The IFFT function uses an inverse Fast Fourier Transform (IFFT) algorithm (also called a Fourier synthesis algorithm) to reverse the Fast Fourier Transform (FFT) performed by the FFT function; that is, the IFFT function takes a frequency domain representation and combines the contributions of all the different frequencies to recover the original signal. A signal can be either real or complex, and can have one, two, or three dimensions. If the signal length is not a power of two, the function either pads or truncates it to the closest power of two.