小信号测量放大系统设计

The System Design of Measure and Enlarging of Little Signal

本设计为小信号测量放大系统,目的是将压力所产生的信号通过压力传感器转换为微弱的电信号。其重点是对该微弱小信号进行三级放大,因为该电路需要做到输入较小的微弱信号,并具有高输入阻抗、高增益、高共模抑制比等特性,所以在该小信号放大电路的前两级采用ICL7650作为该段的放大芯片,并对该电路进行了定量计算。又因为我们要实现对不同测量范围的四路放大进行操控,所以我们将在第三级采用具有很低的输入失调电压和漂移特性的OP07放大器。经实验证明,该放大电路灵敏度高,稳定性好,达到了预期的放大效果。在程序部分我们将采用AVR单片机的A/D转换程序实现对电信号进行处理,然后采用一定的算法建立起电压信号和压力信号之间的对应关系,使我们可以获得其对应压力值,并且在显示屏上得以显示。

The design for small signal measurement amplification system, the purpose is to pressure generated by pressure sensor signal conversion for weak signals. This design is the focus of the small of the weak signal level 3 amplification. Because this circuit need to do less input weak signal, and have high input impedance, high power gain, high common mode rejection ratio features, so in this small signal amplifier circuit before the two levels of the ICL7650 as the current amplification chip, and the circuit quantitative calcu- lation. And because we want to realize to the different measuring range for four road amplification handling, so we will be in the third grade have very low input voltage and drift characteristics of the disorder OP07 amplifier. Proved by the experiment the amplifier cir- cuit high sensitivity, stability, achieve the expected amplification effect. In parts of the program we will use the AVR SCM A/D con- version program realization process of electrical signals, and then set up by A certain algorithm voltage signal and the corresponding relations between the pressure signal, so that we can get the corresponding pressure value, and on the screen to display.