标签: 抗锯齿滤波器

Analogfilterscanbefoundinalmosteveryelectroniccircuit.Audiosystemsusethemforpreamplification,equalization,andtonecontrol.Incommunicationsys-tems,filtersareusedfortuninginspecificfrequenciesandeliminatingothers.Digitalsignalprocessingsys-temsusefilterstopreventthealiasingofout-of-bandnoiseandinterference.Thisapplicationnoteinvestigatesthedesignofanalogfiltersthatreducetheinfluenceofextraneousnoiseindataacquisitionsystems.Thesetypesofsystemspri-marilyutilizelow-passfilters,digitalfiltersoracombina-tionofboth.Withtheanaloglow-passfilter,highfrequencynoiseandinterferencecanberemovedfromthesignalpathpriortotheanalog-to-digital(A/D)con-version.Inthismanner,thedigitaloutputcodeoftheconversiondoesnotcontainundesirablealiasedhar-monicinformation.Incontrast,adigitalfiltercanbeuti-lizedtoreducein-bandfrequencynoisebyusingaveragingtechniques.AN699Anti-Aliasing,AnalogFiltersforDataAcquisitionSystemsAuthor:BonnieC.BakerANALOGVERSUSDIGITALFILTERSMicrochipTechnologyInc.Asystemthatincludesananalogfilter,adigitalfilterorbothisshowninFigure1.WhenananalogfilterisINTRODUCTIONimplemented,itisdonepriortotheanalog-to-digitalconversion.Incontrast,whenadigitalfilterisimple-Analogfiltersca……