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TianjinUniversityofTechnologyandEducation毕业设计专业：通信工程班级学号：通信0303–17学生姓名：华夏指导教师：白云高级工程师二〇〇七年六月天津工程师范学院本科生毕业设计无线调频发射器的设计TheDesignofWirelessFrequencyModulationTransmitter专业班级：通班学生姓名：华夏指导教师：蓝云高级工程师系别：电子工程系2007年6月摘要利用无线通信信道的远距离语音传输业务，是近年来发展很快的一门技术。由于语音业务对误码不敏感，可以采用调频方式发送信息。调频发射器可以使音频信息传送到附近的任意FM接收机。本设计中使用AT89S52控制调频发射的频率，选择了数码管显示发射的频率状态。选择了ROHMBH1415F集成电路产生调频调制发射信号的频率。芯片的主要特征:体积小，准确性高，而且容易产生发射频率。这个系统的各个部分可以进行深入的独立设计研究，现在把它们组合成一个典型的调频发射系统。本设计使用模拟调频技术，在88MHz--98MHz的频段上，实现了线路输入语音信号的小功率远距离单工发送。系统发射功率大约20mW，发射距离大于20m，本系统可实现无明显失真的语音传输。关键词：调频；语音传输；ROHMBH1415ABSTRACTTheremoteaudioservicecodethroughwirelesscommunicationchannelsisafastdevelopingtechnologyinrecentyears.Astheaudioservicecodeisnotsensitivetothemistakencode,thefrequencymodulationcanbeusedtosendinformation.TheFMTransmitterwillallowalmostanyaudiosourcetobetransmittedtoanynearbyFMreceiver.TheAT89S52tobeusedtocontrolthetransmissionfrequency.TheLEDwaschosen,providingenoughspaceforalloutputsituations.TheROHMBH1415Fintegratedcircuitwaschosentocreatethefrequencymodulatedaudiooutputsignal.Chipfeaturesinclude:smallsize,accuracy,andeasilyprogrammedtransmissionfrequency.ThesesystemcomponentshavebeenthoroughlyresearchedseparatelyandarenowintheprocessofbeingintegratedtoproduceaworkingprototypeFMTransmitter.Thesimulatingfrequencymodulationtechniquewasadoptedinthedesign.Inthefrequencyintervalof88MHz---98MHz,theaudiosignalscanbesentoutandreceivedwiththesmallpowerinalongdistance.Theemissivepowerofthesystemisabout20mWandtheemissivedistanceismorethan20m.Thereisnoobviousdistortionintheaudiotransmission.KeyWords：frequencymodulation；audiotransmission；ROHMBH1415FI目录1引言..............................................................................................................................11.1通信的发展.......................................................................................................11.2广播的发展现状...............................................................................................11.3设计思路...........................................................................................................22系统概述.......................................................................................................................32.1系统功能要求...................................................................................................32.2系统组成............................................................................................................33方案论证与比较..........................................................................................................53.1无线调频发射电路设计方案论证与选择.......................................................53.2压控振荡器方案论证与选择...........................................................................64系统硬件电路的设计..................................................................................................74.1单片机控制电路...............................................................................................74.1.1内部结构................................................................................................74.1.2引脚功能................................................................................................94.2调频调制发射电路.........................................................................................114.2.1调频调制电路的特点..........................................................................114.2.2结构图..................................................................................................114.2.3允许的最大值......................................................................................124.2.4工作范围..............................................................................................124.2.5调频调制发射电路的组成..................................................................124.3键盘部分.........................................................................................................144.3.1单片机键盘和键盘接口概述..............................................................144.3.2单片机键盘接口和键功能的实现......................................................154.4LC振荡电路..................................................................................................164.5调频放大电路.................................................................................................174.6电源模块设计.................................................................................................174.6.1单元电源电路设计..............................................................................174.6.2直流稳压电源的检测..........................................................................175系统程序的设计........................................................................................................18II5.1主程序.............................................................................................................185.2延时子程序.....................................................................................................195.3LED动态扫描子程序......................................................................................195.4频率数据转换子程序.......................................