Error detection system for two-state fiber optic sensors
US4762992A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 10, 1987 |
| Grant date | Aug 9, 1988 |
| Priority date | — |
| Expiry date | Jun 10, 2007 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L25/06
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An error detection system is provided for a two-state fiber optic sensor. An amplified photodetector signal is sampled by each of an ON-OFF threshold detector, a disconnect threshold detector and a slope detector. The ON-OFF threshold detector monitors whether the detector signal is above or below an ON-OFF threshold value corresponding to the parameter being sensed and activates an appropriate sensor output. The disconnect threshold detector monitors the constant low level detector signal corresponding to low level light received by the detector even when the thresold detector is in the OFF state, and triggers an error signal should the detector signal fall below a disconnect threshold value. The slope detector monitors the rate of change of the detector signal. Where the detector signal changes rapidly, such as during normal sensor switching, the slope detector permits the detector signal to pass to a latch, which retains in memory the last detector signal which changed rapidly enough to trigger the slope detector and produces an output corresponding to the ON-OFF status of the last detector signal in memory. A slowly changing detector will not trigger the slope detector. Where t…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.