文档介绍：本科毕业设计(论文)

题目:基于FPGA的数字频率合成器设计

教学单位: 工程技术系
专业: 电子信息工程
学号: 0811100123
姓名: 张琼
指导教师: 黄文准
2012年 5月
摘要
直接(Direct Digital Synthesis 简称 DDS)是十九世纪七十年代提出的一种全数字化结构的频率合成方法,采用一个恒定的输入参考时钟源,以数据处理的方式产生频率相位可调的输出信号。经过三十多年的发展,已成为现代频率合成的主要方式。具有频率分辨率高、频率转换速度快、相位连续、相位噪声低等优点,被广泛应用在通信、雷达、遥控遥测、导航、PCS/PCN 系统等领域。近年来兴起的现场可编程门阵列(FPGA)具有集成度高、速度快、可靠性强等优点,非常适合设计 DDS 系统的数字部分。
本文主要讨论了直接数字频率合成器的实现,并通过改进其关键部分的结构,对直接数字频率合成器进行了研究。
本文首先分析了直接数字频率合成器的工作原理及其结构,并对实现相位幅度的各种方法予以详细分析。对 DDS 的关键部分数控振荡器 NCO 进行了优化设计,采用 Brent-Kung 二元树结构和选择进位加法器相结合实现相位累加器,减小了系统延时;用 Verilog 硬件语言对设计的各部分进行编程,在 Quartus‖软件上对其进行仿真,验证设计的合理性,并对系统的整体性能进行了仿真。
关键词:直接数字频率合成,相位累加器,低通滤波器,FPGA
Abstract
Direct Digital Synthesis technology that was put forward is a method of all-digital frequency synthesis at the seventies of the eenth, which betake a constant signal source of input reference clock to produce output signal of phase and frequency’s adjustable to the way of date processing .
After 30 years of development, it has e the main form of frequency synthesize. Because of excellences of high frequency resolution 、 fast frequency conversion speed、phase continuous、low phase noise and so on, DDS is widely used in field munication、radar、remote telemetry、navigation、PCS/PCN system. In recent years the rising field programmable gate array (FPGA ) with excellences of high integration、fast speed、high reliability、rich resources and so on, is very suitable for the digital part design of DDS system.
The article focuses on the realization of direct digital frequency synthesizer, and study the direct digital frequency synthesize by improving the key part structure of DDS.
In this paper, first, we analyze the working principle and structure of direct digital synthesizer , and detailedly analyze various methods of phase transforming scope. Optimizing NCO design of a key part of DDS, bining the Brent-Kung binary tree structure and carry select adder to realize the phase accumulator, and reduce the delay. Using Verilog hardware design l