【摘要】 微弱电流信号测量需求已越来越强烈,SR570是美国SRS公司研制的一款高性能低噪声电流前置放大器,广泛应用于微弱电流信号测量领域。针对该仪器使用过程中,因输入信号选择与参数设置不当易出现输入/输出过载的问题,本文首先对仪器内部电路工作原理进行了分析,然后指出了造成仪器输入/输出过载警告的原因。并在Proteus 7.0的ISIS Professional环境下搭建了报警电路的模型,对引起输入/输出过载的控制信号的上限值做了定量的分析,仿真结果表明控制信号的绝对值小于6.4 V时,可以有效避免仪器出现过载。这对仪器使用过程中输入信号的选择与参数的设置提供了理论依据。更多还原

【Abstract】 The demand for measuring weak current signal is increasing urgently,The SR570 is a highperformance low-noise current preamplifier developed by SRS Inc in USA,and widely used in the field of weak current signal measurement.To solve the input/output overload problems caused by improper input selection and incorrect parameters setting in using process,this paper analyzes the SR570’s overall internal circuit firstly,and then reveals the causes of input/output overload problems.Simultaneously,it builds the same circuit models in ISIS Professional environment of Proteus 7.0,makes a quantitative analysis for the input/output control signals,simulation results show that instrument can effectively avoid overload if the absolute value of the control signal is less than 6.4 V.It’s provided a theoretical basis of selection proper input and setting correct parameters.更多还原