Alarm system responsive to the breaking of glass

摘要

An alarm system for detecting the pattern of acoustic signals resulting from the breaking of glass utilizes transducers to convert the acoustic waves to electrical signals and then analyzes the signal strength, the frequency content and the pattern of the signal and no signal intervals to discriminate the breaking of glass from background or spurious noises. The system also determines the level of background noise and compensates therefor in determining whether an alarm signal is to be generated.