Texas Instruments TLV320AIC3007EVM-K TV Converter Box User Manual


 
4.9.3DigitalEffectsFilters
4.9.3.1ShelfFilters
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TLV320AIC3007EVMSoftware
Thedigitaleffectfilters(thebiquadfilters)oftheTLV320AIC3007areselectedusingthecheckboxes
showninFigure19.Thede-emphasisfiltersaredescribedintheTLV320AIC3007datasheet,andtheir
coefficientscanbechanged(seeFigure17).
Figure19.EnablingFilters
WhendesigningfiltersforusewithTLV320AIC3007,thesoftwareallowsforseveraldifferentfiltertypesto
beused.Theseoptionsareshownonatabcontrolinthelowerleftcornerofthescreen.Whenafilter
typeisselected,andsuitableinputparametersdefined,theresponseareshownintheEffectFilter
Responsegraph.RegardlessofthesettingforenablingtheEffectFilter,thefiltercoefficientsarenot
loadedintotheTLV320AIC3007untiltheDownloadCoefficientsbuttonispressed.Toavoidnoiseduring
theupdateofcoefficients,itisrecommendedthattheuserunchecktheEffectFilterenablecheckboxes
beforedownloadingcoefficients.OncethedesiredcoefficientsareintheTLV320AIC3007,enablethe
EffectFiltersbycheckingtheboxesagain.
Ashelffilterisasimplefilterthatappliesagain(positiveornegative)tofrequenciesaboveorbelowa
certaincornerfrequency.AsshowninFigure20,inBassmode,ashelffilterappliesagaintofrequencies
belowthecornerfrequency;inTreblemode,thegainisappliedtofrequenciesabovethecorner
frequency.
Figure20.ShelfFilters
Tousethesefilters,enterthegaindesiredandthecornerfrequency.Choosethemodetouse(Bassor
Treble);theresponseisplottedontheEffectFilterResponsegraph.
SLAU286June2009TLV320AIC3007EVM-K23
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