Detection of an RFID device by an RF reader unit operating in a reduced power state
US6476708B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | Mar 20, 1998 |
| Grant date | Nov 5, 2002 |
| Priority date | — |
| Expiry date | Mar 20, 2018 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06K19/0723
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A method is provided for operating an RF transponder system to detect the presence of an RFID device in the proximal space of an RF reader unit having an excitation signal generator circuit and an RFID device detection circuit. The excitation signal generator circuit unit initially operates in a reduced power state, generating ring signals in response to a reduced electrical current and transmitting the ring signals into the proximal space. The RFID device detection circuit evaluates the ring signals to determine variations in an RFID device detection parameter. When the variations pass a variation threshold level due to the presence of the RFID device, the ring signals are terminated and the excitation signal generator circuit switches to an increased power state, wherein the excitation signal generator circuit generates an RF excitation signal which is transmitted to the RFID device.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.