Nowadays, detecting fetal ECG using abdominal signal is a commonly used method, but fetal ECG signal will be affected by maternal ECG. Current FECG extraction algorithms are mainly aiming at multiple channels signal. They often assume there is only one fetus and did not consider multiple births. This paper proposed a single channel blind source separation algorithm to process single abdominal acquired signal. This algorithm decomposed single abdominal signal into multiple intrinsic mode function (IMF) utilizing empirical mode decomposition (EMD). Correlation matrix of IMF was calculated and independent ECG signal number was estimated using eigenvalue method. Nonnegative matrix was constructed according to determined number and decomposed IMF. Separation of MECG and FECG was achieved utilizing nonnegative matrix factorization (NMF). Experiments selected four channels man-made signal and two channels ECG to verify correctness and feasibility of proposed algorithm. Results showed that the proposed algorithm could determine number of independent signal in single acquired signal. FECG could be extracted from single channel observed signal and the algorithm can be used to solve separation of MECG and FECG.
