TRANSMITTER FOR RECOGNIZING PRESENCE OF INDIVIDUAL BODY

摘要

PURPOSE:To enable the checking of the presence of an individual body existing within a specified range with a small apparatus, by performing a frequency division or multiplication of an electromagnetic wave having a specified frequency with a transmitter/ receiver which performs a response transmission after a delay time varying with an individual body in response to the electromagnetic wave having an assigned frequency. CONSTITUTION:A transmitting/receiving terminal is provided in a specified range of monitoring area to transmit an electromagnetic wave with an assigned frequency repeatedly for specified time and at a fixed cycle and individual persons in the monitoring area are provided with badges which are prepared to transmit a response signal after a delay time varying with individual persons when receiving an assigned frequency. When a badge receives the electromagnetic wave of a specified frequency by an antenna 40 and an output of a waveform shaping device 418 is inputted to a control section 43 through a receiving section RX46, a timer of a processor 431 starts to perform a response transmission after a given time limit. A transmitting section TX of the badge multiplies 421 the frequency from a waveform shaping unit 410 of the receiving section RX, demodulates it intermittently with a modulator 422 and performs a response transmission from the antenna 40.