基于混沌理论的微弱信号检测及自跟踪扫频电路实现

Electronic circuit realization of auto-tracking and sweep-frequency of weak signal detection based on chaos theory

为解决工程实际中因待测信号常常被淹没在噪声背景中而传统信号检测方法难以检测等问题,将基于混沌理论的非线性信号检测技术应用到实际工程故障诊断中,开展了基于Duffing振子的微弱信号检测原理的分析,建立了混沌振子与微弱信号检测之间的关系,提出了基于Duffing振子的微弱信号检测方法,利用混沌系统相变对周期小信号的敏感性和对噪声具有免疫力的特点,设计制作了基于Duffing振子的微弱信号检测电路;对微弱信号检测的自适应进行了研究,利用AVR单片机及AD9850等芯片实现了信号检测电路的自动跟踪扫频功能,最后开展了该信号检测电路对不同频率微弱信号的检测试验。研究结果表明,用该电路可以实现在工程中常见的噪声背景下的中、低频率微弱周期信号的检测。

Aiming at the problems of weak signal generally hidden in the background of strong noise and it is difficult to be detected by the traditional signal detection methods, chaos detection technology in the fault diagnosis of nonlinear to practical engineering was used, the prin- ciple of weak signal detection of Duffing oscillator was investigated. After the analysis of principle of chaos detection, the system state equa- tion which was used to design the electronic circuit was established. The method of auto-tracking and sweep-frequency to detect arbitrarily weak signal under strong noise background was studied and the electronic circuit was designed. The self-adaption of weak signal detection was investigated, the automatic tracking frequency sweep function of the signal detection circuit was realized using by AVR MCU and AD9850 chip. The different frequency of weak signal detection was tested. The results indicate that the weak medium-low frequency signals can be de- tected from the background of noise by using the circuit.