宽带大功率声呐AM信号发射机的设计与实现

Design and implementation of wideband and high power sonar AM signal transmitter

发射机是宽带大功率声呐的重要组成部分,其性能关系着声呐系统工作的有效性。本文研究一种程控的宽带大功率声呐AM信号发射机,信号源基于Delta-sigma DA原理设计,以现场可编程门阵列(Field-programmable gate array,FPGA)为核心器件,采用"FPGA+滤波器"的简化电路结构,单个IO引脚即可实现一个通道AM信号的产生,功率放大电路采用并联推挽的乙类线性放大电路结构,驱动相控基阵使其声源级水池测试可达238 d B,且具备连续相控发射15个脉宽5 ms脉冲信号的能力,达到了50%的相对带宽。水池测试验证了设计方案,工作稳定可靠。

Transmitter is an important constituent of broadband large power sonar, and its performance affects the effectiveness of the sonar system. A programmed sonar transmitter scheme was proposed and implemented, the signal generation circuit took FPGA（ Field-programmable gate array） as key device and the AM signal was generated based on Delta-sigma DAC theory by simplified architecture of FPGA added filter, so only one I/O could produce a channel AM signal. The power amplifier circuit that using the parallel connection push-pull B- amplifier could drive the sonar＇s source level to 238 dB, and could transmit fifteen burst signals with five millisecond pulse width. The design scheme was examined by pool experiments which verify its reliability.