Original sentence: A cavity resonator, usually used in reference to electromagnetic resonators, is one in which the waves exist in a hollow space inside the device.Although its usage has broadened, the term usually refers to a physical object that oscillates at specific frequencies because its dimensions are an integral multiple of the wavelength or half-wavelength at those frequencies.Bushholz (General Electric Company).Carter (Radio Corporation of America).Cavity resonator.Cavity resonator circuit.Electrical circuit arrangement.Electromagnetic resonator.Frequency stabilization at ultra high frequencies.High efficiency resonate circuit.High frequency resonator and circuit therefor.High frequency tanks and resonant cavities.High-power high-frequency electron discharge apparatus.Inductance-capacitance resonance circuit.Modulation system.Resonant system for ultra short waves.Schelkunoff (Bell Laboratories).The oscillations or waves in a resonator can be either electromagnetic or mechanical (including acoustic).Transmission of guided waves.Transmitter and receiver for electromagnetic waves.Ultra short wave radio system.Willi Engbert
Edited sentence: A cavity resonator, usually used in reference to electromagnetic resonators, is one in which waves exist in a hollow space inside the device.The oscillations in a resonator can be either electromagnetic or mechanical (including acoustic)