Showing papers on "Data acquisition published in 1991"

New Fast GPS code-acquisition technique using FFT

Abstract: A new spread-spectrum code-acquisition technique for the navigation systems Navstar/GPS and Glonass is introduced. This technique uses the FFT to compute the correlation function, thereby eliminating the time-consuming code phase shift process. Comparisons with existing systems show a theoretical reduction in acquisition time of about 2000 times.

Technology Independent Large Signal Non Quasi-Static FET Models by Direct Construction from Automatically Characterized Device Data

Abstract: This paper describes a new, general and accurate, large signal GaAs FET model for nonlinear (e.g. harmonic balance) circuit simulation, its fast and unambiguous construction (model generation) by explicit calculations applied to the raw device data, and the adaptive, automated data acquisition system used to characterize the device. The model implementation in a harmonic balance simulator, the model generation procedure, and the automated data acquisition system form an efficient, practical, commercially available package. for state-of-the-art nonlinear circuit design.

The Oxford submicron nuclear microscopy facility

Abstract: This paper describes the unique nuclear microprobe facility now established in the University of Oxford. The system, which uses a dedicated small accelerator, operates on a regular daily basis, therefore the emphasis of the design has been on achieving reliable, high-quality performance while minimising overheads of alignment in the focusing system and off-line data processing. The beam-optical system from the ion source to the final lens is described. The final lens has been specially developed to have negligible sextupole-field contamination which allows submicron operation using simple alignment procedures. The system uses up to three beam lines with specialised target chambers. These are described briefly. The data acquisition system uses distributed processing with a VMEbus 68020 microcomputer system handling collection and on-line sorting of data from up to six detectors, a graphics workstation for operator interfacing and a mainframe computer for archiving and off-line processing of data. The components of the system communicate via Ethernet and a low-failure-rate/highthroughput communications protocol has been developed. The archiving procedures are designed to handle high volumes of data (up to 100 Mb per day) with efficient data compression, transparent recall of recent data and simple restoration of archived data.

The oxford submicron nuclear microscopy facility

Abstract: This paper describes the unique nuclear microprobe facility now established in the University of Oxford. The system, which uses a dedicated small accelerator, operates on a regular daily basis, therefore the emphasis of the design has been on achieving reliable, high-quality performance while minimising overheads of alignment in the focusing system and off-line data processing. The beam-optical system from the ion source to the final lens is described. The final lens has been specially developed to have negligible sextupole-field contamination which allows submicron operation using simple alignment procedures. The system uses up to three beam lines with specialised target chambers. These are described briefly. The data acquisition system uses distributed processing with a VMEbus 68020 microcomputer system handling collection and on-line sorting of data from up to six detectors, a graphics workstation for operator interfacing and a mainframe computer for archiving and off-line processing of data. The components of the system communicate via Ethernet and a low-failure-rate/highthroughput communications protocol has been developed. The archiving procedures are designed to handle high volumes of data (up to 100 Mb per day) with efficient data compression, transparent recall of recent data and simple restoration of archived data.

Image forming device

Abstract: PROBLEM TO BE SOLVED: To provide a low-cost, image-forming device capable of outputting images only to a central part excluding the periphery of a paper sheet. SOLUTION: The image-forming device comprises: a first size acquisition means 11 for acquiring the size of an output paper sheet; a second size acquisition means 12 for acquiring the size of a first region for outputting images that is smaller than the output paper sheet at the center of the output paper sheet; a read region determination means 13 for determining an image read region, based on the size of a paper sheet acquired by the first size acquisition means 11 and the first region acquired by the second size acquisition means 12; an input image data acquisition means 14 for acquiring input image data by reading images in the image read region on a document; an image data conversion means 15 for converting the acquired input image data to output image data; and an image output means 16 for outputting images based on output image data obtained by the image data conversion means 15 into the first region of the output paper sheet. COPYRIGHT: (C)2009,JPO&INPIT

Substation load distribution monitor system

Abstract: The monitoring and control system of the present invention provides a distributed intelligence, data acquisition and control system which collects and analyzes large amounts of data representing power usage from a power distribution substation. The system also provides the capability of various control functions for the substation. The system provides communications capabilities between local devices and also with a remote computer. The system provides real time monitoring of power usage and real time control of various functions in the substation.

Harmonic power flow determination using the fast Fourier transform

Abstract: Multichannel data acquisition systems and commercially available digital signal processing software packages make the determination of harmonic power flow possible provided the limitations of the analysis techniques are understood. The authors describe how data from a typical acquisition system can be processed using the fast Fourier transform and discuss possible errors (e.g. those due to leakage) and how to avoid them using techniques such as skewing correction and windowing. Guidelines on the practical application of the transform in analyzing measured data are presented. The analysis method has been used successfully to analyze data obtained at a traction (railway supply) substation which had a sixth-harmonic resonance caused by the interaction of a harmonic filter and the only supply system. >

Data handling

Abstract: Software packages for integrated data acquisition, analysis, display, and reporting are discussed. Highlights of new packages are faster data capture, extended computationally-intensive analyses, and better visualization. Major upgrades of a number of PC packages and the role of the workstation as the pacesetter of the marketplace are noted. Data acquisition for DSP boards and the increased use of icons are addressed. Embedded systems software for DSP and CASE tools are mentioned. A table of representative packages is included. >

A versatile PC-based range finding system

Abstract: The authors present an active triangulation-based range finding system composed of an independent laser system generating a sheet of light projected on the object to be measured, which is placed on a linear or a rotary table driven by a personal computer. This computer includes a video digitizer board to which two cameras, looking at the scene from both sides of the sheet of light, are connected. Besides its low cost, this system has several advantages over similar systems. First of all, two cameras are used to limit the occlusion problem, and a method is proposed to integrate range data obtained from these cameras into a single range image. The calibration of each camera is very simple, provides subpixel accuracy, and is performed only once as the laser or the camera does not move. The data acquisition uses an interpolation technique that produces very accurate depth measurements. The system also provides intensity data in registration with the range data. The application of all these techniques is illustrated by showing numerous examples of the range and intensity data acquisition from various complex objects. >

Strategies to improve contrast in turboFLASH imaging: reordered phase encoding and k-space segmentation.

Abstract: TurboFLASH (fast low-angle shot) sequences enable the acquisition of an image in a fraction of a second. However, unique to T1-weighted ultra-fast imaging, the magnetization variation during image acquisition can produce artifacts along the phase-encoding direction. In this study, the signal behavior and nature of these artifacts were analyzed with various acquisition schemes to improve image contrast. The magnetization variation during image acquisition and its filtering effect on the image were simulated for three different approaches to T1-weighted turboFLASH imaging: standard turboFLASH with (a) mono-tonically ascending phase-encoding steps, (b) reordered phase encoding, and (c) k-space segmentation. Each of the modified data acquisition schemes has advantages. However, for sub-second imaging, reordered phase encoding produced improved image contrast over that of standard turboFLASH, and segmented k-space imaging gave superior tissue contrast compared with that of both standard and reordered turboFLASH, with imaging time that permits breath-hold studies.

A fast, time averaging data acquisition system for the PC‐AT bus

Abstract: A data acquisition system designed for magnetic resonance instrumentation is presented. Its performance may be suitable for a broad set of applications where repetitive and noisy signals must be time‐averaged in order to increase the signal‐to‐noise ratio. The system is built from easily available, low cost parts on a standard board for the PC‐AT (16‐bit) bus. 12‐bit data acquisition and 32‐bit time averaging take place in the memory of the PC under control of its CPU. The sustained data rate, including on‐line signal averaging, can be as high as 250 kHz (500 kHz with interlaced data acquisitions). Timing is accomplished by on‐board software programmable hardware timers. The CPU is then free for other tasks during the time, if any, between acquisition scans. Thus on‐line display of the time‐averaged data and their FT spectrum may be performed without impairing the timing accuracy, which is limited by the 10‐MHz board clock to 100 ns. All functions of the interface are controlled by machine‐language routines, callable from within quickbasic programs.

Portable personal computer with passive backplane having a doublesided staggered connector array

Abstract: A portable personal computer that utilizes a combination of an open ended card cage and a passive backplane with a double-sided staggered array of connectors that allows for the horizontal placement of a large number of computer circuit boards in a low profile design as well as allowing easy access to the circuit boards for repair and replacement The open ended cage design also affords adequate cooling of the circuit components in the confines of a portable case. By hinging the card cage to the portable case, increased accessibility to the circuit boards is afforded. A welding data acquisition and control system embodiment is described that utilizes the portable computer for the acquisition of welding data for use in either operator or automated welding control. The system is capable of utilizing a wide range of welding programs for a wide rang of welding processes. The system is capable of utilizing analog and digital data inputs and can produce both analog and digital outputs for operator and automated welding process control.

Automated measurement method for 360° profilometry of 3-D diffuse objects

Abstract: An automated measurement method for 360° surface topography of 3-D diffuse objects is presented The method is based on the simple principle of triangulation with structured illumination The geometric specifications of the structured light module used in the system are analyzed on a computer Using an advantageous data acquisition schedule, high data acquisition rates and measuring accuracy can be achieved The system comprises a structured lighting projector, a 2-D detector array, and a microcomputer for control and processing Experimental results for 3-D objects are offered

Data Acquisition Techniques Using PCs

Abstract: From the Publisher: Data Acquisition Techniques Using Personal Computers, 2E offers all the information needed to implement a PC-based data acquisition system. The book covers all aspects of setting up a system ranging from sensors, to data acquisition cards, to PC hardware, to software. It shows how to include circuits that transform analog reality into digital data that the computer can understand. The coverage involves almost all areas of industry and applications of instrumentation in electrical engineering (ie. control, robotics), biomedial engineering, and mechanical systems. Praise for the First Edition "A mix of tutorial and reference information for engineers setting up or using a PC-based data acquisition system. Spanning many disciplines, this well-illustrated book gives the readers enough information to build a system from scratch or to simply piece together appropriate commercial hardware and software products...a useful book for anyone who wants their PC to acquire, analyze or display data." (EDN)

Automated data collection and analysis system for MOSFET radiation detectors

Abstract: Metal oxide semiconductor field effect transistors(MOSFET) have been used as radiationdosimeters. Because of their small detector size, minimal power requirements, and signal integration characteristics, they offer unique possibilities as real‐time dose monitors in radiotherapy. An automated data collection and analysis system for use with MOSFETradiationdosimeters has been designed and built. The objective was to design a system which can acquire and process the MOSFET signals in real time, in any radiation field encountered in radiotherapy. In particular, major problems have been solved arising from the intrinsic drifts of the MOSFET signal during low dose rate measurements. These signal drifts are significant when the MOSFETdetector is used in applications such as on‐line monitoring of radiationdosedelivery in brachytherapy or radioimmunotherapy. The data collection and analysis system includes a portable IBM‐compatible personal computer fitted with digital‐to‐analog and analog‐to‐digital converter boards. A single‐chip programmable current supply is used to power the MOSFETdosimeters. Intrinsic and extrinsic drifts in signal due to ion diffusion and electron tunneling are corrected by deconvolution of the collected data in real time or after data collection. The data acquisition system and signal‐processing methodologies are described.

System for fixing tariffs and proportional collection of fees in public transport

Abstract: The invention relates to a system intended for fixing tariffs and for collection of transport fares in public transport networks. The device comprises code number media (11) put at the disposal of the users, proximity detectors (5) and a data acquisition ADP system (10, 20, 22) at several levels. This device permits fare collection strictly in relation to the distance travelled by each user, the boarding and alighting stops of each user being computed daily by a central data processing system.

Data converter for CT data acquisition system

Abstract: A data acquisition system employs data conversion circuitry well suited to large multisensor systems such as computerized tomography systems utilizing X-ray detectors. The data conversion system consists of a number of detectors or similar signal sources and a corresponding number of data registers and accumulation registers. Each data register contains a previous sample output of a signal source. Differential data conversion is employed such that the difference between the previous output and the current signal source output is added to the data register in order to update it to the current signal source output. Each signal source is repeatedly sampled and the samples accumulated in an accumulation register. The data conversion system thus provides increased system linearity, accuracy, and dynamic range, and yields improved measurement simultaneity of a large number of signal sources. These factors combine to result in substantial improvement in image resolution after suitable processing by a computer. Increased resolution and dynamic range is achieved through oversampling and a differential data conversion technique, which may be implemented at relatively low cost with largely conventional components.

Automatic modeling of physical phenomena : application to ultrasonic data

Abstract: The physical modeling of natural phenomena is treated in this paper as an information transforming process which can be performed by a general modeler composed of an array of sensors, a central processing unit, a memory, and an array of actuators. The most characteristic property of such a system is its capability of predicting some properties of observed phenomena from partial perception and past experience. This property is realized if the central processing unit is acting as an estimator of a conditional average. As the condition, the partial set of signals from the sensor array is employed, while the complementary set is estimated from it. In the estimation the smoothed empirical probability distribution is employed. It is constructed from the empirical samples obtained by a set of prototype experiments and stored as a data base in the memory. The proposed modeler was simulated on a laboratory minicomputer which was part of a general data acquisition system. It was applied to the modeling of acoustic emission and ultrasonic scattering phenomena. It is shown experimentally that forward and inverse acoustic emission problems can be solved and a simple characterization of material inhomogeneities can be performed by the modeler. A mutual mapping of conditional data to estimated ones and the reverse is the basis of an iteration procedure which corresponds to a discrete dynamical process in the multidimensional data space. Numerical examples show that attractors of this process are the vectors of the data base. Therefore, the iteration can be efficiently applied for noise reduction. The operation of this dynamical system is comparable to the operation of neural networks in which the memory corresponds to the data base.

Real-Time Principal Component Analysis Using Parallel Kalman Filter Networks for Peak Purity Analysis

Abstract: A new approach for pedorming principal component analysls (PCA) during data acquisition is descrlbed. The method is based on a network of multllkmar models whkh are fit to data with the dlscrete Kaiman filter. Appilcatlon to absorbance matrices such as those obtained in chromatography wlth multiwavelength detection is considered. Multivariate data projected into two- and three-dlmenslonal subspaces are fit with linear and planar models, respectively. Model deviations, detected using principles of adaptive Kalman filtering, are used to elucidate the rank of the data set. Principal component eigenvectors are then constructed from the individual models. Results of this initial work using simulated and experimental data demonstrate that extraction of the flrst two principal components is readily accomplished and eigenvectors obtained are in good agreement wlth tradltlonai batch PCA results. Extendon to more principal components should be possible although It wlli increase the number and complexity of models. Advantages of the new algorithm include its recursive implementation, parallel structure, and ability to Indicate model errors as a function of time. The procedure should prove particularly useful for self-modeling curve resolution applications In chromatography.

Pan-da And Beyond Data Acquisition For the Next Generation Experiments

Abstract: We report on the status of the PAN-DA data acquisition system presented at the last Real Time Conference. Since that time, PAN-DA has been successfully used in the fixed target program at Fermilab. We also report on the plans and strategies for development of a new data acquisition system for the next generation of fixed target experiments at Fermilab. 10 refs., 3 figs.

Solving data acquisition and processing problems in power systems using a pattern analysis approach

Abstract: The authors propose a new methodology for the combined solution of the topological identification observability analysis and bad data processing problems in power systems. The solution is based on a pattern analysis approach. An efficient framework is suggested for solving data acquisition and processing problems, as well as joining pattern analysis and analytical procedures. Two different techniques of pattern analysis are combined to produce a classifier and an estimator with unique characteristics to deal with noisy environments. Unobservable network areas, multiple interacting bad data and bad critical measurements can be efficiently treated. The patterns required for the training process can be acquired from the SCADA system and/or from load-flow simulations. Test results are presented for the IEEE 24-busbar reliability test system. >

Data acquisition system having novel, low power circuit for time-division-multiplexing sensor array signals

Abstract: An electronic circuit architecture time-division-multiplexes analog sensorignals from a distributed sensor array onto a common transmission line in a digitally encoded format. The architecture synchronizes the multiplexing, sampling and encoding to ensure a proper settling of the analog data signals and is fabricated to be compact with low power consumption for a cost-effective implementation for a number of sensors.

One-minute rain rate distributions in Japan derived from AMeDAS one-hour rain rate data

Abstract: By examining measured 1-min rain rate data presently available and 1-h rain rate data obtained by AMeDAS (Automated Meteorological Data Acquisition System) in Japan, a simple conversion method of 1-h rain rate data to 1-min rain rate distribution is presented. The prediction accuracy of the method is evaluated, and good accuracy is confirmed. Maps are given of the mean and standard deviation (normalized by the mean value) of 1-min rain rate for 0.01% of time based on AMeDAS data in Japan. Moreover, the effect of a record-breaking heavy rain even on long-term statistics is discussed. Since the method has been successfully applied to various locations in Japan, it can be expected to be applicable to regions of the world where 1-min rain rate data have not yet been available. >

PANDA: A simple, portable seismic array for local- to regional-scale seismic experiments

Abstract: A portable array for numerical data acquisition (PANDA) was designed and built in-house at the Center for Earthquake Research and Information (CERI), Memphis State University. The design goal was a transportable set of instruments that could record high-quality seismic data. By making modifications to traditional seismic network technology and using a super-microcomputer workstation for digital data acquisition, this array provides a set of reliable and cost-effective instruments for the collection and analysis of high-resolution seismic data. The field equipment and central recording system are designed to overcome several major limitations in existing seismic network technologies, such as low dynamic range, single-component recording, lack of a common time base between stations, topographic constraints in radio telemetry, and lack of field processing capabilities. PANDA overcomes these limitations. To increase the dynamic range and record full three-component data, each PANDA station has six channels divided into two three-component sets. One set is operated at high gain and the other at low gain, giving a minimum of 90 dB dynamic range. Modular design of the PANDA station electronics facilitates field maintenance and also permits the stations to be run in several additional modes (e.g., with both sets of three channels operating at high gain) or with different sensors on each set. Each telemetry link to the central recording site carries data from two stations (12 channels) by repeating data from an “outer” seismic station through an “inner” seismic station and repeater combination. In addition, several repeat-only stations were built. This ability to repeat signals increases the aperture of PANDA to more than 150 km and overcomes topographic limitations on station locations. Other design features include low power consumption, solar power operation, and transmission of daily calibration and diagnostic signals. These features enable the stations to operate unattended for long periods and provide verification of station performance from the central recording site. The central recording system is based on a high-performance super-micro-computer workstation with a 256 channel A/D front end, which allows both real time digital recording with a common time base and immediate processing of the data. A 40-station network with 6 channels per station uses 240 channels, leaving 16 channels for auxiliary inputs such as time codes and spares. PANDA was field tested in the Arkansas earthquake swarm region from October 1986 to April 1987. It was then deployed in San Juan, Argentina, from August 1987 to May 1988, and in Jujuy, Argentina, from September 1988 to May 1989. A total of more than 20,000 earthquakes were recorded during the two Argentina experiments.

Monte Carlo simulation in SPECT: complete 3D modelling of source, collimator and tomographic data acquisition

Abstract: A sophisticated SPECT (single-photon-emission computed tomography) simulation package has been developed, permitting full tomographic acquisition of data from physically realistic nonuniform and asymmetric 3-D source objects. The package is based on the Los Alamos code MCNP (Monte Carlo for Neutron-Photon transport), which has been extensively modified by the authors to allow complete collimator and source modeling and direct manipulation of the geometric and physical parameters of the nuclear medicine experiment. A brief description of the synthetic SPECT imaging system and its capabilities is presented. The code MCNP and details of the modifications that have been necessary in order to run MCNP for this application are provided. Preliminary experiments to verify the accurate modeling of the imaging situation are also described. Its ability to model two different collimator geometries (parallel-hole and cone-beam) and steps taken to verify the models are discussed. >

Method for using seismic data acquisition technology for acquisition of ground penetrating radar data

Abstract: A method and apparatus are used in the acquisition of data by ground-penetrating radar, wherein the signals thus obtained are input to a pre-amplifier which contains filtering component such as an anti-aliasing filter. The base gain of the system is switch selectable and electronically adjusted to bring the input signal to between one half and full scale on an analog to digital converter input. The converted digital value has a resolution of fifteen bits for processing.