简介：@ChristianNocke

简介：

简介：Thepartlyspecularreflectionandpartlydiffusionreflectionmodelisaconvenientwaytoexpressthephenomenaofsurfacesoundenergyscatteringinroomacoustics.Soundenergydiffusioncoefficientbecomesakeyfactortostudysurfacescattering.Buttherehavebeenveryfewmethodsfordeterminingtheaveragesoundenergydiffusioncoefficient.Vorliinderproposedsuchaneasyonebasedonthecorrelationprinciple.However,hismethodignoredthecorrelationfromdirectsound,inwhichdefectispresent.Anewapproximatemethodforcalculatingsoundenergydiffusioncoefficient,includingdirectsoundandfirststrongreflectionsispresented.Therefore,Vorlaender''''''''sdefectisovercome.Inaddition,withtheaidofdigitalmeasuringtechnology,arelevantmeasuringsystemwasdeveloped.TheexperimentresultshowsthatthemethodisimprovedthanVorlaender's.

简介：Theexistingabsorptioncoefficientmeasurementinawatertubeislimitedinlowfrequencyduetothelimitationofthepulsetubelength.Awide-bandpulsetubemethodbasedonthepost-processinginversefilterisproposed.Afterobtainingtheresponseoftheentiresystem,thetransducerisexcitedwithwide-band,short-durationsignals.Then,thereceivedsignalsareprocessedwithinversefiltersandthe'blurred'reflectivesignalsofstandardreflectorandtestsamplearerecoveredrespectively,finally,thereflectioncoefficientandabsorptioncoefficientarecalculated.Simulationworkisimplementedtoverifytheadvantageofpostprocessinginversefilteroverpre-processinginversefilterintermsoflowfrequencymeasurement.Toverifytheproposedmethod,twodifferentwide-bandpulsesintheseparatefrequencyrangesareadoptedtomeasurethesamerubbermaterial.Theexperimentalresultsindicatethatthewide-bandpulsemethodandCW(ContinuousWave)pulsemethodhavegoodagreementinbothlowfrequencyrangeandhighfrequencyrange.Wide-bandpulsemethodisofhighefficiency,andthelowfrequencyreaches350Hz,whichisabletoextendthelowfrequencyrange.