编号： 课程设计说明书课程设计说明书题 目： 基于 DDS 的信号发生器 院 （系）： 信息与通信学院 专 业： 电子信息工程 学生姓名： 峰之使者 学 号： 指导教师： 2014 年 12 月 21 日摘摘 要要随着信息技术的发展，现代电子系统对波形发生器提出了更高的要求直接数字合成（Direct Digital Synthesize，DDS）是一种重要的频率合成技术，具有分辨率高，频率变换快等优点利用键盘输入波形频率，存入单片机，通过单片机控制诺基亚 5110 液晶屏，让诺基亚 5110 液晶显示输入频率的大小再通过单片机控制AD9851，再经过 AD9851 内部的相位累加器、相位寄存器、正弦查询表、DAC 转换器、内部低通滤波器，然后经低通滤波器后，可输出正弦波,外接一个高速比较器，可以输出方波,通过调节一个滑动变阻器，改变方波的占空比，为了克服有线连接繁琐的缺点，利用了无线模块 NRF24L01 进行数据传输，通过数据通信，可以远距离控制。
关键词：DDS；单片机；AD9851；无线模块 NRF24L01；AbstractWith the development of information technology, modern electronic system puts forward higher requirements on waveform generator.Direct digital synthesis （Direct Digital Synthesize，DDS）is an important kind of frequency synthesis technology, with high resolution, frequency conversion fast, etc.Using the keyboard input waveform frequency, deposited in the single chip microcomputer, through single chip microcomputer control the nokia 5110 LCD screen, let nokia 5110 LCD displays the size of the input frequency.Is controlled by single chip AD9851, then through AD9851 internal phase accumulator, phase registers, sine lookup table, DAC converters, internal low pass filter, and then after low pass filter, output sine wave, external a high-speed comparator, can output pulse, by adjusting a slide rheostat, change the duty cycle square wave, wired connection trival in order to overcome the shortcomings, the use of the wireless module NRF24L01 for data transmission, through the data communication, remote control. Key word：DDS; Entire numerical control; Monolithic integrated circuit; wireless module;目录目录引言 ......................................................................11 任务要求与设计的背景.....................................................1 1.1 设计任务要求............................................................................................................................................1 1.2 课题背景....................................................................................................................................................1 1.3 直接数字频率合成技术的现状................................................................................................................12 系统总体方案的分析和设计 ................................................2 2.1 DDS 技术的基本原理...............................................................................................................................2 2.2 DDS 的工作特点.......................................................................................................................................3 2.3 系统设计原理............................................................................................................................................3 2.4 系统框图分析和设计................................................................................................................................43 系统的硬件设计 ..........................................................4 3.1 单片机最小系统........................................................................................................................................4 3.1.1 时钟电路.................................................................................................................................................4 3.1.2 复位电路.................................................................................................................................................5 3.2 单片机 I/O 口.............................................................................................................................................5 3.3 DDS 芯片...................................................................................................................................................6 3.3.1 AD9851 的串、并行通信......................................................................................................................7 3.3.2 单片机与 AD9851 的接口.....................................................................................................................8 3.4 无线模块....................................................................................................................................................84 信号发生器的软件设计 ....................................................95 电路的总体电路图及实物图 ...............................................10 5.1 系统原理图..............................................................................................................................................10 5.2 系统的 PCB 图.........................................................................................................................................10 5.3 实物图......................................................................................................................................................106 电路的调试及测试结果 ...................................................11 6.1 正弦波测试的波形.......................................................................................。