At present time there are many systems of the information’s sale, particularly production of TV-channels. For example, there is trading network, provided at our market cable television output. Present working let to simplify product’s supply a lot.

In this working is planed to develop the arrangement, which will provide access to the coded TV-signal. For that was considered the existent in our time methods of information protection.

It is possible to sort methods of the signal coding from an unapproved access into the two groups: analog and digital coding. At the same time analog coding have a little use, as it demands very complicated and expensive apparatus. Analog system has no versatility and can’t be adapted to the further improvement.

All this restrictions in the use of analog coding call forth more wide expansion of the digital coding. Free occurrence merit of these methods is their fitness to the further improvement - it is enough to modernize used software. In the digital coding is few methods of the information concealment marked out.

We can sort the encoding schemes for two main categories: block coding and coding of the data stream, or stream coding. With the block coding unnumbered text is divided into the blocks with the fixed dimension, after then every block is coded independently

By the systems engineering is necessary to provide very simple and inexpensive instrument of coding and encoding for authorized users, which has a key; and make the task of the cryptanalyst to make the estimation of an unnumbered text without the key very complicated and expensive.

Method of the coding named substitution. In this method is the substitution of existing initial signal for another kind signal with the help some transformations intended. At that is enough to change the signal, in order to it’s spectrum will stay invariable. Consequently this method has very little use by coding of the radio signals, but has a wide use by the coding of printed text.

Method of the coding by spectrum expansion. There are three methods of spectrum expansion: method of the direct consistency, method of spasmodic frequency tuning, switching of the time intervals. All this methods has a wide use by broadcast of radio signals, telephone connection. For example, connection standard CDMA use the method of spasmodic frequency tuning. By this method is the signal position changed with the carrier frequency synthesizer for pseudovariate. By every sudden change transmit the generator of pseudovariate signal to the carrier frequency synthesizer the frequency word, which determine one from the portion of symbol’s multitude.

By the method of the direct consistency is one frequency band used for synchronous transmit of few signals without mutual interference. Every user gets the individual code. Codes are approximately orthogonal, and so is the mutual correlation of two codes approximately equal to naught. Principal advantage of that system is the possibilities of anisochronous data’s transmit in all range with the different users. The model-based signal is multiplied with the dilative signal, which is with the group 1 fixed; the result is to the channel transmitted. To other is similarly. At the reception side happen the repeated multiply with the fixed with every group code. In case the code is starting, get the initial signal.

System of the switching time intervals is seldom used, mainly in combination with the previous method. All above-listed methods secure high efficiency of off-staged information. But they cannot be used in the system’s work. Therewith these methods appreciably widen the signal’s spectrum, and all TV-signals has definitely limited spectrum (4 megahertz per channel), it would bring to mixing of transmitting information.

Method of ranging. Open data, which are divided into the 8-ranks blocks T(i) (i=1,2,...,m) (m is determined with the data range), are encode in the ranging rate by bitwise adding modulo 2 with the cipher’s range, which is in 8-bits block produced.

8-ranks consistency, called synchropackage, is not secret element of the cipher, but its presence is necessary both at the transmitting side, and at the reception side. Process of output of imitoinsertion is uniform for all coding procedures. Imitoinsertion – it is the block from p-bits, which is before coding of all massage, or parallel to the block coding produced. To become imitoinsertion are open data as the 8-bits blocks presented. First block of the open data Т(1) run to transformation. As the key is that key as for data encoding used. Method of ranging is the most simply and light realized method.

This method doesn’t need complicated apparatus and bulky calculation for the guarantee of high-quality data encoding. In the last time method of ranging become wide distribution in the systems of transmitting the radio signals, telephone connection. Taking into account high versatility and ability to modernization, simplicity of building this method is taken as the basic, and on the base of this method will be structure scheme of electronic system built.

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