| 摘要 |
<p>The pilot signal receiver is esp. suitable for carrier frequency systems and contains a filter (21) to isolate the pilot signal and a half wave rectifier (22). The evaluation circuit (23) compares the pilot signal level with a nominal voltage and activates indicators, alarm and switching circuits if the pilot voltage is unacceptably low. Monitoring and evaluation, using a memory circuit, are done when the rectifier is conducting. During non-conducting periods, information is processed and action taken. Two outputs are obtained, one an immediate response, while the other is delayed for e.g. 4 cycles to eliminate responses to disturbances of very short duration.</p> |
