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IBM Journal of Research and Development

Issue 4 • Date July 1966

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Displaying Results 1 - 14 of 14
  • Diagnosis of Automata Failures: A Calculus and a Method

    Page(s): 278 - 291
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (888 KB)  

    The problem considered is the diagnosis of failures of automata, specifically, failures that manifest themselves as logical malfunctions. A review of previous methods and results is first given. A method termed the “calculus of D-cubes” is then introduced, which allows one to describe and compute the behavior of failing acyclic automata, both internally and externally. An algorithm, called the D-algorithm, is then developed which utilizes this calculus to compute tests to detect failures. First a manual method is presented, by means of an example. Thence, the D-algorithm is precisely described by means of a program written in Iverson notation. Finally, it is shown for the acyclic case in which the automation is constructed from AND's, NAND's, OR's and NOR's that if a test exists, the D-algorithm will compute such a test. View full abstract»

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  • A Numerical Analysis of the Transient Behavior of a Transistor Circuit

    Page(s): 292 - 299
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (429 KB)  

    This paper describes some difficulties encountered in the numerical solution of nonlinear circuit equations. A particular transistor circuit is analyzed to illustrate the nature of the difficulties and how they may be resolved. In this circuit it is possible, without sacrificing accuracy of the physical model, to eliminate unimportant stray parameters whose presence destroys the efficiency of most integration routines. A method based on a potential function is used for deriving the circuit equations and it is shown how these equations can be systematically reduced upon removing the stray parameters. Application of such techniques to the circuit considered reduced the calculation time (on an IBM 7094) from 30 minutes to 7 seconds. View full abstract»

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  • Properties of a Free, Steadily Travelling Electrical Domain in GaAs

    Page(s): 300 - 309
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (623 KB)  

    Experiments are described on the travelling domains of high electric field which can exist in n-type GaAs. A brief discussion of the appearance of stationary domains near the cathode and of the nucleation and transient behaviour of travelling domains is given, but the main topic is the steady-state behaviour of travelling domains. Measurements are reported on the dependence of domain velocity, and of the voltage drop across the domain, on the field E existing outside the domain. It is found that the velocity increases with E, but the voltage decreases. The resulting negative resistance is seen to have important consequences for the stability of the domain in real specimens. View full abstract»

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  • Effect of Domain and Circuit Properties on Oscillations in GaAs

    Page(s): 310 - 320
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (577 KB)  

    A discussion is given of the complications obtaining when a bar of GaAs, generating microwave oscillations, is allowed to interact with an external circuit. Three very different modes of operation can be expected, each corresponding to a mechanism of extinction of the travelling domains of electric field that cause the current modulation. It is seen that the domains may be extinguished (1) when they reach the end of the bar, (2) when the voltage drops too low for the stability of a domain, or (3) when it rises too high. In the last two circumstances, the external circuit plays an important role. Conditions for the existence of the various modes are deduced, and their properties are studied experimentally. View full abstract»

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  • Resonant Excitation of Magnetostrictive Driven Print Wires for High-Speed Printing

    Page(s): 321 - 332
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (783 KB)  

    A developmental resonant wire printing device utilizing ultrasonic vibration is described and results given on some preliminary work on the resonant excitation of magnetostrictive print wires. This paper discusses the characteristics of the magnetostrictive material, the transducer design and some special methods of measuring small, rapid mechanical motion. In the present test setup of the printing device, impact rates up to 1400/sec were obtained. View full abstract»

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  • A High-Speed Read Only Store Using Thick Magnetic Films

    Page(s): 333 - 342
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (614 KB)  

    This paper describes a high-speed, magnetic film, read only store of about 300K bits. The device and its implementation into a system have many unique advantages, including loose magnetic tolerances, minimal delay in the cell, linear drive-sense coupling, and ease of information change. View full abstract»

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  • Localized-Field Permanent Magnet Array for the Thick-Film Read Only Store

    Page(s): 343 - 345
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (265 KB)  

    Matick, Pleshko, Sie and Terman1 have described the thick-film read only store (TFROS), a semipermanent storage device utilizing changeable cards containing permanent magnets as the storage medium. The purpose of these magnets is to provide a saturating field for the film bit locations in the TFROS. The intention of this Communication is to describe briefly the process used to obtain these magnets and the way they are utilized in the TFROS. The required magnetic properties are covered in Ref. 1 and will not be discussed in detail in this Communication. View full abstract»

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  • Dynamic Laser Wavelength Selection

    Page(s): 346 - 350
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (329 KB)  

    This paper describes the dynamic selection of the emission wavelengths of a laser by insertion of a dispersive tunable electro-optic Q-spoiler within the laser cavity. Five different oscillation wavelengths of an argon ion laser have been individually selected by varying the voltage on the KD*P electro-optic crystals in the Q-spoiler. View full abstract»

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  • Domain Wall Velocities in Thin Magnetic Films

    Page(s): 351 - 354
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (360 KB)  

    Wall mobility measurements employing short pulse drive fields show that in films with thicknesses up to 2000 Å the wall velocity is determined by spin relaxation effects rather than by eddy current damping. Further, it seems probable (a) that for high wall velocities the viscous flow approximation is no longer valid, (b) that Bloch lines are responsible for the low mobility of cross-tie walls and (c) that the energy dissipation that is related to a near moving domain walls is larger in films with higher Hc/Hk ratios View full abstract»

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  • Technical Papers by IBM Authors Published Recently in Other Journals

    Page(s): 355 - 363
    Save to Project icon | PDF file iconPDF (648 KB)  
    Freely Available from IEEE
  • Recent Issued Patents Assigned to IBM

    Page(s): 364 - 365
    Save to Project icon | PDF file iconPDF (243 KB)  
    Freely Available from IEEE
  • Authors

    Page(s): 366 - 367
    Save to Project icon | PDF file iconPDF (214 KB)  
    Freely Available from IEEE
  • Contents of previous two issues

    Page(s): 368
    Save to Project icon | PDF file iconPDF (175 KB)  
    Freely Available from IEEE
  • Errata [Erratum]

    Page(s): 368
    Save to Project icon | PDF file iconPDF (280 KB)  
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Aims & Scope

The IBM Journal of Research and Development is a peer-reviewed technical journal, published bimonthly, which features the work of authors in the science, technology and engineering of information systems.

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Editor-in-Chief
Clifford A. Pickover
IBM T. J. Watson Research Center