FDCombFilter.cxx

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00001 /*
00002  * Copyright (c) 2001-2004 MUSIC TECHNOLOGY GROUP (MTG)
00003  *                         UNIVERSITAT POMPEU FABRA
00004  *
00005  *
00006  * This program is free software; you can redistribute it and/or modify
00007  * it under the terms of the GNU General Public License as published by
00008  * the Free Software Foundation; either version 2 of the License, or
00009  * (at your option) any later version.
00010  *
00011  * This program is distributed in the hope that it will be useful,
00012  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00013  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00014  * GNU General Public License for more details.
00015  *
00016  * You should have received a copy of the GNU General Public License
00017  * along with this program; if not, write to the Free Software
00018  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
00019  *
00020  */
00021 
00022 #include "Complex.hxx"
00023 #include "FDCombFilter.hxx"
00024 
00025 #define CLASS "FDCombFilter"
00026 
00027 namespace CLAM {
00028 
00029 
00030         /* Processing  object Method  implementations */
00031 
00032         FDCombFilter::FDCombFilter(const Config &c)
00033                 : mFreq("Frequency",this)
00034         {
00035                 mFreq.DoControl(0);
00036                 Configure(c);
00037         }
00038 
00039         FDCombFilter::~FDCombFilter()
00040         {}
00041 
00042 
00043         /* The supervised Do() function */
00044 
00045         bool  FDCombFilter::Do() 
00046         {
00047                 CLAM_ASSERT(false,CLASS"::Do(): Supervised mode not implemented");
00048                 return false;
00049         }
00050 
00051         
00052         /* The  unsupervised Do() function */
00053         bool  FDCombFilter::Do(const Spectrum& input, Spectrum& output)
00054         {
00055                 if (mFreq.GetLastValue() <= 0) return false;
00056 
00057                 output.SetSize(input.GetSize());
00058                 Spectrum tmpSpec=input;
00059                 bool wasDB=false;
00060                 if(output.GetScale()==EScale::eLog)
00061                 {
00062                         wasDB=true;
00063                         output.SetScale(EScale::eLinear);
00064                 }
00065                 
00066                 tmpSpec.ToLinear();
00067 
00068                 
00069                 TData samplingRate=input.GetSpectralRange()*2;
00070                 const TSize sizeSpectrum=input.GetSize();
00071                 TData pitch=mFreq.GetLastValue();
00072                 TData period = pitch /  samplingRate * sizeSpectrum * 2.0; 
00073                 DataArray & inputMag = input.GetMagBuffer();
00074                 DataArray & inputPhase = input.GetPhaseBuffer();
00075                 DataArray & outputMag = output.GetMagBuffer();
00076                 DataArray & outputPhase = output.GetPhaseBuffer();
00077                 
00078                 TData twoPiOverPeriod = TWO_PI/period;
00079                 TData oneOverTwo = 1./2.0;
00080                 for(unsigned i=0; i<sizeSpectrum; i++)
00081                 {
00082                         //todo: this loop is very inefficient because of the sin and cos but there are ways of optimizing
00083                         //these kind of iterative sine computations
00084                         TData combReal = (1.f +CLAM_cos(i*twoPiOverPeriod)) * oneOverTwo;
00085                         TData combImag = (1.f -CLAM_sin(i*twoPiOverPeriod)) * oneOverTwo;
00086                         
00087                         TData mag=inputMag[i];
00088                         TData phase=inputPhase[i];
00089                         TData real=mag*CLAM_cos(phase);
00090                         TData imag=mag*CLAM_sin(phase);
00091 
00092                         TData newReal=real*combReal-imag*combImag;
00093                         TData newImag=real*combImag+imag*combReal;
00094                         TData newMag=CLAM_sqrt(newReal*newReal+newImag*newImag);
00095                         TData newPhase=CLAM_atan2(newImag,newReal);
00096                         
00097                         outputMag[i] = newMag;
00098                         outputPhase[i] = newPhase;
00099                 }
00100 
00101                 if(wasDB) output.ToDB();
00102 
00103                 return true;
00104         }
00105 
00106 
00107 };//namespace CLAM
00108 
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