基于multisim及鎖相環(huán)的2PSK2ASK2FSK的調(diào)制解調(diào)電路仿真

1、 LANZHOU UNIVERSITY OF TECHNOLOGY畢業(yè)設(shè)計題 目 基于Multisim的鎖相環(huán)解調(diào)系統(tǒng)仿真 學生姓名 學 號 專業(yè)班級 指導教師 學 院 計算機與通信學院 辯論日期 基于Multisim的鎖相環(huán)解調(diào)系統(tǒng)仿真PLL Demodulation System Simulation Based on Multisim摘 要實現(xiàn)調(diào)頻波解調(diào)的方法有很多而鎖相環(huán)鑒頻是利用現(xiàn)代鎖相環(huán)技術(shù)來實現(xiàn)鑒頻具有工作穩(wěn)定失真小信噪比高等優(yōu)點所以被廣泛用在通信電路系統(tǒng)中鎖相環(huán)鑒相檢測輸入信號和輸出信號的相位差并將檢測出的相位差信號轉(zhuǎn)換成電壓信號輸出該信號經(jīng)低通濾波器濾波后形成壓控振蕩器的控制

2、電壓對振蕩器輸出信號的頻率實施控制該文首先介紹了鎖相環(huán)技術(shù)開展的現(xiàn)狀方向以及背景并對PLL的原理進行了闡述在以上的根底上分別設(shè)計了2ASK2PSK2FSK的調(diào)制解調(diào)電路其最后采用Multisim軟件進行仿真2ASK2FSK2PSK在整個電路設(shè)計中力求要做到電路簡單并完成任務書提到的要求Multisim鎖相環(huán)AbstrackThere are many ways to realize frequency wave demodulation and PLL frequency which has the advantages of stable operation small distortion

3、 high signal-to-noise ratio and so on is achieved by using modern PLL frequency technology so it is widely used in communication circuit system Phase-locked loop through the difference of the phase detection of input signal and the output signal phase and the detected phase difference signal into ou

4、tput voltage signal the signal through a low pass filter After the formation of the voltage control oscillator the output signal of the oscillator frequency controlThis paper first introduces the present situation development direction phase-locked loop technology as well as the background and the p

5、rinciple of PLL is discussed On the basis of the above the modulation and demodulation circuit of 2ASK 2PSK 2FSK which function is a digital baseband signal is modulated by an analog signal and output were designed and then useing the PLL demodulation finally using Multisim software simulation In th

6、e 2ASK 2FSK 2PSK demodulation the output of the low pass filter waveform distortion is relatively large but finally it can regenerate digital baseband pulse sampling decision circuit after shaping In the circuit design and strive to do a simple circuit and complete the task book mentioned requiremen

7、tsKeywords modulate modulation PLLultisim目 錄第1章 緒論111 研究背景112 研究現(xiàn)狀113 研究內(nèi)容介紹2第2章 根本原理321 Multisim介紹322 鎖相環(huán)根本原理5221鎖相環(huán)的根本組成5222 鎖相環(huán)的工作原理5第3章 調(diào)制解調(diào)電路設(shè)計831 2FSK調(diào)制解調(diào)電路設(shè)計8311 2FSK調(diào)制電路設(shè)計原理8312 2FSK調(diào)制單元電路的設(shè)計9313 2FSK解調(diào)單元電路的設(shè)計13314 2FSK解調(diào)電路的整體設(shè)計1532 2PSK調(diào)制解調(diào)電路設(shè)計17321 2PSK調(diào)制解調(diào)電路設(shè)計原理17322 2PSK調(diào)制與解調(diào)電路的設(shè)計與仿真1833

8、 2ASK調(diào)制解調(diào)電路設(shè)計19331 2ASK調(diào)制解調(diào)電路設(shè)計原理19332 2ASK調(diào)制與解調(diào)電路的設(shè)計與仿真2034 解調(diào)結(jié)果分析22總結(jié)24參考文獻25附錄 外文翻譯 26致謝50第1章 緒論11 研究背景 實現(xiàn)調(diào)頻波解調(diào)的方法有很多而鎖相環(huán)鑒頻是利用現(xiàn)代鎖相環(huán)技術(shù)來實現(xiàn)鑒頻方法具有工作穩(wěn)定失真小信噪比高等優(yōu)點所以被廣泛用在通信電路系統(tǒng)中鎖相環(huán)路是一種反應電路鎖相環(huán)的英文全稱是Phase-Locked Loop簡稱PLL其作用是使得電路相位同步因鎖相環(huán)可以實現(xiàn)輸出信號頻率對輸入信號頻率的自動跟蹤所以鎖相環(huán)通常用于閉環(huán)跟蹤電路鎖相環(huán)在工作的過程中當輸出信號的頻率與輸入信號的頻率相等時輸出電

9、壓與輸入電壓保持固定的相位差值即輸出電壓與輸入電壓的相位被鎖住它還具有載波跟蹤特性作為一個窄帶跟蹤濾波器可提取淹沒在噪聲中的信號用高穩(wěn)定的參考振蕩器鎖定可提供高穩(wěn)定的頻率源可進行高精度的香味與頻率測量等等如今鎖相環(huán)解調(diào)器在通信雷達測量和自動化控制等領(lǐng)域應用極為廣泛隨著電子技術(shù)的開展對鎖相環(huán)解調(diào)的研究和應用得到了越來越多的關(guān)注現(xiàn)在通過分析與研究加深對鎖相環(huán)解調(diào)方式的理解并根據(jù)它的原理設(shè)計出2FSK2PSK2ASKSDH網(wǎng)絡中在汽車MP3無線發(fā)射器中測量汽車轉(zhuǎn)速都是十分典型的應用調(diào)頻波的特點是頻率隨調(diào)制信號幅度的變化而變化壓控振蕩器的振蕩頻率取決于輸入電壓的幅度當載波信號的頻率與鎖相環(huán)的固有振蕩頻

10、率0相等時壓控振蕩器輸出信號的頻率將保持0不變假設(shè)壓控振蕩器的輸入信號除了有鎖相環(huán)低通濾波器輸出的信號uc外還有調(diào)制信號ui那么壓控振蕩器輸出信號的頻率就是以0為中心隨調(diào)制信號幅度的變化而變化的調(diào)頻波信號當然鎖相環(huán)的許多優(yōu)越性使得鎖相環(huán)解調(diào)技術(shù)在很多我們周圍都可以見到的物品中發(fā)揮著其巨大的成效如今鎖相環(huán)路理論與研究日臻完善應用范圍普及整個電子技術(shù)領(lǐng)域隨著通信及電子系統(tǒng)的飛速開展促使集成鎖相環(huán)和數(shù)字鎖相環(huán)突飛猛進現(xiàn)在品種齊全繁多提高系統(tǒng)的工作穩(wěn)定性和可靠性和小型化目前仍朝著集成化數(shù)字化多用化方向迅速開展13 研究內(nèi)容介紹調(diào)制和解調(diào)電路是通信設(shè)備中重要組成局部用待傳輸?shù)牡皖l信號去控制高頻載波參數(shù)電

11、路稱為調(diào)制電路解調(diào)是調(diào)制的逆過程從高頻已調(diào)信號中復原出原調(diào)制信號稱為解調(diào)電路該文主要建立了2ASK2FSK2PSK解調(diào)鎖相環(huán)路的輸出信號頻率可以精確地跟蹤輸入?yún)⒖夹盘栴l率的變化環(huán)路鎖定后輸入?yún)⒖夹盘柡洼敵鰠⒖夹盘栔g的穩(wěn)態(tài)相位誤差可以通過增加環(huán)路增益被控制在所需數(shù)值范圍內(nèi)這種輸出信號頻率隨輸入?yún)⒖夹盘栴l率變化的特性稱為鎖相環(huán)的跟蹤特性利用此特性可以做載波跟蹤型鎖相環(huán)及調(diào)制跟蹤型鎖相環(huán)為了實現(xiàn)信息的遠距離傳輸收信端接收到信號后必須進行解調(diào)才能恢復原信號所謂的解調(diào)就是用攜帶信息的輸出信號uo來復原載波信號ui的參數(shù)載波信號的參數(shù)有幅度頻率和位相所以解調(diào)有調(diào)幅AM調(diào)頻FM和調(diào)相PM三種調(diào)幅波的特點是

12、頻率與載波信號的頻率相等幅度隨輸入信號幅度的變化而變化調(diào)頻波的特點是幅度與載波信號的幅度相等頻率隨輸入信號幅度的變化而變化調(diào)相波的特點是幅度與載波信號的幅度相等相位隨輸入信號幅度的變化而變化中調(diào)制出2FSK2ASK2PSK調(diào)制時采用的是鎖相環(huán)解調(diào)出來最后用Multisim進行仿真出效果2ASK2FSK2PSK第2章 根本原理21 Multisim介紹隨著電子技術(shù)和計算機技術(shù)的開展電子產(chǎn)品已與計算機緊密相連電子產(chǎn)品的智能化日益完善電路的集成度越來越高而產(chǎn)品的更新周期卻越來越短Multisim 10是加拿大 Interactive Image Technologies公司 2001 年推出的 Mu

13、ltisim 最新版本可以設(shè)計測試和演示各種電子電路包括電工電路模擬電路數(shù)字電路射頻電路及局部微機接口電路等可以對被仿真的電路中的元器件設(shè)置各種故障如開路短路和不同程度的漏電等從而觀察不同故障情況它有豐富的元件庫為用戶提供元器件模型的擴充和技術(shù)虛擬測試儀器儀表種類齊全其操作方法與實際儀器十分相似具有較為詳細的電路分析功能可以完成電路的瞬態(tài)分析和穩(wěn)態(tài)分析時域和頻域分析器件的線性和非線性分析電路的噪聲分析和失真分析離散傅里葉分析電路零極點分析交直流靈敏度分析等 18 種電路分析方法提供了多種輸入輸出接口Multisim10可以與國內(nèi)外流行的印刷電路板設(shè)計自動化軟件Protel及電路仿真軟件Pspi

14、ce之間的文件接口也能通過Windows 電路圖送往文字處理系統(tǒng)中進行編輯排版同時還支持VHDL和Verilog HDL語言的電路仿真與設(shè)計Multisim 10 Multisim 10提供了18種儀表儀表工具欄通常位于電路窗口的右邊也可以用鼠標將其拖至菜單的下方呈水平狀Multisim 10具有以下特點 1 Multisim 10是一個電路原理設(shè)計電路功能測試的虛擬仿真軟件其元器件庫提供數(shù)千種電路元器件供實驗選用同時也可以新建或擴充已有的元器件庫而且建庫所需的元器件參數(shù)可以從生產(chǎn)廠商的產(chǎn)品使用手冊中查到因此可以很方便地在工程設(shè)計中使用 2 Multisim 10 的虛擬測試儀器儀表種類齊全有

15、一般實驗用的通用儀器如萬用表信號發(fā)生器雙通道示波器直流電源還有一般實驗室少有或沒有的儀器如波特圖示儀字信號發(fā)生器邏輯分析儀邏輯轉(zhuǎn)換器失真度測量儀頻譜分析儀和網(wǎng)絡分析儀等 3 Multisim 10 具有較詳細的電路分析功能可以完成電路的瞬態(tài)和穩(wěn)態(tài)分析時域和頻域分析器件的線性和非線性分析電路的噪聲和失真分析離散傅里葉分析電路零極點分析交直流靈敏度分析等以幫助設(shè)計人員分析電路的性能 4 Multisim10可以設(shè)計測試和演示各種電子電路包括電工電路模擬電路數(shù)字電路射頻電路及局部微機接口電路等可以對被仿真的電路中的元器件設(shè)置各種故障如開路短路和不同程度的漏電等從而觀察不同故障情況下的電路工作狀況在進

16、行仿真的過程中還可以存儲測試點的所有數(shù)據(jù)列出被仿真電路的所有元器件清單以及存儲測試儀器的工作狀態(tài)顯示波形和具體數(shù)據(jù)Multisim10是一個電路原理設(shè)計電路功能測試的虛擬仿真軟件它用軟件的方法模擬電子線路元器件和儀器儀表實現(xiàn)了軟件即元器件和軟件即儀器 Multisim10是一個電路原理設(shè)計電路功能測試的虛擬仿真軟件該軟件為電子工程師提供了一個電路設(shè)計與仿真平臺不僅與國際著名的模擬電路仿真軟件spice兼容而且具有較強的 VHDL和 Verilog設(shè)計與仿真功能它具有界面形象直觀易懂采用圖形方式創(chuàng)立電路的特點它豐富的元件庫中提供了超過16000個組件全部采用世紀模型確保了仿真結(jié)果的真實性和實用性

17、它采用開放式的庫管理模式能自動地生成模擬和數(shù)字組件模型這對新器件的補充十分有利Multisim10的虛擬測試儀器種類齊全有一般實驗用的通用儀器如萬用表信號發(fā)生器雙通道示波器直流交流電源還有一般實驗室少有或沒有的儀器如波特圖示儀字信號發(fā)生器邏輯分析儀邏輯轉(zhuǎn)換器失真度測試儀頻譜分析儀和網(wǎng)絡分析儀等Multisim10具有較為詳細的電路分析功能可以完成電路的瞬態(tài)和穩(wěn)態(tài)分析時域和頻域分析器件的線性和非線性分析電路的噪聲分析和失真分析離散傅里葉分析電路零極點分析交直流靈敏度分析等電路分析方法以幫助設(shè)計人員分析電路的性能Multisim10可以設(shè)計測試和演示各種電子電路包括電工電路模擬電路數(shù)字電路射頻電路

18、及微機接口電路等可以對被仿真的電路中的元器件設(shè)置各種故障如開路短路和不同程度的漏電等從而觀察不同故障情況下的電路工作狀況在進行仿真的同時軟件還可以存儲測試點的所有數(shù)據(jù)列出被仿真電路的所有元器件清單以及存儲測試儀器的工作狀態(tài)顯示波形和具體數(shù)許多電子設(shè)備要正常工作通常需要外部的輸入信號與內(nèi)部的振蕩信號同步利用鎖相環(huán)路就可以實現(xiàn)這個目的鎖相環(huán)路是一種反應控制電路簡稱鎖相環(huán)PLL鎖相環(huán)的特點是利用外部輸入的參考信號控制環(huán)路內(nèi)部振蕩信號的頻率和相位因鎖相環(huán)可以實現(xiàn)輸出信號頻率對輸入信號頻率的自動跟蹤所以鎖相環(huán)通常用于閉環(huán)跟蹤電路鎖相環(huán)在工作的過程中當輸出信號的頻率與輸入信號的頻率相等時輸出電壓與輸入電壓

19、保持固定的相位差值即輸出電壓與輸入電壓的相位被鎖住這就是鎖相環(huán)名稱的由來鎖相環(huán)通常由鑒相器PD環(huán)路濾波器LF和壓控振蕩器VCO三局部組成鎖相環(huán)組成的原理框圖如下圖圖21 鎖相環(huán)根本組成鎖相環(huán)中的鑒相器又稱為相位比擬器它的作用是檢測輸入信號和輸出信號的相位差并將檢測出的相位差信號轉(zhuǎn)換成電壓信號輸出該信號經(jīng)低通濾波器濾波后形成壓控振蕩器的控制電壓對振蕩器輸出信號的頻率實施控制鎖相環(huán)的工作原理鎖相環(huán)中的鑒相器通常由模擬乘法器組成利用模擬乘法器組成的鑒相器電路如下圖圖22 乘法器鑒相器的工作原理是設(shè)外界輸入的信號電壓和壓控振蕩器輸出的信號電壓分別為 2-2式中的0為壓控振蕩器在輸入控制電壓為零或為直流

20、電壓時的振蕩角頻率稱為電路的固有振蕩角頻率那么模擬乘法器的輸出電壓uD為 2-4 用低通濾波器LF將上式中的和頻分量濾掉剩下的差頻分量作為壓控振蕩器的輸入控制電壓即為 2-6 2-7式中的i為輸入信號的瞬時振蕩角頻率和分別為輸入信號和輸出信號的瞬時位相根據(jù)相量的關(guān)系可得瞬時頻率和瞬時位相的關(guān)系為即 2-9那么瞬時相位差d為 2-11對兩邊求微分可得頻差的關(guān)系式為 2-12 上式等于零說明鎖相環(huán)進入相位鎖定的狀態(tài)此時輸出和輸入信號的頻率和相位保持恒定不變的狀態(tài)為恒定值當上式不等于零時說明鎖相環(huán)的相位還未鎖定輸入信號和輸出信號的頻率不等隨時間而變因壓控振蕩器的壓控特性如下圖該特性說明壓控振蕩器的振

21、蕩頻率u以0為中心隨輸入信號電壓的變化而變化該特性的表達式為圖23 壓控特性上式說明當隨時間而變時壓控振蕩器的振蕩頻率u也隨時間而變鎖相環(huán)進入頻率牽引自動跟蹤捕捉輸入信號的頻率使鎖相環(huán)進入鎖定的狀態(tài)并保持0 i的狀態(tài)不變第3章 調(diào)制解調(diào)電路設(shè)計31 2FSK調(diào)制解調(diào)電路設(shè)計311 2FSK調(diào)制電路設(shè)計原理2FSK即叫做二進制移頻鍵控或二進制頻移鍵控2FSK信號產(chǎn)生的方法一般有兩種一種叫直接調(diào)頻法另一種叫頻移鍵控法1模擬調(diào)頻法即直接利用一個矩形脈沖序列對一個載波進行調(diào)頻而獲得如圖31所示圖31 模擬調(diào)頻法直接調(diào)頻法是頻移鍵控通信方式早期采用的實現(xiàn)方法其優(yōu)點是調(diào)制方便設(shè)備簡單得出的是2FSK信號相

22、位連續(xù)2鍵控法即利用受矩形脈沖序列控制的開關(guān)電路對兩個不同的獨立頻率源進行選通如圖32所示圖 32 鍵控法2FSK鍵控法的特點是轉(zhuǎn)換速度快波形好穩(wěn)定度高且易于實現(xiàn)故應用廣泛但設(shè)備要復雜些得出的是2FSK信號相位不連續(xù)該文采用鍵控法產(chǎn)生2FSK信號即用一個受基帶脈沖控制的開關(guān)電路去選擇兩個獨立頻率源的振蕩作為輸出設(shè)計原理圖如圖33所示圖 33 2FSK調(diào)制原理圖312 2FSK調(diào)制單元電路的設(shè)計要將時鐘脈沖信號經(jīng)過2FSK調(diào)制成為2FSK信號我們采用一個受基帶脈沖控制的開關(guān)電路去選擇兩個獨立的頻率源作為輸出鍵控法產(chǎn)生的2FSK信號頻率穩(wěn)定度可以做得很高并且沒有過度頻率它的轉(zhuǎn)換速度快波形好1四雙向

23、模擬開關(guān)CD4066CD4066的引腳功能如圖34所示每個封裝內(nèi)部有4個獨立的模擬開關(guān)每個模擬開關(guān)有輸入輸出控制三個端子其中輸入端和輸出端可互換當控制端加高電平時開關(guān)導通當控制端加低電平時開關(guān)截止模擬開關(guān)導通時導通電阻為幾十歐姆模擬開關(guān)截止時呈現(xiàn)很高的阻抗可以看成為開路模擬開關(guān)可傳輸數(shù)字信號和模擬信號可傳輸?shù)哪M信號的上限頻率為40MHz各開關(guān)間的串擾很小典型值為50dB圖 34 四雙向模擬開關(guān)CD4066輸入的基帶信號由轉(zhuǎn)換開關(guān)分成兩路一路控制f1 32KHz的載頻另一路經(jīng)倒相去控制f2 16KHz的載頻當基帶信號為1時模擬開關(guān)1翻開模擬開關(guān)2關(guān)閉此時輸出f1 32KHz當基帶信號為0時模擬

24、開關(guān)2開通此時輸出f2 16KHz于是可在輸出端得到2FSK已調(diào)信號如圖35所示圖 35 模擬開關(guān)2變頻電路變頻電路是將輸入的二進制數(shù)字基帶信號通過控制載頻轉(zhuǎn)換成已調(diào)信號即2FSK調(diào)制信號兩路載頻分別經(jīng)射隨LC選頻射隨再送至模擬開關(guān)其中LC選頻電路函數(shù) 選頻網(wǎng)絡如圖36所示圖36 變頻電路圖32FSK調(diào)制的整體電路圖的設(shè)計圖37 2FSK的Multisim調(diào)制仿真電路圖42FSK調(diào)制電路的仿真圖38 脈沖信號輸出波形圖39 變頻電路輸出波形圖310 2FSK的仿真效果圖313 2FSK解調(diào)單元電路的設(shè)計鎖相環(huán)通常由鑒相器PD環(huán)路濾波器LF和壓控振蕩器VCO三局部組成鎖相環(huán)原理框圖如下圖 圖 3

25、11 2FSK解調(diào)原理框圖 1鎖相環(huán)中的鑒相器通常由模擬乘法器組成利用模擬乘法器組成的鑒相器電路如圖312所示圖312 乘法器2低通濾波器如圖313所示用低通濾波器LF將和頻分量濾掉剩下的差頻分量作為壓控振蕩器的輸入控制電壓uCt圖313 環(huán)路濾波器 3壓控振蕩器的壓控特性如圖314所示該特性說明壓控振蕩器的振蕩頻率u以0為中心隨輸入信號電壓uct的變化而變化該特性的表達式為 3-1圖314 壓控特性上式說明當uct隨時間而變時壓控振蕩器的振蕩頻率u也隨時間而變鎖相環(huán)進入頻率牽引自動跟蹤捕捉輸入信號的頻率使鎖相環(huán)進入鎖定的狀態(tài)并保持0 i的狀態(tài)不變壓控振蕩器的電路圖如圖315所示圖315壓控振

26、蕩器4抽樣判決電路LM311工作原理LM311是當2腳電壓高于3腳電壓時輸出高電平反之那么輸出低電平引腳功能如下1腳 GROUNDGND 接地2腳 INPUT 正向輸入端3腳 INPUT- 反相輸入端7腳 OUTPUT 輸出端5腳 BALANCE 平衡6腳 BALANCESTROBE 平衡選通8腳 V 電源4腳 V- 電源- 圖316 LM311引腳圖 圖317 抽樣判決電路圖314 2FSK解調(diào)電路的整體設(shè)計2FSK解調(diào)電路的設(shè)計是采用鎖相環(huán)進行解調(diào)2FSK信號通過鎖相環(huán)最終解調(diào)出數(shù)字基帶信號2FSK基于Multisim仿真的解調(diào)電路的整體電路設(shè)計圖如圖318所示圖318 2FSK的Mult

27、isim的解調(diào)仿真電路圖319 2FSK的Multisim解調(diào)電路的仿真32 2PSK調(diào)制解調(diào)電路設(shè)計321 2PSK調(diào)制解調(diào)電路設(shè)計原理PSK分為二進制相位鍵控2PSK和多進制相位鍵控MPSK該文主要介紹2PSK的調(diào)制與解調(diào)在二進制數(shù)字調(diào)制中當正弦載波的相位隨二進制數(shù)字基帶信號離散變化時那么產(chǎn)生二進制移相鍵控 2PSK 信號通常用已調(diào)信號載波的 0和 180分別表示二進制數(shù)字基帶信號的 1 和 0二進制移相鍵控信號的調(diào)制原理圖如所示其中圖是采用模擬的方法產(chǎn)生2PSK信號圖是采用數(shù)字鍵控的方法產(chǎn)生2PSK信號2PSK時采用的是鍵控法圖 模擬調(diào)頻法圖2PSK信號的解調(diào)通常都是采用相干解調(diào) 解調(diào)器

28、原理圖如圖 2FSK解調(diào)原理相同圖2PSK解調(diào)原理框圖322 2PSK調(diào)制與解調(diào)電路的設(shè)計與仿真2PSK調(diào)制電路采用鍵控法調(diào)制而解調(diào)電路的設(shè)計是采用鎖相環(huán)進行解調(diào)2PSK信號通過鎖相環(huán)最終解調(diào)出數(shù)字基帶信號2PSK基于multisim仿真的調(diào)制解調(diào)電路的整體電路設(shè)計圖如圖323所示圖2PSK調(diào)制解調(diào)電路圖2PSK調(diào)制仿真圖與解調(diào)后的仿真圖如圖324圖2PSK調(diào)制解調(diào)電路圖仿真結(jié)果33 2ASK調(diào)制解調(diào)電路設(shè)計331 2ASK調(diào)制解調(diào)電路設(shè)計原理在二進制數(shù)字振幅調(diào)制中載波的幅度隨著調(diào)制信號的變化而變化實現(xiàn)這種調(diào)制的方式有兩種1相乘法通過相乘器直接將載波和數(shù)字信號相乘得到輸出信號這種直接利用二進制

29、數(shù)字信號的振幅來調(diào)制正弦載波的方式稱為相乘法其電路如下圖在該電路中載波信號和二進制數(shù)字信號同時輸入到相乘器中完成調(diào)制所示圖325模擬相乘法 圖326數(shù)字鍵控法2ASKOOK信號有兩種根本的解調(diào)方法非相干解調(diào)包絡檢波法和相干解調(diào)同步檢測法相應的接收系統(tǒng)如圖327圖328所示圖327非相干解調(diào)方式圖328相干解調(diào)方式該文2ASK的調(diào)制方法采用的是模擬相乘法而調(diào)制那么采用的是相干解調(diào)該文的2ASK解調(diào)原理框圖329如下圖329 2ASK解調(diào)原理框圖332 2ASK調(diào)制與解調(diào)電路的設(shè)計與仿真2ASK調(diào)制電路采用鍵控法調(diào)制而解調(diào)電路的設(shè)計是采用鎖相環(huán)進行解調(diào)2ASK信號通過鎖相環(huán)最終解調(diào)出數(shù)字基帶信號2

30、ASK基于Multisim仿真的調(diào)制解調(diào)電路的整體電路設(shè)計圖如圖330所示圖2ASK調(diào)制解調(diào)電路圖圖 2ASK調(diào)制解調(diào)仿真圖34 解調(diào)結(jié)果分析由于在解調(diào)2ASK2FSK2PSK中C22FSK解調(diào)為例一開始我在C2設(shè)為10nF出來的波形如下列圖332 圖332 C2 10nF時的波形可見解調(diào)出來的基帶信號出現(xiàn)嚴重失真后經(jīng)過不斷的嘗試改變C2的值最終把C2的值設(shè)為100nF終于解調(diào)出很好的數(shù)字基帶信號如下列圖333圖333 C2 100nF時的波形總結(jié)該文分別設(shè)計了2ASK2PSK2FSK其最后采用Multisim軟件進行仿真2ASK2FSK2PSKMultisim的鎖相解調(diào)系統(tǒng)設(shè)計的畢業(yè)設(shè)計任務

31、我首先查閱了大量的書本資料接著又上網(wǎng)搜集了許多有用信息有時候為了找到一個適宜的電路而苦惱有時候又為取得一點成功而由衷的快樂當最終的電路方案設(shè)計出來以后我請教了我的指導老師何老師及學的比擬好的同學他們的一個小小指點就給我們很大啟示和靈感對我的電路圖提出了很多有價值的建議在此對熱心幫助我的老師和同學表示衷心感謝在此次畢業(yè)設(shè)計中我充分體會到了熟練運用相關(guān)軟件的重要性不像以前做的課程設(shè)計并沒有多少工作在計算機里實現(xiàn)的就僅僅畫出了電路圖之后用元器件在面包板上搭電路就行了本次畢業(yè)設(shè)計都高度依賴計算機從仿真到繪制原理圖再到參數(shù)調(diào)節(jié)可以說每一步都很艱難每一步都是我一步一個腳印結(jié)結(jié)實實踩下去的通過畢業(yè)設(shè)計我增強

32、了對通信電子技術(shù)的理解學會查尋資料、比擬方案學會通信電路的設(shè)計、計算進一步提高分析解決實際問題的能力創(chuàng)造一個動腦動手、獨立開展電路實驗的時機鍛煉分析、解決通信電子電路問題的實際本領(lǐng)真正實現(xiàn)由課本知識向?qū)嶋H能力的轉(zhuǎn)化通過典型電路的設(shè)計與仿真加深對根本原理的了解增強了實踐能力參考文獻1出版社出版社 11 謝自美電子線路綜合設(shè)計華中科技大學出版社2006612 BestRoland EPhaseLooked Loop TheoryDesign and Applications McGRAWHill198413 沈偉慈通信電路西安電子科技大學出版社2004附錄 外文翻譯 Bridging the Ga

33、p between the Analog and Digital WorldsMost applications require the co-existence of analog and digital functionality and the benefits of combining this functionality on a single chip are significant Such mixed-signal integration however also presents significant challenges Furthermore digital and a

34、nalog developments tend to evolve at differing rates yet mixed-signal solutions for markets such as industrial automotive and medical must remain available over significant time periods The latest mixed-signal semiconductor processes are helping to address some of these issues and this article will

35、look at some of the issues designers should consider when specifying integrated mixed-signal solutionsMixed-signal solution for the real worldSystem designers often partition the digital portion from the analog section of a given design for a variety of reasons the availability of mixing components

36、for the two technologies the complexity of the digital design or again because of the existence of pure digital processing parts as standard products Placing the analog elements in an integrated circuit definitively allows the system designer to optimize the costs of its entire module This integrati

37、on approach is usually difficult for advanced markets such as telecommunications or computers but makes sense for more mature or conservative markets such as automotive medical and industrial For most of these mature markets applications digital functions are finding their way onto what once were pu

38、re analog designs Adding digital functions to an analog design is helped in part by the development of new process technologies that can handle both short-channel fast-switching digital transistors as well as high-voltage analog transistors For example AMI Semiconductors latest mixed-signal technolo

39、gy offers digital and analog integration capabilities on the same design platform The I3T technology family is based on standard CMOS 035m limiting the imum gate voltage to 33V Some consider this technology outdated from a pure digital designers point of view but it is at the forefront for the autom

40、otive industrial and medical marketsThis list of optional features that enables the design of real SoCs includes high voltage interfacing up to 80V microprocessing capabilities up to 32 bits wireless capabilities up to 28GHz and dense logic design up to 15K gatesmm2 Beside these capabilities NVM int

41、egration is possible E2PROM up to 4 Kbytes Flash memory up to half a megabit or On-Time-Programmable OTP cells for application calibrations The ability to integrate all these features on a chip gives the customer the possibility to be independent from the obsolescence of the stand-alone NVM market w

42、hich is more or less driven by the computer market This advantage is quite relevant when we consider the cost of re-qualifying a module for the OEMs in automotive for instance It also makes sense when considering the long lifespan of the applications embedded into cars the industrial environment or

43、medical self-treatment devices where patient cost is an important considerationNevertheless bridging the gap from digital to analog on a single chip does not occur without issues Clocking noise from high-speed digital circuits for instance often interferes with noise-sensitive analog functions In ad

44、dition switching currents from high-power analog functions can interfere with low-voltage digital processors The goal is to protect low-voltage transistors from the electric field effects of voltages that are 10 to 30 times higherThese important issues are not without solutions For example one of th

45、e latest releases in the I3T family the I3T50 DTI uses a deep trench isolation technique This technique uses a series of isolating trenches that bury deep into the IC substrate effectively creating on-chip pockets where noise and power supply parameters are carefully controlledOn top of its protecti

46、on skills the deep trench technology also helps to minimize die area by allowing dense packing of high-voltage analog pockets with low-voltage regions You can obtain improvements in die area of 10 to 60 percent over designs that use standard junction isolation techniquesAs mentioned earlier the reas

47、on that system designers are using deep sub-micron technologies in those markets is often linked to the availability of devices in those technologies not the complexity of the application itself The complexity can be handled in many cases by an 8-bit microcontroller or 32-bit for high-end applicatio

48、ns Products such as the 035m I3T are able to manage the integration at a reasonable cost A typical application diagram of a real mixed-signal SoC is shown in Figure 19Basically the chip integrates the system functionality from the sensor to the actuator going through some digital processing Conventi

49、onal mixed-signal technology allows analog control and signal processing functions such as amplifiers analog-to-digital converters ADCs and filters to be combined with digital functionality such as microcontrollers memory timers and logic control functions on a single customized chip All signals tha

50、t process an algorithm or arithmetic calculation are digital so conversion of analog to digital signals is mandatory when submitting data for comparison or processing by via a microcontroller while conversion from digital output signals to analog high-voltage signals is required to drive an actuator

51、 or a load The most recent mixed-signal technology AMIS developed significantly simplifies the implementation of such driver functionality by allowing much higher voltage functionality to be integrated into an IC alongside the relatively low voltages required for conventional mixed-signal functions

52、This high-voltage mixed-signal technology is particularly relevant to automotive electronics applications where higher voltage outputs to drive a motor or actuate a relay need to be combined with analog signal conditioning functions and complex digital processingA growing trend in mixed-signal circu

53、it design is to add some type of central processing circuit to the analog circuits For many applications the suitable choice of processing intelligence is an 8-bit microcontroller core such as an 8051 or 6502 8 bits remains the most popular choice as this type of SoC is not intended to replace compl

54、ex high-end central microcontrollers but more decentralized or slave applications such as sensor conditioning circuitry with local as close to the sensor as possible simple intelligence to control relays or motors An automotive example would be the lateral actuation of a cars headlamps when the stee

55、ring wheel is turned to improve the drivers safety and improve field of vision The sensor input would come from the steering angle via a serial link most of the time with a LIN or I2C protocol and the SoC would be close to the motor with an on-board set of algorithms to command the motors movementFo

56、r higher end applications that require more calculation power the move to ARM processors is possible This creates a high-end solution up to date for the mature markets which could last over the applications lifespan because the microcontroller would be a small part of an integrated circuit that emulates the modules functionalitiesIn order to understand how larger geometries can be better suited for some mixed-signal applications one needs to understand all of the characteristics involved Below we will discuss seven key characteristics however this