Question

How is aliasing prevented?

(a) Sampling at the same frequency of the original signal

(b) Sampling at double the frequency of the original signal

(c) Sampling at less than double the frequency of the original signal

(d) Sampling at more than double the frequency of the original signal

The question was asked by my college director while I was bunking the class.

Question is taken from Digital Implementation topic in section Fly by Wire Flight Control of Avionics

Answer 1

The correct answer is (d) Sampling at more than double the frequency of the original signal

To explain I would say: Aliasing occurs when the sampling rate is lower than the frequency of the original signal. The Nyquist theorem states that the sampling rate should be more than twice the frequency of the original signal to avoid aliasing.