/* |
File: Biquad.h |
Abstract: Biquad.h |
Version: 1.0.1 |
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*/ |
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//~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ |
// Biquad.h |
// |
// A generic biquad (two zero - two pole) IIR filter: |
// |
// lopass |
// hipass |
// parametric peaking |
// low shelving |
// high shelving |
//~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ |
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#ifndef __Biquad |
#define __Biquad |
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#include <math.h> |
#include <stdio.h> |
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class Complex; |
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class Biquad |
{ |
public: |
Biquad(); |
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void Reset(); |
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static void GetLopassParams( float inFreq, |
float &a0, |
float &a1, |
float &a2, |
float &b1, |
float &b2 ); |
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// version which also has resonance parameter |
static void GetLopassParams( float inFreq, |
float inResonance, |
float &a0, |
float &a1, |
float &a2, |
float &b1, |
float &b2 ); |
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static void GetHipassParams( float inFreq, |
float &a0, |
float &a1, |
float &a2, |
float &b1, |
float &b2 ); |
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// version which also has resonance parameter |
static void GetHipassParams( float inFreq, |
float inResonance, |
float &a0, |
float &a1, |
float &a2, |
float &b1, |
float &b2 ); |
|
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static void GetLowShelfParams( float inFreq, |
float inDbGain, // +/- 40dB |
float &outA0, |
float &outA1, |
float &outA2, |
float &outB1, |
float &outB2); |
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static void GetHighShelfParams( float inFreq, |
float inDbGain, // +/- 40dB |
float &outA0, |
float &outA1, |
float &outA2, |
float &outB1, |
float &outB2); |
|
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void GetLopassParams( float inFreq ); |
void GetLopassParams( float inFreq, float inResonance ); |
void GetHipassParams( float inFreq ); |
void GetHipassParams( float inFreq, float inResonance ); |
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void GetLowShelfParams( float inFreq, float inDbGain ); |
void GetHighShelfParams( float inFreq, float inDbGain ); |
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void GetAllpassParams( const Complex &inComplexPole ); |
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void GetNotchParams( float inFreq, |
float inQ ); |
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static void PolarToRect( float inTheta, |
float inMag, |
float &outX, |
float &outY ); |
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static void ConjugateRootToQuadCoeffs( float inTheta, |
float inMag, |
float &out0, |
float &out1, |
float &out2 ); |
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static void RealRootsToQuadCoeffs( float inRoot1, |
float inRoot2, |
float &out0, |
float &out1, |
float &out2 ); |
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void SetZeroConjugateRoot( float inZeroTheta, |
float inZeroMag ); |
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void SetPoleConjugateRoot( float inPoleTheta, |
float inPoleMag ); |
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void SetZeroConjugateRoot( const Complex &inComplexZero ); |
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void SetPoleConjugateRoot( const Complex &inComplexPole ); |
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void SetZeroRealRoots( float inRoot1, |
float inRoot2 ); |
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void SetPoleRealRoots( float inRoot1, |
float inRoot2 ); |
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void Process( const float *inSourceP, |
float *inDestP, |
int inFramesToProcess, |
int inInputNumberOfChannels, |
int inOutputNumberOfChannels |
); |
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inline float Process1( float x) |
{ |
float y = mA0*x + mA1*mX1 + mA2*mX2 - mB1*mY1 - mB2*mY2; |
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mX2 = mX1; |
mX1 = x; |
mY2 = mY1; |
mY1 = y; |
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return y; |
} |
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private: |
float mA0; |
float mA1; |
float mA2; |
float mB1; |
float mB2; |
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float mX1; |
float mX2; |
float mY1; |
float mY2; |
}; |
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const double kInv1200 = 1.0 / 1200.0; |
const double kInv440 = 1.0 / 440.0; |
const double kInvLog2 = 1.0 / log(2.0); |
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inline double AbsoluteCentsToHertz(double inAbsCents) {return 440.0 * pow(2.0, (inAbsCents - 6900.0) * kInv1200 );}; |
inline double HertzToAbsoluteCents(double inHertz) {return 1200.0 * kInvLog2 * log(inHertz * kInv440) + 6900.0;}; |
#define kMinAbsoluteCents 1200.0 /* 0 is approx 8.175799Hz :: 1200.0 is approx 16Hz */ |
#define kMaxAbsoluteCents 15023.0 /* approx 48000Hz */ |
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#endif // __Biquad |
