Simple Explanation

A type of filter designed to pass signals within a certain range without ripples in their amplitude.

Concise Technical Definition

An analog or digital filter with a frequency response that is maximally flat in the passband and rolls off toward zero in the stopband without ripple.

Layman-Friendly Analogy

Think of it as sunglasses that block only the harmful UV rays (frequencies), while letting visible light (useful signals) through evenly without any flicker or wave distortions.

Industry Usage Summary

Commonly used in audio processing, communications, and control systems when a smooth passband response is more important than a sharp cutoff.

Engineering Shortcut

Butterworth = Flat passband, smooth response, ideal for audio.

Full Technical Explanation

A Butterworth filter provides the flattest frequency response in the passband, meaning it does not introduce amplitude variations (ripples) before the cutoff frequency. Its gain smoothly decreases beyond the cutoff at a set roll-off rate.