Design of digital filters for detection of fetal electrocardiogram complexes

A comparison, using computer simulation methods, is made between matched and linear phase integer coefficient filters in detecting R-waves in a fetal electrocardiogram signal where the maternal signal is either absent or has been cancelled. It is found that the linear phase filter only sometimes performs as well as the matched filter in detecting the correct times of occurrence of the R-waves. Suggestions are made as to how the linear phase filter can be used to construct an approximate matched filter template