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Electronics & Communication Engineering Journal

Issue 3 • Date May/Jun 1989

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Displaying Results 1 - 5 of 5
  • Optical communications: past, present and future

    Page(s): 105 - 114
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (688 KB)  

    A quiet revolution is taking place in communications technology, where light is replacing its low-frequency counterparts, the radio wave and signals by wire. The author traces the development of optical communication technology from simple beginnings using fire and beacons, through early valve and solid-state devices to integrated optics and advanced fibre systems. Because of the very rapid growth in the area recently, only a sample of current developments can be presented. Leading-edge developments are considered in the light of current and advancing technologies View full abstract»

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  • An introduction to chaos

    Page(s): 115 - 123
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (744 KB)  

    Chaos, apparently disordered behaviour which is nonetheless deterministic, is a universal phenomenon which occurs in many systems in all areas of science. For it to take place, the equations describing the situation must be nonlinear and, therefore, they are rarely solvable in closed form. Since the advent of fast digital computers, the theory of nonlinear systems has become much more accessible to study and is now undergoing rapid development. The authors review some of the universal aspects of chaos and its ramifications in the field of electronics View full abstract»

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  • Generalised theory of uniform transmission lines

    Page(s): 125 - 128
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (320 KB)  

    The conventional circuit theory of uniform two-conductor transmission lines (TEM mode) assumes that at any cross-section the current in one conductor is equal and opposite to that in the other. This is not necessarily true, and even when it is true the resulting theory does not permit solution of some simple problems such as evaluation of the voltage difference between two points on the same conductor. The author presents a more general circuit theory which does permit solution of such problems and does not demand current balance. He shows that when there is current imbalance the expressions for voltage contain a term which depends linearly upon line length, as well as the familiar hyperbolic function terms View full abstract»

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  • The visibility of noise in System I PAL colour television

    Page(s): 139 - 148
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (688 KB)  

    The results of new subjective tests on the visibility of noise in System I PAL colour television are reported. Three forms of noise are considered: white (flat) noise, de-emphasised triangular noise, and the noise resulting from vestigial sideband demodulation (VSB noise). The results are compared with those given by work published 20 years ago and it is concluded that observers today are more critical of noise in pictures: about 21/2 dB less noise is required to produce the same impairment View full abstract»

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  • High performance receivers for optical communications

    Page(s): 129 - 137
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (668 KB)  

    The principles underlying optical detection are reviewed and the practical realisation of devices and receivers for digital optical communications is discussed. Some emphasis is placed on the advanced receiver signal processing techniques-both electronic and optoelectronic-that are now coming forward to provide a performance approaching the fundamental limits imposed by quantum mechanical considerations View full abstract»

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