基于單片機的鎖相頻率合成器畢業設計論文

電子機電論文編號:JD036  有答辯PPT  字數:12624,頁數:39

                                              
                                                                              
目  錄
摘  要.................................................................. I
Abstract............................................................... II
1 緒論 .................................................................1
1.1 課題背景 ...........................................................1
1.2 鎖相技術發展概況 ...................................................1
1.3 鎖相技術的特點 .....................................................2
1.4 頻率合成的方法..................................................... 2
2 鎖相環路和鎖相頻率合成器的基本原理 ...................................4
2.1 鎖相環基本原理 .....................................................4
2.2 鎖相頻率合成器的基本原理 ...........................................6
3 基于單片機的鎖相頻率合成器的設計 .....................................7
3.1 系統簡介........................................................... 7
3.2 方案的選擇......................................................... 7
3.2.1 集成鎖相環頻率合成器芯片的選擇 ...................................7
3.2.2 單片機部分的選擇 .................................................8
3.3 鎖相環路功能模塊電路的設計......................................... 8
3.3.1 壓控振蕩電路 .....................................................8
3.3.2 鎖相環電路....................................................... 9
3.3.3 鎖相環電路分析................................................... 11
3.4 單片機模塊的設計 ...................................................12
3.4.1 單片機模塊的構成及分析........................................... 12
3.4.2 顯示驅動器CD4511................................................. 13
3.4.3 譯碼器74LS138 ....................................................14
3.4.4 單片機與鎖相環的連接 .............................................14
3.5 系統軟件設計....................................................... 14
4 系統功能調試 .........................................................18
4.1 壓控振蕩器的調試 ...................................................18
4.2 偉福仿真系統程序功能 ...............................................18
4.2.1 偉福軟件介紹 .....................................................18
4.2.2 用偉福調試系統程序 ...............................................18
4.3 鎖相環路的調試 .....................................................20
4.4 輸出頻率測量及穩定度............................................... 21
5 結論................................................................. 22
致  謝................................................................. 23
參考文獻............................................................... 24

附錄I：系統程序 ........................................................25

摘  要
    隨著無線電技術的發展，對信號的頻率穩定度和準確度要求越來越高，一般振蕩器不能滿足要求，而高穩定度的晶體振蕩器產生的頻率往往是單一的或者只能在極小的范圍內微調，而且頻率通常都不很高。為了解決頻率穩定度、準確度和頻率高、寬范圍可調之間的矛盾，就需要頻率合成技術。其技術特點是將一個高穩定度和高精度的標準頻率源經過加、減、乘、除的四則運算，產生同樣穩定度和精度的大量離散頻率。
本系統主要分為頻率合成模塊和單片機模塊。單片機模塊包含單片機、鍵盤、LED顯示屏，主要控制系統的各種功能，頻率的合成及各種參數；頻率合成模塊包括與單片機連接的并行接口、頻率合成器、低通濾波器、壓控振蕩器。它可在一定范圍產生各種離散的頻率輸出，輸出范圍為36MHz-38MHz,頻率穩定度。本文主要介紹了該系統的組成原理及設計過程，同時也闡述了設計過程中所遇到的問題及解決方案。
關鍵詞: 單片機；鎖相環；頻率合成； 壓控振蕩；鑒相器 
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