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ID:7931507
大小:4.99 MB
页数:49页
时间:2018-03-02
《the manifold joys of conformal mapping外语英文电子书》由会员上传分享,免费在线阅读,更多相关内容在教育资源-天天文库。
1、ManifoldJoysofConformalMappingJamesA.MoorerTheManifoldJoysofConformalMapping:ApplicationstoDigitalFilteringinthendStudio–2TryJamesA.MoorerThisisaneditedversionofapaperthatappearedintheJournaloftheAudioEngineeringSociety[1].Manytyposhavebeencorrected,andsomesupplementarymate
2、rialhasbeenadded.IthasalsobeencombinedwithanIEEEarticle[2]thatalsoinvolvesconformalmapping.Abstract:Conformalmappingisawell-knowntechniqueformodifyingthecut-offorresonantfrequenciesoffilters.Conformalmappingisappliedtotheproblemofdigitalfiltersforprofessionalaudioproduction
3、.Methodsareexaminedforcomputingthecoefficientsofpresencefilters,suchasparametricequalizerswithorwithoutshelving,andofband-passorband-rejectfilters.Formulasaregivenforthecoefficientsofthesefiltersintermsofthespecifications(centerfrequency,boost/cut,andsoon),whichareexactandr
4、elativelystraightforwardtocompute.Anewkindofshelvingfilterisintroducedthatisequirippleinthepassbandsandcanhaveanarbitrarilynarrowtransitionband(withincreasingfilterorder).IntroductionEverystudiomixingdeskhasafiltersectionforeachandeverychannel.Thesegofromthesimplestbass-tre
5、blecontrolstosophisticatedparametricboost/cutfilters.Alsoquitepopularas“outboard”equipmentaregraphicequalizersandhigh-orderband-stopandnotchfilters.Withthecomingofdigitalaudioitseemscertainthatthemixingdesksofthefuturewillhavetorealizeallthesefunctionsentirelyinthedigitaldo
6、main.Torealizesomeoftherealadvantagesofdigitalcontrol(precisionandrepeatability),thecharacteristicsofsuchfiltersmustbeverywellunderstood,andtheirdesignformulasmustbeexactandexplicit.Inthispaper,wegooversomeofthemostcommonstudiofilters(andsomeratheruncommonones)anddevelopdes
7、ignequationsforeachofthem.Theseequationswillallowtheimplementertocalculateexactlythefiltercoefficientsforthedesiredcharacteristics.Asecondrunningthemeinthepaperisconformalmapping.Weusethismappingasatoolfordecomposingtheproblemoffilterdesignintoindividualstagesofwhicheachone
8、istractable.Sincemanyofthereaderswillnotbefamiliarwiththistechnique,itisexploredin
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