The reader lighter/writer for IC tag and the reader lighter/writer system null transmission

摘要

PROBLEM TO BE SOLVED: To provide a reader/writer for an IC tag and a reader/writer system for an IC tag for obtaining the satisfactory environment of radio communication where radio electric waves can be prevented from interfering with each other in such an environment that a plurality of IC tags or reader/writers coexist in the same radio communication area.;SOLUTION: In this reader/writer for an IC tag, a transmission signal is amplitude shift(Amplitude shift keying: ASK)-modulated by a modulator, and amplified by one or more amplifiers, and the transmission signal is transmitted by an antenna to transmit and receive data in a non-contact state with an IC radio tag. This reader/writer is provided with a function for carrying out on-modulation or off-modulation by ASK modulation before a power amplifier as an amplifier installed immediately before the antenna, and for preparing a communication signal "1" or "0" according to the sequence code(ON-OFF KEYING), and for continuously carrying out off-modulation by suppressing carrier strength by the ASK modulation.;COPYRIGHT: (C)2007,JPO&INPIT