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ID:12480431
大小:37.37 KB
页数:7页
时间:2018-07-17
《外文翻译---脉冲输出型数字涡街流量计的研究》由会员上传分享,免费在线阅读,更多相关内容在学术论文-天天文库。
1、附录AResearchonpulseoutputmodeldigitalvortexflowmetersThevortexflowmeteriswidelyusedindifferentfieldsduetoitsflexibilitytovariousmedia,non-mobileparts,simplestructureandlonglifeetc.However,ithaspoorperformancewhenoperatingatlowflowratewheretheSignal-to-Noiseratioisvery
2、smalloreventhesignalissubmergedbythenoise.Thetraditionalanalogvortexflowmeterhasbenefitsofsteadysignal,highaccuracyandgoodrealtimeintheregularflowrange,whileitalsohasadisadvantageofweaksignaldifficulttodetectatlowflowrate,whichleadstounsatisfyinglowerlimitandasmaller
3、rangeratioof10:1.Basedonthepreviouseffortsapulseoutputmodeldigitalvortexflowmeterisdevelopedsuccessfully,whichinheritstheadvantagesoftheanalogoneandmakeupitsshortagementionedabove.Thedigitalvortexflowmeterwithitsdouble-corestructurethatmeansacoupleofCPUsmadeupofDSPan
4、dMSP430identifiesthevortexsignalsfromnoisesbythefrequencyspectrumanalyzingalgorithminDSPatlowflowratewheretheanalogoneisnotaccurate,orevencan’twork.MeanwhileitworksoutbyitsmicrocontrollerMSP430thefrequencyofthevortexsignalthatissquarewavesoutputfrompre-amplifierforth
5、evortexsignalsintheregularflowrangewheretheSignal-to-Noiseratioisn’ttoomuchsmallandtheanalogoneisaccurateandrealtime.Thisdissertationconsistsoftheory,hardware/softwaredesignandexperiment.Themainpointincludes:1.Theschemecalleddouble-channelworkmodelofthepulseoutputmod
6、eldigitalvortexflowmeterisdesigned.Theprincipleisaswitchoftwodifferentmethodstodetectthevortexsignal.Thatisusingspectrumanalysisofdigitalsignalatlowflowrateandfrequencycountinglikeanalogvortexflowmetersintheregularflowrange.Thecriticalcriterionoftheswitchpointistheun
7、certaintyofthefrequency.2.Apulseoutputmodeldigitalvortexflowmeterisdevelopedsuccessfully.TheflowmeterisstudiedrespectivelyatDN25andDN50pipelinesofthewaterflowexperimentfacilityandDN50andDN100pipelinesofthegasflowexperimentfacilitythatlocateatProcessDetect&ControlLabo
8、ratoryinTianjinUniversity.Andthedatashowsthatthedigitalflowmeterhasthepropertyofabetterlowerlimitthantheanalogoneandabiggerrangerat
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