| 摘要 |
<p>Locating coils (Bx1 to Bxm, bx1 to bxn, By1 to Byp, by1 to byg) constituting a frame and housed in the table, cooperate with a cursor which can move relative to the table and which comprises an AC-powered emitter coil (L). A processing circuit receives induced signals from the locating coils through electromagnetic coupling with the emitter coil and includes synchronous detection means using a reference signal (H) for the phase of the current powering the emitter coil and calculation means (30) for computing information representing the position of the emitter coil relative to the table. The cursor is a wireless cursor comprising a local oscillator circuit powering the coil, and the processing circuit comprises a clock-extraction circuit (50) for supplying the phase reference signal (H) from at least one of the signals received from the locating coils. <IMAGE></p> |
