Fence protection system
US3947835A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jul 1, 1974 |
| Grant date | Mar 30, 1976 |
| Priority date | — |
| Expiry date | Jul 1, 1994 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01B11/1834
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
This fence protection system comprises an elongated electret cable for sensing vibrations on a fence and an electronic processing circuit connected to the cable for discriminating against spurious signals such as those caused by raindrops on the fence and nuisance signals produced by stick dragging on the fence. This circuit comprises a charge amplifier connected directly to the cable transducer and series connected burst width and interburst discriminators in conjunction with parallel connected pulse counter and integrator means feeding an alarm mechanism through an OR gate; signals produced by an intruder climbing or cutting the fence are distinguished from spurious raindrop and stick dragging signals and produce and alarm.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.