Journal of the Institution of Electrical Engineers - Part I: General 

About: Journal of the Institution of Electrical Engineers - Part I: General is an academic journal. The journal publishes majorly in the area(s): Voltage & Degaussing. It has an ISSN identifier of 0367-7559. Over the lifetime, 158 publications have been published receiving 1017 citations.

The nature of the operator's response in manual control, and its implications for controller design

Abstract: This paper gives a brief account of a series of measurements of the movement of the controller handle and of the error of aim under conditions simulating the laying of a gun on a moving target by manually-controlled power operation.The results are analysed with the object of obtaining the “ operator's response, ” i.e. the relationship between the movement made by the operator's hand and the error and its variations as seen by the eye.It is found that the response relationship is non-linear, but the relationship may to a useful extent be approximated by a “ nearest linear law, ” namely that the speed of handle movement is dependent upon both the error and the rate of change of error, subject to a time delay which corresponds to that known to be involved in nerve transmission. The actual movement is found to differ from this relationship, both in being intermittent or jerky and also in being subject to apparently haphazard variations.A project for further investigation is outlined by which the difficulties in more detailed analysis may be overcome.On the basis of the results so far obtained it is shown that an explanation is provided for some of the outstanding phenomena observed in the laying of guns and in other cases of manual control of power-driven apparatus, and it is shown that there is an upper limit to the accuracy of control obtainable.Finally, the paper shows how the error incurred in tracking a target is fundamentally related to and depends upon the time delay which occurs between the stimulus received by the eye and the resulting muscular response, and gives comparative values for the theoretical limit of accuracy obtainable with controllers having various types of response characteristics, as a function of this delay time, for an otherwise ideal operation.The lines along which an improvement of performance may be sought are discussed in the light of these limits and the other phenomena observed.

Electromechanical analogies and their use for the analysis of mechanical and electromechanical systems

Abstract: After some introductory remarks which outline the problem and special features of its treatment, Section 3 explains how complex notation and the impedance concept can be applied directly to the analysis of mechanical systems. This leads naturally to the first or "direct" method of constructing an electrical "model" of a mechanical system, where a mechanical force is represented by a voltage and a mechanical velocity by a current; a mechanical impedance, i.e. the ratio of a force to a velocity is then represented by a proportional electrical impedance. In this analogy a mass is represented by an inductance. It is shown that this representation, when established for one particular frequency, is valid for all other frequencies. Section 4 shows that there exists a perfectly consistent, alternative method of constructing such an electrical model in which all these correspondences are replaced by their dual counterparts and which is therefore called the "indirect" or "inverse" analog). A mechanical force is here represented by an electric current and a mechanical velocity by a voltage. Accordingly, a mechanical impedance is then represented by an electrical admittance of proportional magnitude; in particular a mass is represented by a capacitance. This analogy has the advantage that it enables a circuit diagram of the electrical model to be copied from the diagram of the mechanical system, if this is drawn in accordance with certain conventions. The circuit diagram found by this method is the dual of the circuit found by the first method, and as it is a routine procedure to draw the dual of a given network the second analogy may also be useful when utilizing the first type of analogy. The paper supplements the development of this method by showing how levers fall into the general scheme of this geometrical correspondence if they are interpreted as auto-transformers. It also shows how the circuits of both these analogies may be found with advantage by an al

Internal discharges in dielectrics: their observation and analysis

Abstract: Previous work on the observation of discharge phenomena is reviewed briefly. Methods used by the authors are described, together with means of determining the quantitative significance of the results. It is shown that the h.f. discharge detector is sensitive and convenient in use, while the oscillograph bridge is more informative. The theory of the sequence of discharge on alternating current is developed in the light of experimental observations and yields values for the energy loss in an idealized case in accordance with experiment. Some consideration is given to the choice of method appropriate to various cases, and the sensitivities of a number of methods are compared. The application of discharge detection to two particular cases is described, and the relationship between discharge characteristics and life under certain conditions is established.

Analysis-synthesis telephony with special reference to the vocoder

Abstract: The requirements of a commercial speech-telephone system are considered from first principles and shown to lead naturally to the idea of analysis-synthesis telephony when bandwidth is the main criterion of cost, i.e. in practice, for long distances. The more thoroughly the analysis-synthesis principle is exploited the greater is the resulting potential band economy; the price paid is a restriction in versatility, but not any inherent loss in quality of the reproduced speech. The vocoder, first developed in America before the recent war, is an example of an analysis-synthesis system. Details are given of British Post Office experience in the design and performance of vocoders. Using a high-quality microphone, an articulation efficiency approximately the same as the highest reached on an ordinary commercial circuit has been reliably achieved, though the rather ?inhuman? quality of the synthesized speech may be a disadvantage in some circumstances. A brief review of transmission systems which might be suitable for the vocoder is also given.