The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 21, 1994
Filed:
Oct. 16, 1992
Tom R Petek, Sacramento, CA (US);
C & K Systems, Inc., Folsom, CA (US);
Abstract
A sensor has a reduced probability of generating a false alarm in the presence of a strong high frequency acoustic wave, such a false alarm being caused by the saturation of the microphone which is part of a single microphone glass break sensor. The sensor improves an alarm system's immunity to false alarms by using two microphones instead of one, wherein each microphone is used in combination with a filter and a signal processing stage to detect one of the characteristic components of an acoustic wave generated in a glass break event. The microphone used to detect the low frequency component is fitted with an acoustic filter which attenuates the high frequency component of the wave. This reduces the probability of a false alarm by ensuring that the low frequency electrical signals fed to the alarm system's logic and timing circuit are generated by an external event rather than by the microphone itself.