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Title:
【発明の名称】2チャンネルガラス破損検出装置
Document Type and Number:
Japanese Patent JPH07500438
Kind Code:
A
Abstract:
A glass break detector for detecting the breaking of a window or the like includes an acoustic transducer having a wide band frequency response, coupled to a dual channel filter and signal processing circuit. A low frequency channel detects an initial positive compression wave caused by the inward flex of the window and a high frequency channel detects the acoustic spectrum which is characteristic of breaking glass. The two channels are combined in a logic circuit that is timed so that the low frequency positive flex is detected initially with the high frequency component following shortly thereafter. If both timing conditions are fulfilled, an alarm is initiated. Additional circuitry is provided to inhibit the alarm if a negative compression wave is initially detected. The detection sequence is initiated by a loud sound characteristic of breaking glass.

Inventors:
Smith Richard A
Bernhard Christopher A
Application Number:
JP51417493A
Publication Date:
January 12, 1995
Filing Date:
February 05, 1993
Export Citation:
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Assignee:
Centrol Incorporated
International Classes:
G08B13/04; (IPC1-7): G08B13/04
Attorney, Agent or Firm:
Akihide Sugimura (1 outside)



 
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