| 摘要 |
PROBLEM TO BE SOLVED: To provide a system for preventing a crime that can accurately detect a cutting sound that could happen when a trespasser cuts a windowpane. SOLUTION: When a microphone 11 detects a sound nearby a lock handle of a sash, it converts the sound into a phonetic signal and provides a filter circuit 12 with the phonetic signal. The filter circuit 12 passes only the phonetic signal of a specified frequency element. An amplifier 13 amplifies the phonetic signal that passes through the filter circuit 12 and provides a processing control part 15 with it. The processing control part 15 samples the phonetic signal that is provided by the amplifier 13 at specified hours and compares it with a cutting signal pattern stored in a storage unit 14. When the phonetic signal coincides with the cutting signal pattern, the processing control part 15 transmits a cutting detection signal to a communication unit 2 through a transmission part 16. The communication unit 2 communicates and connects with a monitoring center 4 through a public telephone network 3 and notifies an outbreak of abnormal state.
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