42 research outputs found

    Auto-Routable, Configurable, Daisy Chainable Data Acquisition System

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    A method and apparatus for an acquisition system includes a plurality of sensor input signal lines. At least one of the plurality of sensor input signal lines operatively connects to at least one of a plurality of amplifier circuits. At least one of the plurality of amplifier circuits operatively connects to at least one of a plurality of filter circuits

    Methods and circuitry for reconfigurable SEU/SET tolerance

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    A device is disclosed in one embodiment that has multiple identical sets of programmable functional elements, programmable routing resources, and majority voters that correct errors. The voters accept a mode input for a redundancy mode and a split mode. In the redundancy mode, the programmable functional elements are identical and are programmed identically so the voters produce an output corresponding to the majority of inputs that agree. In a split mode, each voter selects a particular programmable functional element output as the output of the voter. Therefore, in the split mode, the programmable functional elements can perform different functions, operate independently, and/or be connected together to process different parts of the same problem

    Some Improvements in Signal-Conditioning Circuits

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    Two documents present wide-ranging discussions of some issues in the design and operation of signal-conditioning circuits. The first document focuses on active low-pass filter circuits that contain resistors, capacitors, and operational amplifiers. It describes design and operational problems encountered previously, deficiencies of prior designs, and four design improvements to overcome the deficiencies. These improvements are as follows: 1. An offset-calibration feature in which an electronic switch isolates a filter capacitor in order to preserve its voltage during a calibration performed to measure the offset voltage of the operational amplifier; 2. Configuring a pair of complementary operational amplifiers to prevent latchup and decrease the degree of nonlinearity in overall response; 3. Minimizing distortion by taking the filter output from the operational-amplifier output nodes instead of from one of the other nodes as in prior designs; and 4. Providing for switching different feedback resistors to change filter break frequencies. The second document addresses topics in the architecture of signal-conditioning and multiplexing circuitry. Improvements are described as being made with respect to greater compactness, increased flexibility in accommodating a variety of inputs, improvements in filter performance, simplification of wiring, and reconfigurability of designs

    Real-time garbage collection for list processing using restructured cells for increased reference counter size

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    In a list processing system, small reference counters are maintained in conjunction with memory cells for the purpose of identifying memory cells that become available for re-use. The counters are updated as references to the cells are created and destroyed, and when a counter of a cell is decremented to logical zero the cell is immediately returned to a list of free cells. In those cases where a counter must be incremented beyond the maximum value that can be represented in a small counter, the cell is restructured so that the additional reference count can be represented. The restructuring involves allocating an additional cell, distributing counter, tag, and pointer information among the two cells, and linking both cells appropriately into the existing list structure

    Practical Active Capacitor Filter

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    A method and apparatus is described that filters an electrical signal. The filtering uses a capacitor multiplier circuit where the capacitor multiplier circuit uses at least one amplifier circuit and at least one capacitor. A filtered electrical signal results from a direct connection from an output of the at least one amplifier circuit

    Inertia and Double Bending of Light from Equivalence

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    Careful examination of light paths in an accelerated reference frame, with use of Special Relativity, can account fully for the observed bending of light in a gravitational field, not just half of it as reported in 1911. This analysis also leads to a Machian formulation of inertia similar to the one proposed by Einstein in 1912 and later derived from gravitational field equations in Minkowsky Space by Sciama in 1953. There is a clear inference from equivalence that there is some type of inertial mass increase in a gravitational field. It is the purpose of the current paper to suggest that equivalence provides a more complete picture of gravitational effects than previously thought, correctly predicting full light bending, and that since the theory of inertia is derivable from equivalence, any theory based on equivalence must take account of it. Einstein himself clearly was not satisfied with the status of inertia in GRT, as our quotes have shown. Many have tried to account for inertia and met with less than success, for example Davidson s integration of Sciama s inertia into GRT but only for a steady state cosmology [10], and the Machian gravity theory of Brans and Dicke [11]. Yet Mach s idea hasn t gone away, and now it seems that it cannot go away without also disposing of equivalence

    Improved Discrete Approximation of Laplacian of Gaussian

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    An improved method of computing a discrete approximation of the Laplacian of a Gaussian convolution of an image has been devised. The primary advantage of the method is that without substantially degrading the accuracy of the end result, it reduces the amount of information that must be processed and thus reduces the amount of circuitry needed to perform the Laplacian-of- Gaussian (LOG) operation. Some background information is necessary to place the method in context. The method is intended for application to the LOG part of a process of real-time digital filtering of digitized video data that represent brightnesses in pixels in a square array. The particular filtering process of interest is one that converts pixel brightnesses to binary form, thereby reducing the amount of information that must be performed in subsequent correlation processing (e.g., correlations between images in a stereoscopic pair for determining distances or correlations between successive frames of the same image for detecting motions). The Laplacian is often included in the filtering process because it emphasizes edges and textures, while the Gaussian is often included because it smooths out noise that might not be consistent between left and right images or between successive frames of the same image

    SEE Tolerant Self-Calibrating Simple Fractional-N PLL

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    We show a reliable on-chip clock multiplier for SEE testing or RHBD applications. Fine control of clock frequency is provided without complex delta-sigma schemes. Conflicts that can occur with voted PLLs are discussed, and how to avoid them

    Avionics for a Small Robotic Inspection Spacecraft

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    A report describes the tentative design of the avionics of the Mini-AERCam -- a proposed 7.5-in. (approximately 19-cm)-diameter spacecraft that would contain three digital video cameras to be used in visual inspection of the exterior of a larger spacecraft (a space shuttle or the International Space Station). The Mini-AERCam would maneuver by use of its own miniature thrusters under radio control by astronauts inside the larger spacecraft. The design of the Mini-AERCam avionics is subject to a number of constraints, most of which can be summarized as severely competing requirements to maximize radiation hardness and maneuvering, image-acquisition, and data-communication capabilities while minimizing cost, size, and power consumption. The report discusses the design constraints, the engineering approach to satisfying the constraints, and the resulting iterations of the design. The report places special emphasis on the design of a flight computer that would (1) acquire position and orientation data from a Global Positioning System receiver and a microelectromechanical gyroscope, respectively; (2) perform all flight-control (including thruster-control) computations in real time; and (3) control video, tracking, power, and illumination systems
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