毕业设计论文QPSK的FPGA实现.doc

摘要 PAGE IV QPSK的FPGA实现 摘 要 数字调制解调技术在数字通信中占有非常重要的地位, 数字通信技术与FPGA 的结合是现代通信系统发展的一个必然趋势。QPSK数字调制技术，具有频谱利用率高、频谱特性好、抗干扰性能强、传输速率快等突出特点，在移动通信、卫星通信中具有广泛应用价值，但是基于FPGA的全数字QPSK调制解调仍在进一步研究发展中。 本文首先叙述了QPSK调制解调技术的工作原理和数字式调制与解调的特点。其次对QPSK的调制和解调设计展开讨论。设计包括QPSK的调制、解调两部分，基于对整个设计的要求进行分析及对QPSK实现FPGA进行功能的分解，以此划分成比较小的模块，自下而上设计系统； 根据QPSK的原理分别画出QPSK调制、解调的实现框图。设计中设定每个比特对应特定的载波，并以载波作为比较，实现最后的对应的输出结果。最后基于VHDL语言分别完成QPSK的调制与解调，完成系统的设计方案，在MAX+PLUSII 环境下对模块逻辑、时序进行仿真调试的仿真结果表明了该设计的正确性，并综合得出RTL的结构图。 关键词：QPSK,FPGA,调制,解调 FPGA IMPLEMENTATION OF QPSK ABSTRACT Technology of digital modulation and demodulation plays an important role in digital communication system and the combination of digital communication technology and FPGA is certainly a trend.QPSK digital modulation technique has features of high-spectrum utilization ratio，better spectrum specification, stronger anti-interference performance and faster baud rate and has been applied widely in mobile communication system and satellite communication system．But all-digital QPSK modulation and demodulation based on FPGA is still towards further research and development． At first, this paper describes the principle of QPSK modulation and demodulation technology as well as the characteristics of digital modulation and demodulation. In the following words we mainly provide the discussion combined with the research and design of the QPSK modulation and demodulation .This design has two parts, which are QPSK modulation and demodulation .The analysis on the whole design requirement and the decomposition of QPSK function in FPGA lay the basis for the smaller divided modules. Then we can start up the bottom-up design .Respectively, we draw QPSK modulation and demodulation diagram on the basis of the principle of QPSK. The design supposes each bit corresponds to a specific carrier .To achieve the final result of the corresponding output, we should take carrier as a comparison. In the end, we use VHDL to achieve the QPSK modulation and demodulation. After comp