【作者】 李更；

【导师】 周天；

【作者基本信息】 哈尔滨工程大学 ， 信号与信息处理， 2011， 硕士

【摘要】 探鱼仪是一种能够对水下鱼群进行探测与定位的助渔设备,它可以迅速发现鱼群,降低捕捞的盲目性,提高捕鱼效率。本文以多波束探鱼仪课题为背景,在对多波束探鱼仪的多通道发射机、多通道接收机、电源系统以及数字信号处理平台的逻辑设计方案进行了研究的基础上,完成了相应的设计与调试工作。在多通道发射机的设计过程中,首先通过对各种功率放大电路的比较研究,将发射机的电路形式确定为高效率的D类功率放大电路；在多通道发射机的设计过程中重点考虑了功放管选择、变压器设计、阻抗匹配、功放管驱动电路、储能电容计算等问题。电源系统的设计采用集成的DC/DC电源模块实现多种电压的输出,为了使电源输出的噪声与纹波特性可以达到要求,设计了电源模块的外围滤波电路。同时在电源板上还设计了控制电源模块工作顺序的电路模块。多通道接收机由可控增益放大电路、带通滤波器电路及固定增益放大电路等三部分组成。在多通道接收机设计中,低噪声、一致性是重点与难点。本文通过对噪声源、运算放大器和PCB布局布线的研究有效抑制了接收机的噪声。为了保证多通道接收机各通道间的一致性,采用了简化双二次型带通滤波器作为接收机的滤波电路,并通过理论分析与计算确定了滤波器参数。数字信号处理平台以DSP和FPGA为核心器件,其中DSP是计算与控制核心,FPGA在DSP控制下完成相应的功能。本文完成FPGA部分的逻辑编写与调试工作,主要包括发射机的32路发射信号产生、32路数据采集、键盘控制、LCD控制、数模转换器控制等部分,还研究了相控发射的原理与带通采样原理。更多还原

【Abstract】 Fish-finder is an equipment helping to fish, which can detect and locate the position of underwater fish school quickly. Besides, it can reduce the catching blindness and improve the fishing efficiency. This paper does many researches on and complete the design of multi-channel sonar transmitter and receiver, the system power board and the logic of signal processing platform by taking the project of multi-beam fish-finder as background.During the design of multi-channel transmitter, many kinds of amplifiers are first compared carefully, and the D class power amplifier is chosen. Then the key researches points are focused on the choices of amplifier tube, transformer design, technique of matching network, the driver circuit of D class power amplifier and reserved capacitance calculation.The power system board is designed with the DC/DC module to provide many kinds of power supplies. In order to make the noise and ripple of output power to meet the requirement, the peripheral filter circuits of power module are designed and debug. Meanwhile, the circuit that can control the sequence of the power modules is added to the power system board.Multi-channel sonar receiver designed in this paper is mainly composed of Automatic Gain Control circuit, band-pass filter circuit and fixed-plus amplifier circuit. Among the design of multi-channel receiver, the design of low noise and phase coherence are the key points and difficulties. The study of noise source, amplifier and PCB layout wiring in this paper effectively eliminates the noise of the receiver. In order to guarantee the phase coherence of the multi-channel receiver, a GIC band-pass filter is used as receiver filter circuit, and the filter parameters are determined by theoretical analysis and calculation.DSP and FPGA are the core processors on the digital signal processing platform of the multi-beam fish-finder. DSP is the core of calculation and control, and with its assistance FPGA can finish the corresponding function. This paper completes the logic design and its debugging based on FPGA, which mainly includes signal source of transmitter, 32-channel data acquisition, keyboard control, LCD control, D/A control and so on. During the design of signal source module and data acquisition module, the principle of the multi-channel phase control transmitter and band-pass sampling theory are studied.更多还原