System for detecting the passage of a mobile including a passive responder
US5451941A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 10, 1993 |
| Grant date | Sep 19, 1995 |
| Priority date | — |
| Expiry date | May 10, 2013 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB61L25/043
- WIPO fieldTransport
- WIPO sectorMechanical engineering
Abstract
The system comprises an interrogation assembly and a passive responder. One is carried by a mobile and the other by a track. The interrogation assembly includes continuously operating low frequency and medium frequency transmitters. The transmitters have respective antennas directed towards a predetermined zone with respect to the antennas, which is traversed by the responder during movement of the mobile. It further has a unit which is responsive to the characteristics of the responder when the responder is in the zone. The responder has a low frequency reception circuit which controls a medium frequency circuit. Both circuits have radiating circuits which are tuned and the low frequency signal generated in the low frequency circuit is used to short-circuit the medium frequency tuned circuit of the responder, at the rate of low frequency rate.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.