| CPC G06K 19/07773 (2013.01) | 6 Claims |
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1. A radio tag system comprising:
a radio tag communication device; and
a passive radio tag transmitting a response signal to the radio tag communication device according to a backscatter method and a subcarrier method,
wherein the passive radio tag comprises:
an antenna,
an RF switch connected to the antenna and controlled to be turned ON/OFF such that the antenna is controlled to two states, turning ON the RF switch corresponding to an impedance matched state of the antenna when transmitting the response signal,
a control circuit that controls the RF switch such that the response signal is transmitted via the antenna by outputting a predetermined control signal to the RF switch,
a detection circuit that detects signal components from the received radio wave received as a predetermined command from the radio tag communication device via the antenna and the RF switch, and
a sampling circuit that samples the signal components detected by the detection circuit in accordance with timing at which the RF switch is controlled to the matched state by the predetermined control signal,
wherein a time interval of the matched state is set to be shorter than a symbol duration of the received radio wave, and
the control circuit identifies the predetermined command based on a sampling result of the sampling circuit.
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