Topic: Signals and Systems
Consider the analog signal $x(t)=3~cos~100\pi t$. If the signal is sampled at 200 Hz, the discrete time signal obtained will be
- A. $3~cos(\pi n/4)$
- B. $3~cos(\pi n/2)$
- C. $3~cos(\pi n)$
- D. $3~cos(\pi n/3)$
Answer: B. $3~cos(\pi n/2)$
Explanation: $f_{s}=200~Hz$, $T_{s}=\frac{1}{200}sec$. $x(nT_{s})=3~cos(100\pi \cdot \frac{n}{200}) = 3~cos(\frac{\pi n}{2})$.