摘要直扩 MSK 通信系统将直接序列扩频（Direct Sequence Spread Spectrum Communication System，DS-SS）和最小频移键控（Minimum Shift Keying，MSK）调制技术相结合，拥 有截获概率低、保密性好、包络恒定、旁瓣滚降衰减快、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。所以直扩 MSK 信号串行产生的研究具有重要意义。75930

本文首先介绍了扩频通信的基本原理，选用具有良好的自相关特性和互相关特性的 Gold 码作为扩频码序列。介绍了常规 MSK 调制信号的产生方法，由于 MSK 并行调制信 号高数据速率传输硬件实现的复杂性，本文提出利用串行方法产生直扩 MSK 调制信号。 设计一个合适的转换滤波器成为直扩 MSK 信号串行产生的关键。首先证明了利用转换滤 波器可以实现 MSK 信号的调制。为了在硬件平台上的实现，提出利用凸优化的方法设计 FIR 滤波器。通过 Matlab 仿真工具验证了直扩 MSK 信号串行产生方案的可行性。并且在 硬件平台上完成了直扩 MSK 信号串行产生的 FPGA 实现。

毕业论文关键词 直接序列扩频 MSK 串行调制 转换滤波器 凸优化 FPGA

Title SMSK Spread Spectrum Modulation and FPGA Implementation

Abstract This paper describes a system which combines Direct Sequence Spread Spectrum Communication System (DS-SS) and Minimum Shift Keying (MSK)。 This combination provides low probability of interception, fine confidentiality, constant envelope, steep sidelobe attenuation and the insensitivity to nonlinear distortion。 Serial Minimum Shift Keying (SMSK) modulation can meet the demands of the high-data-rate system。 Besides, it changes the problem of maintaining phase orthogonality and balancing amplitude into the design of prosper conversion filter。 So it has important significance to research the SMSK modulation。

This paper firstly introduces the basic principle of spread spectrum communication and selects Gold code which has good self and cross correlation properties as spread spectrum code。 Then it shows the conventional generation method of the MSK modulation。 Due to the complexity of the hardware implementation of the parallel MSK modulation in the high-data-rate transmission, it proposes the use of the serial MSK modulation。 The design of a proper transformed filter is the key to the it。 Firstly, it is proved that the modulation of serial MSK can be realized by using the transformed filter。 In order to be implemented on the hardware platform, the FIR filter is designed by using convex optimization method。 The feasibility of serial MSK modulation is verified through Matlab simulation tool。 The generation of serial MSK modulation is implemented on FPGA。

Keywords  DS-SS  SMSK  transformed filter  convex optimization  FPGA

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 1

1。2 国内外发展现状 1

1。3 论文的主要工作及章节安排 3

2 扩频通信理论基础 5

2。1