Your browser does not support JavaScript!
http://iet.metastore.ingenta.com
1887

Proceedings of the Institution of Electrical Engineers

Volume 116, Issue 1, January 1969

Volumes & issues:

Volume 116, Issue 1

January 1969

Inaugural address. The vital spark
Chairman's address: Electronics Division. Science and profit in the electronics industry
Development, design and test procedures for random generators using chaincodes
Evaluation of performance of random generators employing chaincodes
  • Author(s): M.G. Hartley
  • Source: Proceedings of the Institution of Electrical Engineers, Volume 116, Issue 1, p. 27 –34
  • DOI:  10.1049/piee.1969.0004
  • Type: Article
  • + Show details - Hide details
  • p. 27 –34 (8)
    The objective of this paper is to contrast random generators built by Redshaw and Robinson with simpler generators devised by the author. The test procedures laid down in an earlier paper are followed. Both types of random generator were designed for the simulation of random arrivals of vehicles at road-traffic intersections. There is, however, a wide variety of other applications for such generators. These include message-switching simulation, and the simulation of the operation of the central processor of a multiprogram computer. The tests performed indicated that both classes of generator satisfied criteria for randomness, provided that care was exercised at the design stage.
    Add to favourites
    Export citations
Transistor-feedback-amplifier stabilisation using admittance measurements
  • Author(s): H.G. Brierley
  • Source: Proceedings of the Institution of Electrical Engineers, Volume 116, Issue 1, p. 35 –42
  • DOI:  10.1049/piee.1969.0005
  • Type: Article
  • + Show details - Hide details
  • p. 35 –42 (8)
    A method is described for stabilising a single-loop negative-feedback transistor amplifier based on measurements of a chosen short-circuit-stable closed-loop driving-point admittance between two terminals within the amplifier. A correcting network is synthetised, the admittance of which, when added to the measured admittance, prevents zero encirclement by the locus of the total admittance by an adequate margin. Formulas are given enabling margins against zero encirclement to be interpreted in terms of movements of corner frequencies associated with a frequently used internal amplifier configuration. The method is demonstrated to be straightforward for an amplifier requiring measurements up to 20MHz, and the admittance margins obtained are compared with margins obtained from loop-gain measurements.
    Add to favourites
    Export citations
Analysis of the statistics and threshold of the phase-lock loop
  • Author(s): R. Harrison
  • Source: Proceedings of the Institution of Electrical Engineers, Volume 116, Issue 1, p. 43 –52
  • DOI:  10.1049/piee.1969.0006
  • Type: Article
  • + Show details - Hide details
  • p. 43 –52 (10)
    The mean-square value of the phase error in the phase-lock loop is determined from the linear differential equation. Conditions are then derived, for its minimisation, with an integral plus proportional filter in the loop, for an input consisting of an f.m. f.d.m. carrier plus thermal noise. The statistics of the phase error are then deduced using the Fokker-Planck technique for an arbitrary loop filter. From the statistics, the loss of lock rate is derived and each loss of lock is assumed to produce an inpulse in the baseband. The well known result of Rice is used to determine the output signal/noise ratio, and the point of threshold arising from the loss of lock is shown.
    Add to favourites
    Export citations
Bandpass LC filters having prescribed amplitude and nearly constant group-delay characteristics
  • Author(s): L.J. Stagg
  • Source: Proceedings of the Institution of Electrical Engineers, Volume 116, Issue 1, p. 53 –58
  • DOI:  10.1049/piee.1969.0007
  • Type: Article
  • + Show details - Hide details
  • p. 53 –58 (6)
    The paper describes the synthesis of arithmetically symmetrical, broadband LC filters having prescribed amplitude response and nearly constant group delay, with particular reference to i.f. filters for radio-relay systems. These filters must suppress unwanted signals, particularly the adjacent carrier frequencies, without significantly distorting the required signal. For low distortion, the filters must have both flat amplitude and constant group-delay responses over the passband centre. Filters synthetised for 1800- and 960-channel systems have satisfied these requirements, the transfer-function design and measured characteristics of the filter for the 960-channel system being given as an example. The filters have the advantages that they can be inserted in the i.f. chain without the need for further phase equalisation, and that they give improved amplitude responses compared with conventional filter and equaliser combinations.
    Add to favourites
    Export citations
Transformed hypergeometric transmission lines
  • Author(s): A.G.J. Holt  and  P. Bowron
  • Source: Proceedings of the Institution of Electrical Engineers, Volume 116, Issue 1, p. 59 –64
  • DOI:  10.1049/piee.1969.0008
  • Type: Article
  • + Show details - Hide details
  • p. 59 –64 (6)
    A transformation procedure is described for determining a set of nonautonomic distributions which are complementary to previously described general classes of lines. A table of these distributions is presented, together with the conditions necessary for their evaluation. In particular, for the Gaussian distributed RC line, which is inherent, for example, in some diffused-semiconductor realisations, a solution is obtained in terms of a convergent confluent hypergeometric series which is equivalent to an earlier solution in terms of Hermite polynomials. Finally, its performance is evaluated and experimentally compared with a well known distribution.
    Add to favourites
    Export citations
Driving-point-function synthesis using nonuniform lines
  • Author(s): J.C. Giguere ; M.N.S. Swamy ; B.B. Bhattacharyya
  • Source: Proceedings of the Institution of Electrical Engineers, Volume 116, Issue 1, p. 65 –70
  • DOI:  10.1049/piee.1969.0009
  • Type: Article
  • + Show details - Hide details
  • p. 65 –70 (6)
    Necessary and sufficient conditions for the synthesis of a driving-point function using any two kinds of one-port impedances are presented, and the result is used to develop a procedure for synthetising a driving-point function using tapered lines. The result also provides a short proof for O'Shea's necessary and sufficient conditions for the realisation of a driving-point function using symmetric structures. It is shown that any impedance which can be realised using symmetric lines may always be realised using the one-port impedances of the nonuniform transmission lines used in the construction of the symmetric lines. It is shown that all the existing synthesis procedures for the realisation of a driving-point function using any two one-port impedances are special cases of the general procedure advanced in this paper. Necessary and sufficient conditions for realising a driving-point function as a cascade of symmetric structures have been advanced. These are shown to be equivalent to those for realising the same driving-point function using the open- and short-circuit impedances of a symmetric structure. A procedure for such a cascade synthesis is advanced. If the structure is a uniform line, it provides a simple alternative to Wyndrum's cascade-synthesis procedure. An illustrative example is also included. By using known transformations, all the results may be applied to other types of lines such as lossless lines.
    Add to favourites
    Export citations
Wedge-diffraction functions and their use in quasioptics
  • Author(s): L. Lewin
  • Source: Proceedings of the Institution of Electrical Engineers, Volume 116, Issue 1, p. 71 –76
  • DOI:  10.1049/piee.1969.0010
  • Type: Article
  • + Show details - Hide details
  • p. 71 –76 (6)
    Asymptotic and other formulas are derived ab initio for the field diffracted by a perfectly conducting wedge when illuminated by a line source. In the transition zone between lit and shadowed regions, the field is decomposed into image and diffraction terms which enable the formulas to be used throughout the region for self-consistent field analyses. The wedge-diffraction functions are finding a growing application in the investigation of electromagnetic problems in which the dimensions are too large for waveguide-mode analysis, but too small for geometric optics to apply. Various formulas are scattered throughout the literature. In this paper, they are derived from first principles and presented in a form in which the areas of use are indicated, and the important transition zone near a shadow boundary is explained in some detail.
    Add to favourites
    Export citations
Representation of noise sources in pumped nonlinear systems
  • Author(s): V.K. Prabhu
  • Source: Proceedings of the Institution of Electrical Engineers, Volume 116, Issue 1, p. 77 –83
  • DOI:  10.1049/piee.1969.0011
  • Type: Article
  • + Show details - Hide details
  • p. 77 –83 (7)
    Several different methods have been used to represent physical sources of noise at a frequency ω0 in a linear 2-port network, and this representation usually simplifies the analysis of propagation of noise through the network when it is connected to another network or a set of networks. It is shown that similar methods can be used to represent physical sources of noise in a nonlinear network when it is pumped by a strong signal and when the noise sources present in the system are small. In such a case, the device acts as a linear system to the noise and the terminal noise components are linearly related. This kind of representation simplifies the noise analysis of such systems and enables us to investigate how the noise propagates through the system. It will be shown that, at each port, for each frequency ω0 present in the system, it is necessary to have two equivalent noise sources rather than the one that is required in circuit theory of linear noisy networks.
    Add to favourites
    Export citations
Inhomogeneous dielectric filling to simulate curvature in model Earth-ionosphere waveguide
Microwave absorption and series resistance of silicon-mesa parametric-amplifier diodes
Stability of passive time-variable circuits
Construction of a sensitive microwave noise spectrometer
Chairman's address: Power Division. Engineering unlimited
Single-phase autoreclosure of extra-high-voltage transmission lines. An investigation into the residual fault current and recovery voltage
  • Author(s): Farouk A.M. Rizk
  • Source: Proceedings of the Institution of Electrical Engineers, Volume 116, Issue 1, p. 96 –100
  • DOI:  10.1049/piee.1969.0017
  • Type: Article
  • + Show details - Hide details
  • p. 96 –100 (5)
    The success of single-phase autoreclosure of extra-high-voltage transmission lines is based on the possibility of self extinction of the secondary arc, in spite of the influence of the sound phases. The residual fault current and the recovery voltage of the switched phase are among the most essential factors affecting self extinction of the residual fault.In this paper, a method is developed for the calculation of the recovery voltage and residual fault current during single-pole switching. The power system investigated consists of a remote power station interconnected to a large electrical system, through a single-circuit extra-high-voltage transmission line. The analysis includes the effect of fault location, line length, station parameters, transmission-line loading and the electromechanical swing subsequent to fault occurrence. The effects of the above factors on recovery voltage and residual current are investigated on the basis of numerical computations for a 500 kV transmission system.
    Add to favourites
    Export citations
Calculation of steady-state temperature rise of water-cooled buried cables using a new iterative method
  • Author(s): D.F. Binns
  • Source: Proceedings of the Institution of Electrical Engineers, Volume 116, Issue 1, p. 101 –106
  • DOI:  10.1049/piee.1969.0018
  • Type: Article
  • + Show details - Hide details
  • p. 101 –106 (6)
    The paper describes a new iterative method for calculating the steady-state temperature rise of water-cooled cables buried in a homogeneous soil. Cables and water pipes are represented by line heat sources and sinks of variable magnitude and position, and a computer program is used to calculate the necessary magnitudes and positions of the heat sources and sinks needed to represent the temperature distribution accurately. Open boundaries are used, and this avoids possible errors resulting from the usual practice of imposing isothermal surfaces at finite distances from the cables. It allows a check to be made on boundary conditions used for relaxation calculations or electrolytic-tank measurements. However, the method of analysis described here is considered superior to relaxation for calculating cable temperature rise in a homogeneous soil. A detailed example is given of a calculation carried out at one point in a cable run, including the complete temperature distribution in the soil. A technique is then outlined for applying the method at various points along a cable run, and consequently for calculating the rate of water flow required to maintain an acceptable conductor temperature.
    Add to favourites
    Export citations
Discussion on “Bundle conductors on grid lines in England and Wales”
Discussion on “Prediction of induction-motor dynamic performance in power systems”
Divided-winding-rotor synchronous generator. A comparison of simulated 30 MW conventional- and divided-winding-rotor turbogenerators
  • Author(s): J.A. Soper  and  A.R. Fagg
  • Source: Proceedings of the Institution of Electrical Engineers, Volume 116, Issue 1, p. 113 –126
  • DOI:  10.1049/piee.1969.0021
  • Type: Article
  • + Show details - Hide details
  • p. 113 –126 (14)
    Experiment with a 5kVA machine showed the feasibility of a new form of turbogenerator using a rotor winding of two sections, in X formation, controlling the torque and reactive requirements separately.The performance of a conventionally wound rotor turbogenerator (c.w.r.) of 30MW size, described by Shackshaft, is compared with that of a divided-winding-rotor (d.w.r.) arrangement (CEGB patent application 2240/65) of the same machine.The analogue simulation shows that the d.w.r. can control power and reactive output satisfactorily, without altering the rotor position in relation to the generator air-gap flux. Fully rated stator current at leading power factor can be obtained continuously from no load to full load.The speed of response of the d.w.r.-generator reactive power to a step change of infinite-busbar voltage is, on average, twice that of the c.w.r. Turbogenerator stability is improved, and is shown to be independent of reactive generation or absorption, being affected only by active-power generation.Transient-stability comparisons are made by simulating 3-phase short-circuit faults close up to the high-voltage busbar, with low- and high-impedance connections to the infinite busbar.The c.w.r. simulation at full load with full excitation withstands a fault duration of 0.45s, which comes down, with reducing excitation, to 0.32s when Qu = − 0.225 p.u. and rotor angle = 70°; 0.2s when Qu = − 0.6 p.u. and rotor angle = 100°; and less than 0.1 s when Qu = − 0.9 p.u. and rotor angle = 120°.Comparable d.w.r. simulation of load and excitation conditions all require a fault duration exceeding 0.4s to cause instability. Even the Qu = − 2.3 p.u. condition is simulated without deterioration of control, and requires 0.4s fault duration to cause instability.The high-impedance connection to the infinite-busbar simulation shows, in general, that the maximum fault duration for each type of generator is reduced by 0.1s.
    Add to favourites
    Export citations
Current distribution in sheet- and foil-wound transformers
Irish Branch: Chairman's address. The electrical engineer in the production industry
North-Western Centre: Chairman's address. Earthing for safety
Eddy-current effects in solid unslotted iron rotors
Static sampling distance relay
Transient response and transient stability of power systems
Chairman's address: Control & Automation Division. The transition from research to development in control
Absolute stability of a class of nonlinear sampled-data systems
  • Author(s): J.I. Soliman  and  H. Kwoh
  • Source: Proceedings of the Institution of Electrical Engineers, Volume 116, Issue 1, p. 145 –148
  • DOI:  10.1049/piee.1969.0029
  • Type: Article
  • + Show details - Hide details
  • p. 145 –148 (4)
    The present investigation studies the problem of absolute stability of a class of nonlinear sampled-data control systems with or without integrators in the loop. An absolute-stability criterion has been obtained by the second method of Lyapunov. The same stability criterion has been derived previously by the authors via the Popov approach. The criterion is shown to be a sufficient condition for the existence of a certain type of Lyapunov function which assures global-asymptotic stability of the class of systems under investigation. In contrast to previous results, the criterion does not place any restriction on the number of integrators in the loop. A systematic step-by-step method for applying the inequality is given, and an example illustrating the application of this frequency-domain inequality and a comparison with previous results are presented. The method is found to be versatile and more effective, and, in general, a better stability boundary can be obtained.
    Add to favourites
    Export citations
Discussion on CEGB automatic system-control experiment in the south-western region
Discrete positive-real functions and their application to system stability
Representation of magnetisation curves over extensive range by rational-fraction approximations
  • Author(s): G.F.T. Widger
  • Source: Proceedings of the Institution of Electrical Engineers, Volume 116, Issue 1, p. 156 –160
  • DOI:  10.1049/piee.1969.0032
  • Type: Article
  • + Show details - Hide details
  • p. 156 –160 (5)
    The paper presents a simple mathematical expression which enables representation of all types of magnetisation curves over a very wide range. The equation given is ideally suited for problems which require use of the B/H curve many times, since calculations using it require only a few operations of the basic arithmetic adding, multiplying and dividing.Although the equation is not linear in all the parameters, a method for obtaining the best parameters, in which the problem is first linearised and then restored to its original nonlinear form by a system of iteration, is described.A discussion of the meaning of the best parameters of the equation to fit the data curve, whether it is to be read fromB to H, or H to B, or both ways, is given.Comparison is given between several saturation curves and their mathematical counterparts over magnetising m.m.f. from zero to, in one case, 300000AT/m.
    Add to favourites
    Export citations
South-East Scotland Sub-Centre: Chairman's address
D.C. corona on smooth conductors in air. Steady-state analysis of the ionisation layer
Mersey and North Wales Centre: Chairman's address. The engineer
Potential functions for a compressible and anisotropic plasma medium
  • Author(s): Hollis C. Chen
  • Source: Proceedings of the Institution of Electrical Engineers, Volume 116, Issue 1, p. 169 –172
  • DOI:  10.1049/piee.1969.0036
  • Type: Article
  • + Show details - Hide details
  • p. 169 –172 (4)
    It is shown that, in a compressible and anisotropic plasma medium when both electric and magnetic current sources are present, the longitudinal components of the electric and magnetic fields and the pressure variation satisfy the inhomogeneous coupled wave equations. Generalised potential functions for the solution of such equations are presented. The complicated, difficult problem of analysing sources radiating in a compressible and anisotropic plasma is thus reduced to the solution of Helmholtz equations. Expressions for the determination of the transverse components of the electric and magnetic fields with sources are also derived. As an application of the general formulas, a complete solution for a magnetic line source is worked out in detail.
    Add to favourites
    Export citations
Electromagnetically actuated, fast-closing switch using polythene as the main dielectric
Absolute velocity of d.c. energy transmission by an electromagnetic field between two conductors and implications of relativity

Most viewed content for this Journal

Article
content/journals/piee
Journal
5
Loading

Most cited content for this Journal

We currently have no most cited data available for this content.

Print this page
This is a required field
Please enter a valid email address