Understanding the Inverse DFT (FFT)

1. What does an inverse FFT do?
2. What is the inverse DFT?
3. Can we use FFT for IDFT?
4. How do you find the inverse of a fast Fourier transform?

What does an inverse FFT do?

Inverse Fast Fourier transform (IDFT) is an algorithm to undoes the process of DFT. It is also known as backward Fourier transform. It converts a space or time signal to a signal of the frequency domain.

What is the inverse DFT?

An inverse DFT is a Fourier series, using the DTFT samples as coefficients of complex sinusoids at the corresponding DTFT frequencies. It has the same sample-values as the original input sequence. The DFT is therefore said to be a frequency domain representation of the original input sequence.

Can we use FFT for IDFT?

The same FFT algorithm can be adapted in many ways to compute IDFT in a faster way.

How do you find the inverse of a fast Fourier transform?

X = ifft( Y ) computes the inverse discrete Fourier transform of Y using a fast Fourier transform algorithm. X is the same size as Y . If Y is a vector, then ifft(Y) returns the inverse transform of the vector. If Y is a matrix, then ifft(Y) returns the inverse transform of each column of the matrix.