| 摘要 |
PROBLEM TO BE SOLVED: To accelerate a bit rate by judging the phase of a modulated wave from a transponder as soon as possible in the interrogator. SOLUTION: The transponder 2 sends a signal obtained by inverting the phase of a modulated wave B each time a digital value constituting answer data changes. The interrogator 1 extracts a signal having the same cycle as the modulate wave B and inputs a rectangular wave F(0) having the same cycle as the modulated wave B from an oscillator part 4 to a demodulation part 9. This rectangular wave F(0) is shifted by a shift register to obtain a reference signal synchronized with the modulated wave B. Then data are decided as, for example, '1' and '0' when the modulated wave B and reference wave are coincident in phase and not coincident with each other respectively. |
