FFT Class Reference

A very minimal FFT class. More...

Classes
struct	Complex
	A complex number, for the purposes of the FFT class. More...

Public Member Functions
	FFT (int order, bool isInverse)
	Initialises an object for performing either a forward or inverse FFT with the given size. More...
	~FFT ()
	Destructor. More...
void	perform (const Complex *input, Complex *output) const noexcept
	Performs an out-of-place FFT, either forward or inverse depending on the mode that was passed to this object's constructor. More...
void	performRealOnlyForwardTransform (float *inputOutputData) const noexcept
	Performs an in-place forward transform on a block of real data. More...
void	performRealOnlyInverseTransform (float *inputOutputData) const noexcept
	Performs a reverse operation to data created in performRealOnlyForwardTransform(). More...
void	performFrequencyOnlyForwardTransform (float *inputOutputData) const noexcept
	Takes an array and simply transforms it to the frequency spectrum. More...
int	getSize () const noexcept
	Returns the number of data points that this FFT was created to work with. More...

Detailed Description

A very minimal FFT class.

This is only a simple low-footprint implementation and isn't tuned for speed - it may be useful for simple applications where one of the more complex FFT libraries would be overkill. (But in the future it may end up becoming optimised of course...)

The FFT class itself contains lookup tables, so there's some overhead in creating one, you should create and cache an FFT object for each size/direction of transform that you need, and re-use them to perform the actual operation.

Constructor & Destructor Documentation

FFT::FFT	(	int	order,
		bool	isInverse
	)

Initialises an object for performing either a forward or inverse FFT with the given size.

The the number of points the FFT will operate on will be 2 ^ order.

FFT::~FFT

(

)

Destructor.

Member Function Documentation

void FFT::perform ( const Complex *  input, Complex *  output  ) const

noexcept

Performs an out-of-place FFT, either forward or inverse depending on the mode that was passed to this object's constructor.

The arrays must contain at least getSize() elements.

void FFT::performRealOnlyForwardTransform ( float *  inputOutputData ) const

noexcept

Performs an in-place forward transform on a block of real data.

The size of the array passed in must be 2 * getSize(), and the first half should contain your raw input sample data. On return, the array will contain complex frequency + phase data, and can be passed to performRealOnlyInverseTransform() in order to convert it back to reals.

void FFT::performRealOnlyInverseTransform ( float *  inputOutputData ) const

noexcept

Performs a reverse operation to data created in performRealOnlyForwardTransform().

The size of the array passed in must be 2 * getSize(), containing complex frequency and phase data. On return, the first half of the array will contain the reconstituted samples.

void FFT::performFrequencyOnlyForwardTransform ( float *  inputOutputData ) const

noexcept

Takes an array and simply transforms it to the frequency spectrum.

This may be handy for things like frequency displays or analysis.

int FFT::getSize ( ) const

noexcept

Returns the number of data points that this FFT was created to work with.

References JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR, and JUCE_PUBLIC_IN_DLL_BUILD.

---

The documentation for this class was generated from the following file:

• juce_FFT.h