The underwater - radio buoy for use as obtaining the ocean ' s acoustical parameters , applied for synthetic experimentations that seeing about ocean underwater acoustic environment , can obtain and memorize the data for all kind of underwater acoustic experimentations , for example , acoustic propagation , reverberation , ocean ' s noise etc . the system can not only reduce requires in quantity of using ships and scales in military strength equipment but also keep away from ships environments , reduce background noise and increase the quality of the gathered data 海洋环境参数获取浮标监测系统用于海洋水声环境综合考察试验中，获取和记录水声传播试验数据。该系统不但可以减小参试舰船数量要求，降低兵力配备规模，而且可以远离舰船环境，降低背景噪声，提高所采集数据的质量。因此，浮标的研制对于保证未来海试完成既定试验目标、顺利完成试验项目具有重要意义。
Development in the field of projector design is spurred on mainly by three motivating forces : the extensive research in underwater propagation establishes the advantages of increasing lower frequencies for long range detection , the advent of new active and structural materials leads to substantial improvements in transducer performance , applications of the computer technology 发射换能器设计的发展主要有三方面的推动力：对水声传播的广泛研究确立了低频应用于长距离探测的优势，新的驱动材料和结构材料的发展使得换能器在性能方面得到提高，计算机技术的应用。
This paper describes some experimental investigations of propagation properties of sound in various types and thickness of grain samples using the method of standing wave tube for the first time , extends the sound propagation theory in porous media and develops the sound propagation model in grain , analyzes and identifies the cree ping sound signals of five species of pests 为了深入研究和有效监测粮堆内部深层害虫发出声信号的传播特性，本文首次采用驻波管法，对声信号在不同种类、不同厚度粮食中传播特性进行了检测和分析，并且进一步推广、发展了多孔介质中声传播理论，建立了粮食中声波传播模型。
Then the important reference are provided for the optimal system design and technical parameters selecting of long - range underwater acoustic information transmission system . 2 . the underwater acoustic channel model based on ray theory is studied , and in combination with the system function of coherent multi - path channel , the method for underwater acoustic channel response prediction through eigenrays finding is obtained 研究了基于声线理论的水声信道声场模型，分析并仿真了在多种不同声速条件下的声线传播以及不同海底状况下的声传播；结合相干多途信道的系统函数，通过求取本征声线进行了水声信道响应的预测。
Results rectify that matched field processing based on ray travel time delay is insensitive to the mismatch of sound speed proflle , although the mismatch of ocean bottom depth and receiver location is bad to matched field processing , different forms of cost fimctions could decline the sensitivity 计算结果表明，基于声传播时延的匹配场定位对声速分布失配是不敏感的。虽然接收基阵位置倾斜和海洋深度误差对匹配场处理影响较大，但只要选择适当的代价函数，可以得到克服。
The reasons focusing only on ray travel times are " noise tolerance could be enhanced and the sensitivity to the environment model mismatch may be reduced by neglecting amplitude information ; phase ambiguity is eliminated by employing the group delay of arriving wave packets ; travel times are pseudo - linear functions of sound speed profiles of the medium , and the perturbation of ray travel time is much smaller than sound pressure ' s 之所以选择声传播时间的原因是：噪声容限可以得到提高，并且传播时间的计算可以不考虑声压的信息，从而降低了对环境模型失配的敏感性；相位的起伏也可通过到达包络的群延时来消除；传播时间是介质声速分布的伪线性函数并且传播时间的起伏远小于声压的起伏。
A square sensing area was formed upon each of the saw propagation paths using photoresist . when some kind of material deposits on this area , the saw propagation velocity will decrease due to the mass - loading effect , causing a shift in the device ' s oscillation frequency , which gives indication of the mass deposited . the dual - path architecture , one for sensing and one for reference , was used to compensate for the disturbance of temperature 利用光刻工艺在每个声传播路径上构造了一个方形质量沉积区，当有物质沉积到该区时，由于质量沉积效应，声表面波的波速发生变化，使以延迟线作为反馈回路的振荡器的振荡频率发生变化，并通过这一变化反映出沉积物的质量。
The dissertation is devoted to the study on the characteristics of underwater acoustic channels for mine . based on the comprehensive analysis on the characteristics of underwater acoustic channels , the research on the parameters of target sea area , the acoustic model , the characteristics of underwater acoustic transmission and the parameters of capability of long - range remote control receiving system is systematically conducted through theoretical analysis , computer simulation and testing of circuit 本文对远程遥控水雷系统将要应用的水声信道的传播特性进行了分析，在对远程水声信道特性进行全面分析的基础上，通过理论分析、计算机仿真、硬件电路的实验等对目标海域信道的水文参数、声场分析所用的声场模型、声传播特性和遥控接收系统性能指标进行了系统、深入的研究。
The propagation characteristics of underwater acoustic channels and their influences on long - range information transmission are studied thoroughly . based on the sonar equation , the optimal frequency band is abtained . from the calculation about transmission loss , the source level is forecasted . based on the random time varying channel theory , the fading characteristics of long - range underwater acoustic channels are analyzed 系统、深入地研究了水声信道特性及其对水声远程信息传输系统的影响；从声纳方程出发，确定了系统的最佳工作频段；在声传播损失计算的基础上，给出了声源级的预报；基于时变信道理论，描述了远程水声信道的衰落特性。
