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National Engineering Laboratory

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May 1983

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.S. DEPARTMENT OF COMMERCE, Malcolm Baldrige, Secretary

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1983

ATIONAL BUREAU OF STANDARDS. EmMt Ambter, Director
OF STANDARDS

LISRAF.Y JUL tl 1983'

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SIGNALS AND SYSTEMS PROGRAM, ISSUE FOR OCTOBER 1981 - MARCH 1982

Introducti on

This compilation of abstracts of papers approved for publication by the National

Bureau of Standards covers the work of three technical divisions in the NBS

Center for Electronics and Electrical Engineering for the first half of the

Federal fiscal year, October 1981 through March 1982. These divisions are the

Electrosystems Division at Gaithersburg, MD and the Electromagnetic Fields

Division and Electromagnetic Technology Division in Boulder, CO. The work of

these divisions collectively forms the Signals and Systems Metrology Program of

the Center. A compilation of abstracts covering the work of the Signals and

Systems Metrology Program for the second half of Federal fiscal year 1982 is

available as NBSIR 83-2719-2.

The work of the remaining two divisions of the Center, the Semiconductor

Materials and Processes Division and Semiconductor Devices and Circuits Division

both at Gaithersburg, comprises the Semiconductor Technology Program. Abstracts

covering this work for the entire Federal fiscal year 1982 (October 1981 through

September 1982, fifty-third through fifty-seventh quarters of the Program) have

been published in January 1983 as NBSIR 82-2636, Semiconductor Technology

Program Progress Briefs [single copies available from the Center, see back page

for address].

New Publication Covering Entire Center

Beginning with the first quarter of Federal fiscal year 1982 (October through

December 1982), the Center is initiating publication of a single document to cover work in both the Semiconductor Technology Program and the Signals and

Systems Metrology Program. The new publication will have the same name as the one you are now reading -- CEEE Technical Progress Bulletin -- and replace the

STP Progress Briefs series. The primary purpose of the new Bui letin is to

provide sponsors and other interested parties abstracts of documents approved

for publication as soon as possible. Additional information will be provided on published papers; conference and workshop proceedings; speci al -format

publications, such as magnetic data tapes and videotapes; new measurement

services, including calibration services and standard reference materials; and a six-month calendar of Center events.

Publication Lists

Guides to earlier as well as recent work are the publications lists covering the

work of each division. These are revised and reissued on an approximately

annual basis and are available from the originating division [the publications

from the Semiconductor Technology Program are covered in a single list,

available from either division]. Readers are encouraged to contact any of the

individuals listed on the back page for further information.
CEEE Technical Progress Bulletin Page 1 SIGNALS AND SYSTEMS METROLOGY PROGRAM, ISSUE FOR OCTOBER 1981 - MARCH 1982

Mission of Signals and Systems Program : The Signals and Systems Program of the

Center for Electron! cs and Electrical Engineering provides national reference

standards, measurement methods, supporting theory and data, and traceability to the

national standards. The technical areas addressed In the Program are identified in

the Table of Contents below.

The metrological products of the Program aid economic growth by promoting equity and

efficiency in the marketplace, by removing metrological barriers to improved productivity and innovation, by increasing U. S. competitiveness in international markets

through facilitation of compliance with international agreements, and by providing

technical bases for the development of voluntary standards for domestic and international trade. These metrological products also aid in the development of rational

regulatory policy and promote efficient functioning of technical programs of the

Government.

TABLE OF CONTENTS

INTRODUCTION ... inside front cover

FAST SIGNAL ACQUISTION, PROCESSING, & TRANSMISSION

Waveform Metrology . 2 Cryoelectronic Metrology 2

Antenna Metrology 3

Noise Metrology . 4

Microwave and Millimeter-Wave Metrology 5 Laser Metrology . 5 Optical Fiber Metrology 6

Other Fast Signal 7 ELECTRICAL SYSTEMS

Power Systems Metrology 7 Pulse Power Metrology 9

Magnetic Materials and Measurements . 9

Superconductors 10

ELECTROMAGNETIC INTERFERENCE 10

KEY CONTACTS IN CENTER, CENTER ORGANIZATION . back cover

Note : Abstracts are presented alphabetically by first author within above areas.

Sponsors of Work Covered in this Publication: National Bureau of Standards; NBS Law

tnforcement standards Laboratory; Department of Defense: DoD Calibration

Coordination Group, DoD Electromagnetic Compatibility Analysis Center, U.S. Air

Force, USAF Newark Air Force Station, U.S. Army, U.S. Navy, USN Naval Systems

Research and Development Command, USN Naval Weapons Station, USN Office of Naval

Research; Department of Energy, DoE Bonneville Power Administration; Department of

Health and Human Services, HHS National Center for Devices and Radiological Health

(formerly Bureau of Radiological Health), HHS National Institute of Occupational

Safety and Health; Department of Transportation, DoT National Highway Traffic Safety

Administration; Electric Power Research Institute; and International Copper Research

Association.
Page 2 CEEE Technical Progress Bulletin

FAST SIGNAL ACQUISITION, PROCESSING, & TRANSMISSION

Waveform Metrology

Nahman, N. S., and Guillaume, M. E.,

Deconvolution of Time Domain Waveforms

In the Presence of Noise, NBS Tech.

Note 1047 (October 1981).

Deconvolution or Inverse filtering was used to determine the impulse response

of a system using noisy Input and output

time domain sequences (discrete data).

Frequency and time domain methods were studied along with the synthesis of the

filters required to obtain stable and

smooth results. For the methods studied

it was concluded that the superior technique was provided by an optimal frequency domain method implemented via the

FFT. Also, it is pointed out that the

time domain methods are only In their

infancy and still retain the promise of

avoiding transform domain filtering.

Examples are presented in which the

Impulse responses are determined in the

presence of varying degrees of noise for

a coaxial transmission line, a wave- shaping filter, and a broad-band

antenna.

Souders, T. M., A Dynamic Test Method

for High-Resolution A/D Converters,

IEEE Trans. Instrumentation and Measurement IM-31, pp. 3-5 (March 1982).

A dynamic test method is described for

A/D converters having up to 16 bits of

resolution. The technique exercises the

test converter with stepped input

changes, simulating the output of an S/H

amplifier. Dynamic errors as low as

4 ppm can be measured with 4 us following a step change as large as 20 V.

Cryoelectronic Metrology

Hamilton, C. A., and Lloyd, F. L.

,

Design Limitations for Superconducting

A/D Converters, IEEE Trans. Magnetics

MAG-17, pp. 3414-3419 (November 1981).

This paper reviews the principle of A/D

conversion using superconducting quantum

Interference and describes the results

obtained with this technique. At an accuracy of four or six bits the design

of such converters is straightforward.

Higher accuracy requires careful

consideration of numerous design

constraints including critical current

uncertainty, power supply regulation,

turn-on-delay, signal line crosstalk,

and the threshold curve critical points.

The implications of these constraints

are analyzed with respect to an example

design for an 8-blt converter.

Goldfarb, R. B., Miniature Multipin

Electrical Feedthrough for Vacuum

Use, Cryogenics, p. 746 (December

1981).

A miniature multipin electrical feedthrough for room-temperature vacuum use

is made from commercially available com- ponents and an easily machined bushing.

Kautz, R. L., Chaotic States of rfBiased Josephson Junctions, J. Appl.

Phys. 52, pp. 6241-6246 (October

1981).

The existence of chaotic solutions to

the rf-driven Stewart-McCumber model of

a Josephson junction has recently been

demonstrated. The present paper

describes more fully the range of

junction parameters and frequencies for

which chaotic solutions occur, details

the connection between chaotic states

and instabilities in phase-lock, and

shows that chaotic noise can be much

larger than the thermal noise of a junction.

Peterson, R. L. , Mathematical Modeling

of the Impedance of a Josephson

Junction Noise Thermometer, J. Appl.

Phys. 52, pp. 7321-7326 (December

1981).

Recent experimental work on noise

thermometers consisting of a resistively

shunted superconducting loop containing

a Josephson junction (a resistive SQUID)
CEEE Technical Progress Bulletin Page 3

Cryoelectronic Metrology , cont'd.

has shown some novel behavior of the

SQUID dc Impedance as a function of rf

power. We present a mathematical

analysis of the Intrinsic behavior of a resistive SQUID in the limit of

negligible noise and negligible feedback

to the rf circuit. A nonlinear, firstorder differential equation is thought

to be a reasonable descriptor of this

system. Because the radio frequency

driving the SQUID is much larger than

the Josephson frequency, we are able to

obtain a pair of equations in which no rf oscillating terms appear, and which are amenable to numerical solution. The

dc impedance calculated from these

equations has several, but not all, of

the experimentally observed features.

Zimmerman, J. E., and Sullivan, D. B.,

A Study of Design Principles for

Refrigerators for Low-Power Cryoelectronic Devices, NBS Tech. Note 1049

(January 1982).

This report summarizes a five-year

effort at NBS which has been directed

toward the development of low-power

cryocoolers suited to the support of

superconducting instruments. The report

deals with a variety of aspects of con- struction and operation of refrigerators

as well as with a model which allows one to optimize the design for minimum drive

power. The publications generated by

the program are included as an

appendi x.

Antenna Metrology

Baird, R. C., Microwave Antenna

Measurement Services at the National

Bureau of Standards, Digest, Antenna

Measurement Techniques Association

Meeting (October 1981).

This paper reviews and summarizes the

microwave antenna measurement services

presently available at the National

Bureau of Standards, Boulder, Colorado.

The extrapolation technique, which is

used for accurate calibrations of

transfer-standard antennas, is described

and its limitations pointed out. With

this technique, uncertainties of jT).08

dB to jfO.10 dB in absolute gain and

hT). 05 dB/dB in polarization axial ratio

are achieved routinely. Accurate

antenna evaluations are also accom- plished by means of near-field scanning

methods developed at NBS. Most of these

measurements have utilized planar near- field scanning, but cylindrical scanning

capabilities exist. With this technique, complete patterns are determined

in addition to absolute gain to an accuracy of jK).15 dB and polarization axial

ratio to jK).10 dB. Side lobes can be

obtained down to -50 dB to -60 dB with

a typical accuracy of jfl.O dB at the -40

dB level. Examples of measurement

results for several different types of

antennas are given. Finally, NBS capabilities for measuring the G/T of earth

terminals and the thermal noise properties of sources and antennas are men- tioned briefly.

Estin, A. J., Stubenrauch, C. F.

,

Repjar, A. G. , and Newell, A. C.,

Optimized Wavelength-Sized Scalar Horns

as Antenna Radiation Standards, IEEE

Trans. Instrumentation and Measurement

IM-31, pp. 53-56 (March 1982).

The properties of beamwidth, directivity, and polarization of wavelength-si ze scalar horns are analyzed and optimized

theoretically and confirmed experimentally to determine the usefulness of

such horns as standards. Agreement

between theoretical predictions and

measurements was good.

Hill, D. A., and Wait, J. R., HF

Ground Wave Propagation Over Mixed

Land, Sea, and Sea-Ice Paths, IEEE

Trans. Geoscience and Remote Sensing

GE-19, pp. 210-216 (1981).

Ground wave propagation is analyzed for

a two-section path on a spherical earth.

Each section can be a two-layer medium

which is characterized by a surface

impedance. Specific calculations for a land-to-sea path indicate that the well-
Page 4

Antenna Metrology , cont'd.

known recovery effect In amplitude and

phase is more extreme at higher frequencies but is reduced for elevated

observer heights. Calculations for a sea-to-sea ice path indicate a brief

recovery because of the excitation of

the trapped surface wave over sea ice.

At greater distances from the boundary,

the field may be seriously degraded due

to the sea ice.

Ma, M. T. , Synthesis of Broadband

Antenna Arrays as Possible Over-TheHorizon Radars, Chapter 9 in book.

Research Topics in Electromagnetic Wave

Theory, J. A. Kong, Ed. (John Wiley & Sons, New York), 1981.

Based on the requirements of broadband

operation and other radiation characteristics, the side-terminated vertical

half rhombic is selected as the antenna

element in an array to be included as the central part of an over-the-horizon

radar, which serves as a remote means

for sea study. A nonuni formly spaced

array of 25 elements is synthesized for

the entire high-frequency band. The

array has the capability of providing a maximum transmitting-recei ving product

gain in the order of 60 dB at low takeoff angles, a product azimuth pattern

with a nominal half-power beamwidth of

2°, a product sidelobe level of -38 dB,

and a grating-lobe level of at least

-30 dB, and of covering an approximate

range of 3,000 km and a sector area of

40°.

Yaghjian, A. D. , Efficient Computation

of Antenna Coupling and Fields Within

the Near-Field Region, IEEE Trans.

Antennas and Propagation AP-30 (January

1982).

This paper presents the theory, explains

the techniques, details the important

equations, and describes two computer

programs for calculating efficiently the

mutual coupling at a single frequency

between any two antennas arbitrarily

oriented and separated in free space.

CEEE Technical Progress Bulletin

Both programs emphasize efficiency and

generality, and require, basically, the

complex electric far field of each

antenna, and the Eulerian angles designating the relative orientation of each

antenna. Multiple reflections between

the antennas are neglected but no other

restrictive assumptions are involved.

If an electric field component is

desired instead of coupling, the receiving antenna is replaced by a virtual

antenna with uniform far field.

The first computer program computes

coupling (or fields) versus transverse

displacement of the antennas in a plane

normal to their axis of separation. An

efficient FFT program was made possible

by "collapsing" the far-field input data

and showing that in most cases the spectrum integration need cover only the

sheaf of angles mutually subtended by

the smallest spheres circumscribing the

antennas. Limiting the integration to

this sheaf of angles artifically band

limits the coupling function, thereby

allowing much larger integration increments and reducing run times and storage

requirements to a feasible amount for

electrically large antennas.

The second program is based on a spherical wave representation of the coupling

function and rapidly computes coupling

(or fields) versus separation distance

between the antennas. The spherical wave representation emerged naturally

from an intriguing characteristic proven

for the mutual coupling function; it,

like each rectangular component of electric and magnetic field in free space,

satisfies the homogeneous wave equation.

Noise Metrology

Counas, 6., and Bremer, T. , NBS 30/60

Megahertz Noise Measurement System

Operation and Service Manual, NBSIR

81-1656 (December 1981).

Calibration of coaxial noise sources at

30 and 60 MHz is now being accomplished

using a total power radiometer designed

to operate under computer control. Use
CEEE Technical Progress Bulletin Page 5

Noise Metrology , cont'd.

of the IEEE 488 instrument Bus and

structured software techniques allows use and substitution of commercially

available components with a minimum of

hardware and software modification.

This manual addresses the general theory

of operation, operating procedures, and

maintenance procedures for the NBS

30/60 MHz automated noise measurement

system using a commercially available

desktop calculator as the controller.

Wakefield, J. P. , Addendum to Earth

Terminal Measurement System Maintenance

Manual, NBSIR 81-1641 (October 1981).

This addendum to the Earth Terminal

Measurement System Maintenance Manual,

NBSIR 78-895, describes the equipment

and maintenance procedures required to

support the retrofit package for the

Earth Terminal Measurement System (ETMS)

developed by the National Bureau of

Standards. This retrofit adds a multiinput-port relay module which provides

the capability of connecting three

receiver channels to the ETMS, thereby

enabling measurement of pertinent earth

terminal parameters at as many as three

frequencies in a single measurement

pass. This manual does not include

measurement theory nor measurement operating procedures that are described in

the Earth Terminal Measurement System

Operation Manual, NBSIR 78-879.

Microwave & Millimeter-Wave Metrology

Hoer, C. A., A High-Power Dual SixPort Automatic Network Analyzer Used in

Determining Biological Effects of RF

and Microwave Radiation, IEEE Trans.

Microwave Theory & Techniques MTT-29,

pp. 1356-1364 (December 1981).

The design, calibration, and performance

of a high-power (1-1000 W) automatic

network analyzer based on the six-port

concept are described for the 10-100 MHz

range. Calibration is performed with a length of transmission line as the only

impedance standard needed. A 10-mW

thermistor mount is the standard of

power. Imprecision in measuring

reflection coefficient r is 0.0001 in

magnitude and 0.005/ 1 r | degrees in

phase. Corresponding estimated

systematic errors are 0.001 and 0. 1 /

| r

|

degrees. Imprecision in measuring power

is 0.01 percent of range (20 W, 200 W, or 1000 W) with an estimated systematic

error of 1.25 percent of reading.

Laser Metrology

Simpson, P. A., and Zimmerer, R. W. , A

Water-Cooled 2 kW Calorimeter for Laser

Power Measurement, Proc. ElectroOptics/Laser 81 Conf . , Anaheim,

California, November 17-19, 1981, pp.

237-239.

To meet the growing need for reliable

monitoring of industrial high power C0 2 lasers, a calorimeter was designed to be

both easily used, reliable, and

accurate. A maximum continuous power

input of 2 kilowatts was specified in

order to handle commonly used C0 2 lasers.

A 5.7-cm diameter copper tube 61 cm long

traps the incident laser beam and

absorbs it in a series of internal

reflections. A 4.8-mm copper tube wound

around the outside carries a 1 liter per

minute water flow. A manganin wire

interwinds the cooling coil and is

bonded to the 5.7-cm absorbing tube to

provide substitution electrical heat for

realistic calibration. Power is mea- sured by the rise in the temperature of

the cooling water as indicated by a thermopile.

Two different measurement methods are discussed. First results indicate a sensitivity of 7.8 W/mV. The 1/e

response time is approximately 6 s.

Young, M. , Use of LEDs as YAG Laser

Simulators, Proc. ElectroOptics/Laser 81 Conf., Anaheim,

California, November 17-19, 1981, pp.

222-229.
Page 6 CEEE Technical Progress Bulletin

Laser Metrology , cont'd.

There is wide interest in using light

emitting diodes (LEDs) for calibrating

and testing detectors designed to mea- sure weak, diffuse YA6 laser beams.

Differences of coherence and possible

other differences have given rise to the

question, is such use of an LED either

practically or theoretically justifiable? The purpose of this paper is to

examine the problem in some detail and

to determine if possible the conditions

under which suitably filtered LED radiation will adequately simulate a laser

beam. We conclude that, although there

are certain areas that require special

care, use of an LED as a laser simulator

is entirely feasible.

Optical Fiber Metrology

Danielson, B. L., Backscatter

Signature Simulations, NBS Tech. Note

1050 (December 1981).

This report presents a collection of

computer-generated backscatter signatures which represent realistic replicas

of signals that can be encountered in

optical time-domain reflectometer (OTDR)

systems. Emphasis is placed on illustrating the appearance of backscatter

signatures originating from localized

and distributed imperfections which are superimposed on an otherwise uniform

optical fiber. The details of these

signatures are shown to be a function of

the particular type of fiber perturbation, experimental parameters, and data

reduction methods. This compilation of

simulated responses is intended to

facilitate the correct interpretation of

OTDR signals as well as to point out sources of error which can arise in the

characterization of optical fibers using

backscatter techniques.

Franzen, D. L. , and Kim, E. M. , Long

0 p 1 1 c a 1 - F i b e r Fabry-Perot

Interferometers, Appl. Optics 20, pp.

3991-3992 (December 1981).

A Fabry-Perot Interferometer using

single-mode optical fibers Is described.

A finesse of 14 was obtained for fiber

lengths of a few meters.

Gallawa, R., Optical Waveguide

Communications Glossary, NBS Handbook

140 (January 1982).

Revision of NTIA Special Publication SP

79-4 dated September 1979.

Gallawa, R. L. , Book Review: Optical

Fibre Communication, IEEE Spectrum

18, pp. 81-82 (November 1981).

Review of McGraw-Hill text, prepared by

the technical staff of CSELT, Torimo,

Italy.

Kim, E. M., and Franzen, D. L.

,

Measurement of the Core Diameter of

Graded-Index Optical Fibers: An

Interlaboratory Comparison, Appl.

Optics 21, pp. 3443-3450 (October

1982).

An i nterl aboratory measurement

comparison of optical fiber core

diameter was conducted by the National

Bureau of Standards (NBS) in cooperation

with the Electronic Industries

Association. Participants include NBS

and three fiber manufacturers. Six

graded-index fibers were measured by all

participants using the transmitted near- field method. As a group, the

transmitted near-field measurements were consistent and exhibited an average

standard deviation of 0.5 urn for 50- ym core fibers. These results were also

compared to diameters determined by

refracted near-field and transverse

interference measurements contributed by

other laboratories. For smooth-index

profiles, all three methods agree within

~1 urn; substantial differences between

the transmitted near-field and the other

two methods can exist for fibers having

step structure near the core-cladding

boundary.

Young, M., Book Review: Principles of

Optical Fiber Measurements, Laser

Focus 18, pp. 118-119 (January 1982).
CEEE Technical Progress Bulletin Page 7

Optical Fiber Metrology , cont'd.

Review of Academic Press (New York) text

by Dietrich Marcuse.

Young, M., Optical Fiber Index Profiles by the Refracted-Ray Method (Refracted Near-Field Scanning), Appl.

Optics 20, pp. 3415-3422 (October

1981).

This paper provides an elementary

description and tutorial overview of the

refracted-ray method of measuring fiber

index profiles. It also presents new results concerning the theoretical foundation, the linearity and precision, and

other aspects of the method. In particular, we find that index differences

may be measured to 5% or better and

conclude by showing ~3% agreement with

another laboratory and good agreement

with numerical aperture measurements

performed by participants in an interlaboratory comparison.

Other Fast Signal

Kamper, R. A., Current Trends In NBS

Calibration Services, NCSL Newsletter

22, pp. 38-39 (March 1982).

Recently, the management of NBS has

given close attention to calibration

services and has started several actions

to improve quality and responsiveness

for the future.

Larson, D. R., A Measurement Method

for Determining the Optical and

Electro-Optical Properties of a Thin

Film, NBSIR 81-1652 (December 1981).

A method of determining the complex

refractive index of a thin film on a nonabsorbing substrate is developed.

The optical transmittance spectrum of

the structure is measured and the index

is determined by matching this spectrum

numerically. An iterative procedure for

finding the magnitude of an induced

change in refractive index is also presented. In nonabsorbing spectral

egions, the index and film thickness are

determined directly.

The optical transmittance of sapphire

and thin films of gold and epitaxial

silicon, both on sapphire. Is examined.

The refractive Index of epitaxial sili- con on sapphire, SOS, is determined and

compares favorably with the results of

other investigators.

The measurement method is applied to a thin film of hydrogenated amorphous

silicon, deposited by a capacitivelycoupled rf glow discharge. The index is

tabulated for various wavelengths and a field induced change in index comparable

to that seen in GaAs is measured.

Young, M. , Quantum Noise Limits the

Pinspeck Camera to Simple Objects, J. Optical Society America 72, pp. 402-403

(March 1982).

The pinspeck camera projects a lowcontrast image with a great deal of

veiling glare. Quantum noise determines

that the camera can image only simple

objects that contain no more than a few

hundred picture elements.

ELECTRICAL SYSTEMS

Power Systems Metrology

Kelley, E. F., and Hebner, R. F.,

Electro-Optic Measurement of the

Electric Field Distribution in

Transformer Oil, to be published in

IEEE Trans. Power Apparatus & Systems.

A system has been developed to measure

the electric fields in transformer oil

using the electro-optic Kerr effect.

The system performance was verified by

measuring the electric field and space

charge in nitrobenzene. The field distributions were measured in clean oil,

in oil which had been used as a wash for

a radiator used in a power transformer,

and in oil which was removed from a transformer that had failed. Measurements were made from room temperature to

100°C. Under the conditions studied,

the electric field strengths were
Page 8 CEEE Technical Progress Bulletin

Power Systems Metrology , cont'd.

generally within 10% of the strengths

that would be predicted assuming that

space charge was negligible.

McKnight, R. H. , Kotter, F. R., and

Misakian, M. , Measurement of Ion

Current Density at Ground Level In the

Vicinity of High Voltage DC Transmission Lines, NBSIR 81-2410

(December 1981) [similar material to be

published in IEEE Trans. Power

Apparatus and Systems].

Sensors for measuring vertical current

density at ground level near high voltage dc (HVDC) transmission lines are subject to error when the sensor is not

in the ground plane. The magnitude of

this error, for guarded and unguarded

sensors, has been investigated using

both dc electric fields with space

charge and ac electric fields in a parallel plate facility. For conditions

like those expected under HVDC transmission lines, the results obtained

using ac and dc methods agreed to within

experimental uncertainty. The measured

errors are as large as 25% for guarded sensors and significantly larger for

unguarded sensors. Data for various

sensor elevations and guarding are presented in graphs to aid the designer.

Schmidt, W.F., and Van Brunt, R.J.,

Comments on the Effect of Electron

Detachment in Initiating Breakdown in

Gaseous Dielectrics, Proc. Third Int.

Symposium on Gaseous Dielectrics,

Knoxville, Tennessee, March 7-11, 1982,

pp. 561-563.

This paper represents a summary of the

deliberations of a small group

discussion meeting held at the Third

International Symposium on Gaseous

Dielectrics. The relative importance of

various electron detachment processes in

the initiation of electrical breakdown

in electronegative gases is considered

and discussed.

Van Brunt, R.J., Effects of H2O on the Behavior of SFg Corona, Proc.

Seventh Int. Conference on Gas

Discharges and Their Applications,

London, England, August 31 - September

3, 1981, pp. 255-258.

The effects of trace amounts of H2 O

vapor (<300 ppm) on poi nt-to-pl ane dccorona inceptions and corona pulse

characteristics in SFg were

investigated. Corona discharges were generated in short gaps, 1.0 to 3.0 cm,

for sharp point electrodes of diameter

~0.1 mm, and for gas pressures in the

range of 100 to 400 kPa. Trace levels

of H2 O were introduced by electrical

heating of a wire in the gas, and its

concentration was monitored with a gas

chromatograph-mass spectrometer. Water

vapor was found to significantly enhance

the intensity of corona at a given

voltage, as indicated by an order of

magnitude or more increase in average

discharge current and corona pulse rate.

The presence of small quantities of

H 2 O greatly inhibits formation of

positive streamer burst pulses and

significantly modifies the shape of the corona pulse height distribution. On

the other hand, introduction of H 2 O

results in only a slight reduction in

the overall dielectric strength of

sf6 .

Van Brunt, R. J. , and Leep, D. A.,

Corona- Induced Decomposition of

SF6, Proc. Third Int. Symposium on Gaseous Dielectrics, Knoxville, Tennessee, March 7-11, 1982, pp. 402-409.

The stable, neutral decomposition

products resulting from posititive

point-plane dc-corona in static SFg

gas have been identified with a gas

chromatograph-mass spectrometer. Absolute concentrations of some species have

been measured with a sensitivity of

~1 ppm as a function of total energy

dissipated for discharge power levels

between 50 and 700 mW. The first

detectable gaseous contaminant to appear
CEEE Technical Progress Bulletin Page 9

Power Systems Metrology , cont'd.

is H2 O, presumably liberated by discharge-induced desorption from the electrode. The oxyfluorides SOF 2 , SO 2 F 2 , and SOF 4 are the next most

prominent species to appear. Other

species such as CO, CO2 , CF4 , OCS,

and SO2 were identified. For corona levels below 700 mW, SOF 2 and

SO2 F 2 appear with nearly equal con- centrations, and the production rates

for both are constant and proportional

to discharge power. The presence of

trace amounts of H2 O and other decomposition products is found to have a pronounced effect in suppressing the

pulse burst characteristic of positive

corona in SFg.

Pulse Power Metrology

Hebner, R. E. and Hagler, J. N. , Discussion of 82 WM 255-8, Reconstruction

of High Impulse Voltages Considering

the Step Response of the Measuring

System, to be published in IEEE

Trans. Power Apparatus & Systems.

This discussion requests from the

authors of the original paper further

information about the accuracy of and

the distinctions between the two deconvolution algorithms describe in the

original paper.

Magnetic Materials and Measurements

Fickett, F. R., Electrical Properties

of Materials and Their Measurement at

Low Temperatures, NBS Tech. Note 1053

(March 1982).

A review is given of the electrical

resistance of materials at cryogenic

temperatures. Measurement techniques,

the data base, and uses of the data are presented. The emphasis is on metals

and alloys of technological importance;

a topic which covers a large range of

materials. Similarly, the treatment of

theory and of measurement techniques is

primarily for the user interested in the

more practical aspects of the subject.

In every instance, however, references

are given which allow the reader to

pursue the subject at any level.

Fickett, F. R., Electrical and

Magnetic Properties of Internally

Oxidized Copper and Dilute Copper- Iron

Alloys, J. Phys. F: Met. Phys. 12,

pp. 1753-1769 (January 1982).

Results are presented on studies for

developing an understanding of the

process by which the resistive contribution of transition metal impurities,

primarily iron, in copper is removed by

internal oxidation. The majority of the

investigations were made on a CuFe alloy

series of precisely determined

composition from 1 to 100 atomic parts

per million (at PPM) Fe. Electrical

resistance and magnetic susceptibility

measurements at room temperature and at

4 K on both unoxidized and oxidized

samples are reported. These

measurements, supported by scanning

electron microscopy (SEM) and Curie

temperature determinations, suggest a two-step internal oxidation process at even the lowest impurity levels.

Goldfarb, R. B., Rao, K. V., Chen, H. S., and Patton, C. E. , Further Evidence for a Spin-Glass Phase Transition

in Amorphous Fe-Mn-P-B-Al Alloys, J. Appl . Phys. 53, pp. 2217-2219 (March

1982).

Low field dc susceptibility, thermoremanent magnetization, and hysteresis studies are presented for two amorphous FeMn-P-B-Al alloys of concentrations close

to, and on either side of, the multicritical point in the magnetic phase

diagram. They exhibit spin-glass and

pa ra-ferro-spin -glass transitions,

respectively. For the spin-glass alloy,

the Edwards-Anderson-type order parameter deduced from the dc susceptibility

is found to yield a mean-field-valued

critical exponent. In the alloy with

two magnetic transitions, the temperature dependence of the thermoremanence

and hysteresis indicate a ferro-spinglass transition temperature consistent
Page 10

Magnetic Materials & Meas . , cont ' d

with that deduced from a scaling

approach for the same alloy system.

Superconductors

Ekin, J. W. , Sekine, H. , and Tachikawa,

T., Effect of Strain on the Critical

Current of N b - H f / C u - S n - G

Multlfllamentary Superconductors, J. Appl. Phys. 52, pp. 6252-6256 (October

1981)

.

The critical current of multifilamentary

Nb-Hf/Cu-Sn-Ga has been determined as a function of both field and strain at

fields from 4 to 19 T. The strain

dependence of the critical current is

significantly decreased compared with

that of commercial multifilamentary

Nb 3 Sn superconductors. This reduced

strain sensitivity, coupled with an enhanced critical-current density above

12 T, make this a candidate material for

economic high-field magnet construction.

An analysis of the data in terms of the

strain scaling law indicates that the Hf

and Ga additives do not produce this

improvement through a decrease in the

strain sensitivity of the bulk upper

critical field B*C 2

. Rather, they

reduce the strain sensitivity of the

critical current through a changed shape

of the flux pinning curve and an enhancement in the strain-free maximum

value of B *

C 2 (B* C 2m = 25 T

for Nb-Hf/Cu-Sn-Ga vs. 21 T for Nb 3 Sn).

Fickett, F. R., Electric and Magnetic

Properties of CuSn and CuNI Alloys at 4

K, Cryogenics, pp. 135-138 (March

1982)

.

Results of low-temperature resistivity,

magnetoresistivity, and magnetic susceptibility measurements on CuSn and CuNi

alloys of compositions commonly used in

practical superconductors are presented

and discussed.

CEEE Technical Progress Bulletin

ELECTROMAGNETIC INTERFERENCE

Chew, H. , Modeling of Oil Shale

Retorts for Electromagnetic Sensing

Techniques, NBSIR 81-1653 (November

1981).

We report here some work on the modeling

of oil shale retorts for electromagnetic

sensing techniques. The aim is to

obtain useful information about the

contents of the retort (e.g., rubble

size, void ratio, etc.) by means of

electromagnetic probes. In this work,

the retort is modeled by a spheroid with

an average dielectric constant which

depends on the void ratio. The near field due to a radiating dipole source

in the vicinity of a spheroidal retort

is computed using the Extended Boundary

Condition Method due to Waterman,

Barber, and Yeh. Numerical results are given at 4 MHz for a retort with major

axis 45.7 m (150 ft.), minor axis 25.1 m

(82.5 ft.), bulk dielectric constant 8.8

+ 3. 7 j , and various void ratios. The

results indicate feasibility of

determining the void ratio by remote

electromagnetic measurements. This work

may be of interest beyond the immediate

context of oil shale retort modeling.

Crawford, M. L. , Options to Open-Field

and Shielded Enclosure Electromagnetic

Compatibility Measurements, Proc.

Int. EMC Symposium, Zurich,

Switzerland, March 10-12, 1981.

This paper discusses optional measurement techniques that are being investigated as potential alternatives to using

open-field sites and conventional

shielded enclosures for performing EMC

measurements. Techniques discussed

include: 1) low-Q underground or buried

test chambers, 2) transverse electromagnetic (TEM) transmission line cells, and

3) reverberating or mode tuned/stirred

enclosures.
CEEE Technical Progress Bulletin

ELECTROMAGNETIC INTERFERENCE, cont'd.

Ma, M. T. , and Arthur, M. G. , A Study

of Distribution of Electromagnetic

Fields Inside Buildings with Apertures

Excited by an External Source, NBSIR

82-1659 (February 1982).

Two special cases of the penetration of

electromagnetic fields into a cavity,

building or box are formulated and ana- lyzed. One is to consider the case of

a lossy cavity with small apertures in

free space, based on an application of

the equivalence principle and the use of

a generalized network formulation. It is found that the field strength at the

aperture center is approximately

inversely proportional to the squareroot of the conductivity of the cavity

walls and that high field levels can exist inside the cavity under certain

physical conditions. The second case is

to treat the problem of large buildings

with large apertures on a practical

lossy ground by a combination of theoretical approach and measurement data.

Field levels inside the building for

this latter case depend on the transmitter power, the transmitter-to-building

distance, the ground conductivity, and

the measurement antenna height relative

to that of the transmitter.

Taggart, H. E., Methods of Suppressing

Automotive Interference, NBS Spec.

Publ . 480-44 (November 1981).

The purpose of this report is to review

the sources of electromagnetic interfer- ence (EMI) within a vehicle so that the

reader will have a basic understanding

of the EMI problem, discuss the techniques that have been used successfully

by the auto industry to suppress EMI,

and suggest some newer techniques for

suppressing EMI within an automobile.

The automotive manufacturers utilize

several techniques to reduce EMI emanating from the vehicle. These techniques

include, but are not limited to, resistor spark plugs, resistor spark plug

Page 11

cables, use of silicon grease in the

distributor, use of capacitors as filters, placement of grounding straps

at key locations, conductive fan belt

discharge, and grounding in wheels to

reduce tire static-charge build-up. If

further reduction of EMI is needed to

obtain full utilization of a mobile

communication system, there are additional suppression techniques that can

be employed to achieve this goal. These

are listed. Most of these techniques

are effective at frequencies from

approximately 30 to 1000 MHz. Measurement results show that the EMI from a new production-line automobile, as measured in accordance with SAE Standard

J551g , can be reduced by an additional

10 to 15 dB by employing these additional suppression techniques. A measurement technique is described whereby the

amount of degradation to a mobile

narrowband FM receiver (used by law

enforcement agencies) can be measured.

This same technique can then be used as

a tool to further reduce EMI from the

vehicle.

NBS1 > 4A irev. 2 -ec) U.S. DEPT. OF COMM.

BIBLIOGRAPHIC DATA

SHEET (See instructions)

PUBLICATION OR

REPORT NO.

2. Performing Organ. Report No. Center for Electronics

i Electrical Engineer!*

3. Publication Date May 1983

ng

4. TITLE AND SUBTITLE

Center for Electronics and Electrical Engineering Technical Progress Bulletin,

Covering Signals and Systems Program, October 1981 - March 1982

5. AUTHOR(S)

Compiler J. Franklin Mayo-Wells

6. PERFORMING ORGANIZATION (If joint or other than NBS. see instructions)

national bureau of standards

DEPARTMENT OF COMMERCE

WASHINGTON, D.C. 20234

7. Contract/Grant No.

t. Type of Report & Period Covered

October 1981

March 1982

SPONSORING ORGANIZATION NAME AND COMPLETE ADDRESS (Street. City. State. ZIP) U. S. Department of Commerce

National Bureau of Standards

National Engineering Laboratory

Center for Electronics and Electrical Engineering

10. supplementary notes

All technical information included in this document has been approved for

publication previously.

I | Document describes a computer program; SF-185, FIPS Software Summary, is attached.

11. ABSTRACT (A 200-word or less factual summary of most significant information. If document includes a significant

bi bliography or literature survey, mention it here)

This is the first issue of a new abstract bulletin to be issued quarterly by the

Center for Electronics and Electrical Engineering, National Bureau of Standards.

This issue covers the work of the Center's Signals and Systems Program for the

first half of Federal fiscal year 1982. Abstracts are provided by technical

area for both published papers and papers approved by NBS for publication.

12. KEY WORDS (Six to twelve entries; alphabetical order; capitalize only proper names; and separate key words by semicolons)

antennas; electrical engineering; electrical power; electromagnetic interference;

electronics; instrumentation; lasers; magnetics; microwave; optical fibers;

semi conductors ; superconductors

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