Digital data acquisition system for underwater acoustic simulator
Analog to digital conversion of underwater signals for data processing
Hayre, H. S.↗
SEARCH · Engineering Papers
Results for “data acquisition systems”
Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Optical communications link design for the tracking and data acquisition system
The communications performances of laser intersatellite links for a future NASA data-relay system are analyzed, and block diagrams of necessary optical terminals are generated based on technology projected to be available by 1992. Direct-detection optical communications subsystems are selected to interconnect two geosynchronous (GEO) satellites separated by 160 deg along the GEO arc and to interconnect a low-earth-orbit (LEO) satellite and either of the GEO satellites. The terminal designs are based on power budget calculations performed for the various links with and without an optical background in either the receiver or transmitter fields of view (FOVs). Optical antennas with 18-cm and 30-cm primary mirror diameters on the LEO and GEO satellites can achieve a 0.000001 average bit error rate during normal operations in each of the forward and return optical links with beginning-of-life (BOL) power margins of approximately 7 dB. With an optical background in the receiver FOV, communications in the GEO-GEO return link are interrupted, the LEO-GEO return link is undegraded, and the GEO-GEO and LEO-GEO forward links remain functional with reduced BOL power margins. With an optical background in the transmitter FOV, the GEO-GEO forward and return links are noticeably degraded, the LEO-GEO return link is only slightly degraded, and the LEO-GEO forward link remains undegraded.
Marshalek, R. G.↗
Utilization of LabVIEW in the Thermal/Vacuum Data Acquisition System for the Environmental Test Laboratory at the Jet Propulsion Laboratory
Explore the source record for details and available documents.
Environmental Testing Data Acquisition LabVIEW↗
Real-time detection and data acquisition system for the left ventricular outline
The paper describes the design and capabilities of a computer-interfaced angiocardiographic automated border recognizer for real-time detection and data acquisition regarding the left ventricular outline. The contour detection is based on a thresholding technique that uses an analog comparator to compare the video signal with a constant reference level, which can be used satisfactorily only if the brightness level is roughly constant along a ventricular border. The use of dynamic reference level is described for achieving a marked improvement by having the reference level dynamically adjusted according to local brightness levels on a line-to-line basis. Also discussed are the features of the computer interface designed and implemented for the real-time on-line storage of the obtained border coordinates. Results to date indicate that the system provides an accurate left ventricular contour even in pictures with relatively low contrast. Application of the threshold detection technique to echocardiography is briefly discussed.
Reiber, J. H. C.↗
Digital data-acquisition system for measuring the free decay of acoustical standing waves in a resonant tube
A low-cost digital system based on an 8-bit Apple II microcomputer has been designed to provide on-line control, data acquisition, and evaluation of sound absorption measurements in gases. The measurements are conducted in a resonant tube, in which an acoustical standing wave is excited, the excitation removed, and the sound absorption evaluated from the free decay envelope. The free decay is initiated from the computer keyboard after the standing wave is established, and the microphone response signal is the source of the analog signal for the A/D converter. The acquisition software is written in ASSEMBLY language and the evaluation software in BASIC. This paper describes the acoustical measurement, hardware, software, and system performance and presents measurements of sound absorption in air as an example.
Meredith, R. W.↗
Telecommunications and data acquisition systems support for the Viking 1975 mission to Mars
The background for the Viking Lander Monitor Mission (VLMM) is given, and the technical and operational aspects of the tracking and data acquisition support that the Network was called upon to provide are described. An overview of the science results obtained from the imaging, meteorological, and radio science data is also given. The intensive efforts that were made to recover the mission are described.
Mudgway, D. J.↗
Cardiopulmonary data-acquisition system
Computerized system controls and monitors bicycle and treadmill cardiovascular stress tests. It acquires and reduces stress data and displays heart rate, blood pressure, workload, respiratory rate, exhaled-gas composition, and other variables. Data are printed on hard-copy terminal every 30 seconds for quick operator response to patient. Ergometer workload is controlled in real time according to experimental protocol. Collected data are stored directly on tape in analog form and on floppy disks in digital form for later processing.
Crosier, W. G.↗
Reliable magnetic tape recording for real-time data acquisition systems
The design of a real-time magnetic tape I/O system using automatic error recovery and data spooling is discussed. Real time requirements (data acquired at one rate and recorded at another by queing) must be met and data integrity must be provided regardless of tape failures or I/O errors. Automatic blocking services should be used for multiple local records storage. Avoidance of operational delays and loss of data is essential, noting the problems of the tape drives of the NASA Langley cryogenic wind tunnel. A series of block diagrames and flow charts are included.
Richard W Ross↗
Vibration Pattern Imager (VPI): A control and data acquisition system for scanning laser vibrometers
The Vibration Pattern Imager (VPI) system was designed to control and acquire data from scanning laser vibrometer sensors. The PC computer based system uses a digital signal processing (DSP) board and an analog I/O board to control the sensor and to process the data. The VPI system was originally developed for use with the Ometron VPI Sensor, but can be readily adapted to any commercially available sensor which provides an analog output signal and requires analog inputs for control of mirror positioning. The sensor itself is not part of the VPI system. A graphical interface program, which runs on a PC under the MS-DOS operating system, functions in an interactive mode and communicates with the DSP and I/O boards in a user-friendly fashion through the aid of pop-up menus. Two types of data may be acquired with the VPI system: single point or 'full field.' In the single point mode, time series data is sampled by the A/D converter on the I/O board (at a user-defined sampling rate for a selectable number of samples) and is stored by the PC. The position of the measuring point (adjusted by mirrors in the sensor) is controlled via a mouse input. The mouse input is translated to output voltages by the D/A converter on the I/O board to control the mirror servos. In the 'full field' mode, the measurement point is moved over a user-selectable rectangular area. The time series data is sampled by the A/D converter on the I/O board (at a user-defined sampling rate for a selectable number of samples) and converted to a root-mean-square (rms) value by the DSP board. The rms 'full field' velocity distribution is then uploaded for display and storage on the PC.
Rizzi, Stephen A.↗
Data-Acquisition System For Rotor Vibrations
New system trades hardware for software to reduce cost. Composite train of interspersed blade-detection pulses produced by gates at four probe ports on data-acquisition board. Pulses latch count from high-speed wraparound clock counter and initiate writing of count onto current address of memory. Result: time corresponding to each blade passage stamped into memory.
Posta, Stephen J.↗
Instrumentation and data acquisition systems
A comprehensive and integrated measurement system was identified and a design and development effort initiated to meet the criteria imposed by the National Transonic Facility operating environment. Specific measurement areas receiving concentrated attention include: data acquisition, force measurement, pressure instrumentation, flow visualization techniques, model attitude and model deformation measurement, and temperature measurement. The NTF instrument complex will be centered around four 32-bit, 1-microsecond-cycle-time central processing units connected in a multipoint-distributed network configuration. The principal activities to be supported by these computers are: (1) data base management and processing; (2) research measurement data acquisition and display; (3) tunnel and model control; and (4) process monitoring and communication control. The distributed network approach was chosen to modularize the functional software into definable and implementable parts by the various groups involved in the design and to permit use of similar hardware configurations to improve reliability and maintainability.
Guarino, J. F.↗
Self-calibrating remote atmospheric electromagnetic probe and data acquisition system
Design and development of electromagnetic probe is discussed. Probe is designed to measure wind speed, turbulence levels, and aerosol content of atmosphere. Data are used to construct real-time, three dimensional map of atmospheric composition.
Kadrmas, K. A.↗
DOE/NASA wind turbine data acquisition system. Part 4: Operations and maintenance manual (Plumbrook Station)
Preventive maintenance, calibration procedures, system verification, system operating procedures, systems software fundamentals, data base (program files), and patchboard layout are discussed.
Prenger, S.↗
Development of a simple, self-contained flight test data acquisition system
The flight test system described combines state-of-the-art microprocessor technology and high accuracy instrumentation with parameter identification technology which minimize data and flight time requirements. The system was designed to avoid permanent modifications of the test airplane and allow quick installation. It is capable of longitudinal and lateral-directional stability and control derivative estimation. Details of this system, calibration and flight test procedures, and the results of the Cessna 172 flight test program are presented. The system proved easy to install, simple to operate, and capable of accurate estimation of stability and control parameters in the Cessna 172 flight tests.
Clarke, R.↗
Study of a tracking and data acquisition system for the 1990's. Volume 3: TDAS Communication Mission Model
A parametric description of the communication channels required between the user spacecraft to be supported and the user ground data systems is developed. Scenarios of mission models, which reflect a range of free flyers vs space platform usage as well as levels of NASA activity and potential support for military missions, and potential channel requirements which identify: (1) bounds on TDAS forward and return link data communication demand, and (2) the additional demand for providing navigation/tracking support are covered.
Mccreary, T.↗
Results of shuttle EMU thermal vacuum tests incorporating an infrared imaging camera data acquisition system
Manned tests in Chamber B at NASA JSC were conducted in May and June of 1990 to better quantify the Space Shuttle Extravehicular Mobility Unit's (EMU) thermal performance in the cold environmental extremes of space. Use of an infrared imaging camera with real-time video monitoring of the output significantly added to the scope, quality and interpretation of the test conduct and data acquisition. Results of this test program have been effective in the thermal certification of a new insulation configuration and the '5000 Series' glove. In addition, the acceptable thermal performance of flight garments with visually deteriorated insulation was successfully demonstrated, thereby saving significant inspection and garment replacement cost. This test program also established a new method for collecting data vital to improving crew thermal comfort in a cold environment.
Anderson, James E.↗
A real time data acquisition system by satellite relay
The overall aim was to evaluate the future usefulness of satellites in the performance of coordination and management functions related to the operation of flood control and other multipurpose projects in New England. Results on the data collection portion of the work are presented. The principal task was to develop statistics that demonstrate the relationship between conventional means of acquiring hydrologic data and the contribution made by using the satellite and its data collection platforms. Main interest was in determining the availability, reliability and usability of the data. Significant results on DCS show that the DCP's are reliable and useful and satellite data collection appears feasible on a nationwide basis.
Cooper, S.↗
Telecommunications and data acquisition systems support for Voyager missions to Jupiter and Saturn, 1972-1981, prelaunch through Saturn encounter
The Deep Space Network has supported the Voyager Project for approximately nine years, during which time implementation, testing, and operational support was provided. Four years of this time involved testing prior to launch; the final five years included network operations support and additional network implementation. Intensive and critical support intervals included launch and four planetary encounters. The telecommunications and data acquisition support for the Voyager Missions to Jupiter and Saturn are summarized.
Traxler, M. R.↗