| 摘要 |
<p>A circuit for sensing reception of carrier in an information transmission system which employs valid detection of a carrier including filtering, comparison, and time delay, to determine propriety of a carrier, by a logic arrangement for digital interrogation including a pair of counters under the control of a third counter. Each of the pair of counters is advanced by signals derived from the detection circuitry over a predetermined time frame set by the third counter, and the counter outputs decoded to a deactivation device in the event of improper carrier detection. In addition, a resettable counter monitors the transmission during information flow. Failure to reset, indicating improper carrier, also triggers deactivation.</p> |
