Interrogating Device, RFID interrogator, and RFID interrogating method

摘要

An RFID interrogator includes a data transmitting unit, a data receiving unit, a tag-reception SINR estimating unit, and a transmission controlling unit. The data transmitting unit transmits a transmission signal to an electronic tag. The data receiving unit receives from the electronic tag a response signal in response to the transmission signal within a predetermined time after the transmission signal is transmitted. The tag-reception SINR estimating unit estimates an SINR value related to reception on the electronic tag side as a tag-reception SINR estimation value based on the response signal. The transmission controlling unit variably controls a modulation index of the transmission signal so that the tag-reception SINR estimation value is a reception-allowable predetermined SINR value.