Design And Realization Of The Automatic Measurement System On The Hydrophone's Sensitivity

With the urgent needs of human to marine resources,underwater acoustic engineering has been developed greatly.As the preferred equipment for ocean exploration,sonar becomes an important tool for human beings to develop the marine and is the indispensable component of the navy and civilian maritime industry.As an important part of sonar,underwater acoustic transducer is one of the key research directions of underwater acoustic technology.The sensitivity of hydrophone is one of the most important parameters.With the development of ocean exploration,in recent years more and more underwater acoustic transducers have been used and there are more and more manufacturers of underwater acoustic transducer.The requirements,the domestic and foreign relevant organizations regularly test and analyze the performance of the hydrophone,become more and more strong.The four-channel measurement system of sensitivity is designed to meet the demand of the automatic measurement of the hydrophone sensitivity.System signal generating circuit generates the desired signal and the power amplifier circuit amplifies the signal to push the transducer.Signal receiving section receives the signal processed by the conditioning circuit,starts the synchronous acquisition and store the signal temporarily.Then the data packed will be uploaded to a computer for analysis.The main content of the thesis includes the design of system,the design and realization of the hardware platform,the programming of the corresponding software and so on.According to the different functions,the entire hardware platform can be divided into four units which include the signal conditioning unit,the signal generating unit,the data acquisition and storage unit and the signal processing unit.The signal conditioning unit is mainly responsible for the amplification of the weak signal.The signal generating unit realizes the generation of the self-check signal,single frequency signal and sweep signal for the detection of the sensitivity.The corresponding circuit designs are presented in the thesis.The data acquisition and storage unit is mainly responsible for the synchronous acquisition of the four-channel signal,and the transport of the data cached to RAM.According to the different functions,a piece of FPGA of Cyclone III series(EP3C16Q240C8)and a piece of DSP(TMS320F28335)are taken as the main control chips,and the CY7C68013 serves as the USB interface chip.FPGA has the function of signal amplification,data acquisition,storage and transmission.DSP is mainly responsible for the communication with the host computer,receiving instructions from the host computer and analyzing them.DSP also controls DDS to generate the desired signal,sends the instructions to the FPGA and receives the data from the FPGA.It also uploads the data to the host computer.USB chip is mainly responsible for data communication.At last,tests in laboratory and tank experiments are taken to verify the system's function parameter and performance.The results show the automatic measurement system of hydrophone's sensitivity can operate steadily and meet the requirements of the system's design.