A Design Of Automatic Calibration System For Hydrophone In Air

With the continuous development of our society,land resources tend to be scarce,while abundant marine resources are in a state of pending development.Advanced marine detection equipment is the basis for the development and utilization of marine resources.As the main equipment for underwater communications and detection,sonar plays an irreplaceable role in marine development.With the enthusiasm for marine development,there are more and more types of acoustic transducers.So,how to accurately calibrate the hydrophone becomes the focus of people's attention.According to the need of hydrophone calibration,I designed a low-frequency hydrophone sensitivity calibration system in this paper.The system can realize hydrophone mass rapid measurement by use comparison method in air.The open circuit voltage signal which produced by the hydrophone at the same sound pressure point is collected via the signal modulate circuit,and the data is processed and analyzed by the display software.The main content of this paper includes three parts: the overall design of system,hardware platform and software.The system design includes the research of background,the analysis and calculation of the measurement principle and the design of the main parameters.According to the different functions,the hardware platform of the system can be divided into four units.Four units can be subdivided into eight modules.Among them,the digital core control module uses DSP to control the whole hardware circuit.And it communicates with the upper computer through the USB interface module.The signal conditioning module adjusts the magnification of each channel automatically.The signal acquisition module includes two parts: A/D and RAM,which is responsible for the analog-digital conversion and storage of signals.Besides,the signal generating module is responsible for the system self-checking and for promoting the horn in measurement hydrophone model.Software systems include the each hardware module program,and the display control interface program.The display control interface can realize the three functions of self-check,hydrophone sensitivity measurement and resistance measurement.At the same time,it can also realize data playback,data save and report generation.Finally,the system functions and parameters of each module are all independent tested.Then,I will pack the system of the box packing and do a experiment of sensitivity measure in airtight box.Results show that the system is stable,and basically in line with the expected design requirements.