Duffing系统中微弱信号起始点的检测

Starting point detection of weak signal in Duffing system

为从时域上检测微弱信号在系统中出现的时间点,提出了一种基于Duffing系统的微弱信号起始点的间接检测方法.首先将微弱信号与Duffing系统自身的信号相叠加,混合测量后剔除其中Duffing系统产生的信号,再利用dmey小波对待测信号加入系统造成的轨道偏离过程进行时域分析,可较准确测出微弱信号的起始点.由于混沌系统本身对高斯噪声的自免疫特性,因此本方法具有一定的抗噪性.仿真结果显示:该方法能有效地从时域上检测到微弱信号的起始点,其相对误差可达到10-3s,可应用于心动信号特征参数的提取.

In order to detect the starting point where a weak signal appears in the system from the time domain, an indirectmethod which can detect the starting point of weak signal based on Duffing system is propsed. Firstly, the weaksignal is added with Duffing signal together, after the mixed signal is measured, the Duffing signal is eliminatedfrom the mixed signal. Sencondly, the dmey wavelet is used to analyze the process of track deviation from thetime domain, the starting point can be detected accurately. Because of the immune characteristics of chaoticsystem itself to Gauss noise, the proposed method has a certain anti-noise. The simulation results show that theproposed method can detect the starting point of the weak signal from time domain effectively, the relative errorcan reach 10-3 s. It can be used to extract the characteristic parameters of heart sounds.