均衡器matlab

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1、GraphicGraphicEqualizerEqualizerProjectProject——project2XunWang10112746101.introductionWiththerapidlydevelopmentofdigitaltechnology,peoplehavehigherandhigherrequirementonthegraphics,wavesandsoundsproducedbyelectronics.Intheprocessofreal-timeprocessingdigitalsignals,Thereconst

2、ructionofanalogsignalwhichrelatestoD/AandA/Dtransformisthemostimportantindecidingthequalityoftheoutputsignalofdigitalsystem.Intheprocessesofreadingsoundsignalandtransferitthroughaudiodevices,theamplituderesponsestofrequencyarenotconsistent,thatleadstotheoutputsoundtobenotperf

3、ect.Soweuseequalizertopromotetheperformanceofthesedevicesbycontroltheamplitudesofsignalsindifferentfrequenciesinordertomakeoursenseofhearingcomfortable.2.FilterdesignStep1：calculatetheidealimpulseresponseInordertodesignaFIRdigitalband-passfilter,thefirstthingweshouldtoistoset

4、thefrequencypropertiesofidealband-passfilterwhichcanbeusedtoapproachto.Thefrequencypropertiesofaidealband-passfiltercanbeexpressedas:⎧1ω≤ω≤ω(jω)⎪12Hde=⎨(2-1)⎪⎩0othersInordertoexplaintheproblemclearly,wesetω=(ω+ω)2,ω=(ω−ω)2.012d21ωisthecenterfrequencyofpass-band,ωishalfofthewi

5、dthofpass-band.0dTakingFouriertransformof(jω)He:d1π[]∫(jω)jωhn=Heedωdd2π−π1⎛−(ω0−ωd)jωnω0+ωdjωn⎞=⎜∫()edω+∫edω⎟2π⎝−ω0+ωdω0−ωd⎠⎛−(ω0−ωd)ω0+ωd⎞1⎜⎛1jωn⎞⎛1jωn⎞⎟=⎜e⎟+⎜e⎟2π⎜⎜⎝jn⎟⎠⎜⎝jn⎟⎠⎟⎝−(ω0+ωd)ω0−ωd⎠=1(ej(−(ω0−ωd))n−ej(−(ω0+ωd))n+ej(ω0+ωd)n−ej(ω0−ωd)n)2πjn1=(2jsin((ω+ω)n)−2jsin((ω

6、−ω)n))0d0d2πjn2=sin(ωn)cos(ωn)−∞

7、angeittoadfiniteone.Sowetakeawindowtomultiplyittogeth[n]=h[n]*w[n],whichdisfinite.Takingthemiddlebandasanexample,thefigureofh[n]is:Fig.3realimpulseresponseafterpassedthoroughrectanglewindowFig.4realimpulseresponseafterpassedthoroughbartlettwindowStep4:takefouriertransformonre

8、alimpulseresponsesignalAfterwegeth[n],wejustneedtotakeffttransformon