待测信号线性驱动Duffing振子弱信号检测系统

Weak signal detection system based on Duffing oscillator with linear driven by to-be-detected signal

针对周期驱动的Duffing振子微弱信号检测系统存在临界阈值影响信号检测精度和对待检测信号频率分辨率不高的问题,提出一种以待检测信号为驱动力的Duffing振子线性驱动弱信号检测系统。该系统以待测信号作为系统线性驱动信号,利用系统线性驱动参数的微小变化会导致系统输出状态发生改变的特性,对淹没在背景噪声中的弱信号进行检测。同时,通过计算系统的梅尔尼科夫函数和最大李氏指数,并结合系统相轨迹状态的变化,对该系统检测信号的可行性进行分析。研究结果表明:该检测系统大大提高了对微弱信号频率的分辨能力;检测精度可达10^(-4),即谐波信号频率与驱动力频率之间的相对偏差|ω-ω_1|/ω达10^(-4)时依然可以检测;增强系统对噪声有免疫能力,同时可消除临界阈值对系统检测精度的影响,提高系统检测效率。

Considering that the weak signal detection methods based on Duffing oscillator with periodic driving force signal have the defects that the detection accuracy can be affected by the critical threshold and the frequency resolution is not high enough, a new weak signal detection method was presented based on Duffing oscillator, which was driven by the linear perturbation of the to-be-detected signal. In the method, the small change of the linear perturbation parameters could cause the output change, and then this characteristic could be used to detect the weak signals submerged in the background noise. Meanwhile, based on the Melnikov function and the maximum of Lyapunov exponent, the feasibility of the detection system was analyzed. The results show that the method can greatly improve the frequency resolution of weak signal, and the precision of the frequency achieves 10^（-4）. It can also enhance the noise immunity ability and eliminate the effect of critical threshold on the precision of the system.