毕业设计（论文）-DDS信号源设计精选.doc

目 录 摘 要………………………………………………………………………………………1 Abstract……………………………………………………………………………………1 1概述………………………………………………………………………………………1 1.1 DDS技术简介……………………………………………………………………1 1.2系统概述…………………………………………………………………………2 1.3主要技术及性能指标……………………………………………………………2 2总体设计…………………………………………………………………………………2 2.1系统框图…………………………………………………………………………2 2.2工作原理…………………………………………………………………………2 3系统方案论证……………………………………………………………………………3 4系统所用主要器件介绍…………………………………………………………………4 4.1 AD9850芯片介绍………………………………………………………………4 4.2 AT89C51芯片简介………………………………………………………………7 5硬件电路…………………………………………………………………………………9 5.1键盘扫描及显示电路模块………………………………………………………9 5.2 AD9850波形产生电路模块…………………………………………………10 6软件设计…………………………………………………………………………………12 6.1程序流程…………………………………………………………………………12 6.2键盘及显示部分程序……………………………………………………………12 6.3 AD9850波形产生程序…………………………………………………………14 7设计的制作与调试………………………………………………………………………14 7.1硬件调试…………………………………………………………………………14 7.2 软件调试……………………………………………………………………14 8结束语…………………………………………………………………………………15 参考文献…………………………………………………………………………………15 致谢………………………………………………………………………………………16 附录………………………………………………………………………………………17 DDS信号源设计 摘 要：关键词： Design of the Signal Source Based on DDS Abstract: Direct digital synthesis is a kind of important technique on frequency synthesis. It has many advantages， such as higher frequency resolution， faster frequency transform， and so on. It is widely used in radar， communication and many other fields. This paper presents the design of a simple DDS signal generator which consists of AD9850 and AT89C51.discusses the method of controlling word with frequency and phase， as well as the way of generating standard sinusoidal signal and frequency modulated signal. Finally， it gives structure of the hardware circuit and software. Key words: Direct digital synthesis；AT89C51；AD9850；Signal generator 1概述 1.1 DDS技术简介 近年来，随着频率合成技术广泛应用于现代无线电通信和电子技术的各个方面，DDS技术得到了迅猛发展。目前频率合成主要有三种方法：（1）采用传统的直接频率合成器对模拟信号进行频率合成，其优点是频率合成速度快、噪声低；缺点是需要以引入大量分频、倍频、混频和滤波电路为代价，使电路复杂、体积庞大、成本高，电路调试困难。而且，这种设计方法只能实现标准波形的频率合成，而对于我们所要求的对标准波形的线性叠加却无法实现[1]。（2）采用锁相环式频率合成器