Patent ID: 7822388

Claim:
A transceiver, which selectively transmits a modulated wave to a tag when transmitting a transmitted signal to the tag and a non-modulated wave to the tag when receiving a response signal from the tag, comprising: an oscillator generating a predetermined carrier wave, a modulator modulating the carrier wave generated by the oscillator to generate the modulated wave, a transmission unit transmitting the modulated wave being modulated by the modulator or the non-modulated wave being not modulated, a control unit for causing the transmission unit to transmit the modulated wave to the tag through the modulator when the transmitted signal is transmitted to the tag, and for directly connecting the oscillator to the transmission unit while bypassing the modulator and causing the transmission unit to transmit the non-modulated wave to the tag when the response signal from the tag is received, and a bypass circuit for bypassing the modulator by directly connecting the oscillator to the transmission unit, wherein when the transmission unit transmits the non-modulated wave, the control unit transmits the non-modulated wave to the transmission unit via the bypass circuit, wherein a switch for routing through one of the bypass circuit or the modulator is provided between the oscillator and the transmission unit, and the control unit performs selection of whether the oscillator is connected to the modulator, or directly connected to the transmission unit, by controlling the switch, so that one of the modulated wave or the non-modulated wave is transmitted from the transmission unit.