文档介绍：摘要
摘 要
扩展频谱技术被称为信息时代的三大高技术通信传输方式之一，受到人们的
广泛关注。而最常见的一种方式——直接序列扩频系统应用就更加广泛。和其他
通信系统相比，其实现更加复杂。
伪随机码的捕获问题是直扩系统的关键技术，捕获性能的优劣直接影响整个
扩频系统的性能。对该方法进行细致的学****和研究是十分必要的，并且有很大的
实际意义。
本论文围绕直扩系统的捕获问题展开，首先研究了扩频理论，对直扩信号进
行了分析，对常用的扩频序列进行了讨论，在此基础之上，对时域串行捕获原理、
时域并行捕获原理、频域的 FFT 算法进行了理论分析和探讨，并对这几种方法的
优缺点和实现的复杂性进行了比对，结合 MATLAB 仿真软件，对几种捕获方法
进行了软件仿真。最后为了缩短捕获时间，提出了两种改进方法。
关键词：直扩系统 伪随机码 捕获
Abstract
Abstract
As the one of the three highest technical communication transmission modes, the
spread spectrum communication is getting more and more people’s attention, and the
direct sequence spread spectrum system is one of the most common systems, which is
simplified as Direct Sequence Spread Spectrum (DSSS) system below. Compared with
other communication systems, its application is more extensive and more complicated.
How to acquire the particular pseudorandom noise (PRN) code is the key problem
in DS system, and the acquisition performance directly affects DS system. It is
necessary and important to do deep study and research on the acquisition methods.
So this paper focuses on DS system acquisition. Firstly, the theory of spread
spectrum is studied, the spread spectrum signal is analyzed, and the spread-spectrum
sequence is discussed. Based on these, the Principles of time-domain serial acquisition,
time-domain parallel acquisition and frequency domain acquisition are discussed and
analyzed, and their advantages and disadvantages and their complexity are compared
by matlab simulation and theoretical analysis. Finally, we propose two methods ,
which shorten the acquisition time.
Keyword: DS system PRN code acquisition
目录
目录
第一章 绪论 ........................