| 摘要 |
<p>PURPOSE:To simplify a power supply for generating a magnetic field by using a square wave as a signal of a different phase to be supplied to plural coils arranged on a plane. CONSTITUTION:A number of coils 3-1...3-n are arranged in the x direction on the plane board 2 of a coordinate reader 1. To respective coils 3-1...3-n square wave voltages e'1, e'2... of sequentially equal difference in its phase are applied. A position detector 5 on the reading coordinate reader 1 generates a signal corresponding to a synthetic magnetic field in the position where it is located. The fundamental wave of this signal is detected by a filter 12, compared at 7 with a reference signal 8 in its phase and generates a signal corresponding to the phase of the component of the reference signal.</p> |
