無線數(shù)據(jù)采集和傳輸系統(tǒng)外文翻譯文獻(xiàn)

1、無線數(shù)據(jù)采集和傳輸系統(tǒng)外文翻譯文獻(xiàn)無線數(shù)據(jù)采集和傳輸系統(tǒng)外文翻譯文獻(xiàn)（文檔含中英文對照即英文原文和中文翻譯）譯文：一種無線數(shù)據(jù)采集和傳輸系統(tǒng)的設(shè)計【摘要】在現(xiàn)代無線通信領(lǐng)域主要有一些技術(shù)為無線傳輸網(wǎng)絡(luò)提供解決方法，例如：GSM,CDMA,3G,Wi-Fi。這些方法使得網(wǎng)絡(luò)能夠高效率和高質(zhì)量的工作，但是成本很高。因此要低成本和在沒有基礎(chǔ)設(shè)施或者基礎(chǔ)設(shè)施被破壞的情況下推廣它們是很困難的。根據(jù)這種情況，本論文中數(shù)據(jù)采集和無線傳輸網(wǎng)絡(luò)里的信息終端和無線收發(fā)模塊的關(guān)鍵部件，是依據(jù)nRF905收發(fā)模塊和51系列單片機(jī)的原理設(shè)計而成作為核心硬件，止匕外，結(jié)合目前自組無線網(wǎng)絡(luò)的技術(shù)，可以構(gòu)建一個短距離無無線數(shù)

2、據(jù)采集和傳輸系統(tǒng)外文翻譯文獻(xiàn)線數(shù)據(jù)采集和傳輸網(wǎng)絡(luò)，這個網(wǎng)絡(luò)能夠提供一個工作在ISM（工業(yè)科學(xué)醫(yī)學(xué)）頻段的低功率及高性能的數(shù)據(jù)通信系統(tǒng)。然后提出了一個對無線通信可行的解決方案，這個方案優(yōu)勢在于更強(qiáng)的實(shí)時響應(yīng)，更高的可靠性要求和更小的數(shù)據(jù)量。通過軟件和硬件的調(diào)試和實(shí)際測量，這個系統(tǒng)在我們的解決方案基礎(chǔ)上運(yùn)行良好，達(dá)到了預(yù)期的目標(biāo)并且已經(jīng)成功的應(yīng)用到無線車輛系統(tǒng)?！娟P(guān)鍵詞】自組網(wǎng)絡(luò)；數(shù)據(jù)采集；傳輸網(wǎng)絡(luò)1簡介在現(xiàn)代無線通信里，GSM,CDMA,3G和Wi-Fi因?yàn)槠涓咚俸涂煽康馁|(zhì)量而逐漸成為無線數(shù)據(jù)傳輸網(wǎng)絡(luò)的主流解決方案。它們也有高成本的缺點(diǎn)，因此如果廣泛的應(yīng)用，將會引起大量的資源浪費(fèi)，也不能在小區(qū)域

3、，低速率的數(shù)據(jù)通信中得到提升。多點(diǎn)短距離無線數(shù)據(jù)采集和傳輸網(wǎng)絡(luò)將成為最佳解決方案。此系統(tǒng)支持點(diǎn)對點(diǎn)，點(diǎn)對多點(diǎn)和多點(diǎn)對多點(diǎn)通信系統(tǒng)的發(fā)展。短距離無線通信可以適應(yīng)各種不同的網(wǎng)絡(luò)技術(shù)，例如藍(lán)牙，IEEE802.11,家庭無線網(wǎng)和紅外。與遠(yuǎn)距離無線通信網(wǎng)絡(luò)相比，它們的不同之處在于基本結(jié)構(gòu)，應(yīng)用水平，服務(wù)范圍和業(yè)務(wù)（數(shù)據(jù)，語音）。設(shè)計短距離無線通信網(wǎng)絡(luò)的最初目的是為了提供短距離寬帶無線接入到移動環(huán)境或者制定臨時網(wǎng)絡(luò)，這是在移動環(huán)境里互聯(lián)網(wǎng)更深的發(fā)展。短距離無線通信網(wǎng)絡(luò)最主要的優(yōu)勢是更低的成本和更靈活的應(yīng)用。本文介紹信息終端（單個器件）的硬件和軟件以及多點(diǎn)短距離無線數(shù)據(jù)采集和傳輸網(wǎng)絡(luò)的無線接收模塊的設(shè)計建

4、議，提供一個低功率高性無線數(shù)據(jù)采集和傳輸系統(tǒng)外文翻譯文獻(xiàn)能的工作于ISM（工業(yè)科學(xué)醫(yī)學(xué)）頻段的無線數(shù)據(jù)通信系統(tǒng)。文章剩余部分由如下內(nèi)容組成：在第二部分，我們描述了無線數(shù)據(jù)采集和傳輸系統(tǒng)的通用模塊圖表，第三部分，我們分析此系統(tǒng)硬件設(shè)計的關(guān)鍵技術(shù)，第四部分，介紹系統(tǒng)的軟件設(shè)計，第五部分，展示系統(tǒng)的測試結(jié)果，最后我們在第六部分闡述結(jié)論和進(jìn)一步的工作。2系統(tǒng)實(shí)現(xiàn)模型1 .系統(tǒng)模型作為一個點(diǎn)對多點(diǎn)的多功能無線通信系統(tǒng)，它包含了一個中央監(jiān)控系統(tǒng)和多個遠(yuǎn)程終端單元（圖1）。實(shí)際上，遠(yuǎn)程終端單元是一些在移動過程中可互相通信的移動電臺。另外，中央監(jiān)控系統(tǒng)與遠(yuǎn)程終端單元進(jìn)行雙向通信。在下一部分，設(shè)計信息終端和控制

5、中心的軟件和硬件上的一些關(guān)鍵部件。2 .相關(guān)模型本論文中的系統(tǒng)是根據(jù)OSI（國際標(biāo)準(zhǔn)組織）中的OSI/RM模型里的第一層（物理層）和第二層（數(shù)據(jù)鏈路層）而設(shè)計的，如圖2所示。物理層的功能是通過建立電路和專用芯片組完成的。然而通信協(xié)議里的數(shù)據(jù)鏈路層是由軟件來實(shí)現(xiàn)的。3系統(tǒng)硬件設(shè)計為了設(shè)計，管理和更新的方便，一些硬件單元和節(jié)點(diǎn)根據(jù)它們的功能和電學(xué)特性被劃分成不同的模型。本設(shè)計以射頻收發(fā)芯片nRF905為核心,以模塊搭建設(shè)計為指導(dǎo)思想，搭建無線溫度采集系統(tǒng)，系統(tǒng)主要由數(shù)據(jù)無線數(shù)據(jù)采集和傳輸系統(tǒng)外文翻譯文獻(xiàn)采集模塊和無線傳輸模塊組成。數(shù)據(jù)采集模塊以數(shù)字式溫度傳感器DS18B20監(jiān)測溫度參數(shù)，并將監(jiān)測的

6、溫度參數(shù)簡單處理后通過nRF905無線模塊發(fā)送到接收端口。無線數(shù)據(jù)傳輸模塊通過nRF905芯片進(jìn)行數(shù)據(jù)收發(fā)處理,nRF905芯片的集成度較高，所需的外圍器件較少，因此整體的電路設(shè)計相對比較簡單點(diǎn)。本設(shè)計給出其與MSP430F449的接口電路設(shè)計和接收端通過電平轉(zhuǎn)換芯片MAX3232與PC機(jī)連接。并根據(jù)硬件特性及連接設(shè)計相應(yīng)的軟件流程，并編寫軟件。通過相適應(yīng)的無線傳輸模塊和數(shù)據(jù)采集模塊控制軟件的操控，保證整個硬件系統(tǒng)的流暢運(yùn)作。系統(tǒng)基本結(jié)構(gòu)中包含無線射頻收發(fā)模塊，控制處理模塊，通用串行接口模塊，數(shù)據(jù)緩沖存儲模塊以及多功能電源管理模塊等。1 .收發(fā)器和接收模塊在數(shù)據(jù)發(fā)送過程中，數(shù)據(jù)包將被調(diào)制到高頻

7、然后發(fā)送到目標(biāo)無線射頻傳輸模塊，接收過程中，高頻信號通過無線射頻接收模塊又被解調(diào)成原始數(shù)據(jù)包。NRF905是無線射頻收發(fā)模塊的關(guān)鍵，它的頻率是16兆赫茲的晶體振蕩器。NRF905可以通過印刷式天線接收無線射頻信號，但是為了提高接收機(jī)的靈敏度和抗干擾能力，這種模塊也適用外部天線和濾波器電路。2 .控制處理模塊控制處理模塊包含MCU和外部電路，有兩個功能：一是使所有模塊在其控制下協(xié)調(diào)工作，二是處理和傳輸從接口來的數(shù)據(jù)，例如路由處理，數(shù)據(jù)打包，驗(yàn)證和重傳請求。模塊的關(guān)鍵部件MCU是51系列單片機(jī)，考慮到工業(yè)功能，無線數(shù)據(jù)采集和傳輸系統(tǒng)外文翻譯文獻(xiàn)WINBOND78LE546因其在8位CMOS微處理器

8、里較好的容量特性被而被應(yīng)用，與2.4-2.5伏的寬電壓供電，256比特嵌入式RAM,16KBFlashEPROM以及64KB地址空間，四個8位標(biāo)準(zhǔn)I/O接口，一個標(biāo)準(zhǔn)I/O雙串行口相兼容。SCM的晶體振蕩器頻率是22.1184兆赫茲，電功率為3.3伏適合無線收發(fā)芯片里nRF905的邏輯水平。它的引腳通過與VCC相連受到保護(hù)并保持器穩(wěn)定性。MCU與所有模塊的具體連接如表1所示。4系統(tǒng)軟件設(shè)計系統(tǒng)性能的真實(shí)取決于其有效性和合理的軟件控制。軟件設(shè)計是在硬件環(huán)境的基礎(chǔ)上開發(fā)一個無線網(wǎng)絡(luò)協(xié)議，為了到達(dá)設(shè)計目標(biāo)，這個協(xié)議要有諸如數(shù)據(jù)傳輸，沖突避免，錯誤后重傳以及超時重試的功能。整個網(wǎng)絡(luò)由一個主機(jī)和許多分散

9、的終端組成，每個終端必須有一個無線收發(fā)節(jié)點(diǎn)（此系統(tǒng)支持Nrf905單片無線收發(fā)器），整個無線網(wǎng)絡(luò)的任何節(jié)點(diǎn)都有一個唯一認(rèn)證地址對應(yīng)一個唯一認(rèn)證終端。為了方便起見，每個確定系統(tǒng)的終端無線收發(fā)器節(jié)點(diǎn)地址都是我們自己設(shè)定的4字節(jié)。為了提高系統(tǒng)的穩(wěn)定性，協(xié)議被設(shè)置成停止-等待模式。在數(shù)據(jù)鏈路層，發(fā)送過程大概如下：首先，數(shù)據(jù)源發(fā)送一個連接請求道數(shù)據(jù)目標(biāo)，得到數(shù)據(jù)源的響應(yīng)后傳輸數(shù)據(jù)。接著，每一次傳輸都要等待接收方的回應(yīng)。如果響應(yīng)正確，另一次的傳輸才會開始。當(dāng)所有數(shù)據(jù)傳輸完后，數(shù)據(jù)源將發(fā)送一個釋放信道請求，當(dāng)收到接收方的響應(yīng)后傳輸結(jié)束。接收過程如下：在接收方給數(shù)據(jù)源響應(yīng)后將收到數(shù)據(jù)，然后會發(fā)送一個有效或無效

10、的響應(yīng)，直到收到拆除鏈路請求。接下來，保存數(shù)據(jù)且發(fā)送一個無線數(shù)據(jù)采集和傳輸系統(tǒng)外文翻譯文獻(xiàn)響應(yīng)來結(jié)束整個過程。5系統(tǒng)測試任何兩個節(jié)點(diǎn)之間的通信大都可以通過點(diǎn)對點(diǎn)來測試，因此在系統(tǒng)測試過程中，A節(jié)點(diǎn)和B節(jié)點(diǎn)之間的通信模型對測試圖解來說是一個很好的樣本，就像圖10。閉環(huán)測試電路是通過PC帶雙串口以及兩個RS32口和通信節(jié)點(diǎn)A和B建立起來的。在一個終端，數(shù)據(jù)時通過串口測試輔助工具“串口助手V2.2”發(fā)送，在另一端，監(jiān)控著返回的數(shù)據(jù)。數(shù)據(jù)通過PC的串口A,RS32口發(fā)送，然后數(shù)據(jù)緩沖，最后成功到達(dá)終端無線收發(fā)器模塊。然而,數(shù)據(jù)接收過程是SPI串口，數(shù)據(jù)緩沖，然后RS32口，最后才是PC。在本論文中，根

11、據(jù)以收發(fā)器nRF905和51系列單片機(jī)作為核心硬件的原理設(shè)計一個低功耗高性能的無線數(shù)據(jù)通信系統(tǒng)。提出無線數(shù)據(jù)通信一個可行的解決方案，這個解決方案適合于強(qiáng)大的實(shí)時響應(yīng)，高可靠性要求和小數(shù)據(jù)量，被廣泛的應(yīng)用于各種領(lǐng)域，例如數(shù)據(jù)通信，環(huán)境監(jiān)測和安全保衛(wèi)系統(tǒng)。我們相信在軟件設(shè)計進(jìn)一步精煉和提高以后集成和智能通信協(xié)議將會實(shí)現(xiàn)。測試過程中，用數(shù)字示波器監(jiān)測通信節(jié)點(diǎn)A、B,RS32口和SPI口的數(shù)據(jù)傳輸。在接下來的部分，通過分析來自MOSI/SCK和MISO/SCK的信息來驗(yàn)證系統(tǒng)的正確性。6總結(jié)在本論文中，根據(jù)以收發(fā)器nRF905和51系列單片機(jī)作為核心硬件的原理設(shè)計一個低功耗高性能的無線數(shù)據(jù)通信系統(tǒng)。提

12、出無線數(shù)據(jù)通信無線數(shù)據(jù)采集和傳輸系統(tǒng)外文翻譯文獻(xiàn)一個可行的解決方案，這個解決方案適合于強(qiáng)大的實(shí)時響應(yīng)，高可靠性要求和小數(shù)據(jù)量，被廣泛的應(yīng)用于各種領(lǐng)域，例如數(shù)據(jù)通信，環(huán)境監(jiān)測和安全保衛(wèi)系統(tǒng)。我們相信在軟件設(shè)計進(jìn)一步精煉和提高以后集成和智能通信協(xié)議將會實(shí)現(xiàn)。無線數(shù)據(jù)采集和傳輸系統(tǒng)外文翻譯文獻(xiàn)原文：TheDesignofaWirelessDataAcquisitionandTransmissionSystemAbstract：Inthefieldofmodernwirelesscommunication,therearemainlysometechnologiesthatprovidesolutio

13、nstothewirelessdatatransmissionnetwork,suchas:GSM,CDMA,3GWi-Fi.Thesesolutionsmakenetworkworkwithhighefficiencyandgoodquality,butstillwithhighcost.Soitwasdifficultyinpopularizinginwithlowcostandatthecircumstanceofinfrasturelessorinfrastructuredestruction.Accordingtothissituation,inthispaper,thekeycom

14、ponentsoftheInformationTerminalandthewirelessreceivingmodulesonthedatacollectionandwirelesstransmissionnetworkweredesignedwiththeprincipleoftransceivernRF905and51seriesofsingle-chipcomputerasthecorehardware,besides,combiningwiththecurrenttechnologyontheWirelessAdHocNetworks,ashort-rangwirelessdatasa

15、mplingandtransmissionnetworkwasputtingup,whichprovidesalow-poweredandhigh-performancewirelessdatacommunicationsystem,worksintheISM(IndustrialScientificMedical)Band.Then,anavailablesolutiontothewirelessdatacommunicationswasputforward,andthissolutionwasgoodatstrongerreal-timeresponse,higherreliability

16、requirementandsmallerdataamount.Throughsoftwareandhardwaredebuggingandactualmeasuring,thissystembasedonoursolutionhadworkwell,reachedtheexpectedgoalandbeenalreadysuccessfullyappliedto無線數(shù)據(jù)采集和傳輸系統(tǒng)外文翻譯文獻(xiàn)WirelessvehicleSystem.IndexTermsAdHocNetwork;dataacquisition;transmissionnetwork.I. INTRODUCTIONInmo

17、dernwirelesscommunication,GSM,CDMA,3G,andWi-Fibecomethemainstreamsolutionofwirelessdatatransmissionnetworkbecauseoftheirhighspeedandreliablequality.Theyalsohavetheshortcomingsofhighcost,sowiderapplicationwouldcauseagreatwasteofresources,andtheycannotbepromotedinsmallregional,lowspeeddatacommunicatio

18、ns.Multi-pointshort-rangewirelessdatacollectionandtransmissionnetworkwillbethebestsolution.Thesystemsupportsthedevelopmentofcommunicationsystemofpeer-to-peer,point-to-multipoint,andmultipoint-to-multipoint.Short-rangewirelesscommunicationcanadoptdifferentnetworktechnologies,suchasBluetooth1,IEEE802.

19、112,HomeRF3andInfrared4.Comparedwithlong-distancewirelesscommunicationnetwork,theyaredifferentinthebasicstructure,theapplicationlevel,servicerange,andbusiness(data,voice).Theoriginalintentionofdesignofshort-rangewirelesscommunicationnetworkistoprovideshort-distancebroadbandwirelessaccesstomobileenvi

20、ronmentorformulationoftemporarynetwork,itisthefurtherdevelopmentofinternetinmobileenvironment.Themainadvantageofshort-rangewirelesscommunicationnetworkislowercostandmoreflexibleuse.Thispaperpresentsthedesignproposalofhardwareandsoftwareofinformationterminal(amachine)andwirelessreceivermoduleofmulti-

21、pointshort-rangewireless無線數(shù)據(jù)采集和傳輸系統(tǒng)外文翻譯文獻(xiàn)datacollectionandtransmissionnetwork,whichprovidesalow-poweredandhigh-performancewirelessdatacommunicationsystem,worksintheISM(IndustrialScientificMedical)Band.Theremainderofthispaperisorganizedasfollows.InSectionH,wedescribethegeneralblockdiagramofthewireles

22、sdataacquisitionandtransmissionsystem.InsectionHI,weanalyzethekeytechnologiesaboutthesystemhardwaredesign.Insection,thesystemsoftwaredesignisintroduced.InsectionV,thetestingresultsofsystemispresented.Finally,wepresenttheconclusionandfutureworkinSectionVI.II. SYSTEMIMPLEMENTATIONMODELA. SystemModelAs

23、apointtomulti-pointsmulti-missionwirelesscommunicationsystem,itconsistsofonecentralmonitoringsystem(CMS)andMultipleRemoteTerminalUnits(RTU)(figure1).Infact,thisremoteterminalunitissomekindofremovablestationswhichcancommunicatewithotherstationsintheprocessofmotion.Furthermore,theCMScommunicatewithRTU

24、inbidirectionalway.Inthenextpart,somepivotalsegmentonsoftwareandhardwareoftheinformationterminalandcontrolcenterwasdesigned.B. ReferenceModelThesysteminthispaperisdesignedbasedonthefirstlayer(thephysicallayer)andthesecondlayer(thedatalinklayer)ofthearchitectureofOSI/RM(OpenSystemsInterconnectionRefe

25、renceModel)thattheISO(International10無線數(shù)據(jù)采集和傳輸系統(tǒng)外文翻譯文獻(xiàn)OrganizationforStandardization)proposed,suchasfigure2.Thefunctionofthephysicallayerisfinishedthroughconstructingthecircuitandspecialchips.Otherwise,communicationprotocolsinthedatalinklayerarerealizedbysoftware.m.THEHARDWAREDESIGNOFTHESYSTEMForthe

26、sakeoftheconvenienceofdesign,maintenanceandupdate,somehardwarecircuitcellandnodewasdividedintosomedifferentmoduleaccordingtofunctionalandelectriccharacteristic.ThereareRFTransceivermodule5,controllinganddealingmodule,UniversalSerialinterfacemodule,databufferandstoragemoduleandmultifunctionalpowerman

27、agementmoduleinthebasicstructure(Figure2).Intheprocessofsending,thedatapackageshouldbeenModulatedwithHighfrequencyandsenttoobjectRFTransmittingmodule,intheprocessofreceiving,thehighfrequencysignalhavebeendemodulatedtooriginaldatapackagethroughtheRFreceivermodule.NRF9055isthekeyofRFTransceivermodulew

28、hosefrequencyis16MHzCrystalOscillator.NRF905canreceivetheRFsignalbyPrintedAntenna,butthismoduleadoptstheexternalantennaandFilterCircuitsinordertoimprovethereceiversensitivityandanti-jammingability.B. ControllingandTreatingmodueThecontrollingandtreatingmoduleconsistsofMCUandexternalcircuit,ithavetwof

29、unctions:onemadeallmodule'workingundercontrolandharmony;theotherfunctionistreatingandtransmittingthedatagotfromii無線數(shù)據(jù)采集和傳輸系統(tǒng)外文翻譯文獻(xiàn)interface,suchasrouterprocessing,datapackaging,verificationandrepeatingrequest.Module,keyMCUis51seriesmicroprocessor,andconsideringtheindustrialfunction,theWINBONDwas

30、appliedinthispracticalexperimentbecauseofit'sgoodcapability8-bitCMOSmicroprocessor,compatibilitywith2.4-5.5Vwidevoltageelectricsupply,256BytesembeddedRAM,16KBFlashEPROMand64KBaddressingspace,four8BitstandardI/Ointerfaces,onestandardI/Odualserialinterface.TheCrystalOscillatorfrequencyofSCMis22.11

31、84MHz,andtheelectricpoweris3.3VtoadaptingtonRF905logicallevelinwirelesstransceiverchip.TheimpendingPINwasprotectedbyconnectingwithVCCtokeepingitsstability.ThespecificconnectionbetweenMCUandallmodulesisdescribedinTABLAE1.C. MultifunctionalElectricPowerManagementModuleThemostremarkablecharacteristicis

32、compatibilitywith8-24VwidevoltageelectricsupplyincludingCMOSpowerandTTLpower,respectivelyin5Vand3.3V,whichprovidedallmoduleswiththesuitableandstablepower.Meanwhile,itmeanssomuchinenergysourcesavingbecauseofitselectronicswitch.ThepowersupplytransferchipC851414andAS-1117-3.3istheprimaryingredientinthi

33、smodule.TheC851414madetheelectricvoltagetransferfrom8Vto24V,then,theAS-1117-3.3madeitfrom5Vto3.3V.Furthermore,suitablefiltercapacitanceandinductancewasintroducedtomakepower'sripplecharacteristicperfectaspossible.D. UniversalSerialInterfaceModule12無線數(shù)據(jù)采集和傳輸系統(tǒng)外文翻譯文獻(xiàn)ThemainfunctionofUniversalSerial

34、interfacemoduleisconnectinguniversalterminalequipment,suchassignaloutputequipmentoranalogcollectionequipmentwithADtransfer.Atthesametime,itprovidesentrancetothecomputerterminaldataexchangethroughuniversalRS232serialinterface.E. DataBufferandStorageModuleIthastwokindsoffunction,oneisdatabuffer,theoth

35、erisdatastorage,respectivelyperformedby32KByteRAMand16KByteEEPROM.Databufferdistrictsupervisebufferingsometemporarydata,suchastransmitdata,waitingdata.Datastoragedistrictsupervisesomefixeddatamemory,suchasrouterdata,localhost,localaddressandsomereneweddataforpower-offprotective.F.HighFrequencyShield

36、ingProtectingMouduleInordertopreventelectromagneticinterferencefromenvironment,circuitinourdesigningsystemisprotectedwithmetalenclosure.Atthesametime,preventingthedigitalcircuitinterferefromtheradiofrequencycircuitinthesystem,weplacedthetwocircuitsindifferentisolatedbin,suchasfigure3.Thereisasmallho

37、lewithdiameterlessthan1/4wavelengthinthemetalboxside,whichiseithereasytopassthelineorpreventtheelectromagneticwavefromgettinginit.IV.SYSTEMSOFTWAREDESIGNTherealizationofsystemperformancedependsonitseffectiveandreasonablesoftwarecontrol.Thedesignofthissoftwareisonthebasisofthehardware13無線數(shù)據(jù)采集和傳輸系統(tǒng)外文翻

38、譯文獻(xiàn)environmenttodevelopmentawirelessnetworkprotocolthathavefunctionsasdatatransmission,avoidingconflict,theretransmissionwhenerroroccurs,andovertimeretry,inordertoachievethedesigngoal.Theentirenetworkiscomposedofahostandmanyscatteredterminals,eachterminalmusthaveawirelesstransceivernode(thissystemad

39、optsnRF905single-chipRFtransceiver),anynodesoftheentirewirelessnetworkhasauniqueidentifiedaddresswhichiscomposedofanuniqueidentifiedterminal.Forconvenience'ssake,eachterminalwirelesstransceivern(ddeessesoftheactualsystemissetbyourselves(4bytes).Inordertoimprovethereliabilityofthesystem,theprotoc

40、olisdesignedasstop-waitmode.Indatalinklayer,thesendprocessisroughlyasfollow.Firstly,thedatasourcessendaconnectionrequesttothedatatargets,anditwilltransferdataafterthedatasourcesrespond.Thenwaitforresponsefromdatatargetaftereachtransmission.Iftheresponseiscorrect,anothertransmissionwillstart.Afterall

41、thedatatransmissionisdone,thedatasourcewillsendarequesttoreleasechannelresources,thetransmissionisfinishedwhentheresponsefromthetargetisreceived.Thereceiveprocessisasfollow:thedatatargetwillreceivedataaftergivearesponsetothesource,andwillgiveaeffectiveoruneffectiveresponse,untilreceiveademolitionreq

42、uest.Then,savethedataandsendaresponsetoendtheentireprocess.datavaluesareseriallytransferred,pumpedintoashiftregisterandaretheninternallyavailableforparallelprocessing.Herewealreadyseeanimportantpoint,thatmustbe14無線數(shù)據(jù)采集和傳輸系統(tǒng)外文翻譯文獻(xiàn)consideredinthephilosophyofSPIbussystems:Thelengthoftheshiftregistersis

43、notfixed,butcandifferfromdevicetodevice.Normallytheshiftregistersare8Bitorintegralmultiplesofit.Ofcoursetherealsoshiftregisterswithanoddnumberofbits.Forexampletwocascaded9BitEEPROMscanstore18Bitdata.IfaSPIdeviceisnotselected,itsdataoutputgoesintoahigh-impedancestate,sothatitdoesnotinterferewiththecu

44、rrentlyactivateddevices.WhencascadingseveralSPIdevices,theyaretreatedasoneslaveandthereforeconnectedtothesamechipselect5.Infigure4thecascadeddevicesareevidentlylookedatasonelargerdeviceandreceivethereforethesamechipselect.ThedataoutputoftheprecedingdeviceistiedtothedataV.SYSTEMTESTINGBecausecommunic

45、ationbetweenanytwonodesmaybetestedthroughpointtopoint,inthissystemTestingProcess,communicationmodelbetweennodeAandnodeBisagoodexamplefortestingschematicdiagram,justlikefigure10.Closed-looptestingcircuitisputupthroughPCwithdoubleserialportsandtwoRS232portsandcommunicationnodeAandB.Ononeterminal,dataw

46、assentthroughserialporttestingauxiliarytool“serialportassistantV2.2"ontheotherterminal,returningdataismonitored.DataissentthroughPCsserialportA,RS232port,thendatabufferandfinallywirelesstransceivermodulesuccessively.However,theprocessofdatareceivingwasSPIserial,databuffer,thenRS232port,finallyPC.IntInthispaper,alow-poweredandhigh-performancewirelessdatacommunication15無線數(shù)據(jù)采集和傳輸系統(tǒng)外文翻譯文獻(xiàn)systemweredesignedwiththeprincipleoftransceivernRF905and51seriesofsi