comirva.audio.util
Class FFT

java.lang.Object
  comirva.audio.util.FFT

public final class FFT
extends Object

Class for computing a windowed fast Fourier transform. Implements some of the window functions for the STFT from Harris (1978), Proc. IEEE, 66, 1, 51-83.

Field Summary

static int	FFT_FORWARD used in fft(double[], double[], int) to specify a forward Fourier transform
static int	FFT_INLINE_POWER_PHASE used to specify a inline power phase Fourier transform
static int	FFT_MAGNITUDE used to specify a magnitude Fourier transform
static int	FFT_MAGNITUDE_PHASE used to specify a magnitude phase Fourier transform
static int	FFT_NORMALIZED_POWER used to specify a normalized power Fourier transform
static int	FFT_POWER used to specify a power Fourier transform
static int	FFT_POWER_PHASE used to specify a power phase Fourier transform
static int	FFT_REVERSE used in fft(double[], double[], int) to specify an inverse Fourier transform
static int	WND_BH3 used to specify a 61-dB 3-sample Blackman-Harris window function
static int	WND_BH3MIN used to specify a minimum 3-sample Blackman-Harris window function
static int	WND_BH4 used to specify a 74-dB 4-sample Blackman-Harris window function
static int	WND_BH4MIN used to specify a minimum 4-sample Blackman-Harris window function
static int	WND_GAUSS used to specify a Gaussian window function
static int	WND_HAMMING used to specify a Hamming window function
static int	WND_HANNING used to specify a Hanning window function
static int	WND_HANNINGZ used to specify a Hanning Z window function
static int	WND_NONE used to specify a rectangular window function
static int	WND_RECT used to specify a rectangular window function
static int	WND_USER_DEFINED used to specify a Hanning window function

Constructor Summary

FFT(int transformationType, int windowSize)

FFT(int transformationType, int windowSize, double[] windowFunction)

FFT(int transformationType, int windowSize, int windowFunctionType)

FFT(int transformationType, int windowSize, int windowFunctionType, int support)

Method Summary

int	getTransformationType()
int	getWindowFunctionType()
void	setWindowFunction(int windowFunctionType, int support) This method allows to change the window function to one of the predefined window function types.
void	transform(double[] re, double[] im)

Methods inherited from class java.lang.Object

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

Field Detail

FFT_FORWARD

public static final int FFT_FORWARD

used in fft(double[], double[], int) to specify a forward Fourier transform

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Constant Field Values

FFT_REVERSE

public static final int FFT_REVERSE

used in fft(double[], double[], int) to specify an inverse Fourier transform

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Constant Field Values

FFT_MAGNITUDE

public static final int FFT_MAGNITUDE

used to specify a magnitude Fourier transform

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Constant Field Values

FFT_MAGNITUDE_PHASE

public static final int FFT_MAGNITUDE_PHASE

used to specify a magnitude phase Fourier transform

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Constant Field Values

FFT_NORMALIZED_POWER

public static final int FFT_NORMALIZED_POWER

used to specify a normalized power Fourier transform

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Constant Field Values

FFT_POWER

public static final int FFT_POWER

used to specify a power Fourier transform

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Constant Field Values

FFT_POWER_PHASE

public static final int FFT_POWER_PHASE

used to specify a power phase Fourier transform

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Constant Field Values

FFT_INLINE_POWER_PHASE

public static final int FFT_INLINE_POWER_PHASE

used to specify a inline power phase Fourier transform

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Constant Field Values

WND_NONE

public static final int WND_NONE

used to specify a rectangular window function

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Constant Field Values

WND_RECT

public static final int WND_RECT

used to specify a rectangular window function

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Constant Field Values

WND_HAMMING

public static final int WND_HAMMING

used to specify a Hamming window function

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Constant Field Values

WND_BH3

public static final int WND_BH3

used to specify a 61-dB 3-sample Blackman-Harris window function

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Constant Field Values

WND_BH4

public static final int WND_BH4

used to specify a 74-dB 4-sample Blackman-Harris window function

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Constant Field Values

WND_BH3MIN

public static final int WND_BH3MIN

used to specify a minimum 3-sample Blackman-Harris window function

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Constant Field Values

WND_BH4MIN

public static final int WND_BH4MIN

used to specify a minimum 4-sample Blackman-Harris window function

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Constant Field Values

WND_GAUSS

public static final int WND_GAUSS

used to specify a Gaussian window function

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Constant Field Values

WND_HANNING

public static final int WND_HANNING

used to specify a Hanning window function

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Constant Field Values

WND_USER_DEFINED

public static final int WND_USER_DEFINED

used to specify a Hanning window function

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Constant Field Values

WND_HANNINGZ

public static final int WND_HANNINGZ

used to specify a Hanning Z window function

See Also:

Constant Field Values

Constructor Detail

FFT

public FFT(int transformationType,
           int windowSize)

FFT

public FFT(int transformationType,
           int windowSize,
           int windowFunctionType)

FFT

public FFT(int transformationType,
           int windowSize,
           int windowFunctionType,
           int support)

FFT

public FFT(int transformationType,
           int windowSize,
           double[] windowFunction)

Method Detail

transform

public void transform(double[] re,
                      double[] im)

setWindowFunction

public void setWindowFunction(int windowFunctionType,
                              int support)

This method allows to change the window function to one of the predefined window function types.

Parameters:

windowFunctionType - int the type of the window function

support - int

getTransformationType

public int getTransformationType()

getWindowFunctionType

public int getWindowFunctionType()