多通道声纳信号预处理系统设计

Design of Multi-channel Sonar Signal Preprocessing System

模拟预处理系统是声纳接收机的重要组成部分,为了解决声纳回波信号微弱多变等问题,设计了一款高精度、多通道模拟预处理系统,给出了系统整体框图,分析了其工作原理,并详细介绍了各部分电路。该系统采用压控放大器VCA810设计自动增益控制,实现了±40 dB范围内输入信号的线性、无失真以及恒定输出,并通过截止频率可变的开关电容滤波器实现宽带滤波,且滤波器通频带可通过拨码开关控制,灵活可调。该系统具有体积小、低噪声、低功耗及动态范围大等特点,经试验验证可满足设计要求。

Analog preprocessing system is one of the key components of sonar receiver.A multi-channel analog pre-processing system is designed with high precision to process weak and variable sonar echo signals.The block diagram of the system is given,its working principle is analyzed,and each circuit is discussed.A voltage-controlled amplifier VCA810 is applied to the automatic gain control(AGC) circuit of underwater acoustic signals,achieving a constant and undistorted output for the input signals in the range of 40 dB to 40 dB.The system employs switched capacitor filters for wide band filtering,and the band width can be changed flexibly by dial switch.Experimental result shows that the proposed system meets the design requirements with the features of small size,low noise,low power consumption,and large dynamic range.