短波非实时数据传输系统的设计与实现

发布时间：2019-01-20 10:18

【摘要】：短波通信具有机动灵活、抗毁性好等优点,一直是军事通信大力发展的通信技术。但由于传统短波通信功能单一、可扩展性差,已难以适应现代通信的数字化、网络化、宽带化等需求。在短波通信中引入软件无线电思想,可以很好地解决这一困境,对提高短波通信质量具有十分重要的意义。数字调制解调技术是短波通信中的一个关键技术,也是软件无线电研究的重点,本文基于数字化调制解调技术实现了一个短波非实时数据传输系统。首先,在数据发送部分基于Visual C++编译环境用C语言开发了 PC报文发送控制软件。并设计实现了上位机PC与下位机基带调制模块间信息交互的通信协议。然后,完成了基于DSP芯片的下位机软件无线电基带信号调制电路,设计了电路原理图及PCB线路图,并完成了硬件电路的制板、焊接与调试。在DSP的专用编译环境CCS3.3中用C语言与汇编语言联合开发了 4FTSK(四时四频)调制程序以及其它电路子模块程序。其中,报文发送控制软件包括数据交织模块、编码模块、格式组装模块及串口通信模块。报文发送控制软件完成了对原始报文数据的编码(Golay)、交织、分集处理等功能,然后将其组装成本文所设计的五层数据结构格式,以实现数据三重分集功能。基带调制端由串口通信模块、4FTSK调制模块、数模转换模块、调制信号平衡输出模块及子模块组成,基于直接数字频率合成原理实现了基带信号的4FTSK调制功能。根据4FTSK调制最佳接收原理,开发了数据解调译码软件。该软件完成了对存储音频信息的解调译码。软件解调部分包括采样率变换模块、匹配滤波模块、低通滤波模块、似然判决模块及其子模块。译码部分包括解交织模块、位同步处理模块、帧同步处理模块、分集合并模块、Chase算法软纠错模块。最后,在实验室测试了数据传输系统各部分的工作性能,并对系统进行数据的实际收发测试。实验结果表明,系统的性能达到了项目设计的指标要求。
[Abstract]:HF communication has the advantages of flexible flexibility and good survivability. It has been a communication technology developed vigorously in military communications. However, because of the single function and poor expansibility of traditional shortwave communication, it is difficult to meet the needs of modern communication such as digitalization, networking, broadband and so on. The introduction of the idea of software radio in HF communication can solve this dilemma well, and it is of great significance to improve the quality of HF communication. Digital modulation and demodulation is one of the key technologies in HF communication, and it is also the focus of software radio research. In this paper, a short-wave non-real-time data transmission system based on digital modulation and demodulation is implemented. Firstly, in the data sending part, the PC message sending control software is developed in C language based on Visual C compiler environment. The communication protocol between PC and baseband modulation module is designed and implemented. Then, the base-band signal modulation circuit of software radio based on DSP chip is completed, the circuit schematic diagram and PCB circuit diagram are designed, and the board making, welding and debugging of the hardware circuit are completed. The 4FTSK (04:00 quad-frequency) modulation program and other circuit submodule programs are developed in CCS3.3, a special compiling environment of DSP, using C language and assembly language. The message sending control software includes data interleaving module, coding module, format assembly module and serial communication module. The packet sending control software completes the functions of encoding (Golay), interleaving and diversity processing of the original message data, and then assembles it into the five-layer data structure format designed in this paper to realize the function of triple data diversity. The baseband modulation is composed of serial communication module, 4FTSK modulation module, digital-analog conversion module, modulation signal balance output module and sub-module. The 4FTSK modulation function of baseband signal is realized based on the principle of direct digital frequency synthesis. According to the optimal receiving principle of 4FTSK modulation, the software of data demodulation and decoding is developed. The software completes demodulation and decoding of stored audio information. The software demodulation includes sampling rate transform module, matched filter module, low pass filter module, likelihood decision module and its sub-module. The decoding part includes deinterleaving module, bit synchronization processing module, frame synchronization processing module, diversity merging module and Chase soft error correction module. Finally, the performance of each part of the data transmission system is tested in the laboratory. The experimental results show that the performance of the system meets the requirements of the project design.
【学位授予单位】：大连海事大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN919.6;TN925

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