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American Institute of Electrical Engineers, Part I: Communication and Electronics, Transactions of the

Issue 4 • Date Sept. 1963

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Displaying Results 1 - 21 of 21
  • Queueing characteristics of a telephone data transmission system with feedback

    Page(s): 449 - 455
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    Experimental error data were used to measure the queueing characteristics of a simulated detect and repeat telephone data transmission system operating with a constant rate source. The maximum queue varied considerably as a function of the telephone circuit error sample and data system. Several ratios of source rate to channel rate were used and with ratios of one-half or lower queues of more than 100,000 bits were found. Measurements were also made of the frequency of exceeding a buffer which was smaller than the maximum queue. View full abstract»

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  • Time-division-multiplex electronic telephone exchange system for small pax

    Page(s): 455 - 464
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    An experimental time-division-multiplex electronic telephone exchange on a 200-line 4-wire PAM (pulse amplitude modulation) system is described. The exchange is composed entirely of solid-state devices. The channel time is divided into four phases which are effectively used to reduce the number of circuit elements of the exchange. For reliable operation, common and multiplexed circuits are duplicated, and fault detection and change-over operation are explained. View full abstract»

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  • Transmission characteristics of bell system subscriber loop plant

    Page(s): 464 - 470
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    This paper discusses some principal results of a recent Bell System subscriber loop survey. Statistically sound estimates of various physical and transmission characteristics of the loop plant are presented. This information is useful in appraising the current transmission properties of the plant in the light of existing requirements. It provides a novel basis for evaluating new developments and services affecting present plant. View full abstract»

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  • Switched-mode transistor amplifiers

    Page(s): 470 - 472
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    Switched-mode transistor operation is known to provide greater efficiency than circuits using linear amplifiers. This paper describes some switched-mode circuits and shows how they are used in a high-density carrier system; the improved circuit efficiency which results permits the carrier system to be considerably simplified and heat dissipation to be reduced greatly. View full abstract»

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  • Automatic testing for maintenance purposes in telex networks

    Page(s): 472 - 478
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    Semiautomatic testing in telegraph networks outspeeds manual testing and minimizes human errors. A novel feature is a fully automatic routine tester which logs faults detected so that they can readily be located. Personnel can be concentrated on fault elimination and test intervals shortened with equal or reduced personnel strength. The network's reliability is enhanced as irregularities are detected before trouble can arise. View full abstract»

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  • ¿Vade¿: A versatile automatic data exchange

    Page(s): 478 - 482
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    ITT Federal Laboratories has developed a store and forward switching center capable of interfacing with both synchronous data and start-stop Teletype lines. This machine, designated the ITT 525, fully utilizes its internal speed to eliminate the need for per-line and other special-purpose hardware. State of the art components, a novel system design, and miniature packages are used to provide a flexible and compact, as well as low-cost, system. View full abstract»

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  • A common directory code for digital and analog networks

    Page(s): 483 - 484
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    Free flow of traffic from Telegraphic Message Systems into and out of the switched voice network is now blocked by the lack of common directory codes and methods for direct easy translation from the message traffic codes (Baudot, Fieldata, etc.) into switching instructions for use by the line switching gear. This block may be removed by the choice of message directing codes usable by both systems without the necessity for intricate translating gear. There is inherent in most digital codes, a group of symbols that may be translated directly into digital directing codes usable by both the telephone switching gear and by telegraphic systems. View full abstract»

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  • New transmission test set for exchange-type trunks

    Page(s): 485 - 487
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    The increased use of carrier systems and 1-way dial circuits has increased the complexity of transmission testing. The introduction of direct-distance dialing has made the transmission maintenance requirements far more stringent. The instrument described here, designated as the Model TTS 6, was developed to cope with the increased complexity, to provide a high degree of accuracy, and to permit the use of labor-saving ¿1-man¿ test procedures. View full abstract»

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  • The organization of a multilist-type associative memory

    Page(s): 488 - 492
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    The use of an addressable memory for an associative memory provides a flexibility which it is more difficult to achieve with a memory having associative features built into the hardware. One way to do this is to organize the information in the multilist structure which is the subject of this paper. This scheme has other advantages, such as very high efficiency of information retrieval in large and complex files, which can now be performed in real time. View full abstract»

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  • Incremental computer error analysis

    Page(s): 492 - 498
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    Analyses of two types of computational errors inherent in digital differential analyzer (DDA) operation are presented. Even though the emphasis is on the statistical analysis of round-off error, truncation error is also discussed in detail. The basic functional block of the computer, the integrator, is represented by a transform. Transform representation leads to analytical simplification in that block-diagram algebra and other phases of transform theory can be applied. Analysis of a high-resolution type of DDA is introduced as an extension to the theory. Examples are illustrated in Appendixes I ¿ IV. View full abstract»

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  • Hybrid digital analog pulse-time techniques for flight control system computers

    Page(s): 498 - 503
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    The application of hybrid digital analog pulse-time circuit techniques is presented in two specific examples for flight control system computers. These new circuit techniques make it practical to replace the electromechanical components, such as a-c servomotors, tachometers, synchros, and potentiometers, now used in flight control systems, with completely solidstate circuitry. This will result in increased reliability for flight control systems. View full abstract»

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  • Static amplidyne: A new high-capacity push ¿ Pull power amplifier I ¿ Resistive-inductive loads

    Page(s): 503 - 508
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    A high-capacity static power amplifier with reversible d-c output is described. The circuit consists of six silicon-controlled rectifiers fed from a 3-phase 4-wire a-c supply. The gates are driven by differentially controlled half-wave magnetic amplifiers energized from the line to neutral voltages. The steady-state and the transient operations with resistive and inductive loads are described and static transfer characteristics are calculated for typical loads. A mechanism for the commutation of high inductive loads during output reversal transients is described. This mechanism eliminates altogether line-to-line short circuits and results in extremely fast speed of response. View full abstract»

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  • Ring-core flux-gate magnetometers with self-saturating circuits

    Page(s): 508 - 514
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    In the fundamental-frequency types of flux-gate magnetometer described in this paper, ordinary toroidal cores without air gap operate as field-sensitive elements in self-saturating push-pull circuits, as used in the magnetic amplifier art. The simplest form of such a magnetometer consists essentially of a half-wave bridge circuit, in which the two toroidal magnetic amplifier cores are replaced by the semicircular portions of a single ring core having two or four equally rated gate windings and acting as a flux detector. In a modified arrangement, two half-wave push-pull circuits with ring-core flux-gate elements are combined in a full-wave system, which may be utilized either as a very sensitive magnetometer or as a gradiometer for the measurement of the inhomogeneity of the magnetic fields. View full abstract»

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  • Ignitron discharge growth during high-current pulses

    Page(s): 514 - 523
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    Glass ignitrons were studied carrying up to 21,000 amperes with rise times as short as 1.25 ¿sec (microseconds). Kerr-Cell photographs show discharge growth, constrictions, and an expanding circle of arc spots with speeds up to 2 × 106 cm/sec (centimeters per second). The peak velocity varied with the 0.7 power of capacitor voltage and directly with the peak non-inductive component of anode voltage. Arc-front propagation, by ionic charging of a dielectric film, is discussed and is consistent with the measurements. View full abstract»

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  • Self-saturating magnetic amplifiers with capacitive loads

    Page(s): 523 - 527
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    The steady-state operation of the self-saturating magnetic amplifiers with rectified RC (resistance capacitance) loads is studied. Steady-state gain expressions are derived for square wave and sinusoidal gate supplies. Approximate methods for the evaluation of output quantities are given using a nomogram to simplify the calculations. Certain types of half-cyclic asymmetries peculiar to the capacitive loading are explained and criteria for their practical avoidance are given. View full abstract»

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  • Natural frequencies of negative resistors with parasitics

    Page(s): 527 - 531
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    The regions of allowed natural frequencies in Re p¿0 are determined for two different circuits which physically correspond to linearized equivalent circuits for tunnel diodes. One circuit consists of a parasitic resistance in series with the parallel capacity and negative resistance of a tunnel diode; the other contains series inductance. Passive networks to obtain any possible natural frequency are given. Multiple diode circuits are treated and for identical diodes it is shown that the best results occur with two diodes. View full abstract»

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  • Message buffering in a computer switching center

    Page(s): 532 - 534
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    Storage systems may be compared on the basis of the required number of buffers to be adequate at the same level of probability. The extreme cases of individual as against shared-line buffering are analyzed under the assumption of exponentially distributed message lengths. Finally, a method is indicated for increasing the accuracy of estimates of required storage capacity when the distribution of message lengths is known. View full abstract»

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  • Redundancy techniques (or reliable flight-control computers

    Page(s): 535 - 546
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    Insuring safety of flight in high-performance aircraft requires great advancement in the reliability of flight-control computers. While such improvements are not attainable by component improvement alone, they can be effectively achieved by redundancy. This paper describes a combination of redundancy techniques developed to meet flight-control requirements, using majority logic supplemented by self-combinational networks and parity-check error detection. Alternative redundancy techniques are outlined and simple approximate expressions for reliability are derived, showing the reasons leading to selection of the desired combination. Theory of majority logic is explained, and expressions for optimum voter arrangement and resultant reliability are derived. Implementation of a model flight-control computer, built for the Air Force, is explained. Judicious computer organization enhances reliability of the basic nonredundant layout, achieving a mean lifetime of 1,500 hours (failure probability of 0.005 for an 8-hour mission). For an 8-hour mission, the redundant computer has an equivalent lifetime of 110 years (failure probability of 10¿5). View full abstract»

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  • On conditions for determining ergodicity in a class of stationary random processes

    Page(s): 546 - 553
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    Necessary and sufficient conditions are given for determining that a class of stationary random processes are ergodic in the quadratic mean. The theorems given are wide-sense theorems and refer to relations between temporal averages and probability averages for first-order statistics. This, however, is generally required in engineering applications. View full abstract»

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  • An experimental correlation analyzer for measuring system dynamics

    Page(s): 554 - 562
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    This paper describes an experimental analyzer which utilizes a modified form of the sine-wave correlation principle to measure the dynamic characteristics of systems including industrial processes and instruments. Relatively high accuracy is obtained even when the output is distorted by system nonlinearities or deteriorated by noise. Methods are presented for estimating the system noise characteristics and determining the signal-to-noise ratio improvement to be expected from the use of correlation. Examples are given for the application of the process analyzer to a simulated system, control system components, and an industrial process. View full abstract»

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  • New concepts in systems for electrical measurement

    Page(s): 563 - 568
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    A new concept of more flexible instrumentation for power systems is described. A group of individual transducers is used for measuring the usual electrical quantities and temperature, each producing a high-level d-c output suitable for either analog or digital readout. Conventional d-c mechanisms are used in the end devices, eliminating the need for more complex mechanisms. The operating principles, performance characteristics, and circuit diagrams of six commercially available transducers are given. View full abstract»

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Aims & Scope

This Transactions ceased publication in 1963. The current retitled publication is  IEEE Transactions on Communications.

Full Aims & Scope