| 主权项 |
1. A position detecting method for detecting, using a position detecting apparatus, a position indicated by a position indicator, the position detecting apparatus including a plurality of antenna units, each of which includes at least one antenna, the antennas of the antenna units being arranged in a direction, the position indicator being operable to obtain energy from an external signal upon receipt of the external signal and then to transmit a signal in response to the external signal using the energy obtained thereby, said position detecting method comprising the steps of:
(A) by the position detecting apparatus, transmitting to the position indicator a first excitation signal having a variable frequency, and then, receiving a first response signal transmitted from the position indicator in response to the first excitation signal, via a target one of the antenna units which includes an antenna serving as a target antenna; (B) determining based on the first response signal, by the position detecting apparatus, a target frequency of the first excitation signal at which the first response signal has a maximum energy level; (C) by the position detecting apparatus, continuously transmitting to the position indicator a second excitation signal having the target frequency, and then, receiving a second response signal, which is transmitted from the position indicator in response to the second excitation signal, via a group of the antenna units individually and successively, the group of the antenna units including the target one of the antenna units; and (D) obtaining based on the second response signal, by the position detecting apparatus, position information corresponding to the position that is indicated by the position indicator and that is relative to the position detecting apparatus. |
