直扩系统伪码捕获研究及扩频微波系统的设计与实现

【作者】 魏俊；

【导师】 李式巨；

【作者基本信息】 浙江大学 ， 信息与通信工程， 2007， 硕士

【摘要】 扩频通信技术以其良好的抗干扰性和高的频带利用率，已经在军事领域和民用领域获得了飞速的发展。直接序列扩频通信(DSSS)系统是应用最广泛的一种扩频通信方式。直扩系统中伪随机码捕获是关键技术，因此对码捕获技术的研究具有重要意义。在当前无线频率非常拥挤、通信网要求快速建设的情况下，使用公共频段的扩频数字微波设备能够适应复杂地形，在有线传输网的中继以及各种需要无线连接的紧急通信中都得到了广泛地使用，因此对扩频数字微波设备的研制具有巨大的工程实用价值和社会效益。本文对直扩系统中各种码捕获技术进行了详尽的阐述，并对基于序贯检测原理建立的码捕获技术进行分析和改进，提高了码捕获技术的实用性。同时本文设计了一个可以中继多路E1信号的扩频微波通信系统，并硬件实现了该系统的基本功能。其中在FPGA上实现了基于时分复用的5路E1信号的复接和分接，同时提供在线误码检测功能。在实现的基础上本文还对系统性能进行了相关测试。结果表明系统工作良好，证明系统设计方案正确，硬件实现可靠。更多还原

【Abstract】 Spread Spectrum technology offers many advantages including well immunity to interference and high utilization of bandwidth, thus it plays more and more important role in military field and commercial environment. Among the many Spread Spectrum technologies, Direct Sequence Spread Spectrum (DSSS) is a most popular technique. In DSSS system, one of the key technologies is PN (Pseudo random Number) sequence acquisition. So it has a great significance for research on. PN sequence acquisition.Nowadays Low Frequency Band is limited in radio frequency, and the communication network is required to construct more rapidly. Due to the use of public frequency band and the adaption for the irregular landform, Spread Spectrum digital microwave equipment has widely used in the repeaters of wired transmission Network. In addition the application of Spread Spectrum digital microwave equipment in the urgent wireless communication is very popular too. The development for the Spread Spectrum digital microwave equipment is relatively good for engineering application.In this thesis, the technologies related to PN sequence acquisition have been described first, then a PN sequence acquisition based on a sequential detection has been analyzed and improved. Furthermore, a Spread Spectrum digital microwave system has been implemented for relaying E1 multiplexed signal. The system adopts time division multiplex, and provides 5×E1 signals multiplexing and demultiplexing on FPGA. The system also has function for online data error-rate detection. Experiment results are in excellent agreement with our design criterions.更多还原