成都信息工程学院学位论文电视RF-AV转换电路的设计电视RF-AV转换电路的设计摘要本文介绍了将电视射频信号转换为音视频信号的工作原理。利用TDQ-3型全增补调谐器、声表面滤波器、中频处理芯片TA7680AP和LM386集成运算放大器设计了一个电视RF-AV转换电路。天线接收的空间电视RF信号输入高频调谐器，经高频滤波、放大、调谐、变频等电路处理后，将电视RF信号转换成38MHz第一中频信号，第一中频信号由声表面滤波器进行残留边带滤波后送入中频处理芯片TA7680AP，最后经检波、解调后输出音视频信号。设计的RF-AV转换电路接收频率范围45MHz～860MHz，输出视频1VP-P，阻抗75Ω，音频输出0dbm，阻抗600Ω，具有自动增益控制（AGC）和自动频率微调（AFT）功能。给出了电视RF-AV转换电路、DC32V和DC12V供电电源的电路设计原理图，完成了样机PCB板的设计，制作了样机并对样机进行了调试和检测。关键词：射频；调谐器；声表面滤波器；TA7680；中频处理ThedesignoftheradiofrequencyconvertingtotheaudiofrequencyandthevideofrequencyAbstractThispaperintroducestheprincipleoftheradiofrequencyconvertingtotheaudiofrequencyandthevideofrequency.ThecircuitofRF-AVConversionhasbeendesignedusingalladdedtunerTDQ-3,surfaceacousticwavefilter,IFTA7680APchipandIntegratedOperationalAmplifierLM386.SpacetelevisionRFsignalreceivedbyantennaisinputtedintohigh-frequencyturner.Afterhighfrequencyfilter,amplification,Tuner,frequencyconversionandsoonelectriccircuitprocessing,televisionRFsignaltransformsintothefirstintermediatefrequencysignalwhosefrequencyis38MHz.thefirstintermediatefrequencysignalwhichCarriesonthevestigalsidebandfilterbythesoundsurfacefilter,Then,sentthemintoIFTA7680APchip,thelastbythedetector,theoutputaudioandvideopost-demodulationsignal.ThedesignofRF-AVconversioncircuittoreceivethefrequencyrange45MHz~860MHz,Videooutput1VP-P,Impedance75Ω,theaudiofrequencyoutputs0dbm,theimpedance600Ω,Withtheautomaticgaincontrol(AGC)andAutomaticfrequencycontrol(AFT)function.ThecircuitofRF-AVConversionandDCregulatedpowersupplythattheoutputis12Vandthe32VhavebeengiventhedesignschematicandPCBdiagram,Themanufactureofthesampleproduct.Then,debuggedandtestedthissystem.Keywords:radiofrequency;highfrequencytuner;surfaceacousticwavefilter;TA7680;Intermediatefrequencyprocessing目录论文总页数：18页TOC\o"1-3"\h\z\uHYPERLINK\l"_Toc231523808"1引言PAGEREF_Toc231523808\h1HYPERLINK\l"_Toc231523809"2电路设计基本原理和方案PAGEREF_Toc231523809\h1HYPERLINK\l"_Toc231523810"2.1RF-AV转换电路设计的原理PAGEREF_To