基于DDS芯片AD9850的正弦发生器.doc

基于DDS芯片AD9850的正弦发生器 摘 要 数字化是目前无线电技术的发展趋势，它具有可靠性高、灵活性强、易大规模集成等优点。而直接数字合成技术DDS(direct digital synthesis)正是适应数字通信的发展趋势而产生的。直接数字合成DDS是一种基于波形存储的频率合成技术。它具有频率转换时间短、频率分辨率高、输出相位连续、相位噪声小及可编程等突出特点，在通信和雷达领域中得到了广泛的应用。所以，研究用直接数字合成技术（DDS）合成信号波形具有广泛的现实意义。 论文中论述的系统以直接数字合成技术为基础，采用在线可编程单片机AT89S52为主控制器，结合直接数字频率合成芯片AD9850，实现了从1Hz到20MHz步进为1Hz的频率可调正弦信号以及方波信号的产生。整个系统具有结构简单，控制灵活，信号精度高等特点。设计中，32位频率控制字计算采用了查表与计算相结合的算法，该算法简单快捷，且节约存储空间。 本文主要分以下几章进行论述。第一章是对研究背景、目的和内容的介绍；第二章是原理及相关设计工具介绍；第三、四章是系统总体设计和详细设计部分；第五章是系统调试与分析部分；第六章是结论与展望。 关键词: DDS , AT89S52，AD9850，信号发生器 ABSTRACT The digitization is the present radio technology development tendency, it has the reliability high, the flexibility strong, merit and so on easy large scale integration. But direct digital synthesis technology DDS (direct digital synthesis) is precisely adapts the digital communication development tendency to produce. The direct digital synthesizes DDS is one kind the frequency synthesis technology which saves based on the profile. It has the frequency switching time short, the frequency resolution high, the output phase continuously, the phase noise small and is programmable and so on the prominent characteristic, obtained the widespread application in the correspondence and the radar domain. Therefore, study with the direct digital synthesis technology (DDS) to composite signal profile has the widespread practical significance. In the paper elaborates the system take the direct digital synthesis technology as a foundation, uses the on-line programmable monolithic integrated circuit AT89S52 as the primarily controller, union direct digital frequency synthesis chip AD9850, realized step has entered from 1Hz to 20MHz with the 1Hz frequency may adjust the sine signal as well as the square-wave signal production. The overall system has the structure simply, the control is nimble, signal precision higher characteristic. In the design, 32 frequencies control words computation has used the algorithm which Zha Biao and the computation