Hervé Dedieu

Identifiability and identification of chaotic systems based on adaptive synchronization

Keywords: chaos ; Non-Linear Signal Processing Reference LANOS-CONF-1997-015 Record created on 2004-12-03, modified on 2017-05-12

Maximum likelihood approaches for noncoherent communications with chaotic carriers

This paper deals with two problems. The first one is the noise decontamination of chaotic carriers using a maximum likelihood approach, the second is the design of communications schemes with chaotic carriers. After presenting improvements of the noise decontamination algorithms, we apply them in communication schemes. Experimental evidences show competitive capabilities of the proposed schemes with respect to the existing chaos-based modulation-demodulation techniques. In our approach we assume that the dynamics of the carriers are known in advance.

A new method for solving broadband matching problems

Keywords: Non-Linear Signal Processing Reference LANOS-CONF-1993-012 Record created on 2004-12-03, modified on 2016-08-08

Communications with chaotic time series: probabilistic methods for noise reduction

The paper deals with noise decontamination of chaotic time series under the assumption that some a priori information about the system which produced the time series is known in advance. We show that this a priori information can be quite naturally used in standard maximum likelihood approaches. Focusing on low complexity implementations we derive different quasioptimal maximum-likelihood solutions aimed at off-line and on-line noise cleaning. The obtained results show attractive capabilities for on-line and low-cost implementation.

Signal coding and compression based on chaos control techniques

This paper presents a new technique for signal coding and compression based on chaos control techniques. Given signal (e.g. speech or any other) recorded in a time interval is cut into smaller samples, further each of the sections is stored as a piece of a chaotic trajectory supplied by a chosen chaos generator (coder!). Effective techniques (based on a chaos control procedure) for finding initial conditions of the chaos generator to produce a desired shape of the output signal with a desired accuracy are described. In effect the signal to be coded/compressed can be stored as a set of points-initial conditions of the chosen chaos generator. Recovery of the original signal is straightforward: the stored initial conditions are applied to the coding chaos generator and the solutions taken in appropriate intervals are simply pieced together. Advantages and drawbacks of the proposed technique are discussed.

New broadband‐matching circuit

Keywords: Non-Linear Signal Processing Reference LANOS-ARTICLE-1994-001 Record created on 2004-12-03, modified on 2017-05-12

Identification and control of a particular class of chaotic systems

We show how it is possible to exploit a priori knowledge of the nonlinear dynamics of a system. Given a signal produced by a system, we first identify the parameters of the system and second we code sub-intervals of the signal into initial state-space points of the identified system. As a result of this method a whole waveform is coded as a sequence of points in state- space, a sequence of interval durations and a system of ordinary differential equations. We test these concepts on a challenging example in which the signal to be coded and compressed is produced by a chaotic oscillator.

Noise reduction methods for chaotic communication schemes

This paper deals with two problems; the first one is the noise decontamination of chaotic carriers using a maximum likelihood approach, the second is the design of communications schemes with chaotic carriers. After presenting a noise decontamination procedure we apply it in communication schemes. In our approach we assume that the dynamics of the carriers are known in advance.

A simplified real frequency computation method for broadband matching

The authors present a new method for computing the component values of LC ladder equalizers for broadband matching purposes. The method is inspired by the theory of recursive identification and results in a very compact algorithm. The load has to be known only at a small number of frequencies. Starting from an assumed topology for the equalizer with small random values for the components, the equalizer components are iteratively built to satisfy asymptotically a least mean-square criterion. The method is based on the theory of recursive approximation. The key parameter which must be calculated is the transducer power gain sensitivity with respect to the components of the equalizer. As the vector of sensitivities can be found with ease using two networks the recursive method turns out to be very simple. This is an advantage compared with the great complexity of other known methods, notably Carlins real frequency technique and the Yarman and Fettweis parametric technique.<<ETX>>

Transmission Using Chaotic Systems

The sections in this article are 1 Synchronization of Chaotic Systems 2 Exploiting Chaos Synchronization for Transmission of Information 3 Exploiting Chaos for Information Transmission by Means of Statistical Decision 4 Improving Chaos Transmission by Exploiting the Deterministic Feature of Chaos 5 Summary