, and the full linear systolic array is completely data flow driven at the packet level. Physical computation cells can be mapped to act as one or more logical computation cells, allowing a small array to function logically as a larger array through a logical folding. This mapping also allows defective cells to be bypassed for fault tolerance. The array can be used to compute adaptive weights in digital beamforming radar applications.

Abstract: An adaptive processor which uses the successive range and Doppler outputs of a conventional matched-filter to improve the signal-to-noise ratio for non white noise/clutter. The adaptive processor minimizes the output for a given range and Doppler cell with the constraint that the response to signals returning with specified range and Doppler offsets, with respect to the center of the range-Doppler cell, each have specified values. Weights are derived which can be applied to range-Doppler outputs in the neighborhood of the range-Doppler cell to minimize its output subject to the constraints. The weights depend on an estimate of the cross-covariance matrix of the various outputs of the range-Doppler cells that are to be weighted. The constraint parameters are specified in terms of the ambiguity function of the transmitted waveform.

Abstract: A high speed digital filter for use in digital interpolation and decimation provides a parallel processing implementation for integrator stages of a cascaded integrator-comb (CIC) filter. The parallel structure of the present invention is easily cascadeable since it allows subsequent integrator stages access to intermediate samples generated by preceding integrator stages. The parallel integrator structure may be implemented directly or may be reduced in complexity by removing redundant logic for use in decimator output sections or interpolator input sections. The parallel implementation of a CIC filter allows much higher sample rate filtering to be implemented with fewer standard CMOS logic devices than currently recognized implementations.

Abstract: A method and system for tracking the position of a moving transmitter using angle of arrival measurements from direction finding antenna arrays. Each array includes several elements, with the elements grouped to provide subarrays of different element spacings which are multiple of one half the transmitter wavelength. Ambiguity is rejected by processing angle data received from the subarrays. The signals from the arrays are processed to convert electrical phase delay into spatial angles, the spatial angle data is processed to provide the x,y position, velocity and acceleration of the transmitter. For transmitters mounted in moving vehicles, the system further processes the x,y data and applies a quality weighting factor that filters out multipath factors and permits estimation of vehicle profile information.

Abstract: A message processing system is conditioned to receive messages having a particular structure. A set of descriptors that define the message structure are inputted on a graphical display, and the graphical display is used to condition software that translates message structures to a form that is compatible with the message processing language. Changes in message structure are accommodated by simply inputting a new set of descriptors, without a need to know the message processing language. In one embodiment, message structures are defined by a plurality of fields, with descriptors defining the length and type of the fields, permissible values and fixed/variable length, optional, mandatory, and conditional selections.

Abstract: The present invention provides an arc lamp for producing a high intensity point source of light by magnetically compressing the light emitting element of the arc lamp. Arc lamp point light source 30 includes bulb 32 having two electrode 34, 36 spaced apart to have gap 35 therebetween and hermetically sealed within bulb envelope 44 filled with ionizing gas. Connector 46 is provided for applying a voltage potential across electrodes 34, 36 causing electric current to pass therebetween to generate arc plasma 42. Annular magnet 48 and bar magnet 50 located outboard of bulb envelope 44 generate a magnetic field around arc plasma 42 to compress the volume thereof between electrodes 34, 36.

Abstract: An apparatus shock isolation mounting system includes an apparatus, a base, and an apparatus chassis that carries the apparatus and is vertically slidable with respect to the base. A pair of oppositely disposed, self-centering preloaded springs with internal guide rods are attached between the apparatus chassis and the base. A pair of shock dampers are attached between the apparatus chassis and the base at different locations. The preloaded springs and the shock dampers cooperate to prevent damage to the apparatus by vibration and shock loadings.

Abstract: A method for specifying a video window's boundary coordinates directly from a multi-color video signal to separate the signals high and low variance components. The method converts the analog multi-color video signal into respective color sequences of digital frames and transforms them into another sequence of digital frames that represent the intensity of the multi-color video signal. The method generates difference frames between successive transformed intensity frames and computes a row activity measure and a column activity measure from at least one of the difference frames. The video window's approximate boundary coordinates are determined from said row and column activity measures.

Abstract: The body chemistry of a person is determined by directing a beam of light into the eye of the person, measuring the spectral response of the eye to the beam of light, comparing the measured spectral response to a standard spectral response, and forming a conclusion as to the chemistry of the body from the comparison. The light selected for the measurement does not harm the eye, and is preferably in the ultraviolet or infrared ranges. The response of the eye chosen for measurement is that of reflected, fluoresced, or scattered light. It is preferred to use two or more of these techniques simultaneously, to minimize the likelihood of error. The comparison is made by comparing the measured response of the eye to a standard response from a library of previously established responses.

Abstract: An assembly for mounting a focal plane array. The assembly includes a fixture of thermally conductive material having a first substantially planar surface and a second surface. The fixture is attached to the focal plane array at the first surface and to a frame of a housing at the second surface thereof. In a specific embodiment, the assembly further includes a mechanism for aligning the fixture, with the attached array, to the frame and at least one flexible connector for electrically connecting the focal plane array to a circuit board disposed within the housing. In the illustrative embodiment, the alignment mechanism includes a clocking slot in the second surface of the fixture which is adapted to engage a protrusion on the frame.

Abstract: Projection apparatus comprising high resolution projection display systems that generate a relatively large high resolution image on a display screen, wherein seams and tiling artifacts in observation (image) space are eliminated or minimized. The projection apparatus comprises an image source that includes a plurality of small tiled image displays, relay optics, and a photoactivated reflective liquid crystal light valve. The small tiled or mosaic-like displays that provide source images that are displayed. The images projected by the image displays are imaged onto the light valve. A polarizing beamsplitter is disposed adjacent an output surface of the light valve, and an illumination source provides illumination light that is projected by way of the polarizing beamsplitter onto an output surface of the light valve. The illumination light is reflected from the output surface of the light valve back through the polarizing beamsplitter. A projection lens projects the illumination light onto the display screen.

Abstract: A semiconductor substrate is etched in a two-step sequence, with two different liquid etchants that have different lateral etch rates. The relative time periods for which the etchants are applied are selected to achieve a close match between the actual etch profile and the desired profile. The process is particularly applicable to the formation of a gate recess in a GaAs MESFET for high power amplification.