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inverse Fourier transformation (IFT)

An inverse Fourier transform (IFT) is a mathematical method used to transform signals from the frequency domain to the time domain. It is thus used to determine the time course of a signal from the frequency spectrum and forms the inverse of the Fourier transform, in which a signal is transferred from the time domain to a frequency domain.

There are some relations between mathematical operations in the time and frequency domain. For example, convolution in the time domain corresponds to multiplication in the frequency domain, for which there is a special, optimized implementation in the form of the Fast Fourier Transform( FFT). With these correlations, it is possible, for example, to implement an FIR filter in the frequency domain, transform the input signal into the frequency domain using the Fast Fourier Transform, muliply it, and then transform it back into the time domain.

InWLANs according to 802.11ac, the inverse Fourier transform is used accordingly. Here, frequency-related data from Orthogonal Frequency Division Multiplex( OFDM) is transformed into the time domain for data transmission.

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Englisch: inverse Fourier transformation - IFT
Updated at: 05.05.2014
#Words: 172
Links: method, frequency domain, signal, implementation, fast fourier transformation (FFT)
Translations: DE
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