一种用于水下接收机的自适应增益控制电路设计

Design of Adaptive Gain Control Circuit for Underwater Receiver

常规的自适应增益控制电路可以动态调整接收机的放大倍数,在一定程度上扩大了接收机的输入信号动态范围,但是到达采集模块输入端的不饱和的输入信号动态范围依然有限,对于既需要对小信号进行大倍数放大,又需要确保大信号不饱和的场合不适用。提出一种用于水下接收机的改进型自适应增益控制电路,通过调整场效应管的漏源阻抗,并以该漏源阻抗代替常规水下接收机电路的用于匹配水听器的固定负载阻抗,从而实现水听器负载阻抗动态调整。该电路可以控制前级信号部分或全部到达后续接收机电路,可以使同一接收机电路既可对小信号进行足量放大,又可保证到达采集模块输入端的待处理信号不饱和,因此更加适用于对信号不饱和要求高的便携式水下接收机。

The conventional adaptive gain control circuit can dynamically adjust the magnification of the receiver,which enlarges the dynamic range of the input signal of the receiver to a certain extent.However,the dynamic range of the input signal that reaches the input end of the acquisition module is still limited,so it is not suitable for the occasions where both the large signal amplification and the large signal unsaturated need to be ensured.In this paper,an improved adaptive gain control circuit for underwater receiver is proposed.By adjusting the drain source impedance of the field effect transistor,and replacing the fixed load impedance of the conventional underwater receiver circuit used to match the hydrophone,the adaptive gain control method for dynamic adjustment of the load impedance of the hydrophone is realized.The circuit can control whether the front signal reaches the following receiver circuit partially or completely;it can ensure that the small signal can be amplified sufficiently for the same receiver circuit,and the signal to be processed at the input end of the acquisition module can be unsaturated,so it is more suitable for the portable underwater receiver with high signal unsaturated requirements.