Research On Detection Of Weak Signals Based On Chaos Theory

With the development of science and technology and the continuously exploration to unknown fields, the need of the signal detection is imperative. In the biological medicine, earth science, electrochemical, and other disciplines, the test object is often more difficult to measure, and the application of this technology can measure some signals that can’t measure weak amount in traditional concept, and this makes the accuracy of weak signal higher. Weak signal detection is the technology of getting information from noises. The principle and method of weak signal detection, is a measure of the comprehensive technology and sophisticated technology field.Chaos system which is sensitive to small signal and is not sensitive to noises, has a potential in the weak signal detection. This paper analyzes the four types of dynamic characteristics of chaos, and introduces melnikov method and the principle of detection of amplitude, frequency and phase of the useful signal, and simulates the method. Then, this paper designs a system of detection of amplitude of useful signal. This system has characteristics of friendly interface, easy operation, high precision.Because chaotic signal is easy to drown in the noise, the extraction of the weak signal is very important. Wavelet analysis method "can not only see the forest, and can see the trees", is very favorable to get the weak signal from the noise. This article realized the extraction of chaotic signal through the wavelet transform, and the simulation shows that wavelet transform is helpful in the detection of weak signal. Also in this paper developed a chaotic signal extraction system set based on LabVIEW using wavelet transform, this system can provides a comparatively "clean" signal to the system of detection of amplitude.Finally, this paper measures the temperature of the temperature constant based on chaos theory, the results also further verified chaos theory is useful for the detection of the weak signal, and its successful test has significance for the test system applied in practical project.