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ECE · Q365

Signal Processing

Engineering and GATE · ECE · question 365

Q365

A finite duration discrete-time signal x(n) is obtained by sampling the continuous-time signal x(t) = cos(200πt) at sampling instant t = n/400, n = 0, 1, . . . , 7. The 8-point discrete Fourier transform (DFT) of x(n) is defined as X [ k ] = _n = 0^7 x [ n ]e^ - j kn4,\,k = 0,\,1,\,.....,\,7 Which one of the following statements is true?

A finite duration discrete-time signal x(n) is obtained by sampling the continuous-time signal x(t) = cos(200πt) at sampling instant t = n/400, n = 0, 1, . . . , 7. The 8-point discrete Fourier transform (DFT) of x(n) is defined as
Which one of the following statements is true?
A.
Only X(2) and X(6) are non-zero
Answer
B.
Only X(3) and X(5) are non-zero
C.
All X(k) are non-zero
D.
Only X(4) is non-zero

Answer: Option A

Solution

Answer: Option A
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