Design of an ultrasonic doppler fetal heart rate simulation system

Abstract The simulation of fetal heartbeat based on the vibration of the reflecting target in degassed water is the main method to evaluate the performance of the ultrasonic Doppler fetal heart device. The traditional method of using the motor to drive the connecting rod to swing the reflection target has problems such as weak high-frequency stability and the angle between the movement direction of the reflection target and the direction of sound wave emission. Therefore, a broadband ultrasonic Doppler fetal heart rate simulation system with vertical motion direction is proposed. A fetal heart rate simulation mechanism based on a loudspeaker structure is designed, including a fetal heart rate simulation system which is mainly built on a reflection target made from a long thin rod and a terminal ball, and a high-performance waterproof vibrating film; key circuits, such as a bipolar secondary buffer connection circuit, are composed of D/A conversion circuits, power amplification circuits, etc. The fetal heart rate indication error of the designed simulation system is tested by an oscilloscope and ultrasonic Doppler fetal heart detection device. The experimental results show that the technical indicators of the system meet the requirements, and the fetal heart rate can be simulated efficiently and accurately.