Abstract: A digitizer tablet comprises a plurality of physical antenna loops distributed along the X- and Y-directions of two-dimensional Cartesian coordinates (X, Y) on the digitizer tablet, wherein each physical antenna loop comprises a plurality of logical sections. For the logical sections of each of the physical antenna loops distributed in the same direction, the adjacent logical sections of the logical sections belong to different physical antenna loops.

Abstract: An apparatus for automatically changing the operation of a dual-mode digitizer tablet system. The system comprises a cordless pen device generating an electromagnetic wave of a variable frequency and a cordless mouse device generating an electromagnetic wave of a different frequency. The cordless pen device operates in an absolute mode and the cordless mouse device operates in a relative movement mode. The apparatus comprises a detection loop sensing circuit for detecting electromagnetic waves and a signal processing circuit for extracting the signal of either the pen device or the mouse device. The extracted signal is rectified and digitized for determining the position of the cordless pointing device by a micro-controller. A frequency counter determines the frequency of the detected signal. By detecting and determining the frequency of the electromagnetic wave received in the tablet system, the operation mode is adjusted automatically.