Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filedfiledCritical
Application grantedgrantedCritical
Publication of FR854848ApublicationCriticalpatent/FR854848A/fr
G08B—SIGNALLING SYSTEMS, e.g. PERSONAL CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
G08B13/00—Burglar, theft or intruder alarms
G08B13/16—Actuation by interference with mechanical vibrations in air or other fluid
G08B13/1654—Actuation by interference with mechanical vibrations in air or other fluid using passive vibration detection systems
G08B13/1672—Actuation by interference with mechanical vibrations in air or other fluid using passive vibration detection systems using sonic detecting means, e.g. a microphone operating in the audio frequency range
Landscapes
Engineering & Computer Science
(AREA)
Multimedia
(AREA)
Physics & Mathematics
(AREA)
General Physics & Mathematics
(AREA)
FR854848D1939-01-121939-01-12Perfectionnements aux dispositifs de signalisation
ExpiredFR854848A
(fr)