#include <biquad.h>

Collaboration diagram for Biquad:

Public Member Functions
	Biquad ()

float	filter (float input)

void	reset ()

void	cookSteadyState (float steadyStateInput)

void	configureBandpass (float samplingFrequency, float centerFrequency, float Q)

void	configureLowpass (float samplingFrequency, float cutoffFrequency, float Q=0.54f)

void	configureHighpass (float samplingFrequency, float cutoffFrequency, float Q=0.54f)

Private Attributes
float	a0

float	a1

float	a2

float	b1

float	b2

float	z1

float	z2

Detailed Description

Definition at line 10 of file biquad.h.

Constructor & Destructor Documentation

◆ Biquad()

Biquad::Biquad ( )

Definition at line 12 of file biquad.cpp.

               {
// Default to passthru
    a0 = 1;
    a1 = a2 = b1 = b2 = 0;
 
    reset();
}

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Member Function Documentation

◆ configureBandpass()

void Biquad::configureBandpass	(	float	samplingFrequency,
		float	centerFrequency,
		float	Q
	)

Definition at line 32 of file biquad.cpp.

                                                                                      {
  if (samplingFrequency < 2.5f * centerFrequency) {
    criticalError("Invalid biquad parameters samplingFrequency=%f centerFrequency=%f", samplingFrequency, centerFrequency);
    return;
  }
 
    float K = getK(samplingFrequency, centerFrequency);
    float norm = getNorm(K, Q);
 
    a0 = K / Q * norm;
    a1 = 0;
    a2 = -a0;
    b1 = 2 * (K * K - 1) * norm;
    b2 = (1 - K / Q + K * K) * norm;
}

Referenced by initSoftwareKnock().

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◆ configureHighpass()

void Biquad::configureHighpass	(	float	samplingFrequency,
		float	cutoffFrequency,
		float	Q = `0.54f`
	)

Definition at line 61 of file biquad.cpp.

                                                                                      {
    criticalAssertVoid(samplingFrequency >= 2.5f * cutoffFrequency, "Invalid biquad parameters");
 
    float K = getK(samplingFrequency, cutoffFrequency);
    float norm = getNorm(K, Q);
 
    a0 = 1 * norm;
    a1 = -2 * a0;
    a2 = a0;
    b1 = 2 * (K * K - 1) * norm;
    b2 = (1 - K / Q + K * K) * norm;
}

Referenced by IdleController::init().

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◆ configureLowpass()

void Biquad::configureLowpass	(	float	samplingFrequency,
		float	cutoffFrequency,
		float	Q = `0.54f`
	)

Definition at line 48 of file biquad.cpp.

                                                                                     {
    criticalAssertVoid(samplingFrequency >= 2.5f * cutoffFrequency, "Invalid biquad parameters");
 
    float K = getK(samplingFrequency, cutoffFrequency);
    float norm = getNorm(K, Q);
 
    a0 = K * K * norm;
    a1 = 2 * a0;
    a2 = a0;
    b1 = 2 * (K * K - 1) * norm;
    b2 = (1 - K / Q + K * K) * norm;
}

Referenced by LuaBiQuad::configureLowpass(), FlexConverter::FlexConverter(), FlexSensor::FlexSensor(), and FrequencySensor::initIfValid().

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◆ cookSteadyState()

void Biquad::cookSteadyState ( float steadyStateInput )

Definition at line 84 of file biquad.cpp.

                                                   {
    float Y = steadyStateInput * (a0 + a1 + a2) / (1 + b1 + b2);
 
    float steady_z2 = steadyStateInput * a2 - Y * b2;
    float steady_z1 = steady_z2 + steadyStateInput * a1 - Y * b1;
 
    this->z1 = steady_z1;
    this->z2 = steady_z2;
}

Referenced by LuaBiQuad::filter(), processLastKnockEvent(), and AdcSubscription::UpdateSubscribers().

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◆ filter()

float Biquad::filter ( float input )

Definition at line 74 of file biquad.cpp.

                                {
    float result = input * a0 + z1;
    if (engineConfiguration->verboseQuad) {
        efiPrintf("input %f, a0 %f, z1 %f, result %f", input, a0, z1, result);
    }
    z1 = input * a1 + z2 - b1 * result;
    z2 = input * a2 - b2 * result;
    return result;
}