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Radio and Electronic Engineer

Issue 2 • Date February 1972

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Displaying Results 1 - 7 of 7
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  • A special-purpose computer for the direct digital control of processes

    Page(s): 55 - 64
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1236 KB)  

    A general-purpose digital computer for the on-line control of large scale industrial processes serves the dual purposes of a time-shared controller for each loop by means of programmed algorithms and of a data logger and alarm scanner. The architecture of the general-purpose computer has been criticized regarding its suitability as a timeshared controller. This paper considers this problem and presents a case for the special-purpose digital controller. A research model is described in detail and its performance in a simulated system is given. View full abstract»

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  • Relative merits of quadratic and linear detectors in the direct measurement of noise spectra

    Page(s): 65 - 68
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (441 KB)  

    Initially a brief discussion is presented of the relative merits of quadratic and linear detectors as regards ease and convenience of use following narrow-band filters in the measurement of noise spectra. An analysis is then given of the noise content in the output signals of the two types of detector. The analysis uses results already available in the literature of the subject, but is presented here in a manner which allows a direct and ready comparison. The analysis is not restricted to any one type of narrow-band filter and it is concluded quite generally that neither type of detector has a significant advantage. View full abstract»

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  • The history of positive feedback: The oscillating audion, the regenerative receiver, and other applications up to around 1923

    Page(s): 69 - 80
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (2462 KB)  

    Positive feedback, or regeneration, played an important part in radio engineering during the two or three decades following its development for electronic circuits around 1912¿15. This paper reviews the earlier history of the subject, considers the controversial inventions of 1912¿15 in some detail, and goes on to examine some other applications of positive feedback in self-oscillating detectors, e.g. the autodyne, the homodyne and the super-regenerative receivers. View full abstract»

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  • High-frequency measurement of integrated circuit components

    Page(s): 81 - 84
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1183 KB)  

    A jig for extending a 50 ¿ high frequency measuring system to the pads of a chip device is described. No permanent wire bonds are used and contact may be made with normal aluminium pads. The electrical characterization of the jig up to 1 GHz has been carried out using a General Radio transfer function and immittance bridge, and Y-parameter measurements on typical chip devices have been obtained. The results are applicable to the design of integrated circuits and to device modelling. View full abstract»

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  • Annular resonant structures and their uses as microwave filters

    Page(s): 85 - 90
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (577 KB)  

    Recent trends in the development of microwave integrated circuits have tended to evolve systems with microstrip or triplate interconnexions between the active sections. It is thus desirable that any components incorporated into such microwave systems should be fully compatible with this general circuit form. A new configuration is described for the realization of a microwave band-pass filter. This configuration is particularly suitable for construction in `printed-circuit¿ form and is thus compatible with microstrip and triplate systems. Major advantages accrue from the attenuation characteristic of the filter which does not possess recurrent pass-bands at harmonics (or other overtones) of the design pass-band¿as do simple transmission-line structures. The filter is thus eminently suitable for use in frequency multipliers, parametric amplifiers and other systems in which the harmonic performance of the circuits is of paramount importance. View full abstract»

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  • Electronic control of battery electric vehicles

    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (2499 KB)  

    The paper defines the requirements of a traction control system and considers the characteristics of shunt wound and series wound motors for traction duties. Step control systems are briefly reviewed and their limitations discussed and methods of applying electrical braking to d.c. motors are outlined with particular reference to industrial trucks. Basic pulse control systems are reviewed and a recently introduced electronic vehicle controller, which incorporates several new techniques, is described and the novel features are examined in detail. View full abstract»

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