| 摘要 |
<P>PROBLEM TO BE SOLVED: To solve the problem that an electronic tag system having an interrogator for transmitting interrogation signals and supplying power to a conventional tag and a mobile receiver for receiving responses from the tag separately is equipped with an automatic frequency control circuit which the mobile receiver synchronizes a frequency of local oscillation signal with a frequency of a response signal of the tag, and therefore, that the configuration of the receiving part is complicated and reduction in size and cost is impossible. <P>SOLUTION: The electronic tag system comprises a transmitter for transmitting non-modulated carrier waves, an electronic tag for generating response signals by modulating the received non-modulated carrier waves, and a portable receiver for receiving the response signals. The receiver is equipped with a mixer for distributing the received signals and multiplying the distributed signals to each other, a high-pass filter for removing a direct-current component from the mixer's output, and a demodulator for demodulating received data from the output signals of the high-pass filter. <P>COPYRIGHT: (C)2007,JPO&INPIT |
