基于QPSK调制的扩频系统的FPGA实现

【作者】 何秀慧；

【导师】 吴文；

【作者基本信息】 南京理工大学 ， 通信与信息系统， 2007， 硕士

【摘要】 QPSK是一种线性窄带数字调制技术，具有频谱利用率高、频谱特性好、抗衰落性能强和可用非相干解调等特点。扩频通信是从军事通信中发展起来的一种高性能通信技术，具有抗干扰、抗多径能力强和保密性好等优点，在移动通信和卫星通信中得到广泛应用。所以将QPSK技术应用于扩频通信具有重要的工程意义。本文对QPSK调制的扩频系统的FPGA实现进行了研究，具体工作如下：本文介绍了扩频通信的原理及发展现状，并对QPSK调制的原理进行了详细阐述。本文设计的扩频通信系统主要包括串并／并串转换、差分编／解码、DDS、扩频／解扩、QPSK调制／解调等模块，基于Altera公司的QuartusⅡ4.1开发平台对以上各模块进行了设计和时序仿真，仿真结果证明该系统能正确工作，完成了预定的目标。本文设计的基于FPGA的扩频通信系统具有集成度高、可软件升级等优点，这为设计更高集成度和灵活性的通信系统提供了基础。更多还原

【Abstract】 QPSK is a linear narrowband modulation, which has the features of highspectrum utilization, better spectrum specification, stronger ability ofanti-fading and applicability of non-coherent detection. Spread SpectrumCommunication is a high performance technology developed with theapplication of military communication. It owns advantages of strongeranti-fading ability, better ability of combating the effect of multipathfading and higher security. It is widely used in the mobile communicationand satellite communication systems. Thus, it is significant to implementQPSK modulation in the spread spectrum communication system.Based on QPSK modulation in FPGA ,the direct sequence spread spectrumcommunication system is realized in this dissertation ,which has beencarried out in the following aspects: Firstly, the principle and thedevelopment of spread spectrum communication and QPSK modulation isintroduced ;Secondly, the following modules of the system had been completed,which included parallel-to-serial, serial-to-parallel, differentialencoding and decoding, DDS, spreading and dispreading,QPSK modulation anddemodulation. Verilog HDL language has been adopted for design andimplementing every module on the platform of QuartusII 4.1 of the AlteraCompany. The results of the simulation show that it works well.The spread spectrum system was designed with high integration and canbe upgradeable in software, which could provide for further designs withhigher integration and greater flexibility in the modern communicationsystem in the future.更多还原