| 摘要 |
Conventional warning installations possess electrically interrogated feelers or sensors or generate electrical signals, particularly if they are used for remote monitoring purposes. At the feelers and even more so at the signal lines it is possible for there to be produced spurious signals due to electrostatic charges or electrical or magnetic induction. These spurious signals trip unwarranted warning or alarm signals. The novel warning or alarm installation therefore contains an optical conductor or guide as a signal line, and the feelers are interrogated by means of optical signals. The optical conductor together with an electronic monitoring circuit forms a free-running opto-electronic oscillator which comes to standstill when there is interrupted the oscillating optical signal which is irradiated into the optical conductor and radiated back out of the conductor into the circuit. An alarm or warning circuit associated with the monitoring circuit generates an alarm signal when the opto-electronic oscillator comes to standstill. |
