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/*
* Copyright (C) 2009 Club de Audio FIUBA (Santiago Piccinini, Hernan Ordiales)
*
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
*/
#ifndef _Notch2ndOrder_
#define _Notch2ndOrder_
#include <CLAM/Processing.hxx>
#include <CLAM/AudioInPort.hxx>
#include <CLAM/AudioOutPort.hxx>
#include <CLAM/ProcessingConfig.hxx>
#include "../Filter/Filter.hxx"
#include <math.h>
namespace CLAM {
/** \brief 2nd order fixed notch filter
*
* Transfer function
* Given:
* th = 2 * pi * centralFrequency * samplePeriod
* d = exp(-2 * pi * bandwidth/2.0 * samplePeriod)
* a = ( 1 + d^2) / 2
* b = ( 1 + d^2) * cos(th)
*
* then:
* z^2 - 2 cos (th) z + 1
* H(z) = a ----------------------
* z^2 - b z + d^2
*
* Diference equation:
* y(n) - b * y(n-1) + d^2 * y(n-2) = a * x(n) - a*2*cos(th) * x(n-1) + a * x(n-2)
*/
class Notch2ndOrderConfig : public ProcessingConfig
{
public:
DYNAMIC_TYPE_USING_INTERFACE( Notch2ndOrderConfig, 2, ProcessingConfig );
DYN_ATTRIBUTE( 0, public, TData, CentralFrequency );
DYN_ATTRIBUTE( 1, public, TData, Bandwidth );
protected:
void DefaultInit( )
{
AddAll();
UpdateData();
SetCentralFrequency(200.0);
SetBandwidth(20.0);
}
};
class Notch2ndOrder: public Processing
{
/** This method returns the name of the object
* @return Char pointer with the name of object
*/
const char *GetClassName() const { return "Notch2ndOrder"; }
/** Ports **/
AudioInPort mInput;
AudioOutPort mOutput;
/** **/
TData centralFrequency;
TData bandwidth;
public:
Notch2ndOrder()
:
mInput("Input", this),
mOutput("Output", this)
{
Configure( mConfig );
}
~Notch2ndOrder() {}
typedef Notch2ndOrderConfig Config;
bool Do()
{
mFilter.Do( mInput.GetAudio(), mOutput.GetAudio() );
mInput.Consume();
mOutput.Produce();
return true;
}
const CLAM::ProcessingConfig & GetConfig() const
{
return mConfig;
}
protected:
bool ConcreteConfigure(const CLAM::ProcessingConfig & config)
{
CopyAsConcreteConfig(mConfig, config);
FilterConfig filter_cfg;
filter_cfg.SetAmountOfInputCoefficients(3);
filter_cfg.SetAmountOfOutputCoefficients(3);
mFilter.Configure( filter_cfg );
centralFrequency = mConfig.GetCentralFrequency();
bandwidth = mConfig.GetBandwidth();
TData samplePeriod = 1.0/ mInput.GetSampleRate();
//Auxiliar machinery
TData aux_th = 2 * 3.1416 * centralFrequency * samplePeriod;
TData aux_d = exp( -2 * 3.1416 * (bandwidth / 2.0) * samplePeriod);
TData aux_a = (1 + pow(aux_d, 2)) / 2.0;
TData aux_b = (1 + pow(aux_d, 2)) * cos(aux_th);
//FIR coefs
TData b_k[] = {aux_a, -aux_a*2*cos(aux_th), aux_a};
char bkstr[5];
for(unsigned i=0;i<3;i++)
{
sprintf(bkstr, "b_%i", i);
SendFloatToInControl(mFilter, bkstr, b_k[i]);
}
//IIR coefs
TData a_k[] = {1, -aux_b, pow(aux_d, 2)};
char akstr[5];
for(unsigned i=0;i<3;i++)
{
sprintf(akstr, "a_%i", i);
SendFloatToInControl(mFilter, akstr, a_k[i]);
}
return true;
}
private:
/** Child processings **/
Filter mFilter;
/** Configuration **/
Config mConfig;
};
};//namespace CLAM
#endif // _Notch2ndOrder_
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