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Vojnotehnički glasnik
2011, vol. 59, iss. 2, pp. 111-119
article language: Serbian
document type: Professional Paper
doi:10.5937/vojtehg1102111M


Basic functions of telecommunication channel elements for successful information transmission
Vojna akademija, Beograd

e-mail: milmarkag@yahoo.com

Abstract

The challenge in the field of multimedia telecommunications is an attempt to integrate texts, sound, images and videos coherently and consistently and to ensure simplicity and interactivity of operation. In order to make the proposed multimedia applications acceptable to end-users, the quality of transmission through the network and message presentation should have special attention. The main aims of this paper are the introduction to the communication channel with its basic elements, a detailed description of the information source and the presentation of possible approaches to the analysis of the telecommunication channel. Introduction In the age of mass application of various communication means, end-users of telecommunication channel elements rarely pay attention to the processes taking place in everyday communication and the elements presented in the channel. In order to discuss all the factors that influence the establishment and maintenance of the links, this paper will explain the basic elements of telecommunication channels. Source Every object that generates messages to be transferred to a recipient is called the source of the message. Directors, writers, speakers, books, newspapers, various instruments (thermometer, barometer, ammeter, etc.), computers, a man himself - these are all sources of various messages. In relation to facilities that generate messages, there are different sources of messages. All the messages that they generate belong to discrete or continuous modes of messages. Discrete messages can be presented with element sets, where elements can be considered through different values of observed messages. Each text message of arbitrary length, for example, is made of a finite number of elements - symbols (letters, numbers, punctuation marks), from the set of symbols called the alphabet message source. Continuous messages can be presented with an infinite number of sets of elements where elements can have different values of the observed messages. Coder of messages generated by a message source should be transmitted to the recipient. For that purpose, an appropriate communication channel is used, with appropriate electrical signals as material bearers of the message. Definition of the code and the code system The set of combinations of digits that mirrors the elements of the set A is called a code. The established rule considers situations when each symbol from the set A is associated with the combination of elements of the set B. The function f defining this translation must be defined. This replacement is called a code replacement. Signal coder A coder performs signal transformation of coded messages to an electrical signal adapted for transmission via the transmission system. The most common signals are voltage transmission via cable connection or an electromagnetic field in the radio transmission. Modern systems for transferring discrete messages contain codecs and modems. Portable system A portable system is the medium for signal transmission from the source to the point of receipt. It can be wired and wireless. A wired transmission system is used in the stationary elements of communication systems. Wireless signal transmission is used in all conditions and it is more rational, efficient and economical. On their way through the transmission system, signals are subject to a variety of interferences. For a better insight into the interference impact, the source of interference is added to the whole system. Conclusion The model of the telecommunication channel is a complex system of a series of mutually dependent elements. Effectiveness of these elements is evaluated by the performances of the probability that the transfer of information through the channel will be successful. In a thus modeled telecommunication channel, regardless of the technical means used which is either a system or a circuit, the place and role of each element can be considered, which is the basis for consideration of possible approaches to the protection of information in the telecommunication channel.

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References

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