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4
Application-orienteddesignofactivenoisecontrolsystems
Vibrationoftheplatescanbeperformedbydifferenttypesofpiezoelectricpatches
orshakers.Dependantoncontrolstrategy,theycanbeusedtoreducesound
emissionandtransmissionthroughtheplateleadingtoglobalorlocalcontrol.
Vibratingplatescanalsoplayaroleofsoundsourcesandcanbeusedinsteadof
loudspeakersforclassicalANCsystemstogeneratezonesofquiet.However,
vibratingplatesarehardertocontrolthanloudspeakersbecauseofnonlinearity,
andhighvariationsofamplituderesponse[Fulleretal.,1997],[Pietrzko,2009].
Radiationfromvibratingplatesisstillinscientificinterestofmanyresearchers,
e.g.[Keiretal.,2005],[Zawieskaetal.,2007],[Rdzaneketal.,2011].
1.3ACTIVITYONACTIVENOISECONTROLINPOLANDAND
ABROAD
FirstANCapplicationsdatebacktoCoanda(1930),Lueg(1936),andOlsonand
May(1953).Coanda’sideawasaphase-invertedcancellationbuthisproject
encounteredtechnicalproblemsandthereforeitisrarelymentioned[Pawelczyk,
2005].Luegattenuatedaone-dimensionalacousticwaveinaductusing
feedforwardfromanupstreammicrophone.OlsonandMayappliedfeedbackfrom
adownstreammicrophonetoattenuateambientnoisearoundtheheadrestinaseat.
Althoughtheabovepublicationsareusuallyreferredtoasthefirstreportedworks
onANC,itshouldbenoticedthattheirauthorstookadvantageofthetheoryof
KirchhoffdiffractiondevelopedbyRubinowicz(1917),aPolishscientist.He
describedtheeffectofinterferenceoflightwavesfallingonascreenedge,what
resultedinmutualcompensationatsomeareas.
InPoland,ANCitselfwasfirststudiedbyCzarnecki(1970),whodetermined
conditionsforphasecompensationofsound,anditwasfurtherdevelopedand
promotedbyEngelandKowal(1995).TheANCand/orASACstudieshavebeen
thencontinuedinanumberofcentresinPoland,includingtheAGHUniversityof
