Official PYQ · 2014Set 4 · Q45Discrete-time SignalsMCQ2 marks

GATE EC 2014 Set 4 Q45 — Discrete-time Signals

The $N$ -point DFT $X$ of a sequence $x[n]$ , $0 \leq n \leq N-1$ is given by $X[k] = \frac{1}{\sqrt{N}} \Sigma_{n=0}^{N-1} x[n] e^{-j \frac{2\pi}{N}nk}, \: \: \: 0 \leq k \leq N-1.$ Denote this relation as $X=DFT(x)$ . For $N=4$ , which one of the following sequences satisfies $DFT(DFT(x))=x$ ?

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Answer: B

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Published 10 Oct 2026

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