  The fetal electrocardiogram (fECG) was first recorded from the maternal
abdominal surface in the early 1900s. During the past fifty years, the most
advanced electronics technologies and signal processing algorithms have been
used to convert noninvasive fetal electrocardiography into a reliable
technology for fetal cardiac monitoring. In this chapter, the major signal
processing techniques, which have been developed for the modeling, extraction
and analysis of the fECG from noninvasive maternal abdominal recordings are
reviewed and compared with one another in detail. The major topics of the
chapter include: 1) the electrophysiology of the fECG from the signal
processing viewpoint, 2) the mathematical model of the maternal volume
conduction media and the waveform models of the fECG acquired from body surface
leads, 3) the signal acquisition requirements, 4) model-based techniques for
fECG noise and interference cancellation, including adaptive filters and
semi-blind source separation techniques, and 5) recent algorithmic advances for
fetal motion tracking and online fECG extraction from few number of channels.
