IFFT

The IFFT ( Inverse Fast Fourier Transformation ) is the abbreviation for the inverse function for fast Fourier transformation (FFT). It converts / transforms a signal from the frequency domain back into the time domain .

The IFFT and FFT are very similar. The only difference is that with the IFFT the signs of the exponents of the complex rotation factors have to be inverted and the result has to be multiplied by the factor 1 / n. This additional multiplication can be carried out in the implementation as a shift operation if the factor n in the FFT is a power of two. A more detailed description of this relationship is given in the article on the FFT .

application areas

• Synthesis of time signals in the frequency domain (e.g. generation of electronic sounds)
• digital modulation method (e.g. multi-carrier method: OFDM , English Orthogonal Frequency Division Multiplexing )
• Calculation of the filter coefficients for digital filters (e.g. using the window method )
• Filtering in the frequency domain and reverse transformation in the time domain
• Fourier inverse transformation from the frequency to the time domain in signal analysis

More areas of application can also be found here in the article about the FFT .