Final answer:
An anti-aliasing filter is used to remove high-frequency components from a signal to prevent aliasing and ensure an accurate digital representation of the original analog signal when sampled.
Step-by-step explanation:
The purpose of an anti-aliasing filter is to remove high-frequency components in a signal that can cause aliasing when the signal is sampled. Aliasing is a phenomenon that occurs when high-frequency signals are sampled at a rate that is too low to accurately reconstruct the original signal, according to the Nyquist-Shannon sampling theorem. By filtering out these high frequencies before the sampling process, an anti-aliasing filter ensures that the resulting digital representation is as accurate as possible to the original analog signal.