MOVING BODY DISTINGUISHING DEVICE

摘要

PURPOSE:To make a transponder of light and small construction, suppress the cost therefor, and lessen its power consumption by incorporating the spread modulation/demodulation system in communications of the transponder with an inquirer. CONSTITUTION:The carrier wave generated by a carrier wave transmitter 11 of an inquirer Q is subjected to spread spectrum modulation by a spread modulator 12 with spread codes prepared by a spread code generator 13, and wide band signals are released from an antenna 16. A transponder A having received signal performs modulation for signal received by a symbol modulator 17 with the data stored in a memory 18 and re-radiates the modulated signals from the antenna 16. The inquirer Q having received the re-radiated wide band signal with the antenna 16 performs spread demodulation using a spread demodulator 15 by the same spread code series as used at modulating and turns the spread spectrum wide-band signals into narrow band. The data held by the transponder A can be read by demodulating these signals with a code demodulator 14.