ment; computer performance prediction; computer system acquisition; CPE in auditing; installation management; online system evaluation; queuing models; simulation; workload definition.

The Proceedings record the papers that were presented at the Sixteenth Meeting of the Computer Performance Evaluation Users Group (CPEUG 80) held October 20-23, 1980, in Orlando, Florida. With the theme "CPE Trends in the 80's," CPEUG 80 focused on new applications that are expected to grow in the 80's and changes that may occur in traditional areas during the 80's. The program was divided into two parallel sessions and included technical papers on previously unpublished work, case studies, tutorials, and panels. Technical papers are presented in the Proceedings in their entirety. SP500-67. Computer science & technology: The SRI hierarchical development methodology (HDM) and its application to the development of secure software, K. N. Levitt, P. Neumann, and L. Robinson, Nat. Bur. Stand. (U.S.), Spec. Publ. 50067, 54 pages (Oct. 1980) SN003-003-02258-6, $3.75.

Key words: design methodology; formal specification; formal verification; hierarchical design; programming methodology; security.

This document provides an introduction to the SRI Hierarchical Development Methodology (HDM). The methodology employs a staged decomposition of the development process, which separates design, data representation, and implementation. For any given system development, HDM employs a hierarchical decomposition of the design and formal specifications of modules and their interconnections. Extensive tools are used throughout the development to check the appropriateness of the design and its implementation.

The role of HDM in developing secure systems is considered, and various current efforts using HDM to develop such systems are summarized. The use of the methodology is illustrated by a simple but complete example. A somewhat larger example of part of a secure data management system is also discussed.

Verification is not considered in this document, although HDM does facilitate verification. The consistency of formal specifications and their formal requirements can be formally shown, as can the consistency of programs with their specifications.

SP500-68. Computer science & technology: The Expert Assistance System for the NBS Network Access Machine, S. W. Watkins, Nat. Bur. Stand. (U.S.), Spec. Publ. 500-68, 47 pages (Nov. 1980) SN003-003-02275-6, $2.50.

Key words: command languages; communications; computer access; computer networks; minicomputers; protocols; user interfaces.

The Expert Assistance System (EAS) was developed at the National Bureau of Standards as a prototype to assist network users. Network users are faced with the problem of learning different procedures in order to access similar services on different host systems. A great deal of research has been precipitated by the desire to simplify network usage and many tools have been developed to assist the network user.

One of the approaches taken in network assistance has been to implement an intermediary machine. The intermediary machine translates simple user commands into the sequences of network and system commands required for execution on a target host system; thus, the user learns one set of commands which are applicable on different systems and networks. An ironic consequence of such an approach is that if the user desires to expand the basic set of functions provided by the intermediary machine or to tailor existing functions to individual needs, the user has to learn another command language-that of the intermediary machine itself.

The EAS addresses the problem of building procedures for an intermediary machine. The EAS automatically generates procedures by recording an interaction between a user and network system and then translating this interaction into the commands required for execution on the intermediary machine. Development of the EAS was facilitated by the existence of an intermediary machine at the National Bureau of Standards-the NBS Network Access Machine (NAM).

This report briefly describes the motivation for the development of a network assistance technique, discusses the design and implementation of the EAS at NBS, and then concludes with a view of future enhancements to the current EAS. The context for the description of the EAS is the NBS NAM; however the concepts are applicable to the general field of network user assistance.

SP500-69. Computer science and technology: An analytic study of a shared device among independent computing systems, A. Mink, Nat. Bur. Stand. (U.S.), Spec. Publ. 500-69, 176 pages (Nov. 1980) SN003-003-02227-3, $5.50.

new

Key words: approximate queueing models; computer architecture; modular expansion analysis; performance evaluation; performance modeling; queueing models; queueing networks.

Global queueing network performance models are developed for the increasingly important class of computer networks comprising a number of independent computing systems sharing a single resource. An extensive bibliography and survey of prior work relating to this topic are included. Analytic expressions of performance measures for this class of systems are derived from the general theory of multiclass queueing networks, and computational algorithms for evaluating them are presented that are memory-space efficient (linear vs. exponential) compared with known algorithms for the general theory. This exact analytic model, called the Shared Central Server Model, incurs approximately the same exponential time complexity in its evaluation as do all models based on the general theory; because of this, a simple heuristic approximate model of this class of systems is also presented that is computationally efficient in both time and space. Modular expansion of this class of systems is investigated using the approximate model, and a useful relationship is derived between the number of additional independent computing systems and the incremental increase in capability of the shared resource required to maintain the existing level of system performance.

SP500-70/1. Computer science and technology: NBS minimal BASIC test programs-Version 2, User's manual, Volume 1-Documentation, J. V. Cugini, J. S. Bowden, and M. W Skall, Nat. Bur. Stand. (U.S.), Spec. Publ. 500-70/1, 79 pages (Nov. 1980) SN003-003-02262-4, $4.00.

Key words: BASIC; language processor testing; minimal basic; programming language standards; software standards; software testing.

This publication describes the set of programs developed by NBS for the purpose of testing conformance of implementations of the computer language BASIC to the American National Standard for Minimal BASIC, ANSI X3.60-1978. The Department of Commerce has adopted this ANSI standard as Federal Information Processing Standard 68. By submitting the programs to a candidate implementation, the user can test the various features which an implementation must support in order to conform to the standard. While some programs can determine whether or not a given feature is correctly implemented, others produce output which the user must then interpret to some degree. This manual describes how the programs should be used so as to interpret correctly the results of

the tests. Such interpretation depends strongly on a solid understanding of the conformance rules laid down in the standard, and there is a brief discussion of these rules and how they relate to the test programs and to the various ways in which the language may be implemented.

SP500-70/2. Computer science and technology: NBS minimal BASIC test programs-Version 2, User's manual, Volume 2-Source listings and sample output, J. V. Cugini, J. S. Bowden, and M. W. Skall, Nat. Bur. Stand. (U.S.), Spec. Publ. 500-70/2, 487 pages (Nov. 1980) SN003-003-02263-2, $9.50.

Key words: BASIC; language processor testing; minimal basic; programming language standards; software standards; software testing.

This publication describes the set of programs developed by NBS for the purpose of testing conformance of implementations of the computer language BASIC to the American National Standard for Minimal BASIC, ANSI X3.60-1978. The Department of Commerce has adopted this ANSI standard as Federal Information Processing Standard 68. By submitting the programs to a candidate implementation, the user can test the various features which an implementation must support in order to conform to the standard. While some programs can determine whether or not a given feature is correctly implemented, others produce output which the user must then interpret to some degree. This manual describes how the programs should be used so as to interpret correctly the results of the tests. Such interpretation depends strongly on a solid understanding of the conformance rules laid down in the standard, and there is a brief discussion of these rules and how they relate to the test programs and to the various ways in which the language may be implemented.

SP500-71. Computer science & technology: Remote record access: Requirements, implementation and analysis, H. M. Wood and S. R. Kimbleton, Nat. Bur. Stand. (U.S.), Spec. Publ. 500-71, 46 pages (Dec. 1980) SN003-003-02273-0, $2.25.

Key words: computer networking; data conversion; data transfer; data transformation; data translation; network operating systems.

A key support component for network-wide data sharing is the ability of a process to access remotely stored data at runtime. In order for the accessed data to be useful, a means of overcoming differences in data representation and format is necessary. Such a capability is termed remote record access. This paper identifies some of the problems inherent in the sharing of data among dissimilar computer and data systems. Implementation issues and alternatives are presented, followed by a description of XRRA, the Experimental Remote Record Access component which has been implemented as part of the Experimental Network Operating System (XNOS) at the National Bureau of Standards.

FIPS PUB 76. Guideline for planning and using a data dictionary system, Nat. Bur. Stand. (U.S.), Fed. Info. Process. Stand. Publ. (FIPS PUB) 76, 15 pages (Aug. 1980).

Key words: computer program; database; database management system; data dictionary system; data inventory; data management; data standards; documentation; Federal Information Processing Standards Publication; software.

This guideline provides assistance to Federal ADP Management and technical staff in planning and using Data Dictionary Systems (DDS's). A DDS is a computer software system that is used to assist in organization-wide data management, without restriction to computer data. This document describes the

capabilities of a DDS; addresses selection considerations; provides guidance for preimplementation planning, including such management issues as DDS policies and budgeting, data standardization and control, and coordination of the DDS contents. The document also presents initiation and operation considerations for using a DDS.

TN1122. Summary of on-line or interactive physico-chemical numerical data systems, J. Hilsenrath, Nat. Bur. Stand. (U.S.), Tech. Note 1122, 24 pages (Oct. 1980) SN003-00302259-4, $1.75.

Key words: chemical data; data banks; data bases; data networks; interactive systems; numerical data bases; on-line data; physical data; spectroscopic data systems.

A brief description is given of 51 interactive physico-chemical numerical data systems, most of which are on-line on international computer networks. The systems are listed under five headings: those useful for identification of substances from spectroscopic data; those providing thermodynamic and transport properties of pure components and mixtures; those which perform metallurgical calculations and draw phase diagrams; systems producing complete tables of thermodynamic properties of individual substances; and those for chemical process simulation, optimization, and design. References to published descriptions of the systems, where they exist, are also given.

Key words: APT; automation; computer aided manufacturing; NC machining; NC programming; numerical control; part programming.

A method of APT programming and postprocessor design is described which permits more efficient data preparation for numerical control (NC) machine tools and then allows this data to be quickly and easily exchanged among different NC machines. A rigorous specification is made of the APT postprocessor language based upon new ANSI standards for APT and is coupled with a comprehensive definition of the machining functions which should result from the use of each APT language statement. Individual postprocessors are modified to process each statement in the same manner. Thus, the original intent of the part programmer is always satisfied. A 23% increase in NC manufacturing efficiency is projected. The approach is demonstrated in production by processing a single APT data package on three different milling-drilling type machine tools. This Final Report details the approach taken and the benefits measured.

NBSIR 80-2115. Prospectus for data dictionary system standard, Application Systems Division, 20 pages (Sept. 1980). Order from NTIS as PB80-225204, $5.00.

Key words: computer program; database; database management system; data dictionary system; data inventory; data management; data standards; documentation; software.

A Data Dictionary System is an automated information system to assist in organization-wide data management, without restriction to computer data. This report describes NBS effort to develop a Federal Data Dictionary System standard. It discusses the scope and purpose of the standard, the intended audience, general issues being investigated, and the basic project approach.

NBS-GCR-80-245. Draft report-Features of the transport and session protocols, J. Burruss (NBS contact: LuAnn Riorden), 78 pages (Mar 1980). Order from NTIS as PB80-205214, $8.00.

Key words: communication protocols; computer network protocols; feature analysis; network architecture; networking; session protocol; transport protocols.

The National Bureau of Standards, Institute for Computer Sciences and Technology (ICST), has initiated a program to develop computer network protocol standards as Federal Information Processing Standards (FIPS). FEATURES OF THE TRANSPORT AND SESSION PROTOCOLS is one of a series of draft reports being prepared under the network protocol standards program for distribution to government agencies, voluntary standards organizations, computer and communications equipment manufacturers, and other interested parties. This draft report analyses protocol features as a method of determining the kernel set of essential features of a protocol along with the clusters of value-added features which will support various application categories.

NBS-GCR-80-246. Draft report-Service specification of transport and session protocols, G. Pearson and J. Burruss (NBS contact: LuAnn Riorden), 73 pages (Mar. 1980). Order from NTIS as PB80-226947, $7.00.

Key words: communication protocols; computer network protocols; design specification; formal specification; network architecture; networking; session protocols; transport protocols.

The National Bureau of Standards, Institute for Computer Sciences and Technology (ICST), has initiated a program to develop computer network protocol standards as Federal Information Processing Standards (FIPS). SERVICE SPECIFICATION OF TRANSPORT AND SESSION PROTOCOLS is one of a series of draft reports being prepared under the network protocol standards program for distribution to government agencies, voluntary standards organizations, computer and communications equipment manufacturers, and other interested parties. This draft report specifies the actual operation of the proposed transport and session protocols.

NBS-GCR-80-247. Draft report-Formal description techniques for network protocols, System Development Corp., 7929 Westpark Drive, McLean, Virginia 22102 and Bolt Beranek and Newman Inc., 10 Moulton Street, Cambridge, Massachusetts 02128 (NBS contact: LuAnn Riorden), 89 pages (Aug. 1980). Order from NTIS as PB80-215700, $8.00.

Key words: action table; computer program; finite automata; formal description technique; graphs; natural language; Petri net; state diagram.

The National Bureau of Standards, Institute for Computer Sciences and Technology (ICST), has initiated a program to develop computer network protocol standards as Federal Information Processing Standards (FIPS). FORMAL DESCRIPTION TECHNIQUES FOR NETWORK PROTOCOLS is one of a se

ries of draft reports being prepared under the network protocol standards program for distribution to government agencies, voluntary standards organizations, computer and communications equipment manufacturers, and other interested parties. This draft report contains two formal description techniques, a general survey, and a set of criteria for evaluation of these techniques.

NBS-GCR-80-256. Draft report-Common command language feature analysis, J. Moulton (NBS contact: LuAnn Riorden), 141 pages (June 1980). Order from NTIS as PB80-211261, $10.00.

Key words: common command language; communication protocols; computer network protocols; feature analysis; file access function; file manipulation function; network architecture.

The National Bureau of Standards, Institute for Computer Sciences and Technology (ICST), has initiated a program to develop computer network protocol standards as Federal Information Processing Standards (FIPS). COMMON COMMAND LANGUAGE FEATURE ANALYSIS is one of a series of draft reports being prepared under the network protocol standards program for distribution to government agencies, voluntary standards organization, computer and communications equipment manufacturers, and other interested parties. This draft report analyzes common command language protocol features. NBS-GCR-80-257. Performance requirements for standards processing software, S. J. Fenves (NBS contact: Pam Benjamin), 58 pages (Apr. 1979). Order from NTIS as PB80221112, $7.00.

Key words: codes; computer program; decision table; network; performance requirements; software; specifications; standards; systems analysis/engineering.

A methodology for the analysis and synthesis of standards exists which can provide significant assistance to standard writers and developers. Several of the methods have been implemented as computer programs. With the experience gained in the use of the first generation of programs, this report presents a set of performance requirements for a new generation of standards processing software. It is intended that these requirements serve as a basis for defining functional specifications for the subsequent development of the new software. The performance requirements are organized into six categories (general, database, interaction, user interaction, analysis, and processing environment), and they provide an ability to work with all the major elements of the methodology: decision tables for the meaning of individual provisions, information networks for the precedence between provisions, and classification systems for the production of indexes and outlines. The report also presents a concise overview of the methodology for analysis and synthesis of standards with an annotated, chronological bibliography and brief descriptions of previously developed computer programs.

NBS-GCR-80-258. Functional specifications for standards processing software, S. J. Fenves (NBS contact: Pam Benjamin), 171 pages (June 1979). Order from NTIS as PB80-221120, $11.00.

Key words: codes; computer program; decision table; network; performance requirements; software; specifications; standards; systems analysis/engineering.

This is the second in a series of reports leading to the development of a standards processing software capability. The first report was Performance Requirements for Standards Processing Software. The reader of this report will need to have read and be familiar with the concepts and terms used in the

first report. This report provides the complete functional specifications which establish the technical basis for the development of the software. The salient features are: 1) the integration of all user functions into a single system, 2) maintenance of all information in a data base, 3) facilities for convenient user interaction, 4) facilities for processing and combining large standards subdivided into several units, such as chapters, and 5) facilities for interfacing with additional capabilities to be developed in the future, both external and internal to the system.

NBS-GCR-80-278.

Assessment of computer mass storage technology, Measurement Concept Corporation, Rome, New York 13440 (NBS contact: Linda Ross), 125 pages (Jan. 1980). Order from NTIS as PB80-224926, $9.00.

Key words: computer architecture; computer hardware; computer computer mass storage systems; computers; computer storage.

The objective of this study is to assess the state-of-the-art of computer mass storage devices and technology, giving particular emphasis to computer system architecture implications.

Provided in this report is an overview of the technologies that presently are and, in the near future and intermediate future, can be applied in the construction of mass storage systems. Discussed are implementation considerations of mass storage systems ranging from the most primitive interface techniques to sophisticated back-end data base processor approaches. The concept of data base machines is introduced in particularly the way they impact on architectural requirements of mass storage systems. Finally, the consequences of the eventual use of mass storage systems in distributed and network processing systems are discussed.

The major finding in our report is an expected departure from the traditional tape libraries to physically smaller and denser mass storage systems such as optical disks as part of a hierarchical memory structure. Reasons for this finding can be found in technological arguments and considerations related to interface implementations, data base machinery architecture and distributed networks.

NBS-GCR-80-281. Draft report—Formal methods for communication protocol specification and verification, C. A. Sunshine (NBS contact: LuAnn Riordan), 106 pages (June 1980). Order from NTIS as AD-A083263, $9.00.

Key words: alternating bit protocol; communication protocol; file transfer protocol; protocol specification; readability analysis; service specification transport protocol; verification.

The National Bureau of Standards, Institute for Computer Sciences and Technology (ICST), has initiated a program to develop computer network protocol standards as Federal Information Processing Standards (FIPS). FORMAL METHODS FOR COMMUNICATION PROTOCOL SPECIFICATION AND VERIFICATION is one of a series of draft reports being prepared under the network protocol standards program for distribution to government agencies, voluntary standards organizations, computer and communications equipment manufacturers, and other interested parties. This draft report is a study of methods for specifying and verifying communication protocols. It surveys the state of the art, identifies promising directions for future work, and makes some initial progress in some of these directions.

NBS-GCR-80-288. Microcomputer interfacing standards survey and analysis, Network Analysis Corporation, Washington Operations, 301 Tower Building, Vienna, VA 22108 (NBS contact: Dana Grubb), 205 pages (Aug. 1980). Order from NTIS as PB81-105868, $13.00.

Key words: backplane bus: component level bus; local area networks; microcomputer bus; microcomputer interfacing; microcomputer standards.

This study is a survey of the field of microcomputer interfacing standards for the 1984-1994 time frame. The study identifies the characteristics of the typical microcomputer of the 1984 time frame; identifies and defines interfacing categories for potential standards development; identifies existing and potential candidate standards in each of the interfacing categories; and recommends those candidate standards in each interfacing category that the authors consider appropriate for further consideration.

NBS-GCR-80-289. Draft report-Formal specification of the transport and session protocols, R. Tenney, J. Burruss, and G. Pearson (NBS contact: LuAnn Riorden), 281 pages (June 1980). Order from NTIS as PB81-105322, $16.00.

Key words: communication protocols; computer network protocols; network architecture; networking; protocol design specification; session protocols; transport protocols. The National Bureau of Standards, Institute for Computer Sciences and Technology (ICST), has initiated a program to develop computer network protocol standards as Federal Information Processing Standards (FIPS). FORMAL SPECIFICATION OF THE TRANSPORT AND SESSION PROTOCOLS is one of a series of draft reports being prepared under the network protocol standards program for distribution to government agencies, voluntary standards organization, computer and communications equipment manufacturers, and other interested parties. This report specifies the actual operation of the transport and session control protocols.

Electromagnetic Metrology

TN1022. J. A. Barnes, H. H. Sargent III, and P. V. Tryon, Nat. Bur. Stand. (U.S.), Tech. Note 1022, 24 pages (Sept. 1980) SN003-003-02255-1, $1.75.

Key words: ARMA models; forecasts; Maunder minimum, models; simulation; statistics; sunspots.

The square of a narrowband Gaussian process is used to simulate sunspot cycles at computer speeds. The method is appealing because: (i) the model is extremely simple yet its physical basis, a simple resonance, is a widely occurring natural phenomenon, and (ii) the model recreates practically all of the features of the observed sunspot record. In particular, secular cycles and recurring extensive minima are characteristic of narrowband Gaussian processes. Additionally, the model lends itself to limited prediction of sunspot cycles.

TN1024. Evaluation of three-terminal and four-terminal pair capacitors at high frequencies, R. N. Jones, Nat. Bur. Stand. (U.S.), Tech. Note 1024, 20 pages (Sept. 1980) SN003-00302242-0, $1.50.

Key words: calibration; capacitance; four-terminal pair capacitance; immittance standards; inductance; residual series inductance; resonance techniques; three-terminal

capacitance.

The low frequency (1 kHz) capacitance values of three-terminal and four-terminal pair air dielectric capacitors can be extrapolated to higher frequencies if the residual series inductance is known. A resonance method for evaluating the residual series inductance of these capacitor types, together with the extrapolation procedure, is described. For the region where the product of capacitance in farads and frequency in hertz is 10-2 or less, uncertainties of one percent or less may be obtained.

19495. Hanson, A. G., Bloom, L. R., Day, G. W., Gallawa, R. L., Gray, E. M., Young, M., Optical waveguide communications glossary, NTIA-SP-79-4, 80 pages (U.S. Department of Commerce-National Telecommunications and Information Administration, Sept. 1979).

Key words: communications; fiber optics; guided wave transmission; optical cable; optical communication; optical fiber; optical fiber waveguide; optical transmission; optical waveguide; telecommunications; waveguide.

This glossary defines technical terms specific to optical fiber waveguide communications. The objective is to clarify the vocabulary of this rapidly emerging technology: to provide the nucleus of a common language for communications engineers, manufacturers, systems designers and users.

Selection of terms has been deliberately restrictive. Only those terms specifically relevant to optical waveguide communications have been included. Definitions have been written especially with the communications engineer in mind. This work has been a joint, interactive effort by communications engineers of the Institute for Telecommunications Sciences and physicists of the National Bureau of Standards. Their experience in the fields of communications engineering and physical measurement has been combined in an attempt to produce a language that is unambiguous to both disciplines.

19515. Howe, D. A., Walls, F. L., Bell, H. E., Hellwig, H., A small, passively operated hydrogen maser, Proc. 32d Annual Frequency Control Symposium, Atlantic City, NJ, May 3-June 1, 1979, pp. 554-568 (Electronic Industries Association, 2001 Eye Street, N.W., Washington, DC 20006, 1979).

Key words: dielectrically loaded cavity; frequency stability; frequency standard; hydrogen maser; teflon coating technique.

A compact passive hydrogen maser with many unique features, including a significant reduction in size over previous hydrogen masers, is described. It uses the passive mode of operation, thereby permitting use of a small microwave TE011 cavity which is dielectrically loaded by a low-loss alumina (Al2O3). The cavity is 14.6 cm O.D. and 13.7 cm high, weighing only 4.4 kg. The unloaded cavity Q factor is about 6000. With a conventional source, hexapole state selector, and 4 magnetic shields the volume of the entire H-maser resonator package is only about 20 1.

The teflon coated quartz bulb which is common in other masers has been replaced by a teflon coating on the inside wall of the cavity. This has yielded a simpler design and more rugged H-maser package. The technique for the application of liquid emulsion FEP 120 is discussed.

The cavity and attached endcaps comprise the vacuum envelope, thus allowing use of a single vacuum system. The dimensional stability of the ceramic cavity under barometric changes is sufficiently within the range of the electronic cavity servo that a second vacuum system is not needed. For temperature control, a single oven is located in the magnetic shield

nest.

The electronics for this small passive hydrogen maser is very similar to that previously developed at NBS. Preliminary measurements on a prototype small maser system yield a frequency stability of approximately σy(7) = 6.6 × 10-12 7-1/2 to at least one day, with a measurement bandwidth of 1 kHz.

19542. Bussey, H. E., Dielectric measurements in a shielded open circuit coaxial line, IEEE Trans. Instrum. Meas. IM-29, No. 2, 120-124 (June 1980).

Key words: coaxial line open circuit; coaxial line support bead; dielectric constant; dielectric loss; rf and microwave dielectrics; standard dielectric liquids.

A coaxial transmission line terminated by a shielded open circuit is convenient for dielectric measurements over a frequency range from quasi-static to microwave in a single sample holder. The transmission line analysis including the open circuit termination covered by lossy dielectric is outlined. Examples of measurements of known liquids are given. Errors may arise because the support bead of a coaxial connector may excite various higher modes depending on the perfection of the symmetry and on the product frequency times refractive index of the sample. Criteria are given for the onset of higher modes. 19544. Driver, L. D., Ries, F. X., A wideband RF voltage comparator, (Proc. Conf. on Precision Electromagnetic Measurements, Braunschweig, Federal Republic of Germany, June 23-27, 1980), IEEE No. 80CH1497-71M, 487-488 (Institute of Electrical and Electronics Engineers, New York, NY, 1980).

Key words: linear voltage response; rf voltage comparator; Schottky-barrier diodes; voltage comparator; wideband comparator.

A wideband rf voltage comparator is described which enables highly accurate rf voltage measurements over the range of 10 mV rms to 20 V rms from less than 100 kHz to beyond 1 GHz. This device uses a pair of matched Schottky-barrier diodes in each of two independent dual channel configurations. The coaxial line sections are impedance compensated to assure a VSWR of less than 1.03 up to 1 GHz.

19564. Engen, G. F., A review of the six-port network analyzer development at NBS, (Proc. Conf. on Precision Electromagnetic Measurements, Braunschweig, Federal Republic of Germany, June 23-27, 1980), IEEE Cat. No. 80CH1497-71M, pp. 323-324 (Institute of Electrical and Electronics Engineers, New York, NY, 1980).

Key words: automatic network analyzer; microwave measurements; six-port.

In recent years a network analyzer, providing both amplitude and phase, has been developed which is based upon the use of a non-ideal six-port network and four detectors which provide amplitude response only. The interest in this method is reflected by a bibliography of more than forty items which span the past seven years.

This paper will review this development, highlight the important features, and identify remaining problem areas.

Electronic Technology

SP400-63. Semiconductor measurement technology: A FORTRAN program for calculating the electrical parameters of extrinsic silicon, R. D. Larrabee, W. R. Thurber, and W. M. Bullis, Nat. Bur. Stand. (U.S.), Spec. Publ. 400-63, 54 pages (Oct. 1980) SN003-003-02260-8, $3.75.

Key words: carrier density; computer program; electrical properties of silicon; Hall effect; mobility; resistivity; silicon.

Many electrical properties of silicon are strongly dependent upon the specific nature and density of the active impurities present. Calculation of these electrical properties hinges on the solution of the charge balance equation to determine the position of the Fermi level for each specific case of interest. A FORTRAN program is presented that performs this determination and then calculates some of the often-used electrical parameters of silicon as a function of temperature. Results obtained from this program have proven useful in interpreting Hall effect data, determining the degree of ionization of the separate dopant states as a function of temperature, predicting