Patent ID: 8462136

Claim:
A pointer detection apparatus for detecting a pointer positioned on a conductor pattern, the conductor pattern including a plurality of first conductors disposed in a first direction and a plurality of second conductors disposed in a second direction which crosses the first direction, the pointer detection apparatus comprising: a code supplying circuit configured to provide a plurality of modulated code strings of different codes, each code having a n-code length and being mutually orthogonal to each other, the code supplying circuit being further configured to supply predetermined ones of the modulated code strings to the first conductors disposed in the first direction; a correlation calculation code supplying circuit configured to supply correlation calculation codes that respectively correspond to the code strings; and a correlation calculation circuit configured to demodulate signals produced in the second conductors disposed in the second direction to produce demodulated signals and to carry out correlation calculation between the demodulated signals and the correlation calculation codes; wherein the pointer positioned on said conductor pattern is detected based on results of the correlation calculation carried out by said correlation calculation circuit; and wherein one of the code strings is not supplied to the first conductors, so as not to be subjected to a variation factor introduced by the first conductors and the second conductors, to be thereby used to produce a reference signal for the correlation calculation to detect the pointer positioned on the conductor pattern.