API / geotoolkit / seismic / analysis / transforms / AbstractFFT / AbstractFFT
transforms.AbstractFFT.AbstractFFT
Defines a base class for various discrete fourier transforms Ported from the Saddleback Geosolution's Java implementation
AbstractFFT
Constructors
Methods
Constructors
• new AbstractFFT(real?, imag?, sampleRate?, length?)
| Name | Type | Description |
|---|---|---|
Optional real | Float32Array | The real component of the signal |
Optional imag | Float32Array | The imaginary component of th signal |
Optional sampleRate | number | The data sampling rate in milliseconds |
Optional length | number | The desired length of the transform, must be a power of 2 |
Methods
▸ getClassName(): string
string
▸ getFDSampleRate(): number
Returns the Frequency Domain sample rate. This is the frequency domain sample spacing.
number
FrequencySampleRate Frequency Domain sampling rate in milliseconds (ms)
▸ getHalfLength(): number
Returns half of the length of the calculated FFT (power-of-2)
number
halfLength The half-length of the FFT
▸ getImaginaryComponents(getReference): Float32Array
Gets the imaginary signal component
| Name | Type | Description |
|---|---|---|
getReference | boolean | If true then the reference to signal will be returned. |
Float32Array
realComponent The real signal component
▸ getLength(): number
Returns the length of the calculated FFT (power-of-2).
number
length The length of calculated FFT
▸ getLog2Length(): number
Returns the base 2 logarithm of the transform length
number
logLength Log base 2 of the transform length
▸ getNumberNonZeroSamples(): number
Returns the number of non zero samples that were input inot the last FFT. This is the number of live samples (less than or equal to a power-of-2);
number
nonZero The Number of non-zero samples for input signal
▸ getNyquist(): number
Returns the nyquist frequency for the input signal. This is the calculated nyquist frequency based on the supplied sample rate. This is also known as the folding frequency
number
nyquist The nyquist frequency
▸ getNyquistLength(): number
Returns the sample number of frequency that equals nyquist frequency.
number
frequency The Nyquist frequency
▸ getRealComponents(getReference): Float32Array
Gets the real signal component
| Name | Type | Description |
|---|---|---|
getReference | boolean | If true then the reference to signal will be returned. |
Float32Array
realComponent The real signal component
▸ getSampleRate(): number
Returns the input sample rate of the signal in Milliseconds. This is the sample rate set before calculation.
number
sampleRate Sample rate of input signal in milliseconds (ms)
▸ inverseTransform(): void
Performs the inverse transform
void
▸ setData(real?, imag?, sampleRate?, length?): AbstractFFT
Sets the real and imaginary result array
| Name | Type | Description |
|---|---|---|
Optional real | number[] | Float32Array | The real component of the signal |
Optional imag | number[] | Float32Array | The imaginary component of the signal |
Optional sampleRate | string | number | The data sampling rate in milliseconds |
Optional length | string | number | The desired length of the transform, must be a power of 2 |
▸ setDataUnsafe(real, imag): AbstractFFT
Sets the real and imaginary arrays directly
| Name | Type | Description |
|---|---|---|
real | Float32Array | The imaginary component of the signal |
imag | Float32Array | The real component of the signal |
▸ setSampleRate(sampleRate): AbstractFFT
Sets the input sample rate of the signal in Milliseconds.
| Name | Type | Description |
|---|---|---|
sampleRate | number | Sample rate of input signal in milliseconds (ms) |
this
▸ transform(): void
Performs the transform
void
▸ Static getClassName(): string
string