摘要直扩 MSK 通信系统将扩频通信技术和最小频移键控（Minimum Shift Keying，MSK） 调制技术相结合，拥有低截获性、强抗干扰性、包络恒定、频谱利用率高、能量集中、 对非线性失真不敏感等诸多优点，在战术数据链、民用航空地空数据链、导弹制导指令 传输、雷达宽带数据传输等领域得到了广泛应用。因此，开展直扩 MSK 中频全数字接收 机及其算法的研究具有重要的理论意义和应用价值。76105

对于频偏估计，本文介绍了基于 FFT 变换的多普勒频偏提取算法，并且经过了 Matlab 程序验证。在这之后，仿真分析了几种高精度的频偏估计方法，并做出性能比较。对于 相位跟踪，本文简绍了了采用全数字超前-滞后延迟锁定环对伪码相位进行跟踪，通过仿 真分析确定环路的各项参数；采用 Costas 环来对载波相位进行跟踪，并通过仿真结果验 证跟踪方案的可行性。

毕业论文关键词 同步 锁相环 超前-滞后延迟锁定环 Costas 环

Title Research on carrier synchronization technology of DS-SS MSK system

Abstract DS-SS MSK communication system combines the technology of spread spectrum communication with Minimum shift keying modulation, has the advantages of low capture probability, strong anti-interference ability, constant envelope, high spectrum efficiency, energy concentration, insensitivity to nonlinear distortion。 So that it is widely used in tactical data link, civil aviation air-ground data link, guided missile command transmission, broadband radar data transmission and so on。 Accordingly, it makes sense to research on the intermediate frequency digital receiver and algorithms of DS-SS MSK。

For the frequency offset estimation, this paper described the algorithm based on FFT transformation to extract Doppler offset , and then made a verification on Matlab 。 After that, this paper simulated and analyzed several high-precision methods to estimate frequency offset , and made the performance comparisons。 For phase tracking，this paper introduces that the early-late delay locked loop is designed for code tracking and the loop’s parameters are determined via simulation。 Costas loop is designed for carrier phase tracking and the feasibility is verified via Matlab simulations。

Keywords synchronization phase locked loop the early-late delay locked loop costas loop

本科毕业设计说明书 第 I 页

目 次

1 绪论 1

1。1 课题研究背景和意义 1

1。2 国内外探究现状及动态 2

1。3 本文的主要工作及内容安排 4

2 直扩 MSK 信号的调制与解调 5

2。1 直扩 MSK 信号调制基本原理 5

2。1。1 MSK 信号基本理论 5

2。1。2 直扩 MSK 信号 5

2。2 仿真参数设置 8

2。3 仿真结果 8

2。4 直扩 MSK 信号的解调