0 0 votes For the sequence $x[n] = \{1, -1,1, -1\},$ with $n = 0,1,2,3,$ the DFT is computed as $X(k) = \displaystyle{}\Sigma^3_{n=0}x[n]e^{-j\frac {2\pi}{4}nk}$, for $k = 0,1,2,3.$ The value of k for which $X(k)$ is not zero is 0 1 2 3 Signals and Systems gate2018-in signals-and-systems numerical-answers + – gatecse 2.8k points answer 0 reply
