# IFFT

## Purpose:

Calculates the Inverse Fast Fourier Transform
of a series or series expression with the result in Cartesian (Real/Imaginary)
form.

## Syntax:

IFFT(series)

series |
- |
A series or array. |

## Returns:

A complex series or table in Cartesian
form.

## Example:

W1: 1..5

W2: fft(w1)

W3: real(ifft(W2))

W3 contains the series {1, 2, 3, 4, 5}.

## Remarks:

FFT and IFFT implement
the discrete Fourier transform pair X[k] and x[n] for series *x* of length N and
start index 1 by:

A *mixed
radix* algorithm is employed to compute the IFFT, however series
with lengths that are a power of 2 will be processed faster than other
series. Use the LENGTH function to
find out if a series is a power of 2 points long.

Use IFFTP to get
magnitude/phase output.

IFFT returns a complex result. Use REAL to obtain the real part.

See DADiSP/FFTXL
to optimize the IFFT computation.

## See Also:

FFT

FFTP

IFFTP

IFFTSHIFT

INVPSD

LENGTH

REAL

## References:

Oppenheim and Schafer.

Digital Signal Processing

Prentice Hall, 1975

Digital Signal Processing Committee

Programs for Digital
Signal Processing

I.E.E.E. Press, 1979