Showing papers on "Data acquisition published in 1992"

Peripheral data acquisition, monitor, and adaptive control system via personal computer

Abstract: A peripheral data acquisition, monitor, and adaptive control system is disclosed in which a personal computer (PC) and one or more input/output (I/O) Bridge devices interface signals from electronically-controlled devices to the PC via the keyboard port, thus permitting data, such as measurement data, to be automatically and directly entered into application programs such that the PC can take action and control outputs based upon the measurement data. A software control program is also disclosed which allows the user to configure the system for orienting the user as to which devices are being controlled, reading digital and analog inputs, making decisions based upon the information using specific user-defined conditions, and setting digital outputs. The system is also adapted to interface with a wireless or AC power-line transmission media.

Cerebral biopotential analysis system and method

Abstract: EEG leads are connected to a patient's head (14) by a set of surface electrodes which transmit signals over a patient cable (16) to a 19-channel EEG data acquisition system (12). Data acquisition system (12) filters, amplifies and digitizes the EEG waveforms and sends the digitized data to the microcomputer (18) via high speed synchronous serial line (26). Microcomputer (18) processes the serial data stream to generate computed data arrays. These arrays are then used in conjunction with predetermined reference arrays derived from clinical studies to produce diagnostic indices. These indices are displayed on graphics display (20). Printed output of the diagnostic index is available on the hard copy output device (22) which is connected to the microcomputer (18). Interaction between the operator and the system is provided by means of a keyboard (24) and a pointing device (28) with feedback provided by graphics display (20).

Method and device for optical input of commands or data

Abstract: A method of user command or data acquisition in a processing system is described that allows to analyze human hand and finger motions. The activities are then interpreted as operations on a physically non-existent input device. The resulting optical user/computer interface complements the visual screen-to-user path with a hand-to-image data acquisition link from the user to the processor unit. It allows to emulate different types of manually operated input devices (mouse, keyboard, etc.). Mechanical input units can be replaced by virtual devices, optimized for the current application and for the user's physiology. The speed, simplicity and unambiguity of manual data input will be maintained. Sensing of finger motions can generate feedback to reduce the hazard of repetitive strain injury (RSI) syndrome.

Adjustable dual-detector image data acquisition system

Abstract: An improved image acquisition system allows the angular displacement between two detectors to be adjusted between 90° and 180° to reduce the imaging time for both 360° and 180° scans. A patient table is displaced vertically and horizontally from a lateral axis to allow the body of a patient to be positioned next to the detectors and to improve resolution.

Apparatus for the functional assessment of human activity

Abstract: An apparatus for the functional assessment of human activity. The invention comprises four major components: the data acquisition unit, a body suit interface unit, a body suit having a plurality of mercury switches and a graphics oriented software package. The body suit is made from a non-conductive material, preferably a thermalactyl material with sensors permanently attached in position corresponding to the movements to be measured. The sensors have no direct electrical contact with the human wearer thus permitting the measurement period to extend to many hours. A portable data acquisition unit which is connected to the sensors enables the system to be used "on the job" to obtain mobility measurements under actual conditions. A graphic analysis means, connected to said data acquisition means, is provided for providing a visual display of the length of time that the human has spent in each of the pre-determined positions and the range of motion measured by the data acquisition unit. The system is especially useful in rehabilitation programs for quantifying the extent of mobility to select practical occupational alternatives.

Novel fast GPS/GLONASS code-acquisition technique using low update rate FFT

Abstract: A novel ‘differential’ decoding technique is proposed which enables pre-averaging instead of postintegration for a substantially low update rate ‘FFT-IFT’ correlation in sprcadspectrum (navigational) receivers. N-channel code acquisition can be performed to monitor the time dispersion with FFT time left to analyse frequency dispersion in highly reflective areas (e.g. an urban environment).

Programs of the National Data Buoy Center

Abstract: Platforms of the National Data Buoy Center provide vital meteorological and oceanographic observations from data-sparse marine areas worldwide. The data are essential for real-time weather forecasting and research programs. This paper provides information on the data-acquisition systems, networks, monitoring capabilities, data processing and dissemination, data quality and availability and related technology development for these platforms.

A/D converter performance analysis by a frequency-domain approach

Abstract: An analysis of the frequency domain approach in the test of analog-to-digital convertors (ADCs) is presented. Following the introduction of a spectral analysis algorithm based on the use of windows with minimum sidelobe energy, expressions are given to determine ADC performance parameters. Corrections are introduced to improve accuracy in practical cases, and simulation results are presented to support the discussion. The approach presented is sufficiently precise in the characterization of a device, even with data records of comparatively small size. Provided the appropriate correction factors are taken into account in some determinations, the accuracy is not dissimilar to that of other test methods, with the advantage that both data acquisition and data processing procedures are fairly simple. >

Method and apparatus for adjustment of acquisition parameters in a data acquisition system such as a digital oscilloscope

Abstract: A data acquisition system such as a digital oscilloscope includes a central processing unit which controls the waveform memory, analog to digital converter, trigger generator, and display to automatically adjust the acquisition parameters to optimal values for a particular repetitive waveform received by the data acquisition system. The system initially optimizes the acquisition parameters for determining the length of the input waveform and then determines the input waveform length. Parameters are then determined for best frequency analysis of the input waveform, and the waveform is then frequency analyzed to determine its spectral content. Based on this information, the acquisition parameters are adjusted such that the sampling rate is sufficient to avoid aliasing of the highest significant frequency components of the input waveform while accommodating all or substantially all of the waveform within the memory capacity of the waveform memory, and the voltage range of the analog to digital converter is set so that the range of the input signal will substantially match the input range of the converter.

Peripheral data acquisition, monitor, and control device for a personal computer

Abstract: A peripheral data acquisition, monitor, and control device is disclosed which utilizes an Input/Output (I/O) Bridge device for interfacing signals from electronically-controlled peripheral devices to a personal computer (PC) via the keyboard port, thus permitting data, such as measurement data, to be automatically and directly entered into application programs such that the PC can take action and control outputs based upon the measurement data. The I/O Bridge device automatically inputs information into the host computer without having to manually type the information on the keyboard, and also interfaces with the host computer in order to monitor and control various real-world tasks, such as manufacturing functions.

Real-time computer-optimized electron coincidence spectrometer

Abstract: An electron coincidence spectrometer utilizing real‐time optimization and control by a standard IBM 80286 personal computer is described. Details of the system hardware and software are presented together with a description of the optimization routine adopted for maintaining the tuning of the spectrometer and data acquisition. Data collected by the computer‐controlled spectrometer for (e,2e) coincidence experiments are also presented.

Fault location techniques for radial and loop transmission systems using digital fault recorded data

Abstract: The authors present digital fault location techniques for transmission systems when digital fault recorded data are available at one terminal or two terminals. The systems under consideration are a 115 kV loop transmission system with data available at two terminals and a 69 kV radial transmission system with data available at one terminal. The data under consideration were recorded using digital fault recorders. The conversion of the data to workable data files and the techniques developed to achieve the highest accuracy in determining the fault location are discussed. Intermediate load buses and loads are considered in determining the fault location. An example of the effect of neglecting the presence of these loads is discussed. The fault location techniques are based on both the apparent impedance concept and the use of the three-phase voltage and current phasors. A test case with the exact fault location is presented. The techniques were developed on an IBM PC. >

A VISI Smart Sensor For Fast Range Imaging

Abstract: VLSI technology makes possible a powerful new sensing methodology--the smart sensor. In a smart sensor, transducers are integrated with processing circuitry so that desired information can be intelligently extracted at the point of sensing. Physical limitations force traditional systems to artificially partition sensing and processing functions. By eliminating such partitioning, VLSI smart sensing adds a new dimension to the design of both sensors and sensing algorithms. In this research, a high-performance VLSI range-image sensor has been built using the smart sensing methodology. This sensor measures range via light-stripe triangulation, a mature technology widely used in robotic systems. VLSI-based smart sensing made practical a cell-parallel implementation of the light-stripe method. Experiments with the cell-parallel sensor show that its performance is substantially better than that of traditional light-stripe systems. Range image acquisition time is decreased by two orders of magnitude. Furthermore, the range measurement process is qualitatively different, providing more robust and more accurate 3-D measurements. The success of the cell-parallel sensor can be attributed directly to the use of smart sensing and convincingly demonstrates the power of the technique. One of the most distinguishing features of this work is that it is not just a re-implementation of established algorithms using VLSI. Rather, this thesis demonstrates that intelligent data acquisition makes possible new approaches to sensing that can significantly improve sensor performance.

Alarm processing and fault diagnosis using knowledge based systems for transmission and distribution network control

Abstract: The authors present two expert system developments which are each concerned with utilizing, to the best effect, the increasing volume of SCADA (supervisory control and data acquisition) system data available to power system control staff. The systems presented, APEX and RESPONDD, are aimed at the two related fields of alarm processing and fault diagnosis, respectively. The areas of commonality between these systems are discussed, as well as details specific to each separate system, including a case of study illustrating the practical operation of each. >

A flexible data acquisition system for timing pulsars

Abstract: We describe a flexible, inexpensive data acquisition system built for high‐precision timing observations of pulsars. The system is designed to interface with a wide variety of radio telescope receiver back ends; it permits standardized measurement techniques and data formats in work carried out at a number of different observatories. Copies of the basic ‘‘Mark III’’ system are now in regular use at the Arecibo Observatory, Green Bank, and the Very Large Array. We describe the specifications, hardware, and software implementation of the system, and briefly outline some of its current applications.

Virtual instrument for instantaneous power measurements

Abstract: A computer-based data acquisition system coupled by means of a general-purpose instrumentation bus (IEEE488/GPIB) with a digital oscilloscope is used to create a virtual instrument with instantaneous and average power measurement capability. The software signal-processing capability of the data acquisition system was used to compensate instrument measurement deficiencies and to enhance signal capture. The virtual instrument is shown to provide instantaneous, AC, and fitted-power averages and time-based plots of power variations for both linear and nonlinear system responses to external excitation. Data taken on a resistor, capacitors, an AC-to-DC power converter, and a bipolar junction transistor inverter establish a +or-3% sensitivity with a 10- mu W-100-W range over a 1-Hz-10-MHz frequency span. >

A simulation of dynamic SPECT using radiopharmaceuticals with rapid clearance.

Abstract: Data acquisition in SPECT assumes that there is no change in radionuclide distribution during data collection However, this assumption is not valid in radiopharmaceuticals with rapid temporal changes in radioactivity Artifacts and quantitative errors are studied using phantom studies, mathematical models, and clinical myocardial data Projection data of each model were sequentially multiplied by weighting coefficients that varied mono-exponentially with time, and the SPECT images were reconstructed A long data acquisition time in comparison to the clearance of the tracer can be a significant cause of artifact When the myocardial septum-to-lateral count ratio is used as an index of distortion, a shorter acquisition time than the effective half-life of the tracer is required to reduce the error of the septum-to-lateral count ratio to within 10% Since 180 degrees rotation acquisition causes artifacts depending on the direction of rotation, 360 degrees acquisition is preferable Continuous repetitive rotation acquisition is a suitable method for dynamic SPECT to reduce quantitative errors and artifacts

Digital X-ray imaging

Abstract: The introduction of digital radiographic imaging technology promises consistently high levels of diagnostic image quality, more effective use of radiation and more efficient clinical work practices. Digital X-ray imaging has many facets encompassing the acquisition, processing display, communication and archival of diagnostic information as digital data. Some of these developments are reviewed.< >

A complete calibration procedure for time domain network analyzers

Abstract: A complete calibration procedure for a fast sampling oscilloscope has been developed. This calibration makes it possible to use time-domain-reflected, time-domain-transmitted (TDR-TDT) systems at a quantitative level as a time-domain network analysis (TDNA) system. The data acquisition and calibration programs are implemented on a personal computer. All measurements are achieved in the time domain; the errors are corrected in the frequency domain, after Fourier transform. The bandwidth of the system extends from DC to 20 GHz. A whole calibration is achieved in a time comparable to LRL calibration on a classical network analyzer. >

Fast And Versatile Range Data Acquisition In A Robot Work Cell

Abstract: The paper presents a new concept for the flexible integration of a range sensor into a robot work cell. The sensor itself is based on the Coded Light Approach, which is well- known as a fast and robust active triangulation technique. We propose a depth-eye-in-hand configuration, in which the camera is mounted on the robot's hand while one or more projectors are installed rigidly with respect to the robot's base. The initial calibration of the involved system components is discussed in detail. In addition to this, since the configuration of the optical components changes with the movement of the robot, a fast re- calibration of the optical setup as well as an efficient realization of the triangulation is presented. Detailed experimental results reveal the speed of the range data acquisition as well as the accuracy of the calculated range values.

Data acquisition and control using National Instruments’ ‘‘LabVIEW’’ software

Abstract: Using conventional programming techniques for the production of data acquisition and control software can be a time‐consuming procedure, and the code subsequently produced can often be inflexible and rather difficult to modify in the light of changing experimental requirements. A new generation of commercial software products have recently appeared which it is claimed can significantly reduce development times and give rise to more flexible code and improved user interfaces. An example of such a product is National Instruments’ ‘‘LabVIEW,’’ which presents a novel graphical approach based on Apple Macintosh computer platforms. Extensive use of LabVIEW has been made by the Soft X‐ray Group at Daresbury Laboratory over the past two years, and its performance is reported on here. Several examples of experimental arrangements for which it has been used are described, and an evaluation of the product is made.

A PET camera simulator with multispectral data acquisition capabilities

Abstract: The Sherbrooke positron emission tomography (PET) simulator was designed and built to investigate parameters which influence the performance of a high-resolution PET camera based on avalanche photodiode detectors. The simulator consists of a computer controlled scanning table with 32 detection channels shared between front-end cassettes and FASTBUS boards, and of a PC-based multichannel analyzer (MCA) used as a histogramming memory for multiparametric data acquisition. Tomographic data are collected by scanning one of two opposite arrays of detectors and by rotating the object in a predetermined sequence to simulate a complete ring of detectors with various sampling schemes. All acquisition parameters are programmable through digital-to-analog converters or onboard registers. Data can be acquired in several modes: calibration, where direct or coincident energy spectra from all detectors can be registered simultaneously; standard, where only energy-validated coincident events are histogrammed as lines-of-response addresses; and multispectral, where the LOR address is encoded with the energy information to provide a multiparameter histogram. Data samples obtained in these modes are presented. >

A CAMAC based data acquisition system for flat-panel image array readout

Abstract: A readout system has been developed to facilitate the digitization and subsequent display of image data from two-dimensional, pixellated, flat-panel, amorphous silicon imaging arrays. These arrays have been designed specifically for medical X-ray imaging applications. The readout system is based around hardware and software developed for various experiments at CERN and the Fermi National Accelerator Laboratory. Additional analog signal processing and digital control electronics were constructed specifically for this application at Michigan. The authors report on the form of the resulting data acquisition system, discuss aspects of its performance, and consider the compromises which were involved in its design. Although there are some features of the resulting system which are not optimized for the particular application (e.g., analog noise considerations and data transfer bandwidth), it has been possible to perform numerous investigations of the signal and noise characteristics of these imaging devices. In addition, the first diagnostic and megavoltage images of anatomical detail have been generated, thereby verifying the concept of this new detector technology. >

Parallel acquisition of MR images using time multiplexed coils

Abstract: A new technique for parallel acquisition of magnetic resonance images is described. Two RF coils are time multiplexed into a single receiver channel, halving the effective image acquisition time with no degradation in signal-to-noise ratio. Noise filtering is performed with RF bandpass filters. In principle, the method can be extended to additional coils.

Rotational orientation sensor for laser alignment control system

Abstract: A laser alignment control system is provided for aligning a rotational portion of a machine tool to a master part. The system includes a laser emitter that is mountable to one of the components being aligned and a photosensitive target mountable to the other components. The system further includes a data acquisition subsystem for receiving signals from the target and calculating alignment errors and required corrections for the system. The alignment procedure requires rotating the target for the laser emitter in the rotating tool holder or the master part. The target and/or the laser emitter are provided with a rotational orientation sensor operatively connected to the data acquisition subsystem and operative to produce signals identifying the rotational orientation of the target and/or laser emitter.

HAWAII MR1: A New Underwater Mapping Tool

Abstract: The HIG Acoustic Wide Angle Imaging Instrument, Mapping Researcher 1 (HAWAII MR1) is an ocean floor mapping sonar designed and built at the Hawaii Institute of Geophysics, of the University of Hawaii. Towed behind a ship at a depth of 100 meters, it is capable of measuring both acoustic back scatter reflectivity and bathymetry over a swath up to 25 km wide, in all ocean depths. This system is unique in that it incorporates a network of digital signal processors, in the tow vehicle and in the shipboard data acquisition electronics, which control tow vehicle operation and process the acquired data. The tow vehicle carries two arrays of transducer elements; to reduce crosstalk, the port array operates a t 11 kHz, while starboard uses 12 kHz. Each array consists of two rows of elements, spaced one-half wavelength apart. Both rows are driven by 10 kW amplifiers, transmitting sound pulses in the water 1 - 10 msec long. The transducer arrays are then used to receive reflected sound; the arrays' output passes through programmable gain amplifiers and then is digitized by dual channel 18 bit A/D converters. The direction from which reflected sound arrives at the array is determined by measuring the phase difference between the two rows. The subsurface processors perform quadrature detection, followed by filtering matched to the transmitted pulse length; these data are then converted to block floating-point for telemetry to the surface. At the surface, data are logged in this raw form, as well as processed for display. Bathymetry is calculated from the complex cross-product of the two rows' signals; after additional filtering, phase angles and travel time are converted to cross-track bathymetry. Complex magnitudes are corrected for spreading loss, attenuation, and beam pattern to produce a back scatter image. These images are displayed on a color monitor and on color and gray scale printers. Digital signal processors reduce component count considerably, compared to previous systems; two printed circuit boards, each holding a DSP and 11 other integrated circuits, replace 35 printed circuit boards used in the first generation sonar of this type, SeaMARC II. All data acquisition and signal processing code is loaded from the surface; as the design also incorporates programmable gate arrays, the hardware configuration can also be modified remotely. Digital signal processing technology brings high performance, exceptional versatility, and enhanced reliability to this application.

Real time analysis of tokamak discharge parameters

Abstract: The techniques used in implementing two applications of real time digital analysis of data from the DIII‐D tokamak are described. These tasks, which are demanding in both the speed of data acquisition and the speed of computation, execute on hardware capable of acquiring 40 million data samples per second and executing 80 million floating point operations per second. In the first case, a feedback control algorithm executing at a 10 kHz cycle frequency is used to specify the current in the poloidal field coils in order to control the discharge shape. In the second, fast Fourier transforms of Mirnov probe data are used to find the amplitude and frequency of each of eight toroidal mode numbers as a function of time during the discharge. Data sampled continuously at 500 kHz are used to produce results at 2 ms intervals.

Traffic conditions detection method and arrangement

Abstract: To display the air traffic situation in the environment of traffic landing fields without radar system, a system consisting of a radio data link using the standard aeronautical radio service, a minicomputer for data processing and graphics display and a colour monitor for displaying the air situation is provided. On board the aircraft taken into consideration in this cooperative concept, a data acquisition and display component consisting of a minicomputer for data processing and radio data control, a data modem, a simple monitor like the screen of a weather radar or of a storm scope for displaying traffic information and an interface to the navigation system for determining the intrinsic position data is provided. This system can be expanded on the ground by means of radar and/or triangulation systems so that so-called non-cooperative aircraft can also be reliably handled.