A Data Secured Communication System Design Procedure with a Chaotic Carrier and Synergetic Observer

We have considered the problem of secure communication by means of chaotic carrier communication channels. Data protection is provided if the signal in the communication channel looks like a stochastic or noisy one, i.e., by the steganography property, and also by using advanced and secured approaches of mixing a useful signal into a chaotic carrier. The problem is to find effective and efficient techniques for useful signal reconstruction at the receiver side. We firstly use a synergetic nonlinear mathematical observer to recover the two useful signals transmitted simultaneously over a single communication channel. Compared to a known observer, the synergetic one operates with initial nonlinear models, i.e., it may be applied directly to chaotic systems. In that system structure, we consider the useful signals as unobservable variables and estimate them by the given model of a chaotic generator. A chaotic data transmission system with two channels is demonstrated; the presented mathematical procedure explains the steps of synergetic two-channel observer design. Computer simulation results prove the viability of our approach. The proposed data transmission scheme and the observer design procedure provide effective transmission and reconstruction of informational signals. Reconstruction error is up to approximately 25% but has a very short pulses shape and could be eliminated with further analog or digital filtering algorithms. As an example application, simulation of image transmission and recovery is demonstrated. The study’s results may be used as a basis for further research into secure data transmission system design.

Application Research of Chaotic Carrier Frequency Modulation Technology in Two-Stage Matrix Converter

The harmonics of line to line voltage in two-stage matrix converter (TSMC) with fixed carrier frequency had discrete and high values and produced powerful electromagnetic interference (EMI). In this paper, chaotic carrier frequency modulation technique (CCFMT) was applied in TSMC for the first time to spread sideband range and suppress harmonic peak value. Although this technique could suppress EMI, it would increase the probability of narrow pulses. In order to improve reliability, the rectifier in the two-stage matrix converter uses PWM modulation with zero vector to extend the zero current commutation time, solves the narrow pulse problem, and simplifies the commutation process. At last, an experiment platform was designed and experimental results showed that harmonics of line to line voltage was efficiently suppressed.

Secure communications by chaotic carrier signal using Lorenz model

In this paper, the generation of a chaotic carrier by Lorenz modelis theoretically studied. The encoding techniques has been used ischaos masking of sinusoidal signal (massage), an optical chaoticcommunications system for different receiver configurations isevaluated. It is proved that chaotic carriers allow the successfulencoding and decoding of messages. Focusing on the effect ofchanging the initial conditions of the states of our dynamical systeme.i changing the values (x, y, z, x1, y1, and z1).

Искажения прямоугольного радиоимпульса с хаотической несущей, распространяющегося в диспергирующей резонансно-поглощающей газовой среде

We briefly describe the possible character and peculiarities of dispersion-induced distortions of a rectangular pulse with chaotic carrier modeled using the third-order Chebyshev map of the first kind propagating in a resonantly absorbing gas medium. It is established that, as the pulse goes away from the radiator, its envelope exhibits transformation toward a noiselike shape. In a rather wide region of parameters of the dispersive medium, distortions of the envelope are not accompanied by breakage or principal changes of its autocorrelation and frequency correlation functions.

EMI Reduction in Low Input Ripple DC-DC Converter using Chaos PWM technique

This paper presents a chaotic PWM switching technique for a high boost DC-DC converter with a very low ripple at the input current. The use of a choatic PWM allows a reduction of Electromagnetic In (EMI) at the output of power converters by spreading the energy spectrum of the output voltage. In this paper a chaotic PWM, using the Chua oscillator, has been implemented in Matlab for the converter under study and a comparison with a traditional PWM control has been done. A detailed description of the generation of the chaotic carrier is presented and the effect on the output EMI mitigation has been shown.