中文摘要：

该文针对胎儿心电信号难以提取的问题,提出一种从母体腹壁混合信号中提取胎儿心电信号的方法。首先利用最小二乘支持向量机（LSSVM）拟合母体心电信号传导至腹壁所经历的非线性变换,然后将母体心电信号经由所拟合的非线性变换得到腹壁混合信号中的母体心电成分的最优估计,再从腹壁混合信号中减去母体心电成分的最优估计得到含噪声的胎儿心电信号,最后通过经验模式分解（EMD）抑制胎儿心电信号中的基线漂移和噪声,得到清晰的胎儿心电信号。在胎儿心电信号和母体心电信号QRS波完全重叠的情况下,通过该方法能够提取出清晰的胎儿心电信号。实验结果验证了该方法的有效性。

英文摘要：

A novel method based on Least Squares Support Vector Machine （LSSVM） is proposed to extract the Fetal Electrocardiogram （FECG） signal from the abdominal composite signal of the pregnant woman. The Maternal Electrocardiogram （MECG） component in the abdominal composite signal is a nonlinear transformation of the MECG signal and the nonlinear transformation is identified by LSSVM with limited samples. An optimal estimation of the MECG component in the abdominal composite signal is obtained by the MECG undergoing the nonlinear transformation. The FECG is extracted by removing the optimal estimation of the MECG component from the abdominal composite signal. The baseline shift and noise in the extracted FECG are suppressed by Empirical Mode Decomposition （EMD）. The experimental results show that the clear FECG can be extracted even under the condition of the fetal QRS wave being entirely overlapped with the maternal QRS wave in the abdominal composite signal. The experimental results verify the effectiveness of proposed method.