ELECTROMAGNETIC INDUCTION TYPE TRANSPONDER SYSTEM

摘要

PROBLEM TO BE SOLVED: To embody high reliability, stability and wide-range transmission distance with low cost by constituting a system of a transponder having a modulation part modulating information to be transmitted and a memory part processing two pieces of received information and information to be transmitted and writing/reading information. SOLUTION: The transmission part (a) of an installation-type transmission/ reception device connected to a computer has two independent transmission devices. A first transmission frequency and a second transmission frequency from the first transmission device and the second transmission device are always and simultaneously transmitted. The antenna part and the reception part (b) of the transponder incorporate three types of independent magnetic field antennas and one type of resonation circuit. Magnetic field power components which are induced by the antenna are branched into three. One branched component becomes the driving power of an inner circuit. The next branched component is demodulated by detection circuits and two pieces of demodulated information are suitably processed in a memory part writing/reading information.