Question

If a continuous time signal x(t) with spectrum X(F) is sampled at a rate Fs=1/T samples per second, the spectrum of the sampled signal is _____________

(a) Non periodic repetition

(b) Non periodic non-repetition

(c) Periodic repetition

(d) None of the mentioned

This question was addressed to me in a national level competition.

This question is from IIR Filter Design by Impulse Invariance in chapter Digital Filters Design of Digital Signal Processing

Answer 1

Right answer is (c) Periodic repetition

Best explanation: When a continuous time signal x(t) with spectrum X(F) is sampled at a rate Fs=1/T samples per second, the spectrum of the sampled signal is periodic repetition.