| 摘要 |
PURPOSE:To prevent effectively a stray child or a luggage thief by providing an alarm means generating a sound and raising alarm when the distance between a receiver and a transmitter is parted more than a prescribed value. CONSTITUTION:When the distance between receivers C, D and transmitters A, B is parted more than a prescribed distance, the voice of a proper noun or a specific word is raised from alarm means C1, D1. Since the alarm means C1, D1 are so constituted as to produce the voice different in proper nouns or specific words, even when areas a1, a2 of transmitters of the same constitution come closer, from which receiver alarm is raised is judged quickly.
|
