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Electrical Engineers, Proceedings of the Institution of

Issue 9 • Date September 1972

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Displaying Results 1 - 25 of 45
  • Piccolo 32-tone telegraph system in diplomatic communication

    Publication Year: 1972 , Page(s): 1229 - 1236
    Cited by:  Papers (3)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1407 KB)  

    In 1963, details were published of a new method of teleprinter signalling for use on high-frequency radio circuits. This system (Piccolo) uses a different tone to represent each of the 32 characters of the teleprinter alphabet; the tones are orthogonally related and are detected at the receiver by quenched resonators. Piccolo has been further developed and refined, and has been adopted by the British Foreign & Commonwealth Office as the standard machine-telegraph method for diplomatic wireless communications; it is now in worldwide use. The paper describes the improvements made to the original models, a range of new ancillaries to improve compatibility, selective-calling facilities, and the s.s.b. radio equipment with synthetiser frequency control with which Piccolo is used. Operational techniques and performance figures are quoted. Other applications of the system are discussed, and possibilities for further development are mentioned. View full abstract»

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  • Numerical methods for wavefront analysis

    Publication Year: 1972 , Page(s): 1237 - 1242
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (747 KB)  

    The problem considered is that of calculating the angles of arrival of the components of a multimoded signal from simultaneous measurements of the signal induced in each element of a linear array. A numerical method is described in which the arrival angles are obtained from the roots of a polynomial whose coefficients are solutions of a set of linear equations. This method has been applied to determination of elevation arrival angles for multimode signals in the h.f. band, using data from a vertical array of equally spaced horizontal loops. In this case, the ground is assumed to be perfectly conducting, but the method of analysis is not restricted to this condition. View full abstract»

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  • Radiation of coupled-waveguide antennas

    Publication Year: 1972 , Page(s): 1243 - 1250
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (867 KB)  

    An investigation has been carried out on the two radiated beam patterns of a coupled-waveguide antenna. In general, the shapes of the two beams differ because of propagation asymmetry about the coupling plane. Using the analysis of the coupled-mode theory, it has been shown that, for antennas where very little of the input energy is radiated, the two beams can be made almost similar by appropriate reduction of the phase velocity of the nonradiating waveguide. The same principle, when applied to an efficient antenna, causes deterioration of the sidelobe levels, although the peaks of the two beams can still be maintained equal. For the efficient antenna, the problem of beam-port coupling is also considered with respect to uniform and cosine plus pedestal radiating aperture distributions. View full abstract»

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  • Local-oscillator-circuit optimisation for minimum distortion in double-balanced modulators

    Publication Year: 1972 , Page(s): 1251 - 1256
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (626 KB)  

    The distortion performance of double-balanced switching-diode mixers and modulators may be optimised by suitable design of the local-oscillator circuit. The paper describes simple techniques for defining optimum drive conditions for `split-ring¿, `hybrid¿, and `star¿ modulators. View full abstract»

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  • Susceptance-slope parameter of junction circulators

    Publication Year: 1972 , Page(s): 1257 - 1261
    Cited by:  Papers (5)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (450 KB)  

    The two quantities which define the performance of the junction circulator are its shunt conductance and its susceptance-slope parameter. It is shown in this paper that these two quantities are related in a universal way by the difference between the two split frequencies of the junction resonant modes. For many junctions, the difference between these frequencies is connected in a standard way to the magnetic splitting of the device. It is therefore sufficient to calculate either one of them to characterise fully the junction circulator. In this paper, the susceptance-slope parameter is calculated by forming the input admittance of the constituent resonator. The constituent resonator for the stripline circulator is the one formed by the ferrite disc fed by a single TEM line. It contains all the physical variables of the device. This principle is applied to a number of different geometries. The paper also describes a new quarter-wave-mode circulator. View full abstract»

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  • Computer-controlled queuing system with service interruptions

    Publication Year: 1972 , Page(s): 1262 - 1268
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (645 KB)  

    The paper presents a detailed study of a computer-controlled queuing system with Poisson input, first-come-first-served queue discipline and multiple-exponential servers that are subject to breakdowns and repairs. A generating function for the state probabilities of the system and a necessary and sufficient condition for the existence of statistical equilibrium for the system are derived. Further, a formula for the determination of the first waiting-time distribution in the system is obtained by the use of the theory of Markov chains. View full abstract»

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  • Use of exclusive-OR gates for boolean minimisation

    Publication Year: 1972 , Page(s): 1269 - 1272
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (369 KB)  

    An algorithm for the minimisation of logic functions using XOR (exclusive-OR) gates in addition to AND, OR and INVERT gates is presented. It applies to functions with inherent symmetries, and the saving of hardware compared with that achieved by other minimisation methods is typically 40¿60%. The algorithm could be included in the minimisation part of an automated-logic design program, or used as a logic designer's tool, either in the form of an on-call program or in the form of two templates for quick manual application. View full abstract»

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  • Analysis of a high-efficiency electron collector for a travelling-wave tube

    Publication Year: 1972 , Page(s): 1273 - 1274
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (294 KB)  

    Methods have been developed for the analysis of sophisticated electron-collection systems. The electron beam is treated either by representing it by a finite number of supersized charge carriers or (providing that the angle of divergence of the beam is small) by using a modification of the paraxial-ray equation. The results are employed to obtain a quantitative estimate of the collector efficiency and the heat dissipation on the collector walls. View full abstract»

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  • Generation of trees, cotrees and 2-trees of a linear graph

    Publication Year: 1972 , Page(s): 1275 - 1277
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (404 KB)  

    A new algorithm for finding all trees, cotrees and 2-trees in a connected linear graph is given. The procedure will not generate any duplication, redundancies or cancellation of terms. The method given is based only on the definition of tree, so that no complexity arises. Further, it is shown that, if a certain condition is satisfied by the graph, the 2-trees can be obtained directly from the trees that have been generated. An illustrative example on the algorithm is also given. View full abstract»

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  • Optimisation of slope of difference-mode radiation pattern in sum-and-difference-comparison monopulse radar

    Publication Year: 1972 , Page(s): 1278 - 1279
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (149 KB)  

    The expression of the field pattern due to four squinted horns is deduced by using the Eulerian transformation and translation. This expression is solved by computer to optimise the slope of the difference-mode field pattern. View full abstract»

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  • Propagation and radiation behaviour of corrugated feeds

    Publication Year: 1972
    Cited by:  Papers (3)
    Save to Project icon | PDF file iconPDF (201 KB)  
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  • Crab's-eye filter

    Publication Year: 1972
    Save to Project icon | PDF file iconPDF (148 KB)  
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  • Forbidden regions for the poles of a 3rd-order equal-valued-resistor active lowpass filter

    Publication Year: 1972 , Page(s): 1281 - 1282
    Cited by:  Papers (1)
    Save to Project icon | PDF file iconPDF (285 KB)  
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  • Characteristics of dielectric-tube-loaded coaxial cables

    Publication Year: 1972 , Page(s): 1282 - 1283
    Save to Project icon | PDF file iconPDF (282 KB)  
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  • Fuel gauge for the electric car

    Publication Year: 1972
    Save to Project icon | PDF file iconPDF (145 KB)  
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  • An abundance of sinusoidal RC oscillators

    Publication Year: 1972 , Page(s): 1283 - 1284
    Save to Project icon | PDF file iconPDF (178 KB)  
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  • Stability study of controlled rectifiers using a new discrete model

    Publication Year: 1972 , Page(s): 1285 - 1293
    Cited by:  Papers (16)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (921 KB)  

    The paper is concerned with the stability of closed-loop control systems incorporating controlled rectifiers. A suitable small-signal model for a convertor is developed which takes into account the discrete behaviour of the controlled rectifier. This model permits the use of standard sampled-data control-system theory in the stability analysis of the system. Contrary to usual practice, the a.c. system reactance is not neglected in the modelling. It is shown that the commutation angle is an important factor in the determination of stability boundaries. Finally, again-correction factor is employed to allow for the effect of the ripple under finite-commutation-angle conditions. Discrete Laplace transformation (z transformation) is used throughout the analysis together with root-locus techniques. Stability boundaries derived from the new model and other existing models are compared, and it is shown that experimental results are in good agreement with the theory developed in this paper. View full abstract»

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  • Discussion on "Thermal insulation for energy storage"

    Publication Year: 1972
    Save to Project icon | PDF file iconPDF (188 KB)  
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  • Distributed moving-boundary circuit-breaker model

    Publication Year: 1972 , Page(s): 1295 - 1300
    Cited by:  Papers (1)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (798 KB)  

    The behaviour of the arc in the throat of an air-blast circuit breaker around a current zero is analysed by applying a simplified energy-balance equation to a constant-pressure model having a flexible radial temperature distribution and a variable conducting radius, as determined by a boundary-loss empirical formula derived from the steady v/i characteristic. Such a model, in a single-frequency-fault circuit, is examined on a computer, and clear/fail conditions are determined. Results may be simply displayed by a single curve using co-ordinates of suitably normalised combinations of arc and circuit parameters and initial conditions, if linear gas properties between ¿, S and ¿ ¿ dh are assumed. Alternatively, arcs with nonlinear gas properties may readily be examined in specific cases. The radial S distributions show considerable deviations from steady-state profiles; there are marked variations of instantaneous arc time constants, and the total loss varies widely. This model is therefore able to more faithfully follow real life than could simpler models used previously, and gives encouraging agreement with real test results of, say, voltage and current against time and (dG/dt)/G against power. View full abstract»

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  • General theory of solid-rotor induction machines

    Publication Year: 1972 , Page(s): 1301 - 1308
    Cited by:  Papers (11)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (902 KB)  

    A general theory of the torque/slip and current/slip characteristics of solid-rotor induction machines is developed in terms of dimensionless coefficients, and its validity is demonstrated by measurements on machines in the range 6¿1500 W. Generalised characteristics are presented in the form of curves of the dimensionless coefficients. The analysis is based on an expression for equivalent rotor impedance which is inversely proportional to the product of airgap flux and slip and which has a constant phase angle. Various methods of calculating eddy-current losses in solid rotors give impedances of this form, and the use of some of these in the generalised analysis is assessed. View full abstract»

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  • Prediction of transient performance of isolated saturated synchronous generator

    Publication Year: 1972 , Page(s): 1309 - 1318
    Cited by:  Papers (4)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1153 KB)  

    The paper describes a digital simulation of a 3-phase model of a synchronous generator, directly in phase quantities. It is shown how, on the assumption that saturation arises principally from the resultant direct-axis current, the corresponding nonlinearities may be included in the equations of the model. The equations are developed in a form suitable for the study of both symmetrical and asymmetrical operating conditions of an isolated machine, and a digital-computer program using predictor-corrector techniques is described for their solution. Predictions of the transient conditions following a variety of switching operations are shown to compare closely with experimentally obtained results on a 15 kV A machine. View full abstract»

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  • Standardisation of plant and equipment for public electricity supply. An Area Board's aims and experiences

    Publication Year: 1972 , Page(s): 1319 - 1328
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1489 KB)  

    The paper is a review of the aims and experiences of the London Electricity Board, over the 23 years since its formation in 1948, in standardising all the major items of plant and equipment used in the supply of electricity to the inner areas of Greater London. During this period, a growth in demand of some 2400 MW has been met by replacement and reinforcement of existing systems using a very limited variety of standard designs and sizes. The review describes the development of the standard designs, which range from substation plant installed at points of bulk supply from the Central Electricity Generating Board to terminal equipment installed on the premises of domestic consumers. It covers switchgear, transformers, underground-link disconnection boxes and fusible cutouts for use at voltages ranging from 66 kV to 240 V. View full abstract»

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  • Discussion on ¿Comparisons of synchronous-machine models in the study of the transient behaviour of electrical power systems¿

    Publication Year: 1972 , Page(s): 1329 - 1337
    Save to Project icon | PDF file iconPDF (1586 KB)  
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  • Erratum: Comparisons of synchronous-machine models in the study of the transient behaviour of electrical power systems

    Publication Year: 1972
    Save to Project icon | PDF file iconPDF (113 KB)  
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  • Performance of a synchronous generator with a bridge rectifier

    Publication Year: 1972 , Page(s): 1338 - 1342
    Cited by:  Papers (9)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (518 KB)  

    The performance of a cylindrical-rotor generator, without damper windings, connected to an uncontrolled bridge-rectifier load, is considered. Assuming constant field-flux linkages, equations are derived which enable the performance of generators to be predicted. The commutation angle, the displacement angle and the field-current perturbation are the quantities which characterise generators with rectifier loads. Modification of the equations for a controlled bridge is discussed. The equations are supported by some practical tests on a laboratory machine. View full abstract»

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Aims & Scope

The Proceedings of the Institution of Electrical Engineers was published by the IET between 1963 and 1979.

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