[毕业论文]51系列单片机实现ad9850_dds信号源的研制

A1A0A2A3A4A5A6A8A7A7A9A11A10A12A13A14A4A15A16A17A181目录摘要3第一章方案论证411系统框图412系统模块4121主控制器4122正弦信号的产生7123电压放大10第二章系统硬件设计1021硬件系统总体框图1022硬件模块设计11221正弦信号产生模块11222带负载输出13223DDS技术的实现14224键盘显示15第三章系统软件设计1631初始化98501732初始化LCD1833初始化PIC16F877程序1934AD9850控制字的写入20A19A20A21A22A23A24A25A26A27A27A28A29A30A31A32A33A23A34A35A36A37235键盘扫描显示2136LCD显示24总结26参考文献27致谢28A19A20A21A22A23A24A25A26A27A27A28A29A30A31A32A33A23A34A35A36A373摘要A30系统设计一个正弦信号发生器。，使用PIC16F877单片机作为中央控制器，PIC（PERIPHERALINTERFACECONTROLLER）是一种用来开发的去控制外围设备的集成电路（IC）。一种具有分散作用（多任务）功能的CPU。它的最高操作频率大约都在20MHZ左右，存储器容量用做写程序的大约1K4K字节。传统的频率合成器，通常从一排晶振荡器产生的各种频率通过开关进行频率混合。也有的采用众所周知的锁相环G11PG47G47G12G1935G3308G3244G3747频率合成。G3387G4482G3316字G1935G3308的G1478G3374发G4282，用G3316字控制G1466G1445从一个G1013G2217频率G4183产生多种频率，G1927G4368G2052G3316字合成G1935G3308G11G39G39G54G12G4051G2187G3532G2927。G903设计使用G3255G2072G2464行的G2597G1715G36G39IG1636G3347生产的G36G39G288G240频率合成器正是G4075用G4323种G39G39G54G1935G3308的G1317G3832G3075G2602产G2870G4365一，G36G39G288G240采用G3733G1305G1853CMG50G54G1629G4028，G2915功G1755在G22G17G22G57G1634电G3240G2087为1G24G24G80G58，G2292G4282G1629G3996G1929G3633G1383G1459围为G1640G10880G167，采用28G2038G54G54G50PG950G2635G1503G4461G3833G3252，G2066合G39G39G54G3817片G36G39G288G240，产生0G1081G24MHZ频率G2230G1336的正弦信号G290G1336制信号为1KHZ的正弦G975，G1336制信号的产生采用G39G39G54G1935G3308G290系统采用G3046中G3635G1010单操作G1466G3252，操作G1989单，G2265G2062，G2991系统的G2106G1383G1764G3639G1351G3839高。关键字正弦信号PIC16F877G36G39G288G240G39G39G54G1935G3308ABSTRACTTHESYSTEMDESIGNASINESIGNALGENERATORUSINGPIC16F877MICROCHIPASACENTRALCONTROLLER,PICPERIPHERALINTERFACECONTROLLERISTHEMETHODWHICHUSEDTOCONTROLPERIPHERALSDEVELOPMENTOFINTEGRATEDCIRCUITSICACPUWITHSCATTEREDMULTITASKFUNCTIONITSMAXIMUMOPERATINGFREQUENCYIS20MHZAPPROXIMATELYABOUTTHEMEMORYCAPACITYOFTHEPROCEDURESUSEDTOWRITEABOUT1K4KBYTESTHETRADITIONALFREQUENCYSYNTHESIZERS,USUALLYFORMAROWOFCRYSTALOSCILLATORFREQUENCYBYSWITCHINGFROMAVARIETYOFFREQUENCYMIXEDSOMEUSEDTHEWELLKNOWNPLLTECHNOLOGYTOACHIEVEFREQUENCYSYNTHETICWITHTHERAPIDDEVELOPMENTOFDIGITALTECHNOLOGY,USINGDIGITALCONTROLMETHODSFORMAVARIETYOFSOURCESINAFREQUENCYREFERENCEFREQUENCY,DIRECTDIGITALSYNTHESISTECHNIQUESDDSSUDDENAPPEARANCEASANEWWAYTHEDESIGNUSETHEPOPULARAMERICANADICMOPANYSPRODUCTIONAD9850FREQUENCYSYNTHESIZERSDDSTECHNOLOGYISTHEAPPLICATIONOFTHISPOPULARPRODUCTSTYPICALLYAD9850USEDTOCONTROLCMOSFIRST,THEPOWERLOSSISONLY155MWAT33VSUPPLY,THEEXPANSIONOFINDUSTRIALGRADETEMPERATURERANGEFOR4080DEGREES,28FEETSSOPSURFACEPACKAGINGUSEDFORMOFDDSCHIPAD9850,A015MHZFREQUENCYCOMMUNICATIONSSIGNALSTOTHENEIGHBORINGLETTERPREPARATIONOFTHESINUSOIDALWAVE1KHZ,AMODEMSIGNALSUSEDDDSTECHNOLOGYCHINESEMENUSYSTEMUSEDTHROUGHOUTTHEOPERATION,THEOPERATIONSIMPLE,FASTANDHIGHSYSTEMACCURACYANDSTABILITYKEYWORDSSINESIGNAL；PIC16F877；AD9850；DDSTECHNOLOGYA38A39A40A41A42A43A44A45A46A46A47A48A49A50A51A52A42A53A54A55A564第一章方案论证11系统框图根据题目要求，本系统主要由主控制器模块、正弦信号发生模块、输出电压放大模块、人机界面模块构成如图A57A58A59A58A60A61A62A5712系统模块121主控制器方案一采用通用的51单片机AT89S52作为主控制器，完成数据处理，DDS的频率输出控制，键盘的扫描及液晶显示器的显示控制等。由于51单片机内部的RAM和ROM都比较小，考虑到实现本系统需要大量的数据处理及液晶显示需占用大量的ROM资源等，用51单片机实现本系统就需外扩RAM和ROM，实现起来比较麻烦。而且本系统需要用A/D转换器采样调制信号实现调频信号的输出，使用51单片机就需外扩一片A/D转换芯片，实现也比较麻烦。而且基于整个系统的速度要求，51单片机也不能满足要求。方案二G51G44G38G708G51G72G85G76G83G75G72G85G68G79G44G81G87G72G85G73G68G70G72G38G82G81G87G85G82G79G79G72G85G709G7171一G12193用来G5332发的G2447控制外G3272G16786A63A64A65A66A67A68A69A70A71A72PIC16F877A73A74A64A75A76A77A78A79A80A71A72A81A82A83A84A85A86A71A72AD9850A75A87015MHZA81A82A88A89A90A91A92A93A94A95A96A97A97A98A99A100A101A86A102A93A103A104A105A1065G3803的G19610成电G17347G708G44G38G709G17G4439G1216的G7380G20652G6817作频率大G13434都G33242G19MG43G93G5050G2503，G4396G1660器G4493量用G1582G1901G12255G5219的大G134341G46G252G23G46G4395G14422。G5647G13459G7171G20652G5627能G4628部G5647G13459，G5049作频率G19G794G22G22MG43G93，G2499G2528G7114G6915G6357G3822G13464外G3272G16786G3803。G51G44G381G25G418G26G26G7171一G8466基于G40G51ROM的8G1313G20652G5627能G5506控制器。G994G1866G4439G1227G7696G11468G5415的G5506控制器G11468比，G4439G3324G6203G15904速度和G1207G11733压G13565方面都G7389G5468大的G6925G17839。G51G44G381G25G418G26G26G5506控制器G6164G1867G7389的G1260G17246G5627能主要G5414G2163于G4439的G12946G12628G6363G1208G19610G708RG44SG38G709和G6164采用的G2716G1327G708G43G68G85G89G68G85G71G709G13479构，G4439G1867G7389G2010G12175的G12255G5219G1660器G12366G19400G70812G1313G4497G6363G1208G709和数据G4396G1660器G12366G19400G7088G1313G4497数据G709。G2528G7114G2499G17828用G1016G13435G8981G8712G13459G6363G1208G17839G15904G2474数和G6203G15904，G19512G1114G17351转G6363G1208需要G1016个G2620G7411外，G1866G1325G6164G7389的G6363G1208都G2499G3324单G2620G7411内G6203G15904G17G1866G1260G2195为1G12G51G44G38G7380大的G10317G9869G7171不G6642单G13443的G2163能G3546G12227，而G7171从实际出发，重视产品的G5627能G994G1227G7696比，靠发展G3822G12193型号来满足不G2528层次的应用要求。就实际而言，不G2528的应用对单片机G2163能和资源的需求也G7171不G2528的。G51G44G38系列从低到G20652G7389几十个型号，按照G6363G1208的G1313数G2499以G2010为G22类初G13435产品，中极产品，G20652G13435产品。G2499以满足各G12193需要。G51G44G381G25G418G26G26G7389G23G19个引脚，G1866内部资源为ROM共G23G46、192G4395G14422RAM、8G17347A/D、G22个8G1313定G7114器、2个G38G38G51模块、三个串G15904口、1个并G15904口、11个中断源、G22G22个G44/O脚。2G12G12946G12628G6363G1208使G1866G6203G15904效率大为提G20652。G51G44G38系列8G1313G38MOS单片机G1867G7389独G10317的RG44SG38G13479构，数据G5647G13459和G6363G1208G5647G13459G2010G12175的G2716G1327G5647G13459G708G43G68G85G89G68G85G71G709G13479构，使G6363G1208G1867G7389单G4395长的G10317G5627，且允许G6363G1208G11733的G1313数G2499G3822于8G1313的数据G1313数，这G994传统的采用G38G44SG38G13479构的8G1313单片机G11468比，G2499以达到21的G1207G11733压G13565，速度提G20652G23倍。G22G12产品上市零等待G708ZG72G85G82G87G76MG72G87G82MG68G85KG72G87G709。采用G51G44G38的低G1227OTG51型芯片，G2499使单片机G3324G1866应用G12255G5219G5332发完成后立刻使该产品上市。G23G12G51G44G38G7389G1260G17246G5332发环境。OTG51单片机G5332发系统的实G7114G5627G7171一个重要的G6363标，象普通51单片机的G5332发系统大都采用G20652档型号仿真低档型号，G1866实G7114G5627不尽理想。G51G44G38G3324推出一G8466新型号的G2528G7114推出G11468应的仿真芯片，G6164G7389的G5332发系统由专用的仿真芯片G6915G6357，实G7114G5627非常好。就我个人的经验看，还没G7389出现过仿真G13479果G994实际G17828G15904G13479果不G2528的情况。5G12G1866引脚G1867G7389防瞬态能力,通过限G8981电阻G2499以接至22G19V交G8981电源,G2499直接G994继电器控制电G17347G11468连,无须光电耦合器隔G12175，给应用带来极大方便。A89A90A91A92A93A94A95A96A97A97A98A99A100A101A86A102A93A103A104A105A1066G25G12彻底的保密G5627。G51G44G38以保密熔丝来保护G1207G11733，用户G3324烧入G1207G11733后熔断熔丝，别人再也无法读出，G19512非恢复熔丝。目前，G51G44G38采用熔丝深埋G5049艺，恢复熔丝的G2499能G5627极小。G26G12自带看门G10411定G7114器，G2499以用来提G20652G12255G5219G17828G15904的G2499靠G5627。8G12G11573G11508和低G2163G13803模G5347。G15441G9994G51G44G38G3324这方面G5062不能G994新型的TG44G713MSG51G23G22G19G11468比，G1306G3324大G3822数应用G3342合还G7171能满足需要的。MG76G70G85G82G70G75G76G83G1856G2508生产的G51G44G381G25G418G26G26G7171一G8466基于G40G51ROM的8G1313G20652G5627能G5506控制器。G994G1866G4439G1227G7696G11468G5415的G5506控制器G11468比，G4439G3324G6203G15904速度和G1207G11733压G13565方面都G7389G5468大的G6925G17839。由于G19555G7114G2499以G1092到需要的OG51TG708一次G5627G13546G12255G709产品，G3252而G13565G11713G1114G2045用G51G44G381G25G418G26G26G17839G15904产品G16786G16757G5332发的G2620G7411。G51G44G381G25G418G26G26G5506控制器G6164G1867G7389的G1260G17246G5627能主要G5414G2163于G4439的G12946G12628G6363G1208G19610G708RG44SG38G709和G6164采用的G2716G1327G708G43G68G85G89G68G85G71G709G13479构，G4439G1867G7389G2010G12175的G12255G5219G1660器G12366G19400G70812G1313G4497G6363G1208G709和数据G4396G1660器G12366G19400G7088G1313G4497数据G709。G2528G7114G2499G17828用G1016G13435G8981G8712G13459G6363G1208G17839G15904G2474数和G6203G15904，G19512G1114G17351转G6363G1208需要G1016个G2620G7411外，G1866G1325G6164G7389的G6363G1208都G2499G3324单G2620G7411内G6203G15904。A57A58A59A96A107A108A109A58A98A110A111A112A112A113A114A57本G16786G16757采用方案二，作为主控制器。A89A90A91A92A93A94A95A96A97A97A98A99A100A101A86A102A93A103A104A105A1067122正弦信号产生方案一采用G2465G20316型G47G38G6403G14645G2419理，G17885G6333合G17878的电G4493、电G5875就能产生G11468应的正弦信号。G8504方案器G1226比较G12628单，G1306G7171G19602以达到G20652G12946度的G12255控调G14422，而且G12295定度不G20652，G6937不采用。方案二采用DDSG6228G7427的基本G2419理。DDSG6228G7427G7171基于G49G92G84G88G76G86G87采样定理，G4570模G6323信号G17839G15904采G19610，经量G2282后G4396入G4396G1660器中G708G7609G6226G15932G709，通过G38G51G47DG6122G13785G41G51G42AG17839G15904G4559G3348G7609G15932输出G8886G5430的数据，再经D/A转换G9400G8886G2375G2499恢复G2419G8886G5430。根据G49G92G84G88G76G86G87采样定理G11705，要使信号能G3827恢复，G5529须满足采样频率大于G15999采样信号G7380G20652频率的2倍，G2554G2029G4570产生G9163G2484，经D/A不能恢复G2419信号。G8504方案产生的G8886G5430比较G12295定，G3324G20652频输出G7114G1262产生G3845真，而且电G17347比较复G7446，G6937不采用。方案三直接采用DDSG19610成芯片。AD985G19G7171ADG1856G2508生产的DDS芯片，带并G15904和串G15904G2164G17745方G5347，AD985G19内G2559G2499G13546G12255DDS系统和G20652速比较器,能实现G1852数G4395G13546G12255控制的频率合成。采用G1820G17839的DDSG6228G7427G3324内部G19610成G1114G222G1313G11468G1313G13059G2164器，1G23G1313正/G17139G1325弦和G20652G5627G5627能的1G19G1313D/A转换器以及G20652速比较器。G4439通过并口和串口的频率控制G4395来G16786定G11468应的G13059G2164器的G8505长大小，G11468G1313G13059G2164器的输出数G4395G11468G1313通过G7609G15932G5483到G6164需的频率信号的采样G1552。G9994后通过转换，输出G6164需频率的正弦输出信号的频率。由于DDSG19610成芯片能达到要求，而且G14422G11477G11840G1226电G17347，G12255控调G14422能G3827方便实现。AD985G19的G5049作G2419理为A57A58A59A115A116A117A92A118A119A120串G15904输入方G5347如图G23G6164示，G3324G58G38G47G46的上G2331G8851，G23G19G1313数据由低G1313到G20652G1313G1393次从引脚25G11DG26G12G12239入到输入G4504G4396器，并G3324G41G52G66G56D的G14045G1926作用G991，一次G5627G6183入到数据G4504G4396器，以G7368新的输出频率G11G6122G11468G1313G12。A57A58A59A121A122A117A92A118A119A120A89A90A91A92A93A94A95A96A97A97A98A99A100A101A86A102A93A103A104A105A1068AD985G19主要G5049作G5627能G111G12单电源G5049作G14G22G17G22VG6122G145V。G112G12接口G12628单，G2499用8G1313并G15904口G6122串G15904口直接G16025G17745频率和G11468G1313调制数据。G11G22G12片内G7389G20652G5627能D/A转换器和G20652速比较器，G2499输出正弦G8886和方G8886。G11G23G12G7380G20652G5049作G7114G19059125MG43G93，G222G1313频率控制G4395保G16789G3324125MG43G93的G5049作G7114G19059G991频率G2010G17788率达G19G17G19291G43G93。G115G125G1313调G11468控制G4395，G2499实现G11468G1313调制G2163能。G11G25G12频率转换速率极G5567，G2499达2G17G22G1041G19G26次/G12198。G11G26G12低G2163G13803G3324125MG43G93G7114G19059频率、G145V电源G5049作G7114，G2163G13803为G228G19MG58；11G19MG43G93G7114G19059、G14G22G17G22G89G5049作G7114，G2163G13803为155MG58。G118G12G5049作G9213度G14551G3272G4497G16G23G19G263G794G1485G263。图1G16G25引脚G2163能DG19G252DG268G1313数据输入口，G2499G2010次并G15904转G17745G23G19G1313控制数据，DG26G708G1254425G19脚G709也G2499以作为串G15904数据输入G12483使用；A89A90A91A92A93A94A95A96A97A97A98A99A100A101A86A102A93A103A104A105A1069DG40G49D数G4395G3332；DVDD数G4395电源；G58G38G44G46数G4395G1901入G14045G1926；G41G52G16G56D频率G2059新G2163能信号；G38G47G46G44G49外部G2454考G7114G19059输入，G2499以G7171G38MOS电G4388的G14045G1926G5219列G30AG42G49D模G6323电源；RG40STDA输出电G8981的G1114控制电阻连接G12483，通常接一G2494G22G179G46G8443的电阻到G3332；G52OG56T内部比较器输出G12483；G52OG56TG37内部比较器G1126G15929输出G12483；VG44G49G49内部比较器的G17139G11468输入G12483；VG44G49G51内部比较器的正G11468输入G12483；DAG38G37G47内部的G7061G17347G12483，通常G5760G12366；G44OG56TG37DA的G1126G15929输出G12483；本G16786G16757采用方案三，作为G19G7941G19MG43G93正弦信号发生。123输出电压放大方案一采用G20652频三极G12661G1582G2163率放大。G17885G6333G5700G5415的电阻和电G4493来实现G12538合题目要求的放大倍数。G1306G7171使用三极G12661放大G7114，信号放大的G12295定G5627不G20652，G5468G19602满足题目的要求。G6937不采用。方案二采用G4497频G17828G12651放大器G1582前G13435电压放大，AD8G195G25G2499以达到G22G19G19M的带G4497，而且频率G12295定G5627好。G6164以G3324本G16786G16757中采用G1114方案二。A89A90A91A92A93A94A95A96A97A97A98A99A100A101A86A102A93A103A104A105A10610第二章硬件设计21系统的总体框图如图根据上面的G16782G16789，本系统以G51G44G381G25G418G26G26单片机为G7692心，配合DDS专用芯片AD985G19，完成正弦信号的产生，并辅以各个G2163能模块完成题目的G16786G16757要求。A123A124A125A126A127A128A129A130A131A123D31D22D13D04V6WLCK7FQ_UD8CLKIN9GND10V11RSET12QOUT13QOUTB14IN15IN16DACBL17V18IOUTB20IOUT21RST22V23GND5D7/LOAD25D626D527D428GND19GND24UAD9850VCCRRES23K98714Y66MVCCP34P32P14RD019RD120RD221RD322RD427RD528RD629RD730MCLR/VPP1RB033RB134RB235RB336RB437RB538RB639RB740RA02RA13UPIC16F877VDD1VSS2V03RES4E15E26R/W7A08D09D110D211D312D413D514D615D716SLA17SLK18LCDVCCR2KR250OC1C111D31Q22D42Q53D73Q64D84Q95D135Q126D146Q157D177Q168D188Q19U74LS373R4K7VCCA123A124A132A124A127A128A133A134A1231X5A135A136LCDA137A138A13916F877PICA140A141A142DDSAD98501K15KHZA143A144A145A146A147A148A145A149A150A151A152A153A154A155A156A157A158A159A124A160A160A161A162A163A164A165A166A157A167A168A169A1701122硬件模块设计221正弦信号产生模块正弦信号产生模块的主要部G2010G7171AD985G19。AD985G19采用G1820G17839的G38MOSG5049艺,G1866G2163G13803G3324G22G17G22V供电G7114仅为155MG58,G9213度G14551G3272为G16G23G19G7948G19G263,采用28脚SSOG51G15932面封G16025G5430G5347。图2G17G22为G1866G13464成框图。图中层虚G13459内G7171一个完整的G2499G13546G12255DDS系统,外层虚G13459内包G2559G1114AD985G19的主要G13464成部G2010。AD985G19内G2559G2499G13546G12255DDS系统和G20652速比较器,能实现G1852数G4395G13546G12255控制的频率合成。G2499G13546G12255DDS系统的G7692心G7171G11468G1313G13059G2164器,G4439由一个G2164法器和一个G49G1313G11468G1313G4504G4396器G13464成，G49为G222；每来一个外部G2454考G7114G19059,G11468G1313G4504G4396器便以G8505长M递G2164；G11468G1313G4504G4396器的输出G994G11468G1313控制G4395G11468G2164后G2499输入到正弦G7609询G15932G3332G3348上；正弦G7609询G15932包G2559一个正弦G8886G2620G7411的数G4395幅度信息,每一个G3332G3348对应正弦G8886中G19G794G22G25G19G14551G3272的一个G11468G1313G9869；G7609询G15932把输入G3332G3348的G11468G1313信息映射成正弦G8886幅度信号,G9994后驱动DAG38以输出模G6323量。A123A124A125A171A172A173A174A175A176A160A177A178A131A123G11468G1313G4504G4396器每过2G49/M个外部G2454考G7114G19059后返回到初始状态一次,G11468应G3332正弦G7609询G15932每经过一个循环也回到初始G1313置,从而使整个DDS系统输出一个正弦G8886。输出的正弦G8886G2620G7411TOTG702G49/M，频率G73G82G88G87MG73G70/2G49，TG70、G73G70G2010别为外部G2454考G7114G19059的G2620G7411和频率。AD985G19采用G222G1313的G11468G1313G13059G2164器G4570信号截断成1G23G1313输入到正弦G7609询G15932,G7609询G15932的输出再G15999截断成1G19G1313后输入到DAG38，DAG38输出G1016个G1126G15929的电G8981。DAG38满量G12255输出电G8981通过一个外接电阻RSG40T调G14422,AD985G19G12946密G7114G19059源和G1901入频率G11468G1313控制G4395之后就G2499产生一个频率和G11468G1313都G2499A153A154A155A156A157A158A159A124A160A160A161A162A163A164A165A166A157A167A168A169A17012G13546G12255控制的模G6323正弦G8886输出,G8504正弦G8886G2499直接用作频率信号源G6122经内部的G20652速比较器转换为方G8886输出。G3324125MG43G93的G7114G19059G991,G222G1313的频率控制G4395G2499使AD985G19的输出频率G2010G17788率达G19G17G19291G43G93；并G1867G73895G1313G11468G1313控制G1313,而且允许G11468G1313按增量18G19、9G19,G235,22G175,11G1725G6122这些G4395的G13464合G17839G15904调整。A123A124A125A179A172A173A174A175A176A160A180A181A12325AD9850A182A183A123A153A154A155A156A157A158A159A124A160A160A161A162A163A164A165A166A157A167A168A169A17013D04D13D22D31D428D527D626D725RSET12FQUD8WCLK7RD019RD120RD221RD322RD427RD528RD629RD730MCLR/VPP1RA02RA13A12326AD9850A184PIC16F877A133A134A182A183222带负载输出要达到G25V1V的带G17139G17745输出，我G1216G1820使用G4497频G17828放AD8G195G25G1582前G13435放大，为G1114达到合G17878的电压增益，我G1216使用G1114G1016G13435放大切换，G6925变放大的G13435数以便G17878应增益要求；经G17828放输出的电压电G8981较弱，带G17139G17745能力不强，G6164以输出G12483接上G11145G19电阻，输出幅度能达到G16786G16757的要求。A123A124A125A185A186A187A188A189A153A154A155A156A157A158A159A124A160A160A161A162A163A164A165A166A157A167A168A169A17014223正弦调制信号的产生1K正弦调制信号的产生采用DDSG6228G7427。DDSG6228G7427采用G1852数G4395G6228G7427实现频率合成，和G1866G4439一般的频率合成G6228G7427G11468比，G7389一些突出的G1260G9869和独G10317的G5627能DDSG3324G11468对带G4497、频率转换G7114G19400、频率G2010G17788率、G11468G1313连续G5627、正交输出以及G19610成G2282等一系列G5627能G6363标方面远远超过G1114传统频率合成G6228G7427G6164能达到的G8712平。DDS的实现G2419理如G991图G6164示A123A124A125A175A173A173A190A191A192A193A194A195DDSG6228G7427的实现G1393赖于G20652速、G20652G5627能的数G4395器G1226。G2499G13546G12255逻辑器G1226以G1866速度G20652、规模大、G2499G13546G12255，以及G7389强大G40DA软G1226G6915G6357等G10317G5627，十G2010G17878合实现频率的合成。由于本系统要求产生1G46G43G93的正弦调制信号,G3845真度要求要小,而且G12295定G5627要好,DDS的G3845真度G19512受D/A转换器本身的噪声影响外，还G994G4396G1660深度M和D/AG4395长G7389密切关系G17系采用AG79G87G72G85G68G1856G2508的G38G51G47D器G1226G40G51MG26128，G1866G7380G20652G5049作频率为12G19MG43G93，典型G2499用门5G19G19G19门，DDSG16786G16757电G17347产生的G8886G5430G4396G3324G20652次谐G8886，须G17839G15904低通G9400G8886使G8886G5430平滑，为使通带内的起伏G7380小，我G1216采用G1114巴G10317沃斯二阶低通G9400G8886器，如G991图，巴G10317沃思二阶低通G9400G8886器的截止频率为G73G701/2RG38。由于G2494需产生1G46G43G93的正弦信号,本系统G16786G16757的G9400G8886器的截至频率为2G46G43G93。A153A154A155A156A157A158A159A124A160A160A161A162A163A164A165A166A157A167A168A169A17015A123A124A125A174A196A197A198A199A200A201224LCD液晶显示G3324各G12193智能仪器和便携产品中，G19512G1114能显示G4395G12538，数G4395之外，通常还能显示各G12193突图G5430，曲G13459，和屏幕的上G991滚动，动画，闪烁，G2375文本显示G2163能，数据显示模块的首G17885应该G7171液晶显示器，G3252为G4439能G3827方便、明G1114G3332G16789明传输数据的正确G5627。由于本系统重G9869G3324G994无G13459传输，如果采用不G2559G4395库的液晶显示器，那么大部G2010G7114G19400G1262花G3324G1582G4395库上面。G3252G8504，数据显示模块采用带G4395库的液晶显示器。采用G1114TG42128G25G23A液晶显示器，该显示器G7171128G104G25G23G9869阵G5347液晶，G1866G13479构见G991图G17A123A124A125A126A160A202A203A126A124A175A161A179A172A204A205A206A207A208A180A181A123A153A154A155A156A157A158A159A124A160A160A161A162A163A164A165A166A157A167A168A169A17016RB033TA35RE08RE19RB019RB120RB221RB322RB427RB528RB629RB730U2PIC16F877123456789101112131415161718LCD250VCCGND2KVCCGNDVCCGNDVDDVSS/RESV0E1E2R/WA0D0D1D2D3D4D5D6D7SLASLKA123A124A125A126A126A126A209A210A173A184A211A212A210A126A161A213A175A185A185A193A182A183225键盘扫描输入通常情况G991,需要用键盘输入数据，G6122对G12255G5219G17839G15904G12661理，G3252G8504G3324单片机的应用和调试中，键盘G7171一个G5529不G2499少的部G2010，键盘的扩展G2499以通过一些G1867G7389G10317殊G2163能的G10317殊芯片，如各G12193G12239G1313G4504G4396器实现，G15441G9994接口复G7446，G1306G7171用到的单片机的接口较少，G2499直接用单片机的引脚作为键盘的G15904和列，G1306对单片机G7389G10317殊的较G20652的要求，尽G12661扩展键盘数量受引脚数量的限制，G1306G13546G12255G12628单，而且G4493易扩展。A214A215A216A217A218A219A220A221A222A222A223A224A225A226A227A228A218A229A230A231A23217A233A234A235A236A234A237A238A239A240A241A242第三章系统软件设计软G1226部G2010主要包括G1114G1867G7389友好界面的G6817作菜单，各G12193信号的G16786置和控制。正弦G8886产生过G12255为频率G16786置，数据处理，G9994后控制DDS芯片完成各G12193频率的正弦G8886产生；调频信号产生过G12255通过A/D转换器采G19610调制信号，G9994后根据调制信号的幅度G16757G12651出频偏，把频偏数据G991G17745到DDSG2375G2499实现调频信号的产生。A243A244A245A239A240A246A247F01A245A239A240A248A249A250A251A252A237A253A254A255A103A0A79A1A246A247F01A123A123A2A3A4A5A6A7A8A234A9A9A10A11A12A13A14A15A6A16A17A18A1918软件流程图A233A60A235A236A124A20A21A103A233A12631初始化A/D9850G89G82G76G71G76G81G76G87G66985G19G11G89G82G76G71G12RSTG66985G19G19G30G71G71G86G66G88G83G19G30/清G19512985G19复G1313信号和985G19频率G7368新信号G58RG66985G19G19XG19G19G30G58RG66985G19G71G83G19G66G71G222G30G58RG66985G19G71G83G19G66G712G23G30G58RG66985G19G71G83G19G66G711G25G30G58RG66985G19G71G83G19G66G71G198G30G71G71G86G66G88G831G30/985G19频率G7368新信号G7389效A24A22A23A244A25A24A22A26A27A16A28A45A29A30A31A14A45A29A30A241A32A237A238A33A34A133A35A36A34A37A38A36A34A2A3A4A5A6A7A8A234A9A9A10A11A12A13A14A15A6A16A17A18A1919G89G82G76G71G86G72G87G66G68G71985G19G11G89G82G76G71G12RSTG66985G191G30G71G71G86G66G88G831G30G66G49G82G83G66G11G12G30G66G49G82G83G66G11G12G30RSTG66985G19G19G30G71G71G86G66G88G83G19G30G58RG66985G19G1