Design And Implementation Of Signal Source And Signal Acquisition For Imaging Sonar

With the increasing requirements of ocean exploitation and underwater detection, the development of imaging sonar system obtains extensive attention. The signal source and the signal acquisition system are indispensable and important components of the imaging sonar, make thorough research on them are of great practical significance.High quality signal source is the basic guarantee of the realization of high-performance imaging sonar. DDS technology is of high frequency resolution, fast frequency switching speed, and the ability to switch frequencies while maintaining constant phase, applying this technology into the realization of signal source will definitely guarantee the quality of signal source. Traditional DDS technology use ROM table to realize the phase-amplitude conversation, but it cost huge ROM cell. The dissertation applies the CORDIC algorithm to realize the phase-amplitude conversation instead which saves FPGA resource and achieve higher precision.Multi-channel signal acquisition plays an important role in the imaging system. In order to fully reflect the design ideas of the SOC system on high performance FPGA platform, the thesis suggested a scheme of designing the data acquisition system which is composed of A/D converters, high-performance FPGA, CPCI bus interface and HOTLink serial data transfer interface and realized it. The thesis finished the logic design based on the hardware platform at the same time which completes its data acquisition, storage and transfer function.In order to get the phase information, it is necessary to do orthogonal transformation to get the in phase components and quadrature components of the original data. This dissertation analyzed the methods to realize the algorithm based on band sampling theorem and the basic theory of orthogonal transformation. With combining Verilog HDL and IP Core calling the dissertation realized the digital orthogonal transformation, guarantees its correctness and processing speed and rational optimized the resource usage at the same time.The thesis use FPGA as the control, processing center and transmit bridge, which highly improved its commonality, adaptability and flexibility of the system.