| 摘要 |
PROBLEM TO BE SOLVED: To provide a small-sized, inexpensive vibration detection system having a small-sized, lightweight, and low-cost filter means by using a SAW (surface acoustic wave) device. SOLUTION: An electrical signal outputted by a piezoelectric sensor 2 is amplified by an amplifier circuit 3, to which operating power is supplied from a battery 6, and is passed through the SAW device 4 to allow only an electrical signal of a specific frequency component to be transmitted. An alarm 5, on the basis of the electrical signal of the specific frequency component outputted by the SAW device 4, gives a warning of the detection of specific vibration by a buzzer, light flashing, or the like. COPYRIGHT: (C)2006,JPO&NCIPI
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