本科毕业设计(论文)
题 目：数字频率合成器
学 院：信息工程学院 专 业：xxx 学 号：xxx 学生姓名：XX 指导教师：xxx
二○○ 年 月 日
xxxx2008届毕业设计(论文)
数字频率合成器
XX
摘要
直接数字频率合成（简称DDS）是一种以固定的精确时钟为基准，利用数字处理模块产生频率和相位均可调的输出信号的技术。随着超大规模集成电路和微电子技术的发展，现代高性能、高集成度和小体积的DDS产品正快速取代传统的模拟信号频率合成技术，成为这类问题的新的解决方案。
本文介绍了DDS技术的基本工作原理及特点，并在此基础上详细给出了DDS频率合成器的设计方案。在本系统中，用户通过键盘输入所需要频率信号的数据，，利用单片机计算出频率控制字，并对FPGA芯片EP1C6Q240C8进行编程，最后通过D/A转换器和LFP得到所需要的输出波形。
本系统主要由相位累加模块、波形存储模块、D/A转换模块和LFP模块组成，通过EDA开发软件，在线编译DDS信号源设计文件到FPGA开发板上，得出一个相位可调的正弦信号发生器。只要改变存储波形信息的ROM数据，就可以灵活的实现任意波形发生器。
DDS信号发生器工作稳定，易于实现，输出频率分辨率高，可以满足人们不断提高的要求。
关键字 ：FPGA ；DDS ；相位累加器 ；正弦信号；单片机
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xx：<数字频率合成器>
Direct Digital Synthesizer
Liutao
Abstract
Direct digital synthesis (DDS) is a technique for using digital data processing blocks as a means to generate a frequency-and-phase-tunable output signal referenced to a fixed-frequency precision clock source. With the development of VLSI and microelectronic technology, today’ s high-performance, functionally-integrated , and small package-sized DDS products are fast becoming an alternative to traditional frequency-agile analog synthesizer solutions.
The paper introduces the theory of DDS operation and its features. On the basis of this, the project of DDS signal generator is discussed in detail. In this system user can input the frequency data through a keyboard, and microcontroller C51 will work out the relevant value of the frequency tuning word (FTW),then programs to control an FPGA chip EP1C6Q240C8 ,so that the required output waveform is obtained by D/A converter and LFP.
The system mainly consists of ACCP module, ROM of waveform module, D/A converter module and LFP module , through the EDA software development, online design compiler DDS source documents to the FPGA development board, and arrive at a frequency, phase adjustable sinusoidal signal generator system module. As long as the change in the information storage wave ROM data, the flexibility to achieve arbitrary waveform generators
It has been proved that DDS signal generator has good reliability, ease of implementation and high output frequency resolutions, it can meet the people’s continual elevated requires.
Key words: FPGA ；DDS ；ACCP；Sinusoidal signal；microcontroller
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