Title: Method and apparatus for monitoring sound-conducting media

Abstract: A method of, and apparatus for, monitoring sound-conducting media wherein sound vibrations are transmitted to and absorbed by the sound-conducting medium. The frequency of the transmitted sound vibrations periodically pass through a predetermined frequency range. During an evaluation period the course of any one of the amplitude or phase of the received sound vibrations are compared with the course of the amplitude or phase during one of the preceding evaluation periods, and when there occur predetermined deviations of both amplitude courses or both phase courses from one another there is triggered an alarm signal.

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Inventors: Zetting, Alois (Herrliberg, CH)
Kopfli, Markus (Wil-St. Gallen both of, CH)

Application Number: 743392
Filing Date: 1976-11-19
Publication_date: 1979-02-27
Assignee: Cerberus AG (8708 Mannedorf, CH)
Primary Class(es): 367/93 73/579, 73/630, 340/506, 340/550
Other Classes:
US Patent Ref:

3946377	Mar, 1976	Zetting	340/274.
3967283	Jun, 1976	Clark et al.	343/7.
4023156	May, 1977	Galvin	340/274.
4088989	May, 1978	Solomon	340/506.

Other Refs:
Primary Examiner: Caldwell, Sr., John W.
Assistant Examiner: Nowicki, Joseph E.
Attorney: Kleeman; Werner W.