中文摘要：

利用待测小信号的周期性及混沌信号的相关特性，提出一种将倍频法与经验模式分解法相结合的混沌噪声背景下周期小信号频率估计的新方法。首先利用相关法对原始混合信号进行初步去噪处理，再利用倍频法与经验模式分解法对信号进行自适应分解，最后对分解出来的固有模态函数进行交叉功率谱分析，估计出周期小信号频率。该方法适用于强混沌信号与强观测噪声为背景的周期小信号频率估计。仿真实验结果表明，方法简单有效，计算量小。

英文摘要：

A frequency estimation method for periodical small signal in chaotic background is presented according to the characteristics of periodical small signal and chaotic signal. This method is based on frequency multiplication method and empirical mode decomposition. Firstly, the correlation method is applied to preliminarily remove noises; then the frequency multiplication method and empirical mode decomposition method are used to decompose the mixed signal into many intrinsic mode functions （IMFs）. Through analyzing the cross power spectrums of the intrinsic mode functions, the periodical small signal frequency can be easily estimated. This method is suitable for the situation where the interference signals are the mixture of strong chaotic signals and measurement noises. Simulation experiment results show that the method is simple and effective, and less complicated in calculation.