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Picosecond Time Difference Measurements Utilizing CAMAC-Based ANSI/IEEE-488 Data Acquisition Hardware : Operating Manual IE3, Version 1.0 (open access)

Picosecond Time Difference Measurements Utilizing CAMAC-Based ANSI/IEEE-488 Data Acquisition Hardware : Operating Manual IE3, Version 1.0

Abstract: Automated time-difference measurements at the picosecond level have been achieved. The system described combines the best properties of three common methods: the single heterodyne measurement technique, the frequency divider, and the dual-mixer time-difference measurement system. This particular system combines two instrumentation standards, ANSI/IFEE-583 and ANSI/IEEE-488 with new, modular dual-mixer time-difference measurement hardware. The modular, standardized hardware together with the new measurement techniques permit the data acquisition modules to be contained in a standard CAMAC crate. This system, along with an external controller, is capable of measuring eiqht clocks, at the present time, and is expandable to twenty-four clocks with modified software and additional measurement modules. The system noise performance is described by a (rT = 3 x 10^-12 t^-1 for time difference measurements.
Date: August 1983
Creator: Glaze, D. J. & Stein, S. R.
System: The UNT Digital Library
An Electric and Magnetic Field Sensor for Simultaneous Electromagnetic Near-Field Measurements -- Theory (open access)

An Electric and Magnetic Field Sensor for Simultaneous Electromagnetic Near-Field Measurements -- Theory

Abstract: This paper describes the theory of a single sensor to perform simultaneous electric and magnetic near-field measurements. The theory indicates that it is possible to obtain the magnetic-loop and electric-dipole currents using a loop terminated with identical loads at diametrically opposite points. The theory also indicates that it is possible to obtain an ideal load impedance for achieving equal electric and magnetic field responses of the loop. Preliminary experiments have been performed using plane waves to verify these results. Key words: electric field, electromagnetic interference, electromagnetic radiation, loop, magnetic field, near fields.
Date: April 1983
Creator: Kanda, Motohisa
System: The UNT Digital Library
The Characteristics of Iris-Fed Millimeterwave Rectangular Microstrip Patch Antennas (open access)

The Characteristics of Iris-Fed Millimeterwave Rectangular Microstrip Patch Antennas

From introduction: The fabrication of various iris-fed millimeterwave rectangular microstrip patch antennas is described. A model is proposed to describe the iris-fed antenna. Irises ranging in size from 15 percent of the area of the patch to the fully open waveguide are used to couple energy into the antenna. Resonance of the antenna is observed to be insensitive to the size of the iris for irises up to 115 percent of the size of the patch. A study is also made of th? relationship of coupling to the antenna as a function of position of the iris with respect to the transverse plane of the waveguide, the iris always being centered with respect to the patch. In general, the antenna has a VSWR in the waveguide feed on the order of 5:1 at resonance, except for the fully open waveguide which gives rise to a VSWR of 2.9:1 at resonance. Far-field antenna power patterns are observed to be quite broad with H-plane beamwidths on the order of 1300. Maximum antenna gain is seen to be 4.5 dBi with 3 dBi typical. An initial study is made of the microstrip patch antenna fed from a longitudinal waveguide wall. Results indicate that …
Date: October 1983
Creator: Greenlee, D. H.; Kanda, Motohisa & Chang, David C.
System: The UNT Digital Library
Optical Time-Domain Reflectometer Performance and Calibration Studies (open access)

Optical Time-Domain Reflectometer Performance and Calibration Studies

from Introduction: The measurement accuracy of the optical time-domain reflectometer (OTDR) is restricted in some applications by a limited operational dynamic range and by a lack of standardized test procedures. In an effort to better understand these restrictions, we have measured the range of linearity of some avalanche photodiodes used as backscatter detectors. Also, the effect of input launch conditions is examined and a possible standardized OTDR test procedure is proposed. Using these suggestions, we have made comparisons between attenuation values determined by cutback and backscatter methods and found that good agreement is possible. Finally, some methods are described for checking the response. linearity of OTDR systems.
Date: June 1983
Creator: Danielson, B. L.
System: The UNT Digital Library
Reference Flat Pulse Generator (open access)

Reference Flat Pulse Generator

Introduction: A reference step-like pulse generator is described which has been developed at NBS. This generator can be used for accurately characterizing the step response of various kinds of trap ient recording equipment (oscilloscopes, waveform recorders, transient digitizers, etc.). Basic design principles are given as well as complete circuit diagrams and descriptions. An analysis of the output stage of the generator is presented together with the circuit models for developing a time-domain computer simulation program using extended- SCEPTRE. Preliminary specifications indicate that the NBS Reference Flat Pulse Generator provides a negative-going reference transition duration (90 to 10 percent) of 600 ps, *20 percent with baseline perturbations of less than *2 percent for less than 5 ns.
Date: October 1983
Creator: Andrews, J. R.; Bell, B. A. & Baldwin, E. E.
System: The UNT Digital Library
Introduction to STARPAC: the Standards Time Series and Regression Package (open access)

Introduction to STARPAC: the Standards Time Series and Regression Package

From preface: STARPAC documentation is being published as a series of Technical Notes. This Note is the first in the series. It gives an overview of the STARPAC library, defines conventions used in the documentation, provides an example using STARPAC subroutines, and presents general background material. This Note includes information which is essential for using the STARPAC library, and users should be familiar with its contents before attempting to use any STARPAC subroutine.
Date: October 1983
Creator: Donaldson, Janet R. & Tryon, Peter V.
System: The UNT Digital Library
Nonlinear Least Squares Regression Using STARPAC: The Standards Time Series and Regression Package (open access)

Nonlinear Least Squares Regression Using STARPAC: The Standards Time Series and Regression Package

From preface: This Note documents 16 subroutines for nonlinear least squares regression. Twelve of these compute the least squares estimates, performing either weighted or unweighted analysis with either numerically approximated or user-supplied (analytic) derivatives. The other four are user-callable subroutines for two procedures used within the estimation code: the first selects optimum step sizes for approximating the partial derivatives of the model; and the second checks the validity of a user-supplied derivative subroutine.
Date: October 1983
Creator: Donaldson, Janet R. & Tryon, Peter V.
System: The UNT Digital Library
A Review of Supercritical Fluid Extraction (open access)

A Review of Supercritical Fluid Extraction

Forward: The purpose of this report is to summarize the results obtained from a brief investigation of supercritical fluid extraction principles and applications. This study was one portion of a project funded by the U.S. Department of Energy, Office of Fossil Energy, contract nuriber DE-AI01076PR06010, in response to a preliminary proposal submitted by the authors. This report sometimes uses company trade naries to identify processes and patent holders. This usage implies no endorsement by HBS. Note also that some figures reproduced from other sources do not conform with NBS policy concerning SI units.
Date: December 1983
Creator: Ely, James F. & Baker, Jolene K.
System: The UNT Digital Library
Phase Equilibria: an Informal Symposium (open access)

Phase Equilibria: an Informal Symposium

From introduction: The accurate prediction of phase equilibria plays an important. role in the chemical process industries. A grief overview of final phase equilibria predictive techniques is presented with special emphasis on methods in current use in industry. Areas were better fundamental understanding will lead to improved models are discussed whenever possible.
Date: January 1983
Creator: Eaton, B. E.; Ely, James F.; Hanley, H. J. M.; McCarty, Robert D. & Rainwater, James C.
System: The UNT Digital Library
Design and Error Analysis for the WR10 Thermal Noise Standard (open access)

Design and Error Analysis for the WR10 Thermal Noise Standard

From introduction: This note describes the design and error analysis of a WR10 thermal noise power standard. The standard is designed to operate at the boiling point of liquid nitrogen with a noise temperature accurate to plus or minus 1 K.
Date: December 1983
Creator: Daywitt, William C.
System: The UNT Digital Library