| 摘要 |
PROBLEM TO BE SOLVED: To increase communicating distance between an interrogator and a transponder. SOLUTION: A modulation signal, to be input to a modulator 7 of the interrogator 2, is regulated in an amplitude offset regulator, so that a modulation factor of a transmission signal becomes maximum. The communicating distance between the interrogator 2 and the transponder 3 can always be increased by maximizing the modulation factor of a modulated wave, even when the detecting sensitivity of the transponder 3 is the same, by incorporating a circuit configuration at the interrogator 2 side without having to incorporate an additional circuit for raising the detecting sensitivity in the transponder 3. |
