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

WU Min, ZHAO WenLi, ZHOU Fang

（School of Mechanical Engineering, Hangzhou Dianzi University, Hangzhou 310018, China）

Abstract: 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 principle of weak signal detection of Duffing oscillator was investigated. After the analysis of principle of chaos detection, the system state equation 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 detected from the background of noise by using the circuit.

Key words: Duffing oscillator; autotracking and sweepfrequency; weak signal; detection circuit