單工無線呼叫系統(tǒng)（d題）

1、時間就是金錢，效率就是生命！唯有惜時才能成功，唯有努力方可成就！單工無線呼叫系統(tǒng)（ 單工無線呼叫系統(tǒng)（D 題） 題）摘 要： 要：單工無線呼叫系統(tǒng)分發(fā)射和接收兩大部分。發(fā)射部分采用鎖相環(huán)式頻率合成器技術(shù)， MC145152 和 MC12022 芯片組成鎖相環(huán)，將載波頻率精確鎖定在 35MHz，輸出載波的穩(wěn)定度達到 4×10-5，準確度達到 3×10-5，由變?nèi)荻O管 V149 和集成壓控振蕩器芯片MC1648 實現(xiàn)

2、對載波的調(diào)頻調(diào)制；末級功放選用三極管 2SC1970，使其工作在丙類放大狀態(tài)，提高了放大器的效率，輸出功率達到設(shè)計要求。接收部分以超大規(guī)模 AM/FM 立體聲收音集成芯片 CXA1238S 為主體，靈敏度、鏡像抑制、信噪比等各項性能指標均達到設(shè)計要求；音頻功率放大器采用集成芯片 LM386，電壓放大倍數(shù)最大為 200。采用PT2262/2272 編碼/解碼電路實現(xiàn)了數(shù)據(jù)傳輸業(yè)務(wù)以及對臺號的選擇等功能；音頻輸入和數(shù)據(jù)輸入可自動轉(zhuǎn)換；AT8

3、9S52 作為整個系統(tǒng)的控制部分，程序設(shè)計采用 C 語言在 KEIL51的編譯器上編程實現(xiàn)；顯示采用 128×64 點陣型液晶顯示。經(jīng)測試，整機功能齊全，各項性能指標符合系統(tǒng)要求，接收波形穩(wěn)定，無明顯失真。關(guān)鍵詞： 關(guān)鍵詞： 鎖相環(huán)、壓控振蕩器、靈敏度、編碼/解碼simplex simplex wireless-calling wireless-calling system systemAbstract:The simplex

4、 wireless-calling system consists of two parts: transmit part and receive part.The transmit part adopts the phase-locked loop pattern of frequency synthesizing technology and uses the MC145152 and MC12022 chips to compos

5、e the phase-locked loop.It locks the frequency of the carrier-wave at 35MHz.The stabilization of the carrier-wave can be 4×10-5,the accuracy can be 3×10-5.The frequency modulation and the confection of the carr

6、ier-wave are realized by the capacity-changing diode V149 and the integration voltage-control oscillator MC1648 chip.The end power amplifier uses the audion 2SC1970 to make it work in the third magnifying state,it improv

7、es the efficiency of the magnifier and the power of the output reaches the design demand.The receive part uses the super cosmically AM/FM dimensional sound stereo radio reception integration chip CXA1238S as the main par

8、t.The sensitivity、the mirror-control restrain、the SNR and every capability index all reach the design demand.The audio frequency power amplifier adopts the integration chip LM386.The maximum voltage amplifying multiple

9、is 200.It uses PT2262/2272 coding/decoding circuit to realize the data transmission operation as well as the platform-choosing function.The input of the audio frequency and the data can be automatically transformed. AT89

10、S52 is used as the controlling part of the whole system.The design of the program adopts the C language to make it be programmingly realized in the translator.The display adopts 128×64 lattice LCD to show.After te

11、sted,the whole machine’s function is very complete,every demand can be realized,the receiving wave is stable,without evident distortion.Key word: PLL、 VCO 、 Sensitivity、 Ding/decoding2附錄 附錄 2 主要元器件清單 主要元器件清單 ...