FETAL ULTRASOUND PROCESSING UNIT FOR SEPARATING HEART RATE SIGNALS

A processing unit and method are provided for processing fetal Doppler ultrasound data to extract a set of signals representative of different distinct heart rate signal sources, i.e. maternal heart rate and fetal heart rate. Doppler data is received corresponding to a plurality of different depth zones (16a, 16b, 16c) in the fetal region and, these processed into a set of input channels, each corresponding to a different depth. These are then processed successively by a PCA algorithm followed by an ICA algorithm, which work to unmix the multiple heart rate sources present in each of the input channels, and derive a set of output signals from the ICA which can be taken as representative of separate heart rate sources.