Howtosignalprocessing
- What is the inverse DFT?
- What is difference between DFT and IDFT?
- What happens if we apply DFT twice to a signal?
- What are the disadvantages of direct computation of DFT?
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.
What is difference between DFT and IDFT?
The DFT allows one to convert a set of digital time samples to its frequency domain representation. In contrast, the IDFT can be used to invert the DFT samples, allowing one to reconstruct the signal samples x(k) directly from its frequency domain form, X(m).
What happens if we apply DFT twice to a signal?
Applying the DFT twice results in a scaled, time reversed version of the original series. The transform of a constant function is a DC value only.
What are the disadvantages of direct computation of DFT?
For the computation of N-point DFT, N2 complex multiplications and N[N-1] Complex additions are required. If the value of N is large than the number of into lakhs. This proves inefficiency of direct DFT computation.
