本科毕业设计说明书小功率调频发射机研究DESIGNOFLITTLEPOWERFMTRANSMITTER学院（部）：通信工程专业班级：通信10-1班学生姓名：江传民指导教师：钟鸣宇讲师2014年5月20日安徽理工大学毕业设计I小功率调频发射机摘要本设计为小功率调频发射机，其实就是一个小型电台，可以将声音加载到无线电信号上发射出去,用合适的收音机就能接收，并且可以从扬声器中放出声音。本次设计的发射机由由三部分构成：调频振荡级、缓冲隔离级、功率激励和末级功放级。其基本工作原理是通过振荡级产生稳定的5MHz信号，麦克风采集到人的音频信号，将音频信号加载到5MHz的载波上，通过缓冲隔离级使末级功放和前一级的调频振荡相分开,避免末级功放对振动频率产生影响，提高频率稳定度,功率增益如果都集中在末级功放容易产生自激，故先通过功率激励级对信号的微弱电压进行放大，末级功放一般工作在丙类状态,工作效率ηA大于50%，信号功率大于500mW。关键词:发射机，调频，无线话筒，小功率安徽理工大学毕业设计IILOWPOWERFMTRANSMITTERABSTRACTThedesignforthelowpowerFMtransmitter,isinfactasmallradiostation,voicecanbeloadedintothelaunchoutradiosignals,useasuitableradiocanreceive,andcanemitsoundfromthespeaker.Thedesignofthetransmitterbyconsistsofthreeparts:FMoscillation,cushioningisolationlevels,powerdriveandattheendofthepoweramplifier.Itsbasicworkingprincipleisthroughtheoscillationmagnitude5MHZsignalstability,themicrophonetotheaudiosignal,theaudiosignalisloadedonthecarrierto5MHZ,throughbufferisolationlevelthelevelattheendofthepoweramplifierandtheformerseparatefromprimaryfrequencymodulationoftheoscillation,avoidthelaststageamplifierinfluenceonthevibrationfrequency,toimprovethefrequencystability,powergainifareconcentratedinthelaststageamplifieriseasytoproduceself-excited,sothefirstoftheweakvoltagesignalthroughthepowerstageofamplification,thelaststageamplifiergenerallyworkincclassstatus,theefficiencyetaAgreaterthan50%,signalpowerisgreaterthan500mw,finallywillsignaltheantennatolaunchout.KEYWORDS:transmitter;FM,wirelessmicrophone;lowpower安徽理工大学毕业设计i目录摘要（中文）........................................................IABSTRACT（英文）...................................................II1绪论..............................................................11.1FM发射机的概念..............................................11.2FM发射机的现状..............................................21.3设计技术指标................................................32总体方案设计......................................................52.1调频振荡级...................................................52.2缓冲级.......................................................52.3功率激励和末级功放级.........................................52.2整机电路框图.................................................63单元电路设计......................................................73.1功率激励和末级功放设计......................................73.1.1末级功放级.............................................73.1.2功率激励级.............................................83.1.3末级功放电路参数计算...................................93.1.4功率激励级电路参数计算................................123.2缓冲隔离级..................................................153.2.1缓冲隔离级电路原理....................................153.2.2静态工作点的计算......................................153.3调频振荡级..................................................173.3.1调频的方案分析与选择..................................173.3.2变容二极管相关特性.........
