| 摘要 |
<p>A fetal heart rate counting system which includes a transducer element for transmitting an ultrasound signal into the fetal heart while the fetus is in utero and for receiving a returning Doppler signal frequency shifted by action of the fetal heart. The returning Doppler signal is processed to produce a forward heart movement Doppler signal, a reverse heart movement Doppler signal and the complete Doppler signal, from each of which fetal heart rate data is obtained. A composite fetal heart rate data is then produced from the three processed Doppler signals which is more accurate and complete than the data from any one signal individually.</p> |
