目前,国内常用的脑血流图仪大都利用阻容交流电桥测定脑血管的阻抗变化(如图2所示),人体被测部位对外特性近似简化为等效于一只电阻与一只电容的串联阻抗,并作为电桥的一臂,高频等幅信号作为电桥的交流电源。但在实际使用中,每例测量都需由人反复调节另一桥臂上的电阻和电容,以使电桥平衡。这就给使用带来不便,且平衡 At present, most of the commonly used cerebral hemo-graph apparatus in our country use the RC capacitance bridge to measure the change of the impedance of the cerebrovascular (as shown in Figure 2). The external characteristic of the measured part of the human body is simplified to be equivalent to a resistor and a capacitor Series impedance, and as a bridge arm, high-frequency amplitude signal as the bridge AC power. However, in actual use, the measurement of each case requires repeated adjustment of the resistance and capacitance of the other leg to balance the bridge. This brings inconvenience and balance to use