【作者】 汤作伟；

【导师】 聂伟；

【作者基本信息】 北京化工大学 ， 计算机应用技术， 2007， 硕士

【摘要】 数字调制技术是移动通信系统的重要组成部分，π／4-DQPSK和GMSK调制具有频谱利用率高、抗干扰能力强、误码率低等优点，在移动通信和卫星通信系统中得到广泛的应用。目前，实现数字调制技术的方案很多，但采用DSP实现数字调制技术的方法仍在进一步研究和发展中，因此本文研究π／4-DQPSK和GMSK调制的DSP实现方案具有重要的意义。文中首先介绍了π／4-DQPSK和GMSK调制的发展及国内外研究现状，然后阐述了这两种调制的原理，提出采用DSP和正交调制原理实现π／4-DQPSK和GMSK调制的方法；接着根据系统需求设计了调制器硬件平台，讨论了各部分电路原理和设计方法；同时在CCS2.0上进行软件设计，给出了系统程序以及功能程序流程图和实现方法；最后提供了测试方案，对系统功能和性能进行测试，并对测试结果进行分析。通过测试和实际运行，功能和技术指标均满足设计要求。本文采用全数字实现调制，避免了模拟方式因正交调制信号相位或幅度不平衡产生的边带及本振泄漏，同时可以通过软件更新适应不同的数据速率、调制方式及滤波器特性等，具有很大的灵活性和适应能力。更多还原

【Abstract】 Digital Modulation Technology is an important part of the Mobile Communication Systems.π/4-DQPSK and GMSK modulation have been widely adopted for many Mobile Communication systems and Satellite Communication systems because of many advantages, such as better spectral efficiency, stronger anti-interference performance , lower Bit Error Rate, and so on. Currently, though there exsits various solutions to carry out Digital Modulation Technology, DSP solution is still in researching and developing. Therefore, the resreach ofπ/4-DQPSK and GMSK modulation base on DSP solution is of great significance.In this paper, firstly, the development and resreach progress ofπ/4-DQPSK and GMSK modulation technologies both at home and abroad are introduced. Then, the principle ofπ/4-DQPSK and GMSK are presented, and the DSP and Quadrature Modulation solution which adopt for this paper is proposed. Secondly, the hardware of Modulator is designed accronding to the system’s requirements, the principle and design of each part is given in detail. Meanwhile the densign of software based on CCS2．0 including flow chart and realization of system program and function program are given too, Finally, the performance of system is tested and some experiment results are presented and analyzed. Through test and actual operation, both of the functions and technical specifications meet the design requirements.This system is an all-digital realization, various problems in analog arrroach, such as any I/Q imbalance (phase or amplitude) results in poor side-band suppression and carrier feed-through are eliminated. Other advantages of the DSP solutions including the ability to easily software update to accommodate different data rates, modulation schemes and filter Specifications, etc. In addition, the modulator is also flexible and adoptable too.更多还原