| 摘要 |
<p>PROBLEM TO BE SOLVED: To eliminate the need for equipping a terminal station with an expensive oscillator part and to obtain the passive communication device which can easily be made inexpensive and small-sized by modulating a receive signal from a base station with transmit data by variation in output impedance and sending data. SOLUTION: When an attachment device 22 inputs transmit data to a data process part 21, the data process part 21 passes the data to a radio control part 28. The radio control part 28 varies the output impedance of a transmission part 30 connected to an antenna 26. The variation in the output impedance causes impedance mismatching between the antenna 26 and transmission part 30 and a high-frequency signal 9 is modulated with the transmit data and sent as a high-frequency signal 27 to a base station 10. Namely, when data are communicated from a terminal station 20 to the base station 10, an unmodulated carrier from the base station 10 is modulated at the terminal station 20 with the transmit data by varying the impedance of the end of the antenna 26. Therefore, the need for an expensive oscillator part for the terminal station 20 is eliminated.</p> |
