| 摘要 |
A position detector includes a position indicator. Transmission/reception of electromagnetic waves relative to the position indicator is performed at least twice while the same loop coil is being selected. With a counter circuit and a switch circuit, a phase difference less than or equal to one cycle of a resonant frequency fO is added to a signal in each transmission/reception. The phase of a reception signal generated at the loop coil is adjusted, and the phase-adjusted signal is used as a detection clock by a synchronous detector circuit to perform synchronous detection. By computing the average or the sum of the results, external noise in the reception signals is cancelled out.
|
