Development Of A Self-contained Acquisition System For Acoustic Characteristics Of Seafloor Sediments

The study of the acoustic characteristics of seabed sediments is an indispensable part of exploring the oceans and building national defense,whether it is the development of submarine resources or the laying of underwater pipelines,it is necessary to master the engineering geology of the seabed.The acoustic characteristics of the seabed sediment parameter mainly includes the research the sound velocity and acoustic attenuation,the sound velocity and sound attenuation of sediments can be calculated,and the internal structure and physical characteristics of seabed sediment can be analyzed by the actual measurement of seabed sediment.This paper introduces the research status of acoustic characteristics of seabed sediments,including the progress of equipment development,the progress in the study of sound velocity and acoustic attenuation characteristics.In the case of the long time observation demand of seabed sediments,a self-contained acoustic acquisition system for seabed sediment is developed.This paper explains the acoustic characteristics of the seabed sediment,gives the measurement scheme of acoustic velocity parameters and acoustic attenuation parameters of seabed sediment,describe the principle of measuring the acoustic characteristic parameters of seabed sediment in detail.The acoustic velocity parameters of seabed sediment are calculated by the method of acoustic time-difference method,and the acoustic attenuation parameters of seabed sediment are calculated by using the self-correlation measurement principle in the test technique.Measurement system design mainly includes hardware and software,in terms of hardware circuit;it has signal source circuit,drive circuit,signal modulation circuit,signal sampling circuit,control circuit,data storage circuit and power circuit.Control circuit is the core part,and coordinates and unifies other functional circuits.in terms of system software,single-chip microcomputer program is written with C language,Implement DDS digital signal synthesizer driver program,master-slave communication interface program,microcontroller and CPLD communication interface program and file management chip CH376 driver,The program flow chart of single chip microcomputer is given.CPLD mainly use the verilog language to realize the reading and writing module of SRAM,the frequency division module,CPLD and SRAM interface module,and gives the program module diagram and time sequence simulation diagram of CPLD.In order to perform functional verification of the acoustic characteristics measuring device of the self-contained seabed sediment,builds the corresponding verification platform,the power consumption of the system were measured,and the length of 101 mm organic glass rod is the object of measurement,the pulse wave,sine wave,amplitude modulation wave is used as signal source for experimental measurements,and use an oscilloscope to capture the output waveform of the signal source circuit and the output waveform of receiving transducer,the receiving transducer signal is sampled and processed,comparing the two result,the feasibility of each module circuit in the measurement system is analyzed.Based on the deficiencies found in the experiment,further improvement of the acoustic characteristics measurement device of the self-contained seabed sediment is proposed.