Digital TJY Series Ultrasonic Doppler FetaI Heartbeat Detector is appiled to examine the fetus, its movement and its blood circulation on the principle of Doppler effect. The instrument is very important to the diagnosis of early stage gestation and the development of fetus, and it is able to detect the fetal rhythm, the sound of feta I blood flow or umbilical blood flow, the pulse of uterus artery and twin fetus. There is neither damage nor pain in gravidity during the examination, it is simple to operate; rapid to response and good in repeat.