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Proceedings of the Institution of Electrical Engineers

Volume 122, Issue 10, October 1975

Volumes & issues:

Volume 122, Issue 10

October 1975

Identification of loss mechanisms in 3-phase surface-channel charge-coupled devices
IEE Conference Publication 130. First European Solid State Circuits Conference (ESSCIRC)
Determination of thickness and refractive index of thin transparent multilayer films on silicon from ellipsometric data Computer-program description
  • Author(s): J.G. Doherty  and  W.D. Ryan
  • Source: Proceedings of the Institution of Electrical Engineers, Volume 122, Issue 10, p. 1093 –1094
  • DOI:  10.1049/piee.1975.0269
  • Type: Article
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  • p. 1093 –1094 (2)
    Ellipsometry is commonly employed to evaluate the thicknesses and refractive indices of thin films grown on silicon. To obviate the use of relatively inaccurate graphical techniques in the calculation of film parameters from ellipsometer readings, a computer program, which solves the appropriate equations iteratively, has been written. The program, in Fortran IV, which was developed, primarily, for interactive-mode operation, makes efficient use of computer core and time, and can handle measurements taken from transparent films, comprising up to 50 layers, grown from, or deposited on, silicon substrates.
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Properties of the subsequences of a class of linear product sequences
  • Author(s): G.H. Tomlinson  and  P. Galvin
  • Source: Proceedings of the Institution of Electrical Engineers, Volume 122, Issue 10, p. 1095 –1096
  • DOI:  10.1049/piee.1975.0270
  • Type: Article
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  • p. 1095 –1096 (2)
    The properties of the subsequences of a class of linear product shift-register sequences are studied. The particular class concerns those derived from two m sequences of relatively prime length. Expressions are presented for the moments of the subsequence weight distribution. The expressions display a systematic relationship between the moments and the characteristic polynomials of the parent msequences. The importance of correct choice of parent sequences is demonstrated by the results, which show considerable variationof M-tuple weight distribution for product sequences of the same length but having different characteristic polynomials. Consideration of the expression for third moment provides a means for selecting parent m sequences to minimise skewness of the weight distribution.
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Study of recursive equalisers for data transmission with a comparison of the performance of six systems
  • Author(s): C.J. Macleod ; E. Ciapala ; Z.J. Jelonek
  • Source: Proceedings of the Institution of Electrical Engineers, Volume 122, Issue 10, p. 1097 –1104
  • DOI:  10.1049/piee.1975.0271
  • Type: Article
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  • p. 1097 –1104 (8)
    Adaptive and automatic quantised feedback equalisers of telephone lines for data transmission are studied. In particular, equalisers which use a steepest-descent algorithm with a minimum mean square error criterion are considered, and the effect of 2-level quantisation on the mean square error in the steady state and on the conditions of stability are analysed. The effect of the ‘random walk’ of the tap coefficients on the mean square error in the steady state is also investigated. Finally, a comparison of the performance of six equalisation schemes is made using computer simulation. These schemes include nonrecursive and hybrid networks, with and without signal quantisation.
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Quantisation in non-recursive equalisers for data transmission
  • Author(s): C.J. Macleod ; E. Ciapala ; Z.J. Jelonek
  • Source: Proceedings of the Institution of Electrical Engineers, Volume 122, Issue 10, p. 1105 –1110
  • DOI:  10.1049/piee.1975.0272
  • Type: Article
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  • p. 1105 –1110 (6)
    The effect of 2-level quantisation of the signals within the equaliser on its performance is studied in two cases:(a)when the tap coefficients are updated after every sample of the message, and (b) when the updating is performed after an averaging period equal to the length of a pseudorandom binary signal. In particular, the effect on the stability and the mean square error in the steady state is analysed. A relationship between the mean square error in the steady state and the ‘random walk’of the tap coefficients is derived. Numerous computer-simulation results confirm the analysis.
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Quantitative comparison of routing systems
  • Author(s): R. Couchman
  • Source: Proceedings of the Institution of Electrical Engineers, Volume 122, Issue 10, p. 1111 –1117
  • DOI:  10.1049/piee.1975.0273
  • Type: Article
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  • p. 1111 –1117 (7)
    A study is made of various systems used to route interconnections on printed-circuit boards, and methodsof assessing their quality are proposed. Two novel routing systems are suggested for different operating environments. A large number of randomly generated boards are routed by the new and by the existing methods, thus enabling a statistical comparison to be made. A basic theory of board interconnection is developed, aiding the prediction of routing-system behaviour. Through this theory and numerical experiment, some alternative systems are compared quantitively for the first time.
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IEE Conference Publication 131. Telecommunication transmission
Computer-controlled queuing system with switching network and feedback
Current-conveyor realisation of transfer function
Static torque production in saturated doubly-salient machines
  • Author(s): M.R. Harris ; A. Hughes ; P.J. Lawrenson
  • Source: Proceedings of the Institution of Electrical Engineers, Volume 122, Issue 10, p. 1121 –1127
  • DOI:  10.1049/piee.1975.0277
  • Type: Article
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  • p. 1121 –1127 (7)
    A new theory is presented for the static reluctance torque produced in a doubly-salient machine when themagnetic circuit is strongly saturated, as occurs, for example, in the majority of stepping motors of modernmanufacture. It is shown that, despite saturation, it is still possible to use linear airgap-permeance data to derive expressions for the optimum proportions of tooth, slot and gap, and to establish a limiting value of specific torque. From the point of view of maximising static torque, the smallest possible airgap is the best, and the optimum tooth-width/tooth-pitch ratio is rather less than 0.42. The theoretical conclusions are in line with modern design practice (empirically based), and are well supported by experimental results.
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Transient performance of eddy-current couplings
  • Author(s): E.J. Davies ; M.T. Wright ; R.C. Johnson
  • Source: Proceedings of the Institution of Electrical Engineers, Volume 122, Issue 10, p. 1128 –1136
  • DOI:  10.1049/piee.1975.0278
  • Type: Article
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  • p. 1128 –1136 (9)
    Eddy-current couplings are normally used in conjunction with control systems, yet no transient theory for this machine has previously been published. The constant-slip transient performance is calculated from thedesign information, without using experimental data, and is shown to give good results on a test machine. The damping effects of the solid-iron loss member are shown to be negligible over a wide range of slip speed, so that the main timer constants are associated with the field member, which are easily calculated using standard design methods. Test values of load-flux distribution under transient conditions are given. The effectof the index used to represent the magnetisation curve and of the approximation for flux level at various speeds is discussed. The use of the method to calculate large torque transients at low slips and for incremental voltage steps on the field are briefly described.
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Discussion on “Development of a new range of e.h.v. heavy-duty airblast circuit breakers”
Viscously coupled inertial damping of stepping motors
  • Author(s): P.J. Lawrenson  and  I.E. Kingham
  • Source: Proceedings of the Institution of Electrical Engineers, Volume 122, Issue 10, p. 1137 –1140
  • DOI:  10.1049/piee.1975.0280
  • Type: Article
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  • p. 1137 –1140 (4)
    The discrete-stepping performance of stepping motors, used with viscously coupled inertial dampers, is studied analytically and numerically. Linear and nonlinear system models are employed, and different criteria for optimum performance are considered. Consideration of the envelope of the time response and the integral-of-time-absoluteerror index show that a quite clearly defined optimum exists for both relative-velocity proportional and absolute-velocity proportional damping. Very simple equations for damper design are presented. The theoretical findings are supported by experimental results.
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Investigation of the transient behaviour of a current-fed autopiloted asynchronous induction machine
  • Author(s): Bernard Trannoy ; Michel Boidin ; Bernard de Fornel
  • Source: Proceedings of the Institution of Electrical Engineers, Volume 122, Issue 10, p. 1141 –1145
  • DOI:  10.1049/piee.1975.0281
  • Type: Article
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  • p. 1141 –1145 (5)
    The transfer functions associated with an autopiloted current-fed asynchronous induction machine are determined. The parameters influencing the static and dynamic performance are presented. Subsequently, it is shown how these performances are modified by the conditions imposed at the inputs of the group. Finally, a speed regulation is investigated in the case where the machine is fed with the rotor-current frequency imposed. The results obtained theoretically, with the aid of this model, are confirmed by experimental results from a practical working system.
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Long-term-creep assessment for overhead-line conductors
  • Author(s): J. Bradbury ; P. Dey ; G. Orawski ; K.H. Pickup
  • Source: Proceedings of the Institution of Electrical Engineers, Volume 122, Issue 10, p. 1146 –1152
  • DOI:  10.1049/piee.1975.0282
  • Type: Article
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  • p. 1146 –1152 (7)
    Based on the strain-hardening-material law, a method of long-term-creep prediction is proposed which takes into account all practical line-design and operating conditions and estimates the reduction in conductor tension and the increase in its sag due to creep with acceptable accuracy. Correlation between theory and practice is illustrated by both laboratory and field measurements. Selected examples are given on the application of the method for line design and for the selection of optimum sagging procedure of a line. Areas of further research and investigations on overhead-line creep are indicated.
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Choke–capacitor hybrid as a fluorescent-lamp ballast
Critical evaluation of online identification methods
Mixed method for reduction of multivariable systems with various inputs and outputs
System identification via Walsh functions
Time-of-flight electron-swarm studies of ionisation and attachment in gases
  • Author(s): C.S. Lakshminarasimha ; J. Lucas ; R.A. Snelson
  • Source: Proceedings of the Institution of Electrical Engineers, Volume 122, Issue 10, p. 1162 –1165
  • DOI:  10.1049/piee.1975.0287
  • Type: Article
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  • p. 1162 –1165 (4)
    A technique has been developed to evaluate ionisation and attachment coefficients for electrons travelling in gases across a uniform electric field by measuring the integrated-anode-current/time profile for a pulse of electrons released from the cathode. The main advantage of the method is that the time-resolved technique clearly distinguishes the current due to delayed effects, such as the arrival of negative ions in attaching gases or electrons produced by the metastable collisional ionisation of trace gases present in the inert gases. The method has been adopted to determine ionisation coefficients in hydrogen [85≤E/N≤169 Td (1 Td=10−21Vm2)], nitrogen (226≤E/N≤546) and helium (14≤E/N≤226) and both ionisation and attachment coefficients in oxygen (14≤E/N≤56) and carbon tetraflouride (42≤E/N≤197).
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Method of measuring alternating currents without disturbing the conducting circuit
Effect of the Penning gas on the cathode-fall region of glow discharges

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