"Underwater sound." . . "Sensitivity." . . "Acoustic measurement." . . "Signal to noise ratio." . . "Ambient noise." . . "Voltmeters." . . "Preamplifiers." . . . . "Acoustic Detection and Detectors." . . "Electrical and Electronic Equipment." . . . "An Underwater Sound Level Meter"@en . . . "This thesis describes the design and operation of an underwater sound pressure level meter. The instrument measures ambient noise levels in water."@en . . . . . . . . . . . . . . "Hydrophones." . . "TEXAS UNIV AT AUSTIN DEFENSE RESEARCH LAB." . . "Acoustic filters." . . "Intensity." . .