基于CTIA的微弱信号放大电路研究

Research on Weak Signal Amplifying Circuit Based on CTIA

获得尽可能大的放大倍数与运放饱和输出导致信号失真的矛盾,制约着微弱信号放大调理电路的整体性能。由于水听器及其他产生微弱信号的传感器的一致性原因,其输出信号的微小偏移可能导致放大电路的饱和失真。如果不能很好地解决该问题,数据采集系统将不得不以降低电路放大倍数为代价以获得不失真数据。介绍了一种信号输出直流偏置不依赖于前端输入直流偏置的CTIA型积分放大与采样保持电路。理论上,配合嵌入式系统提供的时序控制与偏置反馈功能,该电路可以很好地解决由于水听器输出一致性原因导致的信号失真问题,保证了电路的放大倍数的需求。

The contradiction between the maximum amplification factor to gain and the saturation output of the op-amp which leads to signal distortion,restricts the overall performance of the weak signal amplifying and conditioning circuit.Due to the consistency of hydrophones and other sensors that produce weak signals,small shifts in their output signals may result in saturation distortion of the amplification circuit.If this problem is not solved well,that data acquisition system will have to obtain undistorted data at the expense of reducing the amplification factor of the circuit.This paper introduces a CTIAtype integrated amplifier and sample-and-hold circuit whose signal output DC bias is independent of front-end input DC bias.In theory,with the timing control and bias feedback function provided by embedded system,this circuit can solve the problem of signal distortion caused by the consistency of hydrophone output,and ensure the requirements of the amplification factor of the circuit.