marytts.signalproc.filter

Class FIRFilter

java.lang.Object

marytts.signalproc.filter.FIRFilter

All Implemented Interfaces:

InlineDataProcessor

Direct Known Subclasses:

AveragingFilter, BandPassFilter, BandRejectFilter, HighPassFilter, LowPassFilter

public class FIRFilter
extends Object
implements InlineDataProcessor

Author:

Marc Schröder A filter corresponding to a finite-impulse-response LTI system. The filtering of the input signal corresponds to a convolution with the impulse response of the system.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
class	FIRFilter.FIROutput

Field Summary

Fields

Modifier and Type	Field and Description
protected double[]	denumeratorCoefficients
protected int	impulseResponseLength
protected int	sliceLength
protected double[]	transformedIR

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	FIRFilter() Create a new, uninitialised FIR filter.
	FIRFilter(double[] impulseResponse) Create a new Finite Impulse Response filter.
	FIRFilter(double[] impulseResponse, int len)

Method Summary

Methods

Modifier and Type	Method and Description
double[]	apply(double[] signal) Apply this filter to the given input signal.
DoubleDataSource	apply(DoubleDataSource signal) Apply this filter to the given input signal.
void	applyInline(double[] data, int off, int len) Perform some in-place processing on the given data.
double[]	getDenumeratorCoefficients()
int	getImpulseResponseLength()
protected void	initialise(double[] impulseResponse, int sliceLen) Initialise the Finite Impulse Response filter.

Methods inherited from class java.lang.Object

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

Field Detail

transformedIR

protected double[] transformedIR

impulseResponseLength

protected int impulseResponseLength

sliceLength

protected int sliceLength

denumeratorCoefficients

protected double[] denumeratorCoefficients

Constructor Detail

FIRFilter

protected FIRFilter()

Create a new, uninitialised FIR filter. Subclasses need to call check initialise(double[] impulseResponse, int sliceLen) .

FIRFilter

public FIRFilter(double[] impulseResponse)

Create a new Finite Impulse Response filter.

Parameters:

impulseResponse - the impulse response signal

FIRFilter

public FIRFilter(double[] impulseResponse,
         int len)

Method Detail

initialise

protected void initialise(double[] impulseResponse,
              int sliceLen)

Initialise the Finite Impulse Response filter.

Parameters:

impulseResponse - the impulse response signal

sliceLen - the length of the slices in which to process the input data. IMPORTANT: impulseResponse.length+sliceLength must be a power of two (256, 512, etc.)

Throws:

IllegalArgumentException - if the slice length is shorter than the impulse response length, or it the sum of both lengths is not a power of two.

apply

public DoubleDataSource apply(DoubleDataSource signal)

Apply this filter to the given input signal. The input signal is filtered piece by piece, as it is read from the data source returned by this method. This is the recommended way to filter longer signals.

Parameters:

signal - the signal to which this filter should be applied

Returns:

a DoubleDataSource from which the data can be read

apply

public double[] apply(double[] signal)

Apply this filter to the given input signal. This method filters the entire signal, and returns the entire filtered signal. For long signals, it is better to use apply(DoubleDataSource).

Parameters:

signal - the signal to which this filter should be applied

Returns:

the filtered signal.

applyInline

public void applyInline(double[] data,
               int off,
               int len)

Description copied from interface: InlineDataProcessor

Perform some in-place processing on the given data.

Specified by:

applyInline in interface InlineDataProcessor

Parameters:

data - data

off - off

len - len

getImpulseResponseLength

public int getImpulseResponseLength()

getDenumeratorCoefficients

public double[] getDenumeratorCoefficients()