net.beadsproject.beads.ugens

Class IIRFilter

java.lang.Object

net.beadsproject.beads.core.Bead

net.beadsproject.beads.core.UGen

net.beadsproject.beads.ugens.IIRFilter

Direct Known Subclasses:

AllpassFilter, BiquadFilter, CombFilter, LPRezFilter, OnePoleFilter

public abstract class IIRFilter
extends UGen

An abstract class that provides methods for analyzing infinite impulse response (IIR) filters. IIR filters built on this class should implement getFilterResponse(float) appropriately.

Version:

0.9.5

Author:

Benito Crawford

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	IIRFilter.IIRFilterAnalysis A holder class for the various filter analysis data.

Nested classes/interfaces inherited from class net.beadsproject.beads.core.UGen

UGen.OutputInitializationRegime, UGen.OutputPauseRegime

Field Summary

Fields inherited from class net.beadsproject.beads.core.UGen

bufferSize, bufIn, bufOut, context, ins, outputInitializationRegime, outputPauseRegime, outs

Constructor Summary

Constructors

Constructor and Description
IIRFilter(AudioContext context, int ins, int outs)

Method Summary

Modifier and Type	Method and Description
protected static IIRFilter.IIRFilterAnalysis	analyzeFilter(float[] bs, float[] as, float freq, float samplingFreq) Does our analysis at the specified frequency.
static IIRFilter.IIRFilterAnalysis	calculateFilterResponse(float[] bs, float[] as, float freq, float samplingFreq) Gets an IIRFilterAnalysis object filled with the filter response characteristics for the specified frequency: frequency response (real), frequency response (imaginary), amplitude response, phase response, phase delay, group delay.
protected static double	calculateGroupDelay(float[] bs, float[] as, float freq, float samplingFreq)
float	getAmplitudeResponse(float freq) Gets the filter's amplitude response at the specified frequency.
abstract IIRFilter.IIRFilterAnalysis	getFilterResponse(float freq)
float	getGroupDelay(float freq) Gets an estimate of the filter's group delay at the specified frequency.
float	getPhaseDelay(float freq) Gets the filter's phase delay at the specified frequency.
float	getPhaseResponse(float freq) Gets the filter's phase response at the specified frequency.

Methods inherited from class net.beadsproject.beads.core.UGen

addDependent, addInput, addInput, calculateBuffer, clearDependents, clearInputConnections, containsInput, crossfadeInput, getConnectedInputs, getContext, getEnvelopes, getIns, getNumberOfConnectedUGens, getNumberOfDependents, getOutBuffer, getOuts, getTimeTakenLastUpdate, getValue, getValue, getValueDouble, getValueDouble, initializeOuts, isTimerMode, isUpdated, noInputs, pause, printInBuffers, printInputList, printOutBuffers, removeAllConnections, removeConnection, removeDependent, setOutsToPause, setTimerMode, setValue, update, zeroIns, zeroOuts

Methods inherited from class net.beadsproject.beads.core.Bead

getKillListener, getName, isDeleted, isPaused, kill, message, messageReceived, setKillListener, setName, start, toString

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

IIRFilter

public IIRFilter(AudioContext context,
                 int ins,
                 int outs)

Method Detail

getFilterResponse

public abstract IIRFilter.IIRFilterAnalysis getFilterResponse(float freq)

getAmplitudeResponse

public float getAmplitudeResponse(float freq)

Gets the filter's amplitude response at the specified frequency.

Parameters:

freq - The frequency to evaluate.

Returns:

The amplitude response.

getPhaseResponse

public float getPhaseResponse(float freq)

Gets the filter's phase response at the specified frequency.

Parameters:

freq - The frequency to evaluate.

Returns:

The phase response.

getPhaseDelay

public float getPhaseDelay(float freq)

Gets the filter's phase delay at the specified frequency.

Parameters:

freq - The frequency to evaluate.

Returns:

The phase delay.

getGroupDelay

public float getGroupDelay(float freq)

Gets an estimate of the filter's group delay at the specified frequency.

Parameters:

freq - The frequency to evaluate.

Returns:

The group delay.

calculateFilterResponse

public static IIRFilter.IIRFilterAnalysis calculateFilterResponse(float[] bs,
                                                                  float[] as,
                                                                  float freq,
                                                                  float samplingFreq)

Gets an IIRFilterAnalysis object filled with the filter response characteristics for the specified frequency: frequency response (real), frequency response (imaginary), amplitude response, phase response, phase delay, group delay.

Parameters:

bs - The b coefficients (corresponding to the x(n) terms of the filter algorithm.

as - The a coefficients (corresponding to the y(n) terms of the filter algorithm.

freq - The frequency to evaluate.

samplingFreq - The sampling frequency.

Returns:

The IIRFilterAnalysis object.

calculateGroupDelay

protected static double calculateGroupDelay(float[] bs,
                                            float[] as,
                                            float freq,
                                            float samplingFreq)

analyzeFilter

protected static IIRFilter.IIRFilterAnalysis analyzeFilter(float[] bs,
                                                           float[] as,
                                                           float freq,
                                                           float samplingFreq)

Does our analysis at the specified frequency.

Parameters:

freq - The frequency to analyze.