Patent ID: 9697392
Date: 2017-07-04
CPC Classifications: G06K

Claim:
1. A reader for reading data, the data being associated with a radio frequency identification (“RFID”) tag and carried by a data signal originating from the RFID tag, the reader comprising processing means and storage means, the storage means having instructions stored thereon, whereby the processing means is operable, under control of the instructions, to: periodically switch the reader from a first state to a second state; wherein, when the reader is in the second state, the reader is operable to determine an occurrence of a tag present event corresponding to the presence of an RFID tag within an RF field generated to activate an RFID tag to transmit a respective data signal carrying data associated with the RFID tag, and one or more other events; following determination of the one or more other events, return the reader to the first state; and following determination of the tag present event, receive and store in the storage means a representation of the data signal originating from the RFID tag, process the RFID tag signal representation to determine the data signal, and read the data of the determined data signal; and, the reader further comprising an RF field generator operable to generate the RF field, and wherein the processing means is operable, under control of the instructions, to control the RF field generated by the RF field generator, and wherein the control comprises activating the RF field generator for a duration of time when there is no RFID tag present in the RF field; and, wherein the processing means is further operable, under control of the instructions, to receive and store in the storage means a representation of at least a portion of a signal detected in the RF field over the duration of time as a second reference representation corresponding to an expected representation of an event comprising an RFID tag not being present in the RF field, and to dynamically subtract the detected signal representation of a present sweep from the second reference representation to generate a resultant representation, and to store the resultant representation separately in the storage means; and, wherein the processing means is further operable, under control of the instructions, to process the resultant representation as it is being created, to determine at an early stage if the resultant representation is substantially zero, indicating that there is no RFID tag present in the RF field, or if the resultant representation is not substantially zero, indicating an anomaly in the RF field that may be related to the presence of an RFID tag.