Question

Overlap in the shifted replicas of the original spectrum after sampling is termed

• A. Offset
• B. Bandwidth
• C. Aliasing
• D. Anti-aliasing

Hint:

Aliasing occurs whenever the sampling frequency is lower than the Nyquist rate.

Answer 1

The Correct Option is C

Concept: Sampling creates periodic replicas of the original spectrum in the frequency domain. If the sampling frequency is too low, these replicas overlap.

Step 1: Recall the sampling theorem.
To avoid overlap, \[ f_s \ge 2f_m. \] This is the Nyquist criterion.

Step 2: Understand spectrum overlap.
When \[ f_s<2f_m, \] the shifted spectral replicas overlap each other. This overlap causes distortion.

Step 3: Name the phenomenon.
The overlap of spectral replicas is called \[ \boxed{\text{Aliasing}}. \]