![](bg4.png)
Figure 6: Power spectrum of (a) Original Abdominal ECG
(b) Extracted fECG (c) Extracted mECG.
4 CONCLUSIONS
Fetal ECG extraction with out disturbing the
morphology is a difficult task. The limitations of
conventional methods led to the design of this
extraction system which improves the estimate the
fetal ECG and maternal ECG. A two stage adaptive
filter system is shown to retrieve fetal ECG from
actual patients maternal ECG. It is not easy to see
how well the fECG extraction is
achieved by
looking at a large number of samples. Thus a frame
of 400 samples is taken for patient 1 and 2000
samples for patient 2, to illustrate the effectiveness
of the algorithm. In this frame there are both
overlapping and non overlapping between maternal
and the fetal components in the abdominal signal.
This is a significant challenge to the extraction
algorithm. The results show that the algorithm was
able to successfully extract the fECG signal. It can
be noted the visual quality of the extracted fECG is
much better. The advantage of this method is that
the reference signal need not closely mimic the
signal to be cancelled. The algorithm was able to
reveal complete fetal ECG such QRS complex, its
shape and duration. This also allows for beat to beat
detection of the fetal R waves. This feature allows us
to investigate fetal heart rate fluctuations. This
feature of the algorithm can be used in early stages
of pregnancy. Consequently, it is possible to
understand the fetal heart rate fluctuations as a
function of gestational time. The algorithm was able
to overcome noise due to sources such as maternal
muscle activity, uterine contractions and external
electrical interference.
ACKNOWLEDGEMENTS
The authors would like to thank Prof. M.
Ramachandran, Director, BITS, Pilani-Dubai for his
constant encouragement and support. We would also
like to thank Physionet.org and SISTA/DAISY for
the fetal ECG data.
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