tunable echo box

tunable echo box

[′tü·nə·bəl ′ek·ō ‚bäks]
(electromagnetism)
Echo box consisting of an adjustable cavity operating in a single mode; if calibrated, the setting of the plunger at resonance will indicate the wavelength.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.