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Radio and Electronic Engineer

Issue 7 • Date July 1974

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Displaying Results 1 - 10 of 10
  • Is a degree essential?

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    Freely Available from IEEE
  • Programmable surface acoustic wave devices utilizing hybrid microelectronic techniques

    Page(s): 343 - 351
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1352 KB)  

    Programmable matched filters can be realized using surface acoustic wave propagation in conjunction with external microelectronic circuitry. Here two devices, a programmable analogue matched filter and a diode convolver, are discussed, highlighting the similarities in constructional technique. Specific device requirements include an r.f. circuit which for 10 MHz signal bandwidth must possess a 310 ¿m pitch. Factors influencing the choice of the thin film hybrid microelectronic technique are outlined and the design, fabrication and performance details are described. View full abstract»

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  • The electronics industry and higher education

    Page(s): 352 - 354
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (447 KB)  

    Organized by the IERE with the association of the IEE, this conference aimed to bridge the gap or interface between industry and higher education. It was held at the week-end and the programme allowed for considerable time for informal discussion between the two sides. It was perhaps unfortunate that the timing of the conference was only shortly after the winter fuel crisis and the end of the 3-day working week in industry: hence, attendance, particularly from industry, was lower than might have been expected. What the conference attendance lacked in quantity, however, it made up in quality! This review of the conference is based on reports prepared by the chairmen of the five sessions, all whom were members of the joint organizing committee and include Professor G. D. Sims (Chairman), Mr. J. R. Thompson, Mr. C. H. G. Jones, Mr. P. G. Tanner and Professor D. S. Campbell. The full list of titles of the papers presented at the conference was published in the February 1974 issue of The Radio and Electronic Engineer (page 104) but it should be noted that, in order to maintain the informal nature of the conference, the papers were not pre-printed and only a 28-page booklet of digests of the 31 contributions is available from the IERE Publications Department, price 50p. View full abstract»

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  • A digital-analogue minimum detector for riometers

    Page(s): 355 - 356
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    A circuit using commercial integrated circuits has been developed to replace the minimum-detector circuitry commonly used in swept-frequency passive ionospheric absorption measurements. The new circuit offers good accuracy and is completely free of decay error. View full abstract»

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  • Binary transversal filters in data modems

    Page(s): 357 - 362
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    The design of a data modulator using binary transversal filters is described. The technique used can be applied to a number of modulation schemes and leads to data modulators which are very suitable for integration. A matched filter demodulator is also described. View full abstract»

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  • The application of suppressed carrier double sideband signals to group delay measurements

    Page(s): 363 - 366
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    A technique is described in which a suppressed carrier d.s.b. test signal is used to measure the variation in group delay within the baseband of a microwave video channel. The method is shown to be capable of avoiding errors caused both by differential sideband attenuation and by unwanted modulation components. A resolution of 5 ns has been achieved in the frequency range 0.5 to 10 MHz. View full abstract»

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  • Variational approach to V-dipole antenna analysis

    Page(s): 367 - 372
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    An analysis of the problem of symmetric, centre-driven V-antenna, using the variational method, is given. In deriving the variational expression for impedance the trial function in the form of a functional series with complex coefficients was assumed. The concerte evaluations were performed using two types of functional series: two-term trigonometric series and polynomials of arbitrary order. The method was used for calculating the input impedance and current distribution for a number of representative examples. The numerical results are in very good agreement with the results obtained by the point-matching method. In addition, the variational results for admittances corresponding to the particular case of a V-dipole completely stretched out are compared with available theoretical and experimental data for the straight symmetrical dipole. The agreement was found to be excellent. View full abstract»

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  • Application of p.c.m. to broadcast quality video signals. Part 1: Subjective study of the coding parameters

    Page(s): 373 - 381
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    This Part describes subjective tests performed to establish the sampling rate and the number of quantizing levels or corresponding bits per sample which should be used to obtain broadcast-quality television pictures from a p.c.m. system handling PAL colour, 625-line, 5.5 MHz video signals according to the UK standard (CCIR Standard I). These tests included an investigation of adding `dither¿ signals to the video signals prior to the p.c.m. encoder as a means of reducing the required number of bits per sample. An effective dither signal is proposed which breaks up coherent quantizing errors such as `contouring¿ effects and replaces them with less noticeable random quantizing errors. A theoretical estimate of the required number of bits per sample is derived by comparing calculated values of the magnitude of quantizing noise with the existing specification for random noise allowable on analogue links. The paper also gives brief details of the p.c.m. coder and decoder developed by the author and used in the tests carried out in the BBC Research Department. View full abstract»

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  • Leeds electronics exhibition

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  • The thames valley section reports¿How one local section serves its members' needs

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    Freely Available from IEEE