| 摘要 |
<p>An infant security system is disclosed which includes a transmitting device (7) that generates at least two uniquely coded signals and is disposed around the leg or ankle of infants in a hospital maternity ward (1), children's ward or the like. An activated magnetic strip (11) is also attached to the transmitting device (7). An associated receiver (13) is placed, for example, on the cart containing the infant's crib or bassinet which will typically be close enough to the infant so that it is well enough within the range of the transmitter. Every few seconds the RF transmitter (7) transmits a coded RF pulse. If an infant with an attached RF transmitter (7) is removed by some predetermined minimum distance from its associated RF receiver (13) or if the RF transmitter (7) becomes inoperative or is shielded, then the RF receiver (13) will not receive the transmitted coded signal which wil trigger an alarm (17,19). If a kidnapper attempts to detach the RF transmitter (7) from the infant, a switch is opened which in turn causes the RF transmitter (7) to emit a second coded signal. Upon detection of the second coded signal, an alarm (17,19) in the RF receiver will be triggered. An alarm is also triggered if an activated magnetic strip (11) on the RF transmitter (7) is transported through a maternity ward exit point (3,5).</p> |
