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Radio and Electronic Engineer

Issue 7 • Date July 1976

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Displaying Results 1 - 12 of 12
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  • The development of an automatic wiring analyser system for testing telephone switching rack backplanes

    Page(s): 323 - 331
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (2450 KB)  

    This paper describes the various stages in the evolution of a computer controlled automatic test system for checking the validity of the backplane wiring of very large electronic telephone exchange switching racks. Although the basic testing requirements are simply wiring continuity and insulation testing, the large physical size and the diversity of hardware to be tested in an essentially random sequence necessitated a very large and complex test system. The solutions to the difficult interface problems and those of handling are described, together with the approach taken to solve the complex software and programming problems, including those caused by the large volume of data to be handled. View full abstract»

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  • Radio propagation in London at 462 MHz

    Page(s): 333 - 336
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (482 KB)  

    Propagation measurements at 462 MHz relevant to a base station on a ten-storey office block and a mobile operating at seventeen locations in London are described. Signal level as a function of range is given and a slightly altered version of Okumura's prediction is shown to agree well with the measurements. Mean signal level distributions are found to be log normally distributed with a standard deviation of 5 dB. The envelope of the received signal level is shown to have a Rayleigh distribution. View full abstract»

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  • A circuit for high-speed carry propagation in l.s.i.-f.e.t. technology

    Page(s): 337 - 341
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (551 KB)  

    A circuit configuration for high-speed carry propagation employing serial floating field effect transistors in parallel digital adders is presented. Circuit parameters affecting the performance of the suggested configuration are evaluated. Results of comparisons with alternative m.s.i. and l.s.i. adder circuits are given and show that the present suggestion is superior to the alternatives. View full abstract»

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  • Trends in failure survival techniques for avionic systems

    Page(s): 343 - 349
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (975 KB)  

    Electronic equipment installed in aircraft has to satisfy extremely demanding requirements to achieve the requisite levels of safety and reliability, while operating in a physical environment at variance with the desirable conditions for long life of electronic components. The techniques in present use are reviewed, in particular the use of digital control systems, and likely future developments are surveyed. View full abstract»

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  • An improved voltage variable resistor m.o.s.t.

    Page(s): 350 - 354
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (475 KB)  

    A method of designing enhancement-mode m.o.s.t.s having controllable turn-on characteristics is described. The m.o.s.t.s are specifically aimed at performing the functions of voltage-controlled resistors and the design called for a log-linear variation in channel resistance with gate voltage over as wide a range as possible. The devices were made using a conventional p-channel oxide gate process with an additional n+ diffusion stage to give the required variation of threshold voltage at different points within the device. In the final form of the m.o.s.t. the log-linear range of channel resistance variation extended from 5M¿ to 500¿ for an applied gate voltage range 4¿15 V. The design method used for these devices could equally well be applied to making composite m.o.s.t.s having another form of channel resistance variation from the log-linear variation studied here. View full abstract»

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  • The floating point unit of the Golem B computer

    Page(s): 355 - 359
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (534 KB)  

    The Golem B computer is a fast machine using emitter-coupled logic and multi-layer circuits. The autonomous floating point arithmetic unit obtains its instructions and operands from buffers loaded ahead of need. Its main part, for 56-bit fractions, uses two 4-operand adder complexes with stored carries. In multiplication instructions, 4 bits of the multiplier are used to form a new partial product in each pass through an adder complex. Division instructions use a base-4 non-restoring algorithm. Addition favours the case of equal or nearly equal exponents, but 112 sum bits are accumulated for all exponent differences. An effort has been made to provide instructions and number formats that will aid the writing of compilers and operating systems. View full abstract»

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  • Accurate analytical determination of quasi-static microstrip line parameters

    Page(s): 360 - 364
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (531 KB)  

    In the design of microstrip components, the analytical equations of Wheeler have an advantage in handling-speed and simplicity over alternative quasi-static analyses involving complex computation by numerical methods. Wheeler equations can produce excessive errors, however, unless care is taken particularly in the choice of changeover point between equations for narrow or wide strips. This paper shows that for alumina-type substrates with 8 < ¿r < 12, the Wheeler analysis and synthesis equations produce results within 1% of those given by selected numerical methods, when the changeover points are correctly chosen. Additional new and modified formulae are presented for the direct calculation of microstrip effective permittivity from either W/h or Z0, also to an absolute accuracy of less than 1%. These complete an accurate set of analytical equations for quasi-static analysis or synthesis of microstrip lines. View full abstract»

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  • Automatic production

    Save to Project icon | PDF file iconPDF (155 KB)  
    Freely Available from IEEE
  • New books received

    Page(s): 370 - 372
    Save to Project icon | PDF file iconPDF (558 KB)  
    Freely Available from IEEE