Passive Acoustic Signal Acquisition System for Non-Invasive Fetal Heart Sound Monitoring Applications.

A simple, low cost and non-invasive personal computer based system for the acquisition of passive acoustic signal is developed. The system hardware consists of a phonocardiographic sensor, a heart sound signal preprocessing circuit, and a personal computer, while the system software consists of a fetal heart sound acquisition program, a signal analysis program, and a data storage function block. The acquisition program is used to switch on or off of the hardware equipments for initializing the sampling rate, the number of acquisition channels and other relevant setups. The collected data in its original form is saved through storage function block for the purpose of further subsequent analysis. In this study, an attempt has been made to develop a phonocardiography based data acquisition system for non-invasive fetal monitoring applications with many advantages like long term home monitoring and high performance to cost ratio. The system was justified by recording the fetal heart sound from 21 subjects with different gestational period. The result shows that the overall accuracy of the system is 98.02%. The developed system can be efficiently used by a fetal heart sound monitoring system for long-term fetal heart rate monitoring in a fully passive manner.