Telecommunications Engineering

by John Dunlop (Author)

• Used

  Hardcover
  1991

  $3.25

  The influence of telecommunications has increased steadily since the introduc- tion oftelegraphy, radio and telephony. Now, most of us are directly dependent on one or more of its many facets for the efficient execution of our work, at home, or in our leisure. Consequently, as a subject for study it has become more and more important, finding its way into a large range of higher education courses, given at a variety oflevels. For many students, telecommunications will be presented as an area of which they should be aware. The course they follow will include the essential features and principles of communicating by electromagnetic energy, without developing them to any great depth. For others, however, the subject is of more specialized interest; they will start with an overview course and proceed to specialize in some aspects at a later time. We have written our book with both types of student in mind. We have brought together a broader range of material than is usually found in one text, and we have tried to combine an analytical approach to important concepts with a descriptive account of system design. In several places we have stressed the approximate nature of analysis, and the need to exercise engineering judgement in its application. The intention has been to avoid too much detail, so that the text will stand on its own as a general undergraduate-level introduction, and it will also provide a strong foundation for those who will eventually develop more specialized interests.

• Used

  Paperback
  1994

  $3.25

  Telecommunication engineering is concerned with the transmission of in- formation between two distant points. Intuitively we may say that a signal contains information if it teils us something we did not already know. This definition is too imprecise for telecommunications studies, and we shall devote a section oftbis chapter to a formal description ofinformation. For the present it is sufficient to say that a signal that contains information varies in an unpredictable or random manner. We have thus specified a primary characteristic of the signals in telecommunications systems; they are random in nature. These random signals can be broadly subdivided into discrete signals that have a fixed number of possible values, and continuous signals that have any value between given Iimits. Whichever type of signal we deal with, the tele- communication system that it uses can be represented by the generalized model of Fig. 1. 1. The centrat feature of this model is the transmission medium or channel. Some examples of channels are coaxial cables, radio links, optical fibres and ultrasonic transmission through solids and liquids. It is clear from these examples that the characteristics of channels can vary widely. The common feature of all channels, however, is that they modify or distort the waveform of the transmitted signal. In some cases the distortion can be so severe that the signal becomes totally unrecognizable. In many instances it is possible to minimize distortion by careful choice of the transmitted signal waveform.