Reader-writer terminal device for contactless IC card, communication system and contactless data carrier

摘要

A transmission circuit transmits a command to a contactless IC card. A receiving circuit receives a transmission signal from the IC card and an amplifying circuit in the receiving circuit amplifies the reception signal. An impedance element to which the reception signal is applied is provided at a preliminary stage of the amplifying circuit. The impedance element is controlled so that the impedance thereof is lowered, and an input signal to be input into the amplifying circuit is muted.