Research And Design Of Networked Digital Hydrophone

Distributed signal acquisition and transmission systems are widely used in the fields of environmental monitoring,pipeline leak detection,marine exploration,noise measurement,and acoustic ray arrays.In order to meet the requirements of underwater acoustic signal acquisition under complex noise interference and transmission environment,this paper designs a networked digital hydrophone based on IEEE1451 networked sensors with adjustable gain,large dynamic range and low self-noise,Low power consumption,reliable data communication.Specific tasks include:1.Based on the system's requirements for sampling rate resolution and communication transmission distance,the overall plan was completed.The controller uses a field programmable gate array(FPGA)to realize the real-time performance and low power consumption of data transmission.It adopts a fully differential signal conditioning structure to amplify weak signals and suppress noise interference.It uses MLVDS communication based on the Mod Bus communication protocol as the standard.The interface completes the data communication between the distributed hydrophone node and the host.2.Designed the acquisition synchronization scheme in the underwater acoustic signal acquisition array.The method of command loopback calculates the delay time of instruction to achieve the purpose of command's execution time of digital hydrophone in synchronization.The method of master-slave array clock synchronization makes the clock phases of the master and slave nodes consistent and the clocks of the hydrophone nodes to achieve the synchronous acquisition of signals between the hydrophones.3.Designed the hardware circuit of the system.Including:the high output impedance matching of underwater acoustic transducer and the conditioning module of sensor signal,high resolution analog-to-digital conversion circuit,FPGA and peripheral configuration circuit,networked sensor configuration circuit and data transmission circuit with MLVDS.The conditioning module consists of a pre-amplifier with high input impedance,a program-controlled gain circuit,and a fully differential multiple feedback filter circuit.4.Use the main control FPGA to design the software of the system.Including:command-controlled gain with program-controlled,high-precision analog-to-digital conversion,data transmission and frame format design based on the Mod Bus transmission protocol,and reading design of TEDS(Transducer Electronic Data Sheet),the design has formed a complete network transmission system.5.Finally,The system joint testing and system index tests were completed,and the test results met the technical indicators.This article is a principle prototype design of a networked digital hydrophone system,which will be practical use after further optimization.