【正文】 . 8 2FSK 調(diào)制解調(diào)電路設(shè)計(jì) ........................................... 8 2FSK 調(diào)制電路設(shè)計(jì)原理 ..................................... 8 2FSK 調(diào)制單元電路的設(shè)計(jì) ................................... 9 2FSK 解調(diào)單元電路的設(shè)計(jì) .................................. 13 2FSK 解調(diào)電路的整體設(shè)計(jì) .................................. 15 2PSK 調(diào)制解調(diào)電路設(shè)計(jì) .......................................... 17 2PSK 調(diào)制解調(diào)電路設(shè)計(jì)原理 ................................ 17 2PSK 調(diào)制與解調(diào)電路的設(shè)計(jì)與仿真 .......................... 18 2ASK 調(diào)制解調(diào)電路設(shè)計(jì) ......................................... 19 2ASK 調(diào)制解調(diào)電路設(shè)計(jì)原理 ............................... 19 2ASK 調(diào)制與解調(diào)電路的設(shè)計(jì)與仿真 ......................... 20 解調(diào) 結(jié)果分析 ................................................... 22 總結(jié) .................................................................... 24 參考文獻(xiàn) ................................................................ 25 附錄： (外文翻譯 ) ........................................................ 26 致謝 .................................................................... 49 1 第 1 章 緒論 研究背景 實(shí)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(shí)現(xiàn)鑒頻方法，具有工作穩(wěn)定失真小，信噪比高等優(yōu)點(diǎn)，所以被廣泛用在通信電路系統(tǒng)中。 鎖相環(huán) 其原理是通過 鑒相檢測輸入信號(hào)和輸出信號(hào)的相位差，并將檢測出的相位差信號(hào)轉(zhuǎn)換成電壓信號(hào)輸出，該信號(hào)經(jīng)低通濾波器濾波后形成 壓控振蕩器的控制電壓，對(duì)振蕩器輸出信號(hào)的頻率實(shí)施控制 。因鎖相環(huán)可以實(shí)現(xiàn)輸出信號(hào)頻率對(duì)輸入信號(hào)頻率的自動(dòng)跟蹤，所以鎖相環(huán)通常用 于閉環(huán)跟蹤電路。當(dāng)載波信號(hào)的頻率與鎖相環(huán)的固有振蕩頻率 ω0 相等時(shí)，壓控振蕩器輸出信號(hào)的頻率將保持 ω0 不變。 該文主要建立了 2ASK、 2FSK、 2PSK 的調(diào)制 解調(diào) 電路 。 3 第 2 章 基本原理 Multisim 介紹 隨著電子技術(shù)和計(jì)算機(jī)技術(shù)的發(fā)展，電子產(chǎn)品已與計(jì)算機(jī)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。 其元器件庫提供數(shù)千種電路元器件供實(shí)驗(yàn)選用 ， 同時(shí)也可以新建或擴(kuò)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(cè)中查到 ， 因此可以很方便地在工程設(shè)計(jì)中使用。 Multisim10 是一個(gè)電路原理設(shè)計(jì)、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(gè)電路設(shè)計(jì)與仿真平臺(tái)，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(qiáng)的 VHDL 和 Verilog 設(shè)計(jì)與仿真功能。鎖相環(huán)的特點(diǎn)是：利用外部輸入的參考信號(hào)控制環(huán)路內(nèi)部振蕩信號(hào)的頻率和相位。即 ()cUt為： 1( ) si n {[ ( ) ] [ ( ) ] }2c m o m i i o oU t K U U t t t t? ? ? ?? ? ? ? （ 26） si n{ [ ] [ ( ) ( ) ] }dm i o i oU t t t t? ? ? ?? ? ? ? （ 27） 式中的 ω i為輸入信號(hào)的 瞬時(shí)振蕩角頻率， ()i t? 和 ()ot? 分別為輸入信號(hào)和輸出信號(hào)的瞬時(shí)位相，根據(jù)相量的關(guān)系可得瞬時(shí)頻率和瞬時(shí)位相的關(guān)系為： 即 ( ) ( ) dot t dt? ? ???? （ 29） 則，瞬時(shí)相位差 θ d 為 [ ] ( ) ( )d i o i ot t t t? ? ? ? ?? ? ? ? （ 210） ()() dtt dt?? ? ） （ 211） 對(duì)兩邊求微分，可得頻差的關(guān)系式為 ( ) [ ( ) ( ) ]d i o i od d t t d t td t d t d t? ? ? ? ????? （ 212） 上式等于零，說明鎖相環(huán)進(jìn)入相位鎖定的狀態(tài)，此時(shí)輸出和輸入信號(hào)的頻率和相位 7 保持恒定不變的狀態(tài)， ()cUt為恒定值。其優(yōu)點(diǎn)是調(diào)制方便，設(shè)備簡單，得出的是 2FSK 信號(hào)，相位連續(xù)。當(dāng)控制端加高電平時(shí)，開關(guān)導(dǎo)通；當(dāng)控制端加低電平時(shí)開關(guān)截止。兩路載頻分別經(jīng)射隨、 LC 選頻、射隨再送至模擬開關(guān)。 2FSK 基于 Multisim仿真的解調(diào)電路的整體電路設(shè)計(jì)圖如圖 ： 16 圖 2FSK的 Multisim的解調(diào)仿真電路 圖 2FSK的 Multisim解調(diào)電路的仿真 17 2PSK 調(diào)制解調(diào)電路設(shè)計(jì) 2PSK 調(diào)制解調(diào)電路設(shè)計(jì)原理 PSK 分為二進(jìn)制相位鍵控（ 2PSK）和多進(jìn)制相 位鍵控（ MPSK）。 碼 型 變換乘 法 器()st2 ()p s ketc o s c t?雙 極 性不 歸 零 圖 模擬調(diào)頻法 2 ()p s ketc o sc t?0?0180移 相 ()st開 關(guān) 電 路 圖 鍵控法 2PSK 信號(hào)的解調(diào)通常都是采用相干解調(diào) , 該文的 解調(diào)器原理圖如圖 與2FSK 解調(diào)原理相同 。該文的2ASK 解調(diào)原理框圖 ： 壓 控 振 蕩 器抽 樣 判 決模 擬 乘 法 器 低 通 濾 波 器調(diào) 制 信 號(hào)基 帶 信 號(hào)定 時(shí) 脈 沖 圖 2ASK 解調(diào)原理框圖 2ASK 調(diào)制與解調(diào)電路的設(shè)計(jì)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(jì)是采用鎖相環(huán)進(jìn)行解調(diào)， 2ASK信號(hào)通過鎖相環(huán)最終解調(diào)出數(shù)字基帶信號(hào)。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(shí)候?yàn)榱苏业揭粋€(gè)合適的電路而苦惱，有時(shí)候又為取得一點(diǎn)成功而由衷的高興。m I3T are able to manage the integration at a reasonable cost. A typical application diagram of a real mixedsignal SoC is shown in Figure . 28 Basically, the chip integrates the system functionality from the sensor to the actuator, going through some digital processing. Conventional mixedsignal technology allows analog control and signal processing functions such as amplifiers, analogtodigital converters (ADCs) and filters to be bined with digital functionality such as microcontrollers, memory, timers and logic control functions on a single, customized chip. All signals that process an algorithm or arithmetic calculation are digital, so conversion of analog to digital signals is mandatory when submitting data for parison or processing by via a microcontroller, while conversion from digital output signals to analog highvoltage signals is required to drive an actuator or a load. The most recent mixedsignal 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 mixedsignal functions. This highvoltage mixedsignal technology is particularly relevant to automotive electronics applications where higher voltage outputs — to drive a motor or actuate a relay — need to be bined with analog signal conditioning functions and plex digital processing. A growing trend in mixedsignal circuit 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 8bit 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 plex highend 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 car’s headlamps when the steering wheel is turned to improve the driver’s safety and improve field of vision. The sensor input would e 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 onboard set of algorithms to mand the motor’s movement. For higher end applications that require more calculation power, the move to ARM processors is possible. This creates a highend solution (up to date for the mature markets) Figure Mixedsignal SoC diagram 29 which could last over the application’s lifespan because the microcontroller would be a small part of an i