Navigation—An overview

While there are some 250 000 civil aircraft in the world, only about 500 of them are in transoceanic service and therefore prime candidates for the systems described in this special issue. The rest mainly depend on short-range systems treated elsewhere. However, there are 25 000 ocean-going merchant ships. The article discusses some nontechnical factors that influence the choice of systems for these markets, including the institutional, the "CNI" factor, the marketplace, cost, redundancy, and vulnerability.     

Material processing—An overview

Laser researchers in the early 1960's found that a ruby laser could easily melt and vaporize small amounts of metal. Many investigations have since been performed to determine the effects of high-power laser radiation on absorbing surfaces. By the late 1960's lasers had become practical production tools. In the early 1970's, advances in the power of CO2lasers led to deep penetration laser welding. This greatly increased the range of metal thickness amenable to laser processing. At present, lasers are used in a practical way for many applications in material processing. For some applications, like trimming of resistors and drilling of holes in ceramics, laser processing is the leading method. For other applications like heat treating, welding, and cutting, laser processing is an economically competitive alternative to conventional techniques. In addition, there are new research possibilities, especially for processing of semiconductors. Areas such as laser-assisted crystal regrowth and annealing of ion-implantation damage point toward new methods of generating semiconductor circuitry. This paper will review the physical phenomena which underlie laser processing applications. It will also give an overview of some of the leading uses for laser-based material processing.     

Automatic vehicle location—An overview

Automatic vehicle location (AVL) techniques have the potential for improving urban vehicle fleet operations. Various approaches to AVL are discussed and an introductory overview of the current state of the art in AVL technology is presented.     

Stored program control-assisted electromechanical switching—An overview

This article provides an overview of localized stored program control applications in existing electromechanical switching systems. Economic factors and design constraints imposed by established system architectures are reviewed. Criteria for introducing stored program control, along with main design considerations for its implementation, are outlined. Examples are given of actual electro-mechanical switching systems that have been modernized with selective application of stored. program control to upgrade system features and capabilities.     

Satellite communication—An overview of the problems and programs

This paper introduces the subject of satellite communication in its broadest aspects, recounts its history and discusses the principal technical problems. It is primarily communications-oriented but relevant spacecraft and launch considerations are summarized. Tabular summaries of the world's satellite communication programs are given.     

Power integrated circuits—A brief overview

A brief overview of developments in power and high-voltage integrated circuits is presented. The technology can be classified into two types: 1) smart power devices that contain one or more common drain, vertical power transistors with control, and protective circuitry built on the same chip, and 2) high-voltage integrated circuits that combine lateral high-voltage with CMOS logic and analog bipolar circuits on the same chip. These technologies are being aimed at display drivers, telecommunications, motor drives, power supplies, and automotive electronics. A rapid growth in their application in the future can be expected.     

1 µm MOSFET VLSI technology: Part I—An overview

This paper attempts to provide a technical perspective for a 1 µm MOSFET VLSI technology described in the technical papers that follow. Highlights of various aspects of the technology development are discussed briefly. These include device design, circuit design, hot-electron effects, processing technology, electron-beam lithography, metal silicide interconnections and radiation effects.     

Statistical geodesy—An engineering perspective

Motivated largely by the needs of the navigation community, engineers have become increasingly involved in understanding and modeling the fine structure of the earth's gravity field. In this endeavor, the engineer has augmented the applied mathematical tools of the "geodesist-scientist" with those of modern estimation and control theory, state-space mathematics, and random process theory. One of the outputs of this involvement has been the development of "statistical geodesy." In this paper, the mathematical structure and applications of statistical geodesy are reviewed, with an emphasis on the engineer's contribution. Geodetic terminology, geopotential theory, and estimation theory are briefly reviewed, and models with a random-process-theory structure are presented for uncertainties in the earth's gravity field. These models are then utilized in a variety of applications: estimation of gravimetric uncertainties, error analysis of inertial navigation systems, gravity gradiometry, satellite altimetry, etc. Finally, a new algorithm is presented-frequency-domain collocation-suitable for the efficient processing of large amounts of gravimetric data.     

Commutation signaling—An antimultipath technique

Two types of commutation signaling for combating multipath are introduced: M × N signaling, in which the signal set cycles successively among N different sets of M signals each; and M + N signaling, in which the signal set at any time consists of M members of an alphabet of M + N signals, N of which are inactive at any epoch. In both cases, the objective is to remove from use any signal sent recently enough that it is still "ringing" in the multipath channel. We consider the problems of minimization of M and N, hence the total number signals used; analysis of 2 × N sets (M = 2 is almost uniformly optimal); analysis of the simplest M + N set, i.e., a 2 + 1 set; and presentation of the results of simulation of M × N and M + N signaling through realistic urban/suburban radio channels. Comparison of these simulations to simulations of other antimultipath techniques is also made. The simulation results are due to Kamil [3].     

Hybrid processing systems—An assessment

The potential of hybrid processing systems is reviewed. The specific systems discussed involve the combination of coherent optical, electrooptical, electronic, and digital subsystems. In particular, progress in diffraction-pattern analysis is reviewed when the diffraction pattern is produced optically, detected, and then operated on electronically. The second type of system is the optical processing system, in which the diffraction pattern is appropriately changed to produce a modified image of the original input. Input transducers, addressable filters, and detection and logic subsystems are key elements of these systems.     

Pluribus—An operational fault-tolerant multiprocessor

The authors describe the Pluribus multiprocessor system, outline several techniques used to achieve fault-tolerance, describe their field experience to date, and mention some potential applications. The Pluribus system places the major responsibility for recovery from failures on the software. Failing hardware modules are removed from the system, spare modules are substituted where available, and appropriate initialization is performed. In applications where the goal is maximum availability rather than totally fault-free operation, this approach represents a considerable savings in complexity and cost over traditional implementations. The software-based reliability approach has been extended to provide enror-handling and recovery mechanisms for the system software structures as well. A number of Pluribus systems have been built and are currently in operation. Experience with these systems has given us confidence in their performance and maintainability, and leads us to suggest other applications that might benefit from this approach.     

An X-band SOS resistive gate—insulator—semiconductor (RIS) switch

The new X-Band Resistive Gate-Insulator-Semiconductor (RIS) switch has been fabricated on silicon-on-sapphire, and its equivalent circuit model characterized. An RIS SPST switch with 20-dB ON/OFF isolation, 1.2-dB insertion loss, and power-handling capacity in excess of 20-W peak has been achieved at X band. The device switching time is on the order of 600 ns, and it requires negligible control holding current in both ON and OFF states. The device is compatible with monolithic integrated-circuit technology and thus is suitable for integration into low-cost monolithic phase shifters or other microwave integrated circuits.     

PACKSATNET—An alternative to data networks

This paper contains a presentation of PACKSATNET, the demonstration data network of Indonesia based on the PALAPA satellite [1] that uses only radio links from the user's premises. PACKSATNET is scheduled to go into operation before the end of 1984, so it is already possible to draw some conclusions about its development phase and to point out its possible expansion into a public data network, taking into account the existing network, technological progress, and the growth of data communication needs.     

New display technologies—An editorial viewpoint

Present-day display technologies, both exploratory and in common use, are reviewed in outline form with emphasis on areas of applicability, advantages, and disadvantages. The comments reflect the authors' own bias, but the basic ideas probably reflect the thinking of most of the members of the display community.     

Conference tutorials—An opportunity for continuing education

The Educational Services Committee of the IEEE Communications Society has sponsored eleven tutorial short courses at its major conferences over the past six years. The experience gained in developing and presenting these tutorials is shared with others so that they may be in a better position to sponsor similar continuing education activities in the future. The conference tutorial is one example of a continuing education activity that can be sponsored by an IEEE Group or Society as a service to its members.     

Large-Signal Diode Modeling—An Alternative Parameter-Extraction Technique

An alternative numerical optimization method of large-signal equivalent-circuit diode modeling using dc and small-signal$S$-parameter measurements is described. In general, there are two ways to extract the equivalent-circuit parameters to model a nonlinear device such as a diode. They are based on numerical optimization or noniterative analytical procedure. The former is usually better in approximating the device response. Nevertheless, it requires arbitrary selection of a voltage-dependent$S$-parameter set to obtain the voltage-independent parameters. In this alternative numerical optimization method, an arbitrary selection of a voltage-dependent$S$-parameter set to obtain the voltage-independent parameters is not required. Validation of this parameter-extraction technique is done via modeling a forward-biased tunnel diode and a reverse-biased varactor diode. The models are further verified by implementing them in designing and developing an oscillator and a voltage-controlled oscillator.     

Magnetic bubbles—An emerging new memory technology

Magnetic bubbles-an emerging storage technique-promise to bridge the capacity-data retrieval time gap left vacant by magnetic core and semiconductor devices on one side and the electromechanical magnetic tape and disk on the other. Improvements in bubble materials, circuit processing, and device design have advanced bubble technology to where it is a solid candidate for applications requiring 10⁶-10⁸bits and retrieval times less than 0.005 s. Bubble chips as large as 65 kbits are currently under development. In this paper, the reader is first introduced to the topics of bubble statics and bubble dynamics, including a discussion of hard bubbles. Next, the operation of bubble devices such as propagation, generation, detection, and replication is described, as well as chip organizations using these functions. Temperature plays an important role and its effect on domain generation and data longevity is described. Fabrication techniques for bubble chips used in prototype mass memory modules and an experimental memory for a repertory telephone are given as are the overall systems' performance. Details of a 32-pin dual in-line bubble package are described. Finally, some predictions into the future are attempted for this technology. This discussion includes self-structuring propagation of bubbles and the bubble lattice file memory concept.     

Atmos—An electrically reprogrammable read-only memory device

An adjustable threshold MOS (Atmos) transistor is described that can be used as an electrically reprogrammable read-only memory by changing the charge content of a floating polysilicon gate. This floating gate is charged negatively (write) by means of a nonavalanche mechanism and charged positively (erase) by the avalanche breakdown of source or drain junction and subsequent hole injection into the oxide. The write time is between 10 and 100 ms, the erase time on the order of 1 s. The charge retention of the floating gate is about 90 percent after storage for 1000 h at 125°C.