Question

What are the main characteristics of Anti aliasing filter?

(a) Ensures that bandwidth of signal to be sampled is limited to frequency range

(b) To limit the additive noise spectrum and other interference, which corrupts the signal

(c) All of the mentioned

(d) None of the mentioned

I had been asked this question during an interview.

The doubt is from Discrete-Time Processing of Continuous Time Signals topic in division Discrete Time Systems Implementation of Digital Signal Processing

Answer 1

The correct answer is (c) All of the mentioned

To explain I would say: The anti aliasing filter is an analog filter which has a twofold purpose. First, it ensures that the bandwidth of the signal to be sampled is limited to the desired frequency range. Using an antialiasing filter is to limit the additive noise spectrum and other interference, which often corrupts the desired signal. Usually, additive noise is wideband and exceeds the bandwidth of the desired signal.