Question

When aliasing takes place?

(a) Sampling signals less than Nyquist Rate

(b) Sampling signals more than Nyquist Rate

(c) Sampling signals equal to Nyquist Rate

(d) Sampling signals at a rate which is twice of Nyquist Rate

I have been asked this question during an online exam.

My question is taken from Frequency Domain Description topic in chapter Amplitude Modulation of Analog Communications

Answer 1

The correct option is (a) Sampling signals less than Nyquist Rate

To explain I would say: Aliasing causes different signals to become indistinguishable during sampling. It happens because sampling rate is less than Nyquist rate. In order to avoid aliasing, signals should be sampled at a rate twice of Nyquist rate.