Modulating the passive modulation technique microwave data

摘要

PROBLEM TO BE SOLVED: To obtain a passive modulation type microwave data carrier system which can prevent transmit and receive data from being absent owing to phasing and reader writers from interferring with each other and improve the security. SOLUTION: A reader writer 1 is provided with a frequency control part 18 and the switching of the oscillation frequency of an oscillator part 17 which oscillates a carrier signal to be supplied to the reader writer transmitting circuit part 13 and reader writer receiving circuit part 15 is controlled with the frequency control signal generated by the frequency control part 18 to optionally switch the communication frequency of the whole passive modulation type microwave data carrier system.