单工无线发射接受系统毕业设计内容摘要.doc

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1、单工无线发射接收系统摘要: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。设计中采用了分立元件构成音频无线发射电路。接收机采用第三代立体声放收音机电路CXA1238组成的单片收音机，外围元件极少。它在片内完成了混频、中放、鉴频及立体声解码等功能，接收机采用电容分压式滤波器，即可提高镜像抑制比，又可使天线达到最佳匹配，具有动态范围大，调整方便的特点。本设计使用模拟调频技术，在32MHz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和接收。系统发射功

2、率大约20mW，发射距离大于5m，本系统可实现无明显失真的语音传输。关键词：单工无线调频语音传输CXA1238SimplexwirelessemissiveandReceivingsystemAbstract：Theremoteaudiotransmissionservicecodethroughwirelesscommunicationchannelsisafastdevelopingtechnologyinrecentyears.Astheaudioservicecodeisnotsensitivetothemista

3、kencode,thefrequencymodulationcanbeusedtosendinformation.Theseparatecomponentswasadoptedtoconsistaudio-frequencywirelessemissivecircuitinthedesign.ThethirdgenerationstereoradiocircuitCXA1238whichconstitutesthesinglechipradiowasusedinthereceiver,sotheperipheralcomp

4、onentsareveryfew.Thefunctionsuchasfrequencymixing,supersonicamplification,frequencydiscriminationandstereodecodingcanbeachievedinthechip.Theelectricfilterwhichwasbasedonthecapacitancepotentiometerwasadoptedinthereceiver.Thiskindoffiltercanbothraisethemirror-imager

5、epressionratioandmaketheantennaattainitsbestmatch.Thetwocharacteristicsofitarelargedynamicandconvenientadjustment.Thesimulatingfrequencymodulationtechniquewasadoptedinthedesign.Inthefrequencyintervalof32MHz,theaudiosignalscanbesentoutandreceivedwiththesmallpowerin

6、alongdistance.Theemissivepowerofthesystemisabout20mWandtheemissivedistanceismorethan5m.Thereisnoobviousdistortionintheaudiotransmission.Keywords:simplexwirelessfrequencymodulationaudiotransmissionCXA1238