测量海底沉积物声学特性的多种波形声源开发与实验

发布时间：2018-05-16 13:32

本文选题：声学特性 + 声源　；参考：《广东工业大学》2016年硕士论文

【摘要】：海底沉积物的声学特性是研究海洋声场环境的基础数据,是构建地声模型不可缺少的研究内容,为海底地质分类、海洋资源开发、国防安全等提供基础资料和关键技术。其中,声速和声衰系数是反映其声特性的两个重要参数,通过对它们的测量,可以判别海底沉积物的物理性质和内部结构特征。当前,海底沉积物声学特性的测量以脉冲波透射法为主。这种脉冲波测量法,通常需要人工判读采集到的声波首波信息。由于沉积物介质不均匀,对透射声波衰减大,采集到的声波信号波形不稳定,给人工判读带来干扰。基于这种情况,本文引入新的波形测量方法,并开发出波形发生装置,尝试多种波形对沉积物进行测量。论文介绍了海底沉积物的声学特性测量现状,包括实验室测量和原位测量。在测量原理方面,在对传统脉冲波测量方法分析的基础上,创新性地提出对海底沉积物用连续波(正弦波、调幅波)互相关测声速和自相关测声衰减的原理,并给出计算方法。在测量装置开发方面,信号板电路、驱动板电路和隔离电源电路组成声源硬件部分；在软件方面,单片机程序采用C语言编写和基于VB的上位机和单片机通信设计,可以实现连续波频率控制以及硬件电路工作模式控制。在项目组前期研究基础上,.搭建了小尺度超声波探针测量和声波信号采集实验平台。最后,验证了多种波形声源装置的功能性,·检验了连续波测量方法的可行性。通过对采集的数据进行分析,初步获得连续波测量海底沉积物声学特性实验结论。较之传统脉冲波测量法需要人工判读接收到的波形起跳点,连续波测量方法可以应用相关计算机技术和matlab软件实现对海底沉积物声学参数快速提取。多种波形声源装置的开发,为探索海底沉积物测量方法提供了基础条件,也为后续改进研究奠定了基础。总结本文的研究工作,多种波形声源装置可以稳定工作；测得的多种波形对比表明连续波波形更稳定,在沉积物声学特性研究方面更有前景。结合试验操作和数据计算中发现的问题和不足,提出进一步的改进措施和意见。
[Abstract]:The acoustic characteristics of seabed sediments are the basic data for studying the environment of ocean sound field and the indispensable research contents for constructing the acoustic model. It provides basic data and key technologies for the geological classification of the seabed, the exploitation of marine resources, the national defense security, and so on. Among them, sound velocity and sound decay coefficient are two important parameters reflecting their acoustic characteristics. The physical properties and internal structural characteristics of seabed sediments can be distinguished by measuring them. At present, the acoustic characteristics of seabed sediments are mainly measured by pulse wave transmission method. This method of pulse wave measurement usually requires manual interpretation of the first wave information. Due to the uneven sediment medium, large attenuation of transmitted sound waves and unstable waveforms of collected acoustic signals, interference is brought to manual interpretation. Based on this situation, a new waveform measurement method is introduced, and a waveform generating device is developed to try to measure sediment with various waveforms. This paper introduces the present situation of measurement of acoustic characteristics of seabed sediment, including laboratory measurement and in situ measurement. On the basis of the analysis of the traditional pulse wave measurement method, the principles of continuous wave (sine wave, amplitude modulated wave) cross-correlation measurement of sound velocity and autocorrelation sound attenuation are put forward, and the calculation method is given. In the aspect of measuring device development, the signal board circuit, the drive board circuit and the isolation power supply circuit constitute the sound source hardware part, in the software aspect, the single chip microcomputer program is written with C language and the communication design between the upper computer and the single chip microcomputer based on VB. Continuous wave frequency control and working mode control of hardware circuit can be realized. On the basis of the preliminary study of the project team. A small scale ultrasonic probe measurement and acoustic signal acquisition experimental platform was built. Finally, the function of various waveform sound source devices is verified, and the feasibility of continuous wave measurement method is verified. By analyzing the collected data, the experimental results of acoustical characteristics of sediment measured by continuous wave are preliminarily obtained. Compared with the traditional pulse wave measurement method, it is necessary to manually interpret the received wave take-off point. The continuous wave measurement method can be used to quickly extract the acoustic parameters of seabed sediment by using relevant computer technology and matlab software. The development of various waveform acoustic sources provides the basic conditions for the exploration of seafloor sediment measurement methods and lays a foundation for further improvement research. Summing up the research work in this paper, a variety of wave source devices can work stably, and the comparison of measured waveforms shows that the continuous wave waveforms are more stable and have a better prospect in the study of sediment acoustic characteristics. Combined with the problems and shortcomings found in experimental operation and data calculation, further improvement measures and suggestions are put forward.
【学位授予单位】：广东工业大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：P733.2

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