Patent ID: 7889083
Filing Date: 2011-02-15
Classification: G01D,G06K

Abstract:
1. A radio frequency identification (RFID) device comprising: an antenna tuned to receive a radio frequency (RF) time-code signal from a public source; a receiving circuit linked to the antenna, wherein the receiving circuit is configured to convert the received RF time-code signal into a digital time-code bit stream; a controller circuit linked to the receiving circuit, wherein the controller circuit is configured to decode the digital time-code bit stream; an internal clock linked to the controller circuit, wherein a time maintained by the internal clock is updated based on the decoded time-code bit stream received from the controller circuit; a microcontroller linked to the receiving circuit; a memory linked to the microcontroller; and a battery linked to and powering the receiving circuit, controller circuit, internal clock, microcontroller and memory.