signalsmith::spectral::WindowedFFT< Sample > Class Template Reference

#include <spectral.h>

Detailed Description

template<typename Sample>
class signalsmith::spectral::WindowedFFT< Sample >

An FFT with built-in windowing and round-trip scaling.

This uses a Modified Real FFT, which applies half-bin shift before the transform. The result therefore has N/2 bins, centred at the frequencies: (i + 0.5)/N.

This avoids the awkward (real-valued) bands for DC-offset and Nyquist.

Static Methods
static int	fastSizeAbove (int size, int divisor=1)
	Returns a fast FFT size <= size More...
static int	fastSizeBelow (int size, int divisor=1)
	Returns a fast FFT size >= size More...

Methods
	WindowedFFT (int size, int rotateSamples=0)
template<class WindowFn >
	WindowedFFT (int size, WindowFn fn, Sample windowOffset=0.5, int rotateSamples=0)
std::vector< Sample > &	setSizeWindow (int size, int rotateSamples=0)
	Sets the size, returning the window for modification (initially all 1s) More...
template<class WindowFn >
void	setSize (int size, WindowFn fn, Sample windowOffset=0.5, int rotateSamples=0)
	Sets the FFT size, with a user-defined functor for the window. More...
void	setSize (int size, int rotateSamples=0)
	Sets the size (using the default Blackman-Harris window) More...
const std::vector< Sample > &	window () const
int	size () const
template<class Input , class Output >
void	fft (Input &&input, Output &&output)
	Performs an FFT (with windowing) More...
template<class Input , class Output >
void	fftRaw (Input &&input, Output &&output)
	Performs an FFT (no windowing or rotation) More...
template<class Input , class Output >
void	ifft (Input &&input, Output &&output)
	Inverse FFT, with windowing and 1/N scaling. More...
template<class Input , class Output >
void	ifftRaw (Input &&input, Output &&output)
	Performs an IFFT (no windowing or rotation) More...

Method Details

fastSizeAbove()

template<typename Sample >

static int signalsmith::spectral::WindowedFFT< Sample >::fastSizeAbove ( int  size, int  divisor = 1  )

inlinestatic

Returns a fast FFT size <= size

fastSizeBelow()

template<typename Sample >

static int signalsmith::spectral::WindowedFFT< Sample >::fastSizeBelow ( int  size, int  divisor = 1  )

inlinestatic

Returns a fast FFT size >= size

fft()

template<typename Sample >

template<class Input , class Output >

void signalsmith::spectral::WindowedFFT< Sample >::fft ( Input &&  input, Output &&  output  )

inline

Performs an FFT (with windowing)

fftRaw()

template<typename Sample >

template<class Input , class Output >

void signalsmith::spectral::WindowedFFT< Sample >::fftRaw ( Input &&  input, Output &&  output  )

inline

Performs an FFT (no windowing or rotation)

ifft()

template<typename Sample >

template<class Input , class Output >

void signalsmith::spectral::WindowedFFT< Sample >::ifft ( Input &&  input, Output &&  output  )

inline

Inverse FFT, with windowing and 1/N scaling.

ifftRaw()

template<typename Sample >

template<class Input , class Output >

void signalsmith::spectral::WindowedFFT< Sample >::ifftRaw ( Input &&  input, Output &&  output  )

inline

Performs an IFFT (no windowing or rotation)

setSize() [1/2]

template<typename Sample >

void signalsmith::spectral::WindowedFFT< Sample >::setSize ( int  size, int  rotateSamples = 0  )

inline

Sets the size (using the default Blackman-Harris window)

setSize() [2/2]

template<typename Sample >

template<class WindowFn >

void signalsmith::spectral::WindowedFFT< Sample >::setSize ( int  size, WindowFn  fn, Sample  windowOffset = 0.5, int  rotateSamples = 0  )

inline

Sets the FFT size, with a user-defined functor for the window.

setSizeWindow()

template<typename Sample >

std::vector<Sample>& signalsmith::spectral::WindowedFFT< Sample >::setSizeWindow ( int  size, int  rotateSamples = 0  )

inline

Sets the size, returning the window for modification (initially all 1s)