A
resonator is a device or system that exhibits
resonance or resonant behavior, that is, it naturally
oscillates at some
frequencies, called its
resonant frequencies, with greater
amplitude than at others. The oscillations in a resonator can be either
electromagnetic or mechanical (including
acoustic). Resonators are used to either generate waves of specific frequencies or to select specific frequencies from a signal. Musical instruments use
acoustic resonators that produce sound waves of specific tones.