Design of Auto Gain Control Circuit with Two-stage Amplification Feedback

设计了一种适用于移动水声通信接收系统的两级放大反馈自动增益控制电路。该电路采用初级放大—滤波—次级放大的信号调理机制,反馈回路同时对两级放大电路进行增益控制,使输出信号稳定在期望值附近,能有效解决移动水声通信中由于收发端相对距离变化、声传播衰减、信道频率选择性衰落、收发端电路频率响应不均匀等因素引起的接收信号时域和频域起伏变化大的问题。海上试验表明:该电路具有良好的幅度均衡性能,能显著提高水声通信质量。An auto gain control(AGC) circuit with two-stage amplification feedback for the receivers of underwater acoustic mobile communication system was presented.The circuit uses the conditioning mechanism of primary amplification—filter—secondary amplification,and the feedback loop controls gains of the two stages amplifiers,making the output signal be stable near the dexpectations so as to effectively solve the problem of signal fluctuation in the time and frequency domains caused by the distance change between transmitter and receiver,sound propagation attenuation,frequency selective fading of underwater acoustics channel and the uneven frequency response of transmitting and receiving circuit.The sea test shows that the circuit has a good performance at amplitude equalization,and can greatly improve the quality of underwater acoustic communication.国家自然科学基金项目(41376040);; 福建省中青年教师教育科研项目(JA15001);; 国家海洋局海洋公益项目(201505027-2