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胸部电阻抗的变化可以用来估计心输出量等心功能参数,其中大部分心功能参数是由阻抗信号的微分值导出的。采用这种方法用计算机来进行阻抗信号的处理大大增强了心脏活动监测的意义。本文介绍的系统由心动图仪和微型计算机及其接口组成。心动图仪包括恒流源发生器、差动电压放大器、滤波放大和微分电路以及其它电路。这部分电路主要是完成阻抗信号的测量,并产生阻抗微分信号。微型计算机的CPU是80286,并配有协处理器80287,从心动图仪输出的阻抗及其微分信号经数
Changes in the impedance of the chest can be used to estimate cardiac output and other cardiac function parameters, most of which are derived from the derivative of the impedance signal. Using this method to process the impedance signal with a computer greatly enhances the significance of heart activity monitoring. This article describes the system by the cardiograph and microcomputer and its interface. Cardiographs include constant current source generators, differential voltage amplifiers, filter amplification and differentiation circuits, and other circuits. This part of the circuit is mainly to complete the impedance signal measurement, and generate impedance differential signal. Microcomputer CPU is 80286, and with a coprocessor 80287, the impedance output from the cardiograph and its differential signal by the number of