【摘要】 本文简述了超声多普勒胎心音信号的特点以及为了获得稳定真实的胎心率描记曲线需要解决的几个关键问题：（１）采用高灵敏度的广角型换能器提高胎心音捕捉能力并降低发射功率以利长期监护，（２）正确选择解调方案提高接收灵敏度，文中对为何选择鉴幅方案和如何提高鉴幅灵敏度作了分析，（３）设计一个可靠的心率脉冲提取电路；（４）设计一个刻度线性的瞬时心率计以逐拍反应心率的变化；（５）利用读数判别电路将由于干扰信号引起的错误读数排除以提高描记质量。本文附有医院临床２２０例的试验结果分析。更多还原

【Abstract】 The characteristics of FHR signal obtained by ultrasonic Doppler means are described briefly The main problems to be solved for a stable and reliable FHR cure tracing are: (1). To use a highly sensitive broad angle transdacer so as to increase its FHR trapping ability and to decrease the transmitting power which facilitates long-term delivery monitoring. (2). To choose a demodulation method which gives higher receiving sensitivity. A comparation between the sensitivities of FM demodulation and AM demodulation is made. (3). To design a reliable heart rate extraction circuit. (4). To design a linear scale beat-to-beat heart rate meter so that heart rate variations can be revealed instantaneously. (5)To eliminate the false reading caused by interfering noise by use of a reading discriminating circuit. 220 cases of clinical application have been made and the results are analyzed.更多还原