【正文】 為－ 50dB。 蘭州理工大學(xué)畢業(yè)設(shè)計(jì) 14 圖 環(huán)路濾波器 3）壓控振蕩器的壓控特性如圖 所示， 該特性說明壓控振蕩器的振蕩頻率 ω u以 ω 0為中心，隨輸入信號(hào)電壓 uc（ t） 的變化而變化。 通常用已調(diào)信號(hào)載波的 0176。 蘭州理工大學(xué)畢業(yè)設(shè)計(jì) 19 圖 2PSK調(diào)制解調(diào)電路圖仿真結(jié)果 2ASK 調(diào)制解調(diào)電路設(shè)計(jì) 2ASK 調(diào)制解調(diào)電路設(shè)計(jì)原理 在二進(jìn)制數(shù)字振幅調(diào)制中，載波的幅度隨著調(diào)制信號(hào)的變化而變化，實(shí)現(xiàn)這種調(diào)制的 方式 有兩種：（ 1） 模擬 相乘法：通過相乘器直接將載波和數(shù)字信號(hào)相乘得到輸出信號(hào)，這種直接利用二進(jìn)制數(shù)字信號(hào)的振幅來調(diào)制正弦載波的方式稱為 模擬 相乘法，其電路如圖 所示。低通濾波器輸出的波形失真比較大，不過最后經(jīng)過抽樣判決電路整形后可以很好的解調(diào)出數(shù)字基帶脈沖。本次 畢業(yè)設(shè)計(jì) 都高度依賴計(jì)算機(jī)，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(gè)腳印結(jié)結(jié)實(shí)實(shí)踩下去的。 蘭州理工大學(xué)畢業(yè)設(shè)計(jì) 25 參考文獻(xiàn) [1]． 熊偉 候傳教 . Multisim7電路設(shè)計(jì)及仿真應(yīng)用 [M]. 清華大學(xué) 出版社 ， 2020 [2]． 陽昌漢 . 高頻電子線路 [M]. 高等教育 出版社 ， 2020 [3]． 吳運(yùn)昌 . 模擬集成電路原理與應(yīng)用 [M]. 華 南理工大學(xué)出版社， 2020 [4]． 沈偉慈 . 通信電路 [M]. 西安電子科技大學(xué)出版社， 2020 [5]． 李爭 . 低噪聲電荷泵鎖相電路設(shè)計(jì)理論與技術(shù)，北京交通大學(xué) .碩士學(xué)位論文 ， 2020 [6]． 鄭繼禹 , 張厥盛 , 萬心平 . 鎖相環(huán)原理與應(yīng)用 [M]. 人民郵電出版社， 1984 [7]． Floyd ,Phase lock Techniques(Second Edition),Publication:New York,John Wiley,1979. [8]． Roland ,Phaselocked Loops Design,Simulation and Application,清華大學(xué)出版社， 2020 [9]． 張輝，曹麗娜 .. 現(xiàn)代通信原理與技術(shù) [M]. 西安電子科技大學(xué)出版社， 2020 [10]． 鄭繼禹 , 張厥盛 , 萬心平 . 鎖相技術(shù) [M]. 西安電子科技大學(xué)出版社， 1994 [11] 謝自美 .電子線路綜合設(shè)計(jì) .華中科技大學(xué)出版社 , [12] Best,Roland E.,Phase—Looked Loop Theory,Design and Applications McGRAW—Hill,1984 [13] 沈偉慈 .通信電路 .西安電子科技大學(xué)出版社， 2020 蘭州理工大學(xué)畢業(yè)設(shè)計(jì) 26 附錄： (外文翻譯 ) Bridging the Gap between the Analog and Digital Worlds Most applications require the coexistence of analog and digital functionality, and the benefits of bining this functionality on a single chip are significant. Such mixedsignal integration, however, also presents significant challenges. Furthermore, digital and analog developments tend to evolve at differing rates, yet mixedsignal solutions for markets such as industrial, automotive and medical, must remain available over significant time periods. The latest mixedsignal semiconductor processes are helping to address some of these issues, and this article will look at some of the issues designers should consider when specifying integrated mixedsignal solutions. Mixedsignal solution for the real world System designers often partition the digital portion from the analog section of a given design for a variety of reasons: the availability of mixing ponents for the two technologies, the plexity 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 integration approach is usually difficult for advanced markets such as telemunications or puters, but makes sense for more mature or conservative markets such as automotive, medical and industrial. For most of these mature market’s applications, digital functions are finding their way onto what once were pure analog designs. Adding digital functions to an analog design is helped in part by the development of new process technologies that can handle both shortchannel, fastswitching digital transistors as well as highvoltage analog transistors. For example, AMI Semiconductor’s latest mixedsignal technology offers digital and analog integration capabilities on the same design platform. The I3T technology family is based on standard CMOS 181。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(hào)如下圖 ： 蘭州理工大學(xué)畢業(yè)設(shè)計(jì) 23 圖 C2=100nF時(shí)的波形 蘭州理工大學(xué)畢業(yè)設(shè)計(jì) 24 總結(jié) 該文 分別設(shè)計(jì)了 2ASK、 2PSK、 2FSK 的調(diào)制解調(diào)電路， 其 功能 為數(shù)字基帶信號(hào) 經(jīng)過調(diào)制輸出一個(gè)模擬信號(hào)，然后用鎖相環(huán)進(jìn)行解調(diào)， 最后采用 Multisim軟件進(jìn)行仿真。（ 2）數(shù)字鍵控法：用開關(guān)電路控制輸出調(diào)制信號(hào)，當(dāng)開關(guān)接載波就有信號(hào)輸出，當(dāng)開關(guān)接地就沒信號(hào)輸出，其電路如圖 。 分別表示二進(jìn)制數(shù)字基帶信號(hào)的 1 和 0。壓控振蕩器的電路圖如圖 ： 圖 蘭州理工大學(xué)畢業(yè)設(shè)計(jì) 15 4）抽樣判決電路（ LM311） 工作原理： LM311是當(dāng) 2腳電壓高于 3腳電壓時(shí)輸出高電平，反之則輸出低電平。當(dāng)基帶信號(hào)為 “1” 時(shí)，模擬開關(guān) 1 打開，模擬開關(guān) 2 關(guān)閉，此時(shí)輸出 f1=32KHz，當(dāng)基帶信號(hào)為 “0” 時(shí)，模擬開關(guān) 2 開通。鍵控法產(chǎn)生的 2FSK 信號(hào)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。 2FSK 信號(hào)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。 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 電路如圖 所示 。在進(jìn)行仿真的同時(shí)，軟件還可以存儲(chǔ)測試點(diǎn)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(chǔ)測試儀器的工作狀態(tài)、顯示波形和具體數(shù) 等。在進(jìn)行仿真的過程中還可以存儲(chǔ)測試點(diǎn)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(chǔ)測試儀器的工作狀態(tài)、顯示波形和具體數(shù)據(jù)。 Multisim 10 把所有的元件分成 13 類庫，再加上放置分層模塊、總線、登錄網(wǎng)站共同組成元件工具欄。調(diào)幅波的特點(diǎn)是頻率與載波信號(hào)的頻率相等，幅度隨輸入信號(hào)幅度的變化而變化；調(diào)頻波的特點(diǎn)是幅度與載波信號(hào)的幅度相等，頻率隨輸入信號(hào)幅度的變化而變化；調(diào)相波的特點(diǎn)是幅 度與載波信號(hào)的幅度相等，相位隨輸入信號(hào)幅度的變化而變化?，F(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，多用化方向迅蘭州理工大學(xué)畢業(yè)設(shè)計(jì) 2 速發(fā)展。 研究現(xiàn)狀 鎖相環(huán)解調(diào)技術(shù)的發(fā)展十分迅速，如今已經(jīng)在很多領(lǐng)域都應(yīng)用了鎖相環(huán)解調(diào)的理論。 關(guān)鍵詞： 調(diào)制；解調(diào)； Multisim；鎖相環(huán) 蘭州理工大學(xué)畢業(yè)設(shè)計(jì) II Abstrack There are many ways to realize frequency wave demodulation, and PLL frequency which has the advantages of stable operation, small distortion, high signaltonoise ratio and so on is achieved by using modern PLL frequency technology, so it is widely used in munication circuit system. Phaselocked loop through the difference of the phase detection of input signal and the output signal phase, and the detected phase difference signal into output voltage signal, the signal through a low pass filter. After the formation of the voltage control oscillator , the output signal of the oscillator frequency control. This paper first introduces the present situation, development direction, phaselocked loop technology as well as the background, and the principle 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 the 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 plete the task book mentioned requirements. Keywords： modulate ； modulation ； PLL； Multisim 蘭州理工大學(xué)畢業(yè)設(shè)計(jì) III 目 錄