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毕业设计（论文）课题数调电视伴音接收电路系科电子工程系专业（方向）应用电子技术专业（通信电子方向）班级电子083学号080202322姓名徐文强完成日期2010-12-15指导教师薛继华数调电视伴音接收电路摘要本课题基于电视接收机原理，充分发挥单片机灵活强大的控制功能，制作了一台数调电视伴音接收机。它具有调谐准确、接收信噪比高、操作简便、人机界面友好等优点。本作品由高频调谐器模块、信号处理模块、单片机控制模块、电源模块四部分组成。当轻触键盘向单片机发出接收频道指令时，经程序运算输出数字形式的调谐电压。由D/A转换成模拟调谐电压加到电子调谐器的VT脚，配合频段选择电压的变化实现调谐接收。为实现不同接收环境下的准确调谐，还可以进行调谐电压的微调控制。高频头输出的中频信号（38MHz的图像中频和31.5MHz的伴音中频）在公共通道完成中差拍出6.5MHz的第二伴音中频信号。伴音通道对第二伴音中频信号进行限幅放大与鉴频得到音频信号。最后，经电压放大和功率放大后推动扬声器，还原出悦耳的电视节目声音。关键词：数调；电视伴音；单片机；接收电路；IDigitalTuningTVSoundReceiverAbstractBasedontelevisionreceiverprinciple,adigitaltuningTVsoundreceiverwasproducedbymakingfulluseofMicroControlUnit(MCU).Ithastheadvantagesofaccuratelytuning、highSNR(Signal-to-NoiseRatio)、operationeasy、friendlyman-machineinterface,etc.Thisrecevierwascomposedoffourparts:electronichighfrequencytuner,signalprocessingblock,MCUmoduleandpower.Digitalformoftuningvoltagewasexportedbyoperationprogramme,whencommandswassenttoMCU.UsingD/Aconver,thetuningvoltagewaschangedintoanalogformandsenttotheVTpinofelectronichighfrequencytuner.Combinedwithfrequencybandsselectionvoltagechangestuningwasrealized.Tuningvoltagecanbefinecontrolledwhenreceivingenvironmentchanged.IntermediateFrequency(IF)signals(38MHzvisionIFand31.5MHzsoundIF)wasbeatedinsignalprocessingblock,then6.5MHzsecondsoundIFsignalwasgenerated.Audiosignalwasgeneratedbyfrequencydetectinginsoundchannel.Finally,aftervoltageandpoweramplification,euphonicTVsoundwasrestoredfromspeaker.Keywords：DigitalTuning;TVsound;MicroControlUnit(MCU);Receiver;IIIII目录摘要.................................................................................................................................................................IAbstract.........................................................................................................................................................II目录..........................................................................................................................................................III1方案分析与选择.........................................................................................................................................11．1高频调谐方案的选择...................................................................................................................11.2信号通道芯片的选择.....................................................................................................................21.3单片机控制方案的选择.................................................................................................................31.4显示模块的选择.............................................................................................................................41.5电源模块方案的选择.....................................................................................................................52数调电视伴音接收电路.............................................................................................................................62.1高频调谐器模块............................................................................................................................62.1.1电子调谐器的基本组成....................................................................................................62.1.2电子调谐器与单片机的接口............................................................................................72.1.3电路测试............................................................................................................................72.2信号处理模块................................................................................................................................82.2.1公共通道............................................................................................................................82.2.2伴音通道..........................................................................................................................102.3单片机控制模块..........................................................................................................................132.3.1DAC0832............................................................................................................................132.3.24×4矩阵键盘.................................................................................................................142.3.3液晶显示屏......................................................................................................................152.3.4程序流程图......................................................................................................................152.4电源模块......................................................................................................................................162.4.1主电源电路.......................................................................................................................162.4.2辅助电源电路..................................................................................................................172.4.3电源电路的调试........................................................................................................