Rfid interrogator device

Abstract

An RFID interrogator device has a transmission section for transmitting a command to an RFID tag and a reception section for receiving an RF signal from the RFID tag and is configured to perform backscatter radio communication with the RFID tag. The RFID interrogator device comprises a time window setting section configured to set a time window at timing of receiving preamble data added to a head of response data transmitted from the RFID tag in response to the command, and an identifying data storage section storing preamble identifying data. The RFID interrogator device compares the data received within the time window, with preamble identifying data stored in the identifying data storage section, thereby determining whether the data received is identical to the preamble data transmitted from the RFID tag.

1 . An RFID interrogator device, transmitting query data to an RFID tag and receiving response data from the RFID tag after lapse of predetermined time, comprising:
 a time window setting section configured to set a time window at timing of receiving predetermined lower bits of preamble data added to a head of response data transmitted from the RFID tag;   an identifying data setting section configured to set the predetermined lower bits of preamble data as preamble identifying data; and   decision means for comparing data received within a range of the time window set by the time window setting section, with preamble identifying data set by the identifying data setting section, thereby determining whether the data received is identical to the preamble data transmitted from the RFID tag.   
     
     
         2 . The RFID interrogator device according to  claim 1 , wherein the time window setting section sets the time window to start at a sum of a time that elapses until the preamble data is received from the RFID tag after the query data has been transmitted to the RFID tag and a time obtained by multiplying the sampling cycle by a difference between the number of preamble data bits and the number of preamble identifying data bits. 
     
     
         3 . The RFID interrogator device according to  claim 1  or  2 , wherein the time window setting section sets the time window based on the number of bits constituting the preamble identifying data and the sampling cycle. 
     
     
         4 . The RFID interrogator device according to  claim 3 , wherein the time window is assigned with a time equivalent to a difference between maximum and minimum values preset for a predetermined response time of the RFID tag.