In this report the problem of forming chaotic signals with prescribed spectrum is discussed. An approach to construction of single-transistor chaotic oscillators with preassigned spectrum on the basis of “active component (transistor) – passive quadripole closed in feedback loop” structure is proposed. On example of capacitive three-point oscillator it is shown that in the oscillator with such ...

We apply a locally linear projection technique which has been developed for noise reduction in deterministically chaotic signals to extract the fetal component from scalar maternal electrocardiographic (ECG) recordings. Although we do not expect the maternal ECG to be deterministic chaotic, typical signals are eeectively connned to a lower dimensional manifold when embedded in delay space. The ...

Presented is a new method for the realization of chaotic oscillator in digital environment. First, two-stroke sampling mathematical regulation developed discrete-time equations to change signal densities signals. This proposed applied Lorenz’s oscillator, which presents complex dynamical behavior. An application shown with simulation through Matlab-Simulink environment time-dependent density ch...

This paper presents the implementation of a multi-user chaos-based communication system in DSP. The system is based on the chaotic phase shift keying (CPSK) digital modulation scheme, where chaotic signals are used as the spreading sequences of a CDMA system. Using chaotic signals offers the advantages of increased security and higher system capacity compared with conventional sequences. The ai...

This paper reports on the design and experimental results of a subthreshold-CMOS chaotic oscillator suitable for single-chip VLSI synthesis of coupled maps generating spatio-temporal chaos. The circuit is autonomous and generates chaotic signals in three state variables in a manner analogous to a Chua circuit. Previous CMOS oscillators operate above threshold and utilize current over two orders...

Chaos based communications have drawn increasing attention over the past years. Chaotic signals are derived from non-linear dynamic systems. They are aperiodic, broadband and deterministic signals that appear random in the time domain. Because of these properties, chaotic signals have been proposed to generate spreading sequences for wide-band secure communication recently. Like conventional DS...

In this paper we propose a new scheme for secure communications using a modified Chua oscillator. A modification of the oscillator is proposed in order to facilitate the decryption. The communication system requires two channels for transmitting the message. One of the channels transmits a chaotic signal generated by the oscillator and is used for synchronization. The second channel transmits t...

Detecting a weak signal from chaotic time series is of general interest in science and engineering. In this work we introduce and investigate a signal detection algorithm for which chaos theory, nonlinear dynamical reconstruction techniques, neural networks, and time-frequency analysis are put together in a synergistic manner. By applying the scheme to numerical simulation and different experim...

The subject of parameter estimation in linear signals embedded in white Gaussian noise has been extensively studied. The subject of nonlinear choatic signals, however, has received much less attention. This paper will examine some of the known techniques for estimating the parameters of chaotic signals such as iterative maps, including the tent map and the logistic map.