org.das2.math.fft

Class FFTUtil

java.lang.Object

org.das2.math.fft.FFTUtil

public class FFTUtil
extends java.lang.Object

Constructor Summary

Constructors

Constructor and Description
FFTUtil()

Method Summary

Modifier and Type	Method and Description
static ComplexArray.Double	fft(GeneralFFT fft, VectorDataSet vds, Units units)
static VectorDataSet	fftPower(GeneralFFT fft, VectorDataSet vds)
static VectorDataSet	fftPower(GeneralFFT fft, VectorDataSet vds, VectorDataSet weights) Produces the power spectrum of the dataset.
static double[]	getFrequencyDomainTags(double fs, int size)
static VectorDataSet	getWindow10PercentEdgeCosine(int size)
static VectorDataSet	getWindowUnity(int size)

Methods inherited from class java.lang.Object

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

Constructor Detail

FFTUtil

public FFTUtil()

Method Detail

fftPower

public static VectorDataSet fftPower(GeneralFFT fft,
                                     VectorDataSet vds)

getWindowUnity

public static VectorDataSet getWindowUnity(int size)

getWindow10PercentEdgeCosine

public static VectorDataSet getWindow10PercentEdgeCosine(int size)

fftPower

public static VectorDataSet fftPower(GeneralFFT fft,
                                     VectorDataSet vds,
                                     VectorDataSet weights)

Produces the power spectrum of the dataset. This is the length of the fourier components squared, normalized by the bandwidth. The result dataset has dimensionless yunits.

Parameters:

vds - VectorDataSet with x units TimeLocationUnits.

fft

public static ComplexArray.Double fft(GeneralFFT fft,
                                      VectorDataSet vds,
                                      Units units)

getFrequencyDomainTags

public static double[] getFrequencyDomainTags(double fs,
                                              int size)

Parameters:

fs - the sampling frequency

Returns:

the frequencies of the bins