What does anti aliasing filter do?

An anti-aliasing filter is a signal processing tool used to prevent aliasing, which occurs when high-frequency signals are sampled at a rate that is insufficient to capture their variations accurately. The filter works by attenuating frequencies above a certain cutoff frequency before sampling, ensuring that only the relevant lower frequencies are preserved. This helps maintain the integrity of the signal and produces a more accurate digital representation, reducing distortion in the sampled data.