robert@464: //
robert@464: //  Biquad.h
robert@464: //
robert@464: //  Created by Nigel Redmon on 11/24/12
robert@464: //  EarLevel Engineering: earlevel.com
robert@464: //  Copyright 2012 Nigel Redmon
robert@464: //
robert@464: //  For a complete explanation of the Biquad code:
robert@464: //  http://www.earlevel.com/main/2012/11/25/biquad-c-source-code/
robert@464: //
robert@464: //  License:
robert@464: //
robert@464: //  This source code is provided as is, without warranty.
robert@464: //  You may copy and distribute verbatim copies of this document.
robert@464: //  You may modify and use this source code to create binary code
robert@464: //  for your own purposes, free or commercial.
robert@464: //
robert@464: 
robert@464: #ifndef Biquad_h
robert@464: #define Biquad_h
robert@464: 
robert@464: enum {
robert@464:     bq_type_lowpass = 0,
robert@464:     bq_type_highpass,
robert@464:     bq_type_bandpass,
robert@464:     bq_type_notch,
robert@464:     bq_type_peak,
robert@464:     bq_type_lowshelf,
robert@464:     bq_type_highshelf
robert@464: };
robert@464: 
robert@464: class Biquad {
robert@464: public:
robert@464:     Biquad();
robert@464:     Biquad(int type, double Fc, double Q, double peakGainDB);
robert@464:     ~Biquad();
robert@464:     void setType(int type);
robert@464:     void setQ(double Q);
robert@464:     void setFc(double Fc);
robert@464:     void setPeakGain(double peakGainDB);
robert@464:     void setBiquad(int type, double Fc, double Q, double peakGain);
robert@464:     float process(float in);
robert@464:     
robert@464:     double getQ();
robert@464:     double getFc();
robert@464:     double getPeakGain();
robert@464: 
robert@464:     double getStartingQ();
robert@464: 	double getStartingFc();
robert@464: 	double getStartingPeakGain();
robert@464: 
robert@464: protected:
robert@464:     void calcBiquad(void);
robert@464: 
robert@464:     int type;
robert@464:     double a0, a1, a2, b1, b2;
robert@464:     double Fc, Q, peakGain;
robert@464:     double startFc, startQ, startPeakGain;
robert@464:     double z1, z2;
robert@464: };
robert@464: 
robert@464: inline double Biquad::getQ()
robert@464: {
robert@464: 	return Q;
robert@464: }
robert@464: 
robert@464: inline double Biquad::getFc()
robert@464: {
robert@464: 	return Fc;
robert@464: }
robert@464: 
robert@464: inline double Biquad::getPeakGain()
robert@464: {
robert@464: 	return peakGain;
robert@464: }
robert@464: 
robert@464: inline double Biquad::getStartingQ()
robert@464: {
robert@464: 	return startQ;
robert@464: }
robert@464: 
robert@464: inline double Biquad::getStartingFc()
robert@464: {
robert@464: 	return startFc;
robert@464: }
robert@464: 
robert@464: inline double Biquad::getStartingPeakGain()
robert@464: {
robert@464: 	return startPeakGain;
robert@464: }
robert@464: 
robert@464: inline float Biquad::process(float in) {
robert@464:     double out = in * a0 + z1;
robert@464:     z1 = in * a1 + z2 - b1 * out;
robert@464:     z2 = in * a2 - b2 * out;
robert@464:     return out;
robert@464: }
robert@464: 
robert@464: #endif // Biquad_h