High-pressure Resistant Hydro-acoustic Acquisition System Based On FPGA

The ocean have particularly rich sources, containing a large amount of energy, mineral,biology, etc. The information of ocean mainly rely on acoustic wave for long distance transmission. Hydro-acoustic transducer can measure the acoustic signals in the water and convert them to voltage signal. Then hydro-acoustic acquisition system can collect and transfer acoustic signals. The acquisition of acoustic signals plays an important role in the research of ocean sources and marine military. As a consequence, the research of hydro-acoustic acquisition is extremely important.Subject research and design a high-pressure resistant hydro-acoustic acquisition system based on FPGA by the existing acquisition scheme. According to requirement of project and the working environment of system, a feasible scheme is put forward with existing experimental experience. The subject mainly completed the design of hardware and software with hydro-acoustic acquisition system, and the research of High-pressure resistant.The system takes FPGA as the kernel control chip. The acoustic signals from hydro-acoustic transducer are transferred in operational amplifier to condition. Then the signals enter into A/D transformation chip for analog digital conversion to digital signals. The converted signals begin caching in the FIFO buffer after serial-parallel conversion. The buffered digital signals are transferred to MAC(medium access controller) and then to physical layer by GMII(Media Independent Interface). Afterwards, the signals are transferred on optical fiber according to the serial interface of physical layer chip 88E1111. In the end,the signals are transferred to remote computer by optical fiber to realize the data transmission of real-time and long distance.The deep sea within 1000 m are the working environment of system, which results in system getting maximum pressure 10 MPa. In order to solve this problem, this subject uses apotting materials for potting circuit board, reducing the stress on the circuit to achieve protection effect. The ANSYS Multiphysics simulation software is used to simulate different potting materials on the protection of the circuit board, then a suitable sealing material is selected.Finally, data acquisition experiment is completed, verifying the feasibility and validity of the functional design of the system, which has a certain reference value for the research of the high-pressure hydro-acoustic acquisition system later on.