Use of a FIR filter for fetal phonocardiography processing

Fetal phonocardiography (fPCG) is becoming a very useful tool for monitoring the foetus status. Measured signals in the abdominal area are often affected by many artifacts, so the Finite Impulse Response Filter (FIR filter) for noise suppression has been tested in this work. Testing is performed on 37 synthetic records and the evaluation of filter efficiency is performed on the basis of determining the signal-to noise-ratio (SNR) and using Bland-Atman statistics and the calculated value of the standard deviation (SD), sensitivity value (Se), Positive predictive value (PPV), accuracy (ACC) and F1, which is the overall probability of correct detection of beats. Testing is done for different FIR filter settings, and the results have shown that the FIR filter can be effectively used to reduce noise in the fPCG signal when the filter order is set to 1000.