Information technology is ordered set of information procedures of formation, gathering, transmission, transformation, storage, measurement, processing and information interchange.

For example, technological processes of maintenance by the information of the persons who are accepting decisions, in aggregate form are constituting information technology of the theory of acceptance of the decisions.

We aspire usually to dispose information, which has operative, qualitative, homogeneous, economic, continuous character. It means information should reflect essential properties of objects, be exact, authentic, reliable, uniformly submitted, convenient for comprehension, ensuring opportunity for management in real time. It should been received with rather small expenses of resources.

The integrated criterion of quality of the used information and information technologies is a level of society’s information culture.

Society’s information culture is common characteristic who in a society, what information, and what for, as well how creates, collects, processes and uses information in the daily ability to live.

Information “know – how” plays a conducting role in creation and distribution of scientific, technical, economic and cultural knowledge, in satisfaction of people needs in intercourse, in development of democracy, publicity and construction of an open society. Society’s information culture promotes increase of socio and economic efficiency of all public manufacture. The further development so information means as of mass media, telephony, computerization, computer science and computer facilities, mobile radio communication, broadcasting, TV, facsimile communication, data transmission, space communication, radio navigation, radar-location and others contributes to growth of information culture.

The intensive growth of volume of the information come on each man ("information explosion") is observed in last quarter XX century and beginning XXI century. For example, volume of the information necessary for management by work of the modern airport, grows proportionally to square of volume increase of an airline traffic. This example deserves of the special development.

The civil aircraft of the world now more and more becomes a dynamically developing part of “noosphera”. Annually only in Commonwealth of the Independent States by air transport more than 110 millions of the passengers and more than 3 millions tons of cargoes and mail. The network of air lines of CIS connects more than 4 thousand cities and occupied items. The CIS planes make flights in capitals and large cities of 97 foreign states. The CIS airlines have turned to the modern joint-stock enterprises, became "by the bridge of the world and friendship" between the peoples. On their share it is necessary almost third of all air transportations in the world. Therefore level of information culture of the specialists of civil aviation should correspond to the international level.

The object of information engineering represents any technical system, in which apply those or other information technologies.

Information transmits as the messages.

The message is the information expressed in the certain form and intended for transmission from a source to the user (to the consumer of the information).

The examples of the messages are served by the texts of the documents, telegrams and photo telegrams, letters, speech, music, art pictures and other works of art. The television images, photos given on an output of the computer, orders in a control system of air movement or flight of a concrete air vessel also are kinds of the messages. The messages form, code, transfer and process according to needs (requirements) of subject activity and interests of the users. The senders and addressees of the messages can be both people, and technical devices, to which they "charge" to form, to accumulate, to transform, to transmit, to receive and to process the information.

The coding is an information technology of transformation of symbols (elements) of the messages in numbers of this or that notation (code words, combination), which by that or different way then will transform to signals in the transmitter. The decoding is an information technology of transformation of the received signals in code words (number), which correspond to the received symbols (elements) of copies of the messages in the receiver.

It is uneasy to understand, that coding and decoding are mutually return operations.

The error is a random event, which consists that the received symbol of the message does not coincide with the transmitted symbol.

The material carriers of information are signals, its are necessary for message transmission.

The signal is a physical process, which parameters are capable to display the message.

In the theory fundamentals of information transmission there consider basically electrical signals - change of currents and voltage. However methods of this theory are applicable and to other signals. For example, they are applicable to hydro acoustic and optical signals, to change of intensity of an electromagnetic field.

The modulation is an information technology of management of information parameters of signals - carriers of the information - according to the regularity of change in time of the messages. The demodulation is an information technology of management of processing of the received modulated signal for receiving of the message copy.

The operations of modulation and demodulation are mutually return operations. If the copy of the message does not correspond to the transmitted original of the message, they speak that the distortions of signals in the channel and influence of interferences took place.

An interference is any extraneous signal (noise), which influence on a useful transmitted signal results in its distortion, result is that the received signal does not coincide with transmitted signal.

A(t) S(t) Z(t) B(t)

SI K M LC D_m D_k UI

T ransmitter (t) Receiver

IS

Fig.1.1. The block diagram of single-channel system of information transmission

For work of a source it is necessary to choose the alphabet (language) and the way of formation of the messages by a source. The work of coders and decoders requires generating of code signals. The work of modulators and demodulators requires generating of signals - carriers.

The coder and modulator in common form the transmitter, and demodulator and decoder - receiver.

The communication line is any physical environment, which is capable to pass signals (air, water, wire and etc).