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Volume 125
Issue 7
Proceedings of the Institution of Electrical Engineers
Volume 125, Issue 7, July 1978
Volumes & issues:

Volume 126 (1979)

Volume 125 (1978)

Volume 124 (1977)

Volume 123 (1976)

Volume 122 (1975)

Volume 121 (1974)

Volume 120 (1973)

Volume 119 (1972)

Volume 118 (1971)

Volume 117 (1970)

Volume 116 (1969)

Volume 115 (1968)

Volume 114 (1967)

Volume 113 (1966)

Volume 112 (1965)

Volume 111 (1964)

Volume 110 (1963)
Volume 125, Issue 7
July 1978
Simple nullsteering antenna for frequencyagile radars
 Author(s): R. Voles
 Source: Proceedings of the Institution of Electrical Engineers, Volume 125, Issue 7, p. 623 –625
 DOI: 10.1049/piee.1978.0150
 Type: Article
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p.
623
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A nullsteering technique is described that is applicable to mechanically scanned antennas that can be synthesised as a number of identical subarrays. The process generates a substantially stationary polar pattern in space in which the nulls are locked to the directions of the interfering sources. The system is particularly suited to frequencyagile radars. The average system loss is 3 dB per source suppressed.
Possibility of automatically acquiring the optimal adjusting step in adaptive equalisers
 Author(s): E. Cecchi ; G. Martinelli ; G. Orlandi ; G. Orlandi ; M. Salerno
 Source: Proceedings of the Institution of Electrical Engineers, Volume 125, Issue 7, p. 626 –632
 DOI: 10.1049/piee.1978.0151
 Type: Article
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p.
626
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(7)
The possibility of rendering a gradienttype adaptive equaliser able to acquire automatically the optimal adjusting step has been proved in the paper by proposing a new type of equaliser. The mentioned possibility enables the equaliser to be independent of the channel characteristic and very slightly dependent on the noise.
Spurious radiation from microstrip
 Author(s): L. Lewin
 Source: Proceedings of the Institution of Electrical Engineers, Volume 125, Issue 7, p. 633 –642
 DOI: 10.1049/piee.1978.0152
 Type: Article
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p.
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The method of an earlier paper is applied to calculate the disturbances due to a number of discontinuities encountered in typical antenna feed and network structures, such as impedance changes, power dividers, Tjunctions, open and short circuits etc., and these are compared for relative radiation. Error estimates due to some secondary effects are calculated and shown to be generally negligible. The process of radiation from an open circuit is studied in detail and it is shown that, although most of the radiation comes from the tip, a substantial amount is radiated and also absorbed to. about a freespace wavelength behind the discontinuity. A method analogous to the induced e.m.f. method is formulated and shown to confirm existing results for radiated power. A distinction is made between the phase centre for radiation, which is usually located at a discontinuity, and the source region for radiation. The two are not coincident and the latter may be quite extensive for microstrip radiations. The results are applied to show how the disturbances can affect the performance of a comb antenna and how they can also be utilised to enhance the efficiency of a stripend radiator on a thin substrate.
Application of power transistors to polyphase regenerative power convertors
 Author(s): A.R. Daniels and D.T. Slattery
 Source: Proceedings of the Institution of Electrical Engineers, Volume 125, Issue 7, p. 643 –647
 DOI: 10.1049/piee.1978.0153
 Type: Article
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p.
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An important mode of operation of a general power amplifier using power transistors is described, whose output is a variablefrequency 3phase current. The convertor operates from a fixed 3phase source without a d.c. link, utilises only 18 power transistors and provides a regenerative output.
20th Hunter Memorial Lecture. Microelectronics and the power engineer
 Author(s): E. Paddison
 Source: Proceedings of the Institution of Electrical Engineers, Volume 125, Issue 7, p. 648 –656
 DOI: 10.1049/piee.1978.0154
 Type: Article
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p.
648
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Problems of the power engineer can be provided with better solutions using microelectronics. Some of the significant powerengineering problems are examined together with microelectronic components available for solutions. A number of examples are given of solutions to selected power problems and these include the use of microcomputers for protection control and data collection for metering, remote load control, static distance protection, ‘hifi’ capacitor voltage transformers, phasecomparison protection, pilotwire protection, transformerdifferential protection, overcurrent protection of lowvoltage networks, instrument transducers, powerfactor correction and control of unwanted interference. The aim of this paper is to provide an insight into the functioning of engineers in this environment, an understanding of the problems that exist and an awareness of the advances that are being made in the solutions that are provided.
Theories of linear induction motors with completely filled and half filled endslots
 Author(s): Mohammad ElHosainy Isma'eel
 Source: Proceedings of the Institution of Electrical Engineers, Volume 125, Issue 7, p. 657 –665
 DOI: 10.1049/piee.1978.0155
 Type: Article
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p.
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(9)
New theories for linear induction motors (l.i.m.s) with completely filled and halffilled primary endslots are presented. End effects due both to the discrete nature of the windings and the finite iron length are taken into account by formulating the boundaryvalue problem on the basis of the m.m.f. distribution and representing the m.m.f. wave packets of the stator windings by Fourier integrals. The paper reveals that the stationary pulsating m.m.f. wave, which appears in the air gap of an l.i.m. with completely filled slots owing to the finite length of the stator iron core, has a very adverse influence on the motor performance, a phenomenon which has not been previously discussed. A new theory of compensation is proposed to improve the performance of this type of motor. The paper also shows that idealised theories of the l.i.m. are very special cases of those given here. A simplified formulation of the boundaryvalue problem of the l.i.m., taking into account the end effects due both to the discrete nature of the windings and the finite stator iron length, is also given. The results are compared with published experimental data, and with those obtained from an idealised l.i.m. excited by a sinusoidally distributed current sheet of the same magnitude.
General theory of induction machines with unlaminated secondary and constantcurrent excitation
 Author(s): B.J. Chalmers and M.M.K. El Attar
 Source: Proceedings of the Institution of Electrical Engineers, Volume 125, Issue 7, p. 666 –670
 DOI: 10.1049/piee.1978.0156
 Type: Article
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p.
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A general theory of induction machines with unlaminated secondary and constantcurrent excitation is presented, based on a previous treatment of such machines with constantvoltage supply. The results are presented in the form of generalised curves of nondimensional coefficients, which, in conjunction with simple scaling factors, enable the torque/speed characteristic of a given machine to be evaluated. A computational method is described for taking into account saturation in the magnetic circuit and the validity of the treatment is demonstrated by correlation with tests up to high levels of saturation. The results are particularly relevant to modern eddycurrent machines such as dynamometers, brakes and couplings.
Asymmetrical fault analysis using the bus impedance matrix
 Author(s): C.B. Gray and P.N.P. Singh
 Source: Proceedings of the Institution of Electrical Engineers, Volume 125, Issue 7, p. 671 –672
 DOI: 10.1049/piee.1978.0157
 Type: Article
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p.
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The method of the busbar impedance matrix is applied to the solution of asymmetrical faults through the use of sequence impedances and Kron's constraint matrix. An algorithm is proposed to facilitate the routine solution of complex configurations including simultaneous and crosscountry faults.
Electronicfiring system for machines with thyristorassisted commutation
 Author(s): A.W. Bingham and R.E. Colyer
 Source: Proceedings of the Institution of Electrical Engineers, Volume 125, Issue 7, p. 673 –674
 DOI: 10.1049/piee.1978.0158
 Type: Article
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p.
673
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(2)
Gustalleviation control systems for aircraft
 Author(s): D. McLean
 Source: Proceedings of the Institution of Electrical Engineers, Volume 125, Issue 7, p. 675 –685
 DOI: 10.1049/piee.1978.0159
 Type: Article
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p.
675
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The use of active control technology (a.c.t.) to alleviate the effects on both the dynamic and structural responses of an aircraft flying through atmospheric turbulence, while maintaining an acceptable degree of flighthandling qualities, is discussed.Two control schemes, derived from optimalcontrol theory and the algebraic theory of model following, are presented, and their value as practical methods of achieving satisfactory ride comfort in a gusty environment is discussed. A possible weakness in current methods of mathematical modelling of flexible, or deformable, aircraft is indicated.
Image registration using the likelihood ratio
 Author(s): R. Voles
 Source: Proceedings of the Institution of Electrical Engineers, Volume 125, Issue 7, p. 686 –690
 DOI: 10.1049/piee.1978.0160
 Type: Article
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p.
686
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Application of the principle of maximum likelihood to the problem of image registration is shown to yield an optimum process which is analogous to that of conventional cross correlation but in which the product function is replaced by a new function that has been called the ‘likelihood correlation’ function. This function is defined by the separate and joint probability distributions of the contents of the two pictures to be registered. The form of the likelihood correlation function is particularly simple in two special cases of practical interest and a suitable embodiment is described. It is shown that a number of algorithms described in the literature are special cases of the likelihood correlation function. Possible embodiments of this function in the general case are outlined. It is suggested that the likelihood correlation function has wider applicability than just for image registration.
Identification of a class of nonlinear systems using correlation analysis
 Author(s): S.A. Billings and S.Y. Fakhouri
 Source: Proceedings of the Institution of Electrical Engineers, Volume 125, Issue 7, p. 691 –697
 DOI: 10.1049/piee.1978.0161
 Type: Article
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p.
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An algorithm is presented for the identification of nonlinear systems which can be described by a model consisting of a linear system in cascade with a nonlinear element followed by another linear system. Crosscorrelation techniques are employed to decouple the identification of the linear dynamics from the characterisation of the nonlinear element when the input is a white Gaussian signal. Parameterisation of both the linear and nonlinear component subsystems is discussed and the results of a simulation study are included to illustrate the validity of the algorithm.
Numerical determination of a performance index for improved system response
 Author(s): J.R. Smith and D.C. Stringfellow
 Source: Proceedings of the Institution of Electrical Engineers, Volume 125, Issue 7, p. 698 –700
 DOI: 10.1049/piee.1978.0162
 Type: Article
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p.
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The paper describes a computer program for the systematic numerical predetermination of a performance index J=∫^{∞}_{0} (x^{t}Qx+u^{2})dt such that the synthesised feedback controller that minimises J results in a controlled system with satisfactory eigenvalues that all lie to the left of the set {ss=α, α≤0} in the complex plane. The computer algorithm, which is based on the derivatives of the eigenvalues with respect to the coefficients of Q, may be used in isolation or can be included in an overall synthesis procedure. Examples illustrating the method are included.
Analytic applications of tsypkin's method relay with hysteresis and dead zone
 Author(s): U.M. Rao ; D.P. Atherton ; S.R. Atre ; V.P. Lele
 Source: Proceedings of the Institution of Electrical Engineers, Volume 125, Issue 7, page: 700 –700
 DOI: 10.1049/piee.1978.0163
 Type: Article
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p.
700
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Calculation of eddy currents by dual energy methods
 Author(s): P. Hammond ; J. Penman ; J. Penman
 Source: Proceedings of the Institution of Electrical Engineers, Volume 125, Issue 7, p. 701 –708
 DOI: 10.1049/piee.1978.0164
 Type: Article
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p.
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The resistances and reactances of eddycurrent systems are calculated by a method which gives upper and lower bounds to their values. The method is applicable to nonlinear systems and to systems having a complicated geometry.
Radiation pressure
 Author(s): P. Vigoureux
 Source: Proceedings of the Institution of Electrical Engineers, Volume 125, Issue 7, p. 709 –713
 DOI: 10.1049/piee.1978.0165
 Type: Article
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p.
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Electromagnetic waves, sound waves, the waves of a vibrating string etc carry momentum and exert, on an obstacle in their path, a force equal to the rate of momentum change produced by the obstacle. A very general energy theorem is applied to the calculation of the momentum, and shows that, in an unbounded medium, waves of intensity J have momentum J/v^{2} per unit volume, where v is the velocity of propagation. In a dispersive medium the phase velocity must be used to calculate the radiation pressure, i.e. the radiation force per unit area, in terms of intensity.
Effect of pollution on the breakdown voltage of air
 Author(s): M. Lotfy ElSayed ; E. Mohamed ElRefaie ; M. Mohamed Awad
 Source: Proceedings of the Institution of Electrical Engineers, Volume 125, Issue 7, page: 714 –714
 DOI: 10.1049/piee.1978.0166
 Type: Article
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p.
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