基于固体中声载波的信号传输研究

发布时间：2018-10-29 20:20

【摘要】：针对电磁屏蔽和密封环境等特殊环境下传统电磁波通信和线缆通信效果不佳、实施不便的情况,本文利用超声波在固体中衰减慢,穿透力强,不受电磁屏蔽和干扰影响等特性,设计了一种以超声波作为载波,在固体媒介中进行信号传输的系统,为特殊环境下的信号传输提供了一种有效的补充手段。首先,为了保证系统能够实现并稳定运行,从基础理论出发,对声波在固体中的基本传播特性和超声波换能器的特性及匹配问题进行了分析。在分析了对信号传输造成干扰的次级声波的形成机理及消除方法后,对整个信号传输系统和信道进行分析,并建立了系统和信道数学模型。然后,完成了基于固体中声载波的信号传输系统的软硬件系统的设计。硬件系统以STM32为控制处理核心,利用以场效应管和变压器为核心的驱动电路激励超声换能器,并通过以保护电路、滤波电路和信号判定电路为核心的信号调理电路对超声波接收信号进行处理。采用集成开发环境MDK进行软件系统的开发,分别对系统运行控制与状态监控软件模块、信号发送软件模块和信号接收软件模块进行了设计与实现,完成了信号的收发功能。为了提高信号传输质量,降低信号传输时的干扰,借鉴传统数字通信技术,总结出了基于系统辨识和均衡器的次级声波消除方案和基于二进制频移键控(2FSK)的调制解调系统设计方案,并通过MATLAB软件进行了仿真与验证。最后,对系统的硬件和软件进行了整体调试,并完成了信号传输系统的功能和性能测试。测试结果表明,系统的硬件电路和软件算法设计可行,能够完成通过超声波加载信号在高纯度尼龙棒中进行500bps以下的低速率信号传输。本文所完成的研究工作,为后续研究工作的进一步开展提供了软硬件平台,具备后续开发的潜质。
[Abstract]:In view of the poor effect of traditional electromagnetic wave communication and cable communication in special environment, such as electromagnetic shielding and sealing environment, this paper makes use of the characteristics of ultrasonic wave in solids, such as slow attenuation, strong penetration, not affected by electromagnetic shielding and interference, etc. A system for signal transmission in solid media using ultrasonic wave as carrier is designed, which provides an effective supplementary method for signal transmission in special environment. Firstly, in order to ensure that the system can be realized and run stably, the basic propagation characteristics of acoustic wave in solid and the characteristics and matching of ultrasonic transducer are analyzed based on the basic theory. After analyzing the formation mechanism and elimination method of secondary sound wave which interferes with signal transmission, the whole signal transmission system and channel are analyzed, and the mathematical model of system and channel is established. Then, the hardware and software design of the signal transmission system based on solid medium acoustic carrier is completed. The hardware system uses STM32 as the control processing core, uses the driving circuit based on FET and transformer as the core to excite the ultrasonic transducer, and uses the protective circuit to protect the ultrasonic transducer. The filter circuit and the signal judging circuit are used to process the ultrasonic signal. The software system is developed with the integrated development environment (MDK). The system operation control and status monitoring software module, the signal sending software module and the signal receiving software module are designed and implemented respectively. In order to improve the quality of signal transmission and reduce the interference of signal transmission, the traditional digital communication technology is used for reference. The scheme of subsonic cancellation based on system identification and equalizer and the design of modulation and demodulation system based on binary frequency shift keying (2FSK) are summarized and simulated and verified by MATLAB software. Finally, the hardware and software of the system are debugged, and the function and performance of the signal transmission system are tested. The test results show that the hardware circuit and software algorithm of the system are feasible and can transmit the low rate signal below 500bps in the high purity nylon rod by ultrasonic loading signal. The research work completed in this paper provides the software and hardware platform for the further development of the further research work and has the potential for further development.
【学位授予单位】：南京信息工程大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN911

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