Question

The DFT of a signal x(n) of length N is X(k). When X(k) is given and x(n) is computed from it, the length of x(n)

(a) Is increased to infinity

(b) Remains N

(c) Becomes 2N – 1

(d) Becomes N2

The question was asked during an interview.

The query is from The Z-transform Analysis of Sampled-Data Control Systems in section Digital Control Systems of Control Systems

Answer 1

Right choice is (a) Is increased to infinity

Explanation: When X (k) is given and x (n) is computed from it, the length of x (n) is increased to infinity.