Study On Method Of Harmonic Parameter Estimation In Chaotic Noise Background

Chaotic signal is come from a determinate system which looks like ruleless and seemingly stochastic behavior , it is a ubiquitous complicated dynamics and natural phenomena. the determinate system mean the chaotic function is known and unchanged.The stochastic character of chaos is that the evolvement of chaos function depend on initial conditions sensitively and is unpredictable for long time . Chaos theory mainly study on nonlinear dynamics system , the purpose of chaotic theory is discovering possible basic rules which hide in the seemingly random phenomena .The direct bridge between chaotic theory and practice is analyzing the Chaotic systems by using nonlinear dynamics theory .In fact , many nature phenomena is nonlinear and traditional linear theory can not explain the phenomena. Chaotic theory study has achieve many fruit since 1970's,including mechanism research of chaos , how to produce chaos ,the judgement of chaos and phase space reconstruction ect. Today ,the new trend of chaotic research is change from abstract mathematics problem to engineering field.Chaotic signal processing is a re-new branch of non-linear signal processing. It has abundant research tasks in natural and engineering field,such as ocean, geology ,biology and chemistry etc, it also can be used in chaotic secure communication , digital water mark and electronic warfare. At present, chaotic signal processing becomes a popular science research field. As an important branch of chaotic signal processing, harmonic signal parameter estimation from chaotic background has important theory and application value. For example, the target signal character parameter estimation from seaclutter(which has been proved to be chaotic),fetal electrocardiogram extracted from matrix in biomedicine ,weak signal extracted from visual evoked potential and resistingchaotic interference all belong to signal extraction character parameter from chaotic background. The theory of harmonic parameter estimation in the chaotic noise background is a new research field in recent ten years ,thus it has no systemic theory. The method of harmonic parameter estimation in chaotic background must closely depend on the character and attribute of chaotic signal which is different from other signal process method .The attribute of chaotic signal including predictable for short time, phase space reconstruction, controllable, fraction ect. Now, most of chaotic signal processing theory are based on predictable for short time and phase space reconstruction, a few researcher use chaotic fraction to study signal detection. Based on the above,the paper presents a single variable drive method to estimate harmonic parameter. First of all,we changed the chaotic synchronization problem to stabilization of chaotic synchronization error system .second , we consider the chaotic synchronization driving by mixed signals (chaotic signal ,harmonic signal and other noise) as the stabilization of interfered system ,and give some proof of the theory. Last, when chaotic synchronization occurred , the error data series between drive and response signal have the harmonic signal , using signal processing method ,it's easy to estimate the harmonic frequency.The main characteristic of the method can be generalized as: (1) the method is mix of controlling theory and signal processing theory , because it actually belongs to chaotic control theory. (2)the method only study the chaotic synchronization driving by onevariable.(3) The MUSIC method is presented to analyzing the synchronization error. simulation results are very good.(4) The method is suit for the situation where background interference signals is mixture of strong chaotic signal and strong other kind of noise, which is advantage of other kind of chaotic signal methods .Chatic signal processing is an emerging area of research,also is a complex project.This paper porposed a single-variable drive method to estimate harmonic parameter and do system simulation by Matlab while chaotic parameter is decided and perterbation.The results show that the method can effectively estimate the harmonic parameters in the background of the noise of chaos and strong white noise.At the same time ,the method has the advantages of small calculation and high accuracy. Theoretical analysis and simulation tests confirmed the effectiveness of the method.