基于单片机的锁相频率合成器毕业设计论文

论文编号:JD036  有答辩PPT  字数:12624,页数:39

摘  要
    随着无线电技术的发展，对信号的频率稳定度和准确度要求越来越高，一般振荡器不能满足要求，而高稳定度的晶体振荡器产生的频率往往是单一的或者只能在极小的范围内微调，而且频率通常都不很高。为了解决频率稳定度、准确度和频率高、宽范围可调之间的矛盾，就需要频率合成技术。其技术特点是将一个高稳定度和高精度的标准频率源经过加、减、乘、除的四则运算，产生同样稳定度和精度的大量离散频率。
本系统主要分为频率合成模块和单片机模块。单片机模块包含单片机、键盘、LED显示屏，主要控制系统的各种功能，频率的合成及各种参数；频率合成模块包括与单片机连接的并行接口、频率合成器、低通滤波器、压控振荡器。它可在一定范围产生各种离散的频率输出，输出范围为36MHz-38MHz,频率稳定度。本文主要介绍了该系统的组成原理及设计过程，同时也阐述了设计过程中所遇到的问题及解决方案。
关键词: 单片机；锁相环；频率合成； 压控振荡；鉴相器 
Abstract：With the development of radio technology for signal frequency stability and accuracy for demanding high, the general oscillator can not meet the requirements and the high degree of stability arising from the crystal oscillator frequency are often single or only in the context of minimal fine-tuning, but the frequency is usually not very high. To address the frequency stability, accuracy and high frequency, wide scope of powers between the contradictions requires frequency synthetic technology. Their technical characteristics is a high stability frequency source for standard and high-precision through Canada, reduced, by, the mathematical operations, and have the same stability and accuracy for the large number of discrete frequencies.
   This system is divided into primarily the frequency synthesizes module and the MCU module. I mainly am responsible for the MCU module and the frequency synthesizes module of the system. The MCU module which includes the MCU, KB and LED display, mainly controls various functions of the system, the frequency synthesizes and various parameters. The range of output frequency is 36MHz-38MHz. The thesis mainly introduces the constitute principle of the system and the designing process and expatiates design problem met in process and solutions.
Key words: MCU ; PLL ; The frequency synthesizes ; VCO ; PD 
                                                                                                       
                                                                      
                                                                              
目  录
摘  要.................................................................. I
Abstract............................................................... II
1 绪论 .................................................................1
1.1 课题背景 ...........................................................1
1.2 锁相技术发展概况 ...................................................1
1.3 锁相技术的特点 .....................................................2
1.4 频率合成的方法..................................................... 2
2 锁相环路和锁相频率合成器的基本原理 ...................................4
2.1 锁相环基本原理 .....................................................4
2.2 锁相频率合成器的基本原理 ...........................................6
3 基于单片机的锁相频率合成器的设计 .....................................7
3.1 系统简介........................................................... 7
3.2 方案的选择......................................................... 7
3.2.1 集成锁相环频率合成器芯片的选择 ...................................7
3.2.2 单片机部分的选择 .................................................8
3.3 锁相环路功能模块电路的设计......................................... 8
3.3.1 压控振荡电路 .....................................................8
3.3.2 锁相环电路....................................................... 9
3.3.3 锁相环电路分析................................................... 11
3.4 单片机模块的设计 ...................................................12
3.4.1 单片机模块的构成及分析........................................... 12
3.4.2 显示驱动器CD4511................................................. 13
3.4.3 译码器74LS138 ....................................................14
3.4.4 单片机与锁相环的连接 .............................................14
3.5 系统软件设计....................................................... 14
4 系统功能调试 .........................................................18
4.1 压控振荡器的调试 ...................................................18
4.2 伟福仿真系统程序功能 ...............................................18
4.2.1 伟福软件介绍 .....................................................18
4.2.2 用伟福调试系统程序 ...............................................18
4.3 锁相环路的调试 .....................................................20
4.4 输出频率测量及稳定度............................................... 21
5 结论................................................................. 22
致  谢................................................................. 23
参考文献............................................................... 24
附录I：系统程序 ........................................................25