Research On Weak Signal Chaotic Detecting System Based On Erbium-Doped Fiber

Weak signal detection of signal processing has been an important subject for a long time, and also been thought by domestic and foreign scholars as the hot and difficult subject, especially for weak sinusoidal signal detection study which not only has important theoretical significance, but also is very important for us to detect weak signal in strong noise environment, to detect and extract useful weak signal is also a critical technology in radar, sonar, vibration measurement, fault diagnosis, communication and biomedical fields have a wide range of applications. Today there has been the principal means of detection: Based on Fourier and wavelet transform in frequency domain processing method, time-domain autocorrelation and cross-correlation detection method, stochastic resonance detection method and so on. and in the most recent decades, with the non-linear science's development, for detecting weak signals under strong noise environment, the chaotic oscillator which has gradually become a new method for detecting weak signals, and has new application prospects. In the chaotic oscillator detection system, if we introduce the signal into the chaotic oscillator of the system as a perturbation parameter, the computer could determine the existence of a specific analytic signals through the change of the state of the system too, while you can extract the signal amplitude, frequency and other parameters in order to achieve the purpose of extracting the signal.In this paper, from a system perspective to analyze and design an erbium-doped fiber used for transmission of the weak signal detection system, combined with the traditional detection method: autocorrelation method as pre-treatment of measured signals in order to achieve the right weak signals of unknown buried in strong background noise, and to improve the signal to noise ratio, because of characters of the optical fiber transmission: low-loss, long-distance and strong resistance to electronic interference, erbium-doped fiber is used here as a weak signal transmission medium. In the half-way through the role of erbium-doped fiber amplifier to achieve a long-distance all-optical transmission, compared with the traditional photoelectric mode, reducing the half-way signal loss, and is an important step of the all-optical network .the main technical contain designing a high-precision, real-time method: judgment of chaotic threshold between chaotic state and periodic state for chaos-based weak signal detection system to judge the threshold of the state of chaotic and the cycles', which is the key technology, in the aspect of the weak signal frequency tests, analyze and improve the detection of intermittent chaos and cycle' method and design a new big amplitude intermittent chaos and cycle' method. In the last, in the aspect of amplitude detection I have designed a new, highly effective detection algorithm. Especially I do an in-depth research and improvements on the real-time detection and algorithmic complexity issues which has troubled the traditional weak signal detection. And at the same time a large number of simulation studies have been done to confirm the validity of the results.