Charging a transponder in a security system
US5790014A · kind A · utility
12Cited by
13References
13Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Apr 21, 1997 |
| Grant date | Aug 4, 1998 |
| Priority date | — |
| Expiry date | Apr 21, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG07C2009/00603
- WIPO fieldTransport
- WIPO sectorMechanical engineering
Abstract
A security system utilizing a key-mounted transponder achieves fast and accurate charging of the transponder by using a frequency search and acquisition phase which attempts partial charging pulses at a plurality of spaced frequencies. After a successful partial charging, a frequency calibration signal is received from the transponder which provides a reference in the transceiver for producing a pulse for fully charging the transponder. Frequency search and acquisition allows robust system operation while using low cost and low tolerance parts.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.