A fetal ECG signal monitoring system using digital signal processor

The authors describe the implementation of a real-time fetal ECG (electrocardiogram) monitoring system in which an adaptive multichannel noise canceller is realized using the TMS32020 programmable digital signal processor. An ECG signal from the electrode placed on the mother's abdomen and three ECGs from those on the chest are applied as the desired signal and the reference inputs, respectively, of the multichannel filter. The coefficients of the filter are updated using the LMS (least-mean-square) algorithm, such that the output of the multichannel filter copies the maternal ECG embedded in the abdominal ECG. The enhanced fetal ECG is obtained by subtracting the filter output from the abdominal ECG, and the difference signal is recorded.<>