可控增益测量放大电路设计与仿真

Design and Simulation of Controlled Gain Measurement Amplifier Circuit

前端测量放大电路是测量仪器的最关键部分,其性能优劣直接决定了测量仪器的测量精度。提出了一种以仪用放大电路为基础的测量放大电路模型,并设计出一种利用D/A转换器实现增益控制、利用对称正反向比例放大电路实现信号输入方式转换的测量放大电路。经仿真测试,该电路差模放大倍数很大、共模抑制比很高,性能优良,可广泛应用于测量仪器的前端测量电路。

The front-end measurement amplifier circuit is the most critical part of the measuring instrument,and its performance directly determines the measurement accuracy of the measuring instrument.This paper presents a measurement amplifier circuit model based on instrument amplifier circuit,and designs a measurement amplifier circuit which uses D/A converter to achieve gain control and symmetric forward and reverse proportional amplifier circuit to achieve signal input mode conversion.The simulation results show that the circuit has high differential-mode amplification,high common-mode rejection and excellent performance,it can be widely used in front-end measuring circuits of measuring instruments.