| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a method for duplex transmission between a terminal and a transponder in an electromagnetic transponder system. SOLUTION: Each of the terminal 40 and the transponder 10 is provided with an oscillation circuit 24, a modulation means and a demodulation means, the amplitude modulation transmission of a signal to be transmitted from the terminal 40 to the transponder 10 and the transmission of a signal from the transponder 10 to the terminal 40 and suited so as to follow the phase demodulation of the terminal 40 are simultaneously executed and an amplitude modulation rate is <100%. The terminal 40 includes a means 44 for mutually comparing a transmission signal and a reception signal clipped by respective clipping means 42, 43, and the transponder 10 includes an amplitude demodulation means set up to a level following attenuation generated by a return modulation means.</p> |
