Politanskyi R. The development of noise immunity systems using pseudorandom and fractal signals.

In the thesis there was developed a new method of complex signals generation, which were called fractal comb-structured signal. The calculation by the method of noise equivalent revealed that the value of the base of this signal can reach up to 200 units. In the thesis investigated methods to improve secrecy of telecommunication systems which transmit an encrypted text messages through open channel of communication system using stream encryption method for text encoding, which uses binary pseudorandom number sequences as a key. It is shown that the using of linear block codes led to reduction the duration of synchronization in the noisy channel. In the thesis are provided the research of the basic properties of binary pseudorandom sequences, which are formed with the aid of threshold method, based on pseudorandom sequences of real numbers, generated by system with discrete mapping function. The processes of transmitting of harmonic and frequency-modulated signals through ring oscillator have been investigated. These processes can be used in the system of data transferring with adding of pseudorandom and informational signals. The method of mathematical modeling features cross-correlation between the input information and the chaotic signal generator by the ratio between the amplitude information signal and power pseudo-random signal in which the transmission process tends secrecy and resistance to noise in the channel. Experimentally investigated and modeled processes transmission harmonic signal added to the chaotic signal generator Liu allocation method of signal generated by a controlled oscillator circuit in synchronization with the feedback; set one set of values of the parameters in which the system is able to generate pseudo fluctuations. Investigated the physical boundaries of the coding system noise immunity of digital information, which is based on a comparison of parameters of clusters formed in the phase space samples the received signal; proposed and patented a block diagram of a decoder, the use of which provides the ability to decode the information without the need to determine the level of noise in the channel in terms of complex electromagnetic conditions. And developed and investigated a new class of complex signals, called fractal comb-structure signal. Calculation base signal noise equivalent method revealed that the base value is 200. The system of digital information transfer using fractal comb-structure signal as a carrier signal have been constructed. The thesis describes the main characteristics (cyclical, balance and correlation) of a binary pseudo-random sequences generated by the threshold method using discrete chaotic maps. For the audio transmission system method for synchronizing transmitter and receiver which uses the transmission of the current value of the discrete chaotic map is proposed. Several noise-immunity and crypto systems based on the phenomenon of chaotic synchronization of Liu, Lorenz, Chua and ring oscillators systems are proposed and investigated. The method of cluster coding is proposed and its noise-immunity is investigated, the method of decoding is developed which can operate under difficult noise conditions. A new class of broadband signals is proposed and investigated, which called fractal comb-structure signal and the system of transmission of digital information is constructed, which uses this signal as a working signal.