TRANSMITTER-RECEIVER FOR RADIO COMMUNICATION, RFID SYSTEM AND RECEIVING METHOD OF TRANSMITTER-RECEIVER FOR RADIO COMMUNICATION

摘要

PROBLEM TO BE SOLVED: To provide a transmitter-receiver for radio communication capable of appropriately demodulating a received signal even if a communication null phenomenon appears.

SOLUTION: The transmitter-receiver 2 for radio communication of one embodiment is provided with a transmission circuit 14 for generating a transmission signal; a demodulator circuit 26 for demodulating a received signal; an antenna circuit 22 for transmitting the transmission signal from the transmission circuit 14, receiving the received signal and leading the received signal to the demodulator circuit 26; a phase-shifting circuit 18 connected between the transmission circuit 14 and the antenna circuit 22; and a switching circuit for switching whether to output a superposed signal of the transmission signal and the received signal between the phase-shifting circuit 18 and the antenna circuit 22 to the demodulator circuit 26 or output a superimposed signal of the transmission signal and the received signal between the transmission circuit 14 and the phase shifting circuit 18 to the demodulator circuit 26.

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