| 摘要 |
A geographically specific emergency alert system includes a code generator unit in which geographic areas to be alerted and types of severity of alerts are selected and code strings generated to represent the affected areas and alert types selected. The code strings are broadcast by modulating the audio carrier of a television signal and received on receiver units positioned in areas within the broadcast market of a television station providing the alerting service. Location codes or entered into the receiver units by the users according to the areas in which the receiver units are used. When an alert is broadcast, each receiver unit decodes a location code string in the signal. If it matches that set on the receiver, an alert code string is decoded to activate a alarm devices connected to the receiver, such as an audible alarm generator, LED, etc., in accordance with the type or severity of alert that was broadcast. |
