548 Matching Results

Search Results

Advanced search parameters have been applied.


Description: A summary of a study on the feasibility of constructing a computer about a hundred times faster than present computers using presently available components amd techniques is presented. (W. L.H.)
Date: October 1, 1957
Creator: Gillies, D.B.; Meagher, R.E.; Muller, D.E.; McKay, R.W.; Nash, J.P.; Robertson, J.E. et al.
Partner: UNT Libraries Government Documents Department

System of Automatic Processing and Indexing of Reports

Description: The rapidly increasing volume ot new data in scientific and technical fields demands faster and better ways to communicate the new information to those concerned. A working system. System of Automatic Processing and Indexing of Reports (SAPIR), for doing this is described. SAPIR makes use of the Keyword-in- Context Index principle, by which certain keywords, together with surrounding words that act as modifiers, are selected from the titles of the technical publications. These keywords with their modifiers serve as index entries from each title, therefore there will be as many index entries generated as there are keywords contained in the title. The index entries are sorted alphabetically by the keywords. The first letters of the keywords in each of the index entries form a column in the printed format, which makes scanning for the soughtafter item easier. The SAPIR system is automatic and the list of citations is machine- generated on an IBM 1401 Computer. (auth)
Date: July 12, 1961
Creator: Turner, L. D. & Kennedy, J. H.
Partner: UNT Libraries Government Documents Department


Description: A program is described for computing a quantity, Q, proportional to the neutron scalar flux, in an infinite heterogeneous slab system. The system is generated by a two-region unit cell. Q is the average track length per unit length, in a given interval, arising from the neutron traffic established by a spatially distributed monenergetic source. The program is coded for the IBM 704 computer. (auth)
Date: February 1, 1958
Creator: Beeler, J.R. & Popp, J.D.
Partner: UNT Libraries Government Documents Department


Description: A digital-to-analog converter is described which is a part of a system that converts punched-tape digital data to analog data in a series of points drawn by an x-y plotter. The converter is designed to plot accurately tapes that contain information other than coded numerical coordinates. Operation of the converter is also described along with format requirements and power supplies. (J.R.D.)
Date: January 17, 1962
Creator: Wall, G.N.
Partner: UNT Libraries Government Documents Department


Description: The objective of the Applied Mathematics Division is to provide mathematical assistance to other scientists in the Lab. This goal is achieved by (1) conducting research in numerical analysis and other branches of mathematics, (2) providing mathematical consultation, and (3) operating a computational service, using both digital and analog machines. Publications, papers, seminars, lectures, and courses are listed. A summary listing of computer programs developed or in progress is given. (For preceding period see AHL-5954.) (W.D.M)
Date: October 31, 1960
Partner: UNT Libraries Government Documents Department


Description: Presented at ihe Ninth Meeting of the Supersonic Wind-Tunnel Assoc., Univ. of Southern Calif., and U. S. Naval Air Missile Test Center, Point Mugu, Calif., Apr. The Sandia 12 x 12-inch, transonic, blowdown tunnel facility is being equipped with a 10-channel digital datagathering system. The design and operation of ihe system are discussed. (W.J.H.)
Date: April 1, 1958
Creator: Botner, W T
Partner: UNT Libraries Government Documents Department

Test and verification of a reactor protection system application-specific integrated circuit

Description: Application-specific integrated circuits (ASICs) were utilized in the design of nuclear plant safety systems because they have certain advantages over software-based systems and analog-based systems. An advantage they have over software-based systems is that an ASIC design can be simple enough to not include branch statements and also can be thoroughly tested. A circuit card on which an ASIC is mounted can be configured to replace various versions of older analog equipment with fewer design types required. The approach to design and testing of ASICs for safety system applications is discussed in this paper. Included are discussions of the ASIC architecture, how it is structured to assist testing, and of the functional and enhanced circuit testing.
Date: March 1, 1997
Creator: Battle, R.E.; Turner, G.W.; Vandermolen, R.I.; Vitalbo, C. & Naser, J.
Partner: UNT Libraries Government Documents Department

Global orbit feedback utilizing analog and digital technologies

Description: At the NSLS, an analog global orbit feedback system is used in regular operations, and a digital global orbit feedback system is available in machine physics studies on the X-Ray Ring. Here, the authors discuss the relative merits of utilizing analog and digital technology in orbit feedback. Results of experiments are reported characterizing the performance of the analog and digital systems when operated individually or together. They give their thoughts on plans for future development of the orbit feedback systems at the NSLS.
Date: July 1997
Creator: Singh, O.; Tang, Y.; Ramamoorthy, S.; Krinsky, S. & Yu, L. H.
Partner: UNT Libraries Government Documents Department

Test system electronic reference signal injection

Description: A concept for a method of injecting reference signals into waveform monitoring systems which has negligible effect on measurement accuracy is presented. Equations are provided which allow a test system designer to tailor the injection design to meet specific requirements. Examples of typical use are included. The signal injection concept presented has been successfully employed at GE Neutron Devices. It has been incorporated in quality assurance test systems to provide a fiducial or time zero reference marker for time correlation of waveforms monitored by independent digital oscilloscopes. It has also been found to be useful for the injection of simulated product waveforms employed for automatic test system calibration and/or operational verification just prior to product testing.
Date: June 1, 1991
Creator: Roubik, J.C.
Partner: UNT Libraries Government Documents Department

RF beam control system for the Brookhaven Relativistic Heavy Ion Collider, RHIC

Description: The Relativistic Heavy Ion Collider, RHIC, is two counter-rotating rings with six interaction points. The RF Beam Control system for each ring will control two 28 MHz cavities for acceleration, and five 197 MHz cavities for preserving the 5 ns bunch length during 10 hour beam stores. Digital technology is used extensively in: Direct Digital Synthesis of rf signals and Digital Signal Processing for, the realization of state-variable feedback loops, real-time calculation of rf frequency, and bunch-by-bunch phase measurement of the 120 bunches. DSP technology enables programming the parameters of the feedback loops in order to obtain closed-loop dynamics that are independent of synchrotron frequency.
Date: August 1, 1998
Creator: Brennan, J.M.; Campbell, A.; DeLong, J.; Hayes, T.; Onillon, E.; Rose, J. et al.
Partner: UNT Libraries Government Documents Department

Bandwidth utilization maximization of scientific RF communication systems

Description: A method for more efficiently utilizing the frequency bandwidth allocated for data transmission is presented. Current space and range communication systems use modulation and coding schemes that transmit 0.5 to 1.0 bits per second per Hertz of radio frequency bandwidth. The goal in this LDRD project is to increase the bandwidth utilization by employing advanced digital communications techniques. This is done with little or no increase in the transmit power which is usually very limited on airborne systems. Teaming with New Mexico State University, an implementation of trellis coded modulation (TCM), a coding and modulation scheme pioneered by Ungerboeck, was developed for this application and simulated on a computer. TCM provides a means for reliably transmitting data while simultaneously increasing bandwidth efficiency. The penalty is increased receiver complexity. In particular, the trellis decoder requires high-speed, application-specific digital signal processing (DSP) chips. A system solution based on the QualComm Viterbi decoder and the Graychip DSP receiver chips is presented.
Date: January 1, 1997
Creator: Rey, D.; Ryan, W. & Ross, M.
Partner: UNT Libraries Government Documents Department

Ultra-low power microwave CHFET integrated circuit development

Description: This report summarizes work on the development of ultra-low power microwave CHFET integrated circuit development. Power consumption of microwave circuits has been reduced by factors of 50--1,000 over commercially available circuits. Positive threshold field effect transistors (nJFETs and PHEMTs) have been used to design and fabricate microwave circuits with power levels of 1 milliwatt or less. 0.7 {micro}m gate nJFETs are suitable for both digital CHFET integrated circuits as well as low power microwave circuits. Both hybrid amplifiers and MMICs were demonstrated at the 1 mW level at 2.4 GHz. Advanced devices were also developed and characterized for even lower power levels. Amplifiers with 0.3 {micro}m JFETs were simulated with 8--10 dB gain down to power levels of 250 microwatts ({mu}W). However 0.25 {micro}m PHEMTs proved superior to the JFETs with amplifier gain of 8 dB at 217 MHz and 50 {mu}W power levels but they are not integrable with the digital CHFET technology.
Date: April 1, 1998
Creator: Baca, A.G.; Hietala, V.M.; Greenway, D.; Sloan, L.R.; Shul, R.J.; Muyshondt, G.P. et al.
Partner: UNT Libraries Government Documents Department