| 摘要 |
A two unit electronic monitoring apparatus to enable a person to monitor the whereabouts of a monitored person, pet or article and to locate the latter if he, she or it becomes separated from the monitoring person. One unit comprises a radio transmitter and the other a radio receiver having condition responsive means to actuate a sound alarm when the received signal falls below a predetermined threshold level due to the distance between the transmitter and receiver exceeding a preset distance.
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