A test and simulation device for Doppler-based fetal heart rate monitoring

Abstract

The Doppler effect is the preferred technique in fetal heart rate (FHR) monitoring devices. The main objective of the recent studies on the Doppler FHR has been to improve the accuracy. On the other hand, a reliable fetal heart simulator becomes essential for testing Doppler FHR monitoring devices. The motivation of this study is to design a reliable system that will be used to test Doppler FHR monitors. This device generates a similar Doppler frequency shift of fetal cardiac activity including the heart's wall and valve motions. The components of this system are basically a signal generator using a microcontroller and a modified relay. The relay is the most important and studied component that affects the Doppler frequency shift. Thus, the relay's contact distance and length as well as its closing and opening velocities have been modified to produce an appropriate Doppler shift to fetal cardiac motion. This device has been tested and its reliability has been proved.