AnAudioEqualisation Linear PhaseFIRFilter Design Method usingRBFbasedSmoothing andInterpolation
Anthony Zaknich, G. E. Lee · 2006
A methodforthedesign ofaudioequalisation linear phaseFIRfilters isdeveloped byusing avariant ofthe Tuneable Approximate Piecewise Linear Regression (TAPLR) methodtomodeltherequired FIR magnitude frequency response. ThisTAPLR modelincorporates asetofcontiguous piecewise linear (afrine) sections whicharecoupledand smoothed byasingle tuning parameter associated withasetof bandwidth weighted Radial Basis Functions (RBFs) assigned to eachlinear section. Themaindifference between this variant and theoriginal TAPLR methodisthatitincorporates RBFswith variable bandwidths thatcanbecentred andsetaccording to standard nonlinear frequency spacings asusedforaudio system response measurements, thereby producing a moreaccurate response model. TheTAPLR smoothing mechanism isusedto achieve therequired degree ofFIRfilter bandlimiting toavoid aliasing effects andtheGibbsphenomenon. Sometypical audio FIRfilter design examples areprovided toshowthevalueand versatility ofthemethodascompared withthestandard windowing design approach.