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ID:25493713
大小:71.55 KB
页数:7页
时间:2018-11-20
《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,更多相关内容在工程资料-天天文库。
1、附录AResearchonpulseoutputmodeldigitalvortexflowmetersThevortexflowmeteriswidelyusedindifferentfieldsduetoitsflexibilitytovariousmedia,non-mobileparts,simplestructureandlonglifeetc.However,ithaspoorperformancewhenoperatingatlowflowratewheretheSignal-to-Noiserati
2、oisverysmalloreventhesignalissubmergedbythenoise.Thetraditionalanalogvortexflowmeterhasbenefitsofsteadysignal,highaccuracyandgoodrealtimeintheregularflowrange,whileitalsohasadisadvantageofweaksignaldifficulttodetectatlowflowrate,whichleadstounsatisfyinglowerli
3、mitandasmallerrangeratioof10:1.Basedonthepreviouseffortsapulseoutputmodeldigitalvortexflowmeterisdevelopedsuccessfully,whichinheritstheadvantagesoftheanalogoneandmakeupitsshortagementionedabove.Thedigitalvortexflowmeterwithitsdouble-corestructurethatmeansacoup
4、leofCPUsmadeupofDSPandMSP430identifiesthevortexsignalsfromnoisesbythefrequencyspectrumanalyzingalgorithminDSPatlowflowratewheretheanalogoneisnotaccurate,orevencan’twork.MeanwhileitworksoutbyitsmicrocontrollerMSP430thefrequencyofthevortexsignalthatissquarewaves
5、outputfrompre-amplifierforthevortexsignalsintheregularflowrangewheretheSignal-to-Noiseratioisn’ttoomuchsmallandtheanalogoneisaccurateandrealtime.Thisdissertationconsistsoftheory,hardware/softwaredesignandexperiment.Themainpointincludes:1.Theschemecalleddouble-
6、channelworkmodelofthepulseoutputmodeldigitalvortexflowmeterisdesigned.Theprincipleisaswitchoftwodifferentmethodstodetectthevortexsignal.Thatisusingspectrumanalysisofdigitalsignalatlowflowrateandfrequencycountinglikeanalogvortexflowmetersintheregularflowrange.T
7、hecriticalcriterionoftheswitchpointistheuncertaintyofthefrequency.2.Apulseoutputmodeldigitalvortexflowmeterisdevelopedsuccessfully.TheflowmeterisstudiedrespectivelyatDN25andDN50pipelinesofthewaterflowexperimentfacilityandDN50andDN100pipelinesofthegasflowexperi
8、mentfacilitythatlocateatProcessDetect&ControlLaboratoryinTianjinUniversity.Andthedatashowsthatthedigitalflowmeterhasthepropertyofabetterlowerlimitthantheanalogoneandabiggerrangerat
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